The Practical Course in Clinical Medicine, Study Guides, Projects, Research of Clinical Medicine

Download The Practical Course in Clinical Medicine and more Study Guides, Projects, Research Clinical Medicine in PDF only on Docsity! DEPARTMENT OF ESSENTIAL TRANINIG IN CLINICAL MEDICINE DIAGNOSTICS Medical University of Lodz GUIDE to THE PRACTICAL COURSE IN CLINICAL MEDICINE Edited by Władysław Grabski and Dariusz Nowak Department of Clinical and Experimental Physiology Faculty of Biomedical Sciences and Postgraduate Training, Department of Nursing and Obstetrics Łódź 2009 5 The Contents 1. Communication skills Tadeusz Pietras MD, PhD 2. The essentials of physical examination: medical interview physical examination prof. Władysław Grabski MD, PhD a) Practical guide to chest exam Izabela Grabska MD, PhD b) Practical guide to abdomen examination Małgorzata Saryusz-Wolska MD, PhD 3. Clinical reasoning – quality and quantification Piotr Białasiewicz MD, PhD 4. Electrocardiography and the basic analysis Krzysztof ChiŜyński MD, PhD, Sławomir Ceranka MD, PhD, Janusz Kawiński MD, PhD 5. The procedures at the site of road accident Maciej Morawski MD, PhD 6. The assessment of essential vital signs Jan Ruxer MD, PhD 7. The essential resuscitation in adults Paweł Kolasiński MD, PhD 8. Desmurgy – imposition of uni-, bi- and triaxial swatches Jolanta Glińska MD, PhD 6 9. Procedures of the intravenous cannula insertion Maciej Morawski MD, PhD 10. Wound suturing Wojciech R. Kuzański MD, PhD 11. Breast examination Włodzimierz Cieśla MD, PhD 12. Principles of catheterization – catheter types prof. Waldemar RóŜański MD, PhD 13. Gynecological examination Włodzimierz Cieśla MD, PhD 14. Ophthamoscopy Agata Wesołek-Czernik MD, PhD Hanna Grymin MD, PhD 15. Otolaryngological examination prof. BoŜydar Latkowski MD, PhD Niebudek-Bogusz MD, PhD 16. Assessment of practical clinical skills prof. Dariusz Nowak MD, PhD, prof. Michał Karasek MD, PhD Marek Kasielski MD, PhD 7 Tadeusz Pietras Communication skills during medical examination An appropriate contact with the patient requires applying professional knowledge about psychological aspects of interpersonal relations. While examining the patient, most doctors apply just the experience or abilities to establish interpersonal contacts that have been acquired on a social level. This knowledge would definitely be insufficient in unusual and problematic situations. For many years, clinical and social aspects of doctors’ psychological education have been neglected. The ability of conversation should be based on appropriate education, not only on personal intuition or own experience. The relation between the doctor and the patient is appropriate only if it complies with a set of principles in interpersonal contact. These are: disinterestedness, universality, functional specificity and affective neutralism. These terms, being derived from social clinical psychology, need some comment. Disinterestedness is meant as care provided for the patient benefit and well being, without exploit or regard of own interest, which is quite contrary to the common practice in business relations. Universality is medical impartiality and objectivity, despite the relations with the patient. Doctor is obliged by the acknowledged verities of medical society and international associations and by the law. In the medical profession scientific knowledge should dominate over subjective world-views, even if it is against doctor’s sense of values. Functional specificity in contacts between the patient and doctor is a restriction in going into patient’s personal feelings, if the medical diagnostic process does not demand it. Affective neutralism means doctor’s emotional distance. It enables to separate proper medical functioning from personal relations, which are not allowed on medical examination (e.g. sexual or business relations). Affective neutralism does not exclude empathy or emotional support or psychotherapy methods. It is rather an ability to be emotionally neutral to continue the diagnostic process properly. Excessive involvement affects clear thinking and making right decisions. It has been claimed in psychology that appropriate emotional stimulation is necessary to perform an intentional action correctly. Excessive involvement is the source of psychological stress, affects thinking and making decisions. Similarly, decreased involvement can impair a proper performance of a task. Doctor’s contact with patient is rooted in the cultural habits of their social environment. These patterns should be used cautiously, not to 10 Informing patient about the diagnosis and recommendations is another important issue. It is patient’s right to ask the question: “What is my health problem?” and receive an answer. If patient knows something about his disease, he usually accepts it and integrates with his own health convictions that can sometimes be divergent from medical knowledge. It is different if the diagnosis causes patient’s fear or concerns for future. Tradition in Polish medical practice implies that a bad diagnosis, such as cancer should be concealed. Meanwhile, the law and principles of medicine in the Western Europe countries oblige doctor to tell the whole truth about the diagnosis. Telling the sad truth in a possibly non-traumatic way seems most important. Doctors in Poland are not prepared for this kind of conversations. Practical part The aim of the class is to watch your own performance of taking history from a patient. The conversation is recorded on a tape using two video cameras. One is directed at the doctor (student), the other one - at the patient. The images of the patient and doctor are presented simultaneously on the screen of the video player. After taking history it is played back to be analyzed by the student and the whole group. Pay attention to: • way of introducing yourself and asking for the permission to examine the patient, • ability to communicate, • doctor’s mimics and non-verbal communication, • way of eliciting history, accuracy, including: - taking personal data, - detailed family history, - main complaints, - the course of the disease, - past history, - the course of the main ailment, - profession, - addictions and habits, • coherence of the asked questions 11 • creating a preliminary hypothesis Keep in mind that the vision of you on videotape differs from your own vision of yourself (“real me” differs from “perfect me”); own evaluation is usually decreased. 12 Władysław Grabski ESSENTIALS OF EXAMINING THE PATIENT „A doctor is expected to be able to show his compassion and understanding, since the patient in not a mere sum of symptoms, impaired functions, injured organs and rough emotions – the patient is a human being, who is full of both fear and hope; the one who is looking for relief and support.” T. R. Harrison According to the quoted above concept, a student – future doctor, should learn ideas, observations and schemes that have been used in the art of medicine by Polish and foreign masters, i.e. professors: Witold Orłowski, Edward Szczeklik, Jan Tatoń, T. Harrison and W. W. Keen. Their ideas help us determine doctor’s attitude towards the patient and can be achieved by studying the consecutive stages of work with the patient. These are: taking history, physical examination, clinical reasoning, tentative diagnosis, choosing instrumental examinations and accessory laboratory tests, basic diagnosis, differential diagnosis and treatment (Fig. 1). Acquiring all these abilities makes a student turn into a doctor. This textbook as well as the practical course using phantoms will certainly prove helpful in achieving the necessary skills. The textbook includes the schemes of: a) obtaining history - when the patient is investigated in a planned, reasonable and not suggestive way b) performing physical examination – which is also taught at the early stages of medical education, when students learn that physical manifestations are objective and verifiable results of a pathological process. 15 A. Manifestations that are patient’s sensations – impossible to verify – syndromes (anamnesis) B. Physical examination reveals symptoms of the disease – signs – revealed thanks to appropriate methods of examination (physical examination). Description of patient’s examination – anamnesis + physical examination is called case history. It should include every fact of medical significance that has taken place before visiting the doctor. ref. A. ANAMNESIS Start the examination with coming into contact with the patient. o Greet the patient – e.g. Good morning, Mr. Kowalski! o Shake his hand. o Put your hand on his hand. o Introduce yourself. o Ask his name, profession, marital status. This attitude enables a doctor or a student to establish a proper relation with the patient, which makes further cooperation easier. Ask the patient about the reason for his visit; what are his complaints? Let him talk about his complaints using his own words as long as necessary. Listen carefully and make notes. Do not demonstrate irritation if the history is unclear or if you think that some information is not important or contributory. If you interrupt too fast, you may miss an important syndrome, if you keep listening you will know which symptoms are important for your patient. Let the patient talk for about 2 minutes. Patients talk about their complaints in many ways. Sometimes they do not make any distinction between important and irrelevant symptoms and tend to cover the crucial theme by exposing inessential details. 16 That is why you should take over the conversation – ask more detailed questions, interrupt patient to avoid too complicated, long stories. If you think that you obtained the crucial information, stop the conversation politely but firmly. You may also get involved in the statement – follow the story – formulate questions to determine the symptoms and the progress of syndromes that made the patient visit the doctor. The disease picture is thereby formed providing the information about: o circumstances and sequence of symptom appearance (e.g. dietary indiscretion, cold, fatigue) o permanency, intensity, frequency and duration of the disease and accompanying symptoms. o medications used – which (names) and if they brought a relief, the symptoms were passing away (in what situations) In a disease that starts suddenly, severely e.g. with fever or pain, the patient can point precisely to the onset of the distress and its duration. In a chronic disease, which starts imperceptibly, the duration is difficult to assess and only combined efforts of both patient and doctor (student) may finally be successful. Determination of the disease duration may immediately suggest the right route to diagnosis. Sometimes, instead of describing the symptoms the patient informs that he suffers from asthma, angina pectoris or tuberculosis. Then, he should be enquired about the syndromes of the mentioned diseases. 17 GENERAL COMPLAINTS Having obtained the history including general complaints, complete it with general ailments and symptoms from the particular organs. Consider questions referring to their function. While history taking, the doctor (student), should mention the most common disorders bothering patients, as the patient forgets to tell about them if they do not occur on examination. GENERAL MALAISE • if it occurred suddenly • if it has aggravated gradually (since when) If the patients suffers from: HEADACHES – in which area, circumstances, seasons, time of the day, permanent or periodic; if they are accompanied by vision impairment, photophobia, nausea or vomiting. VERTIGO – accompanying symptoms, circumstances of the onset, permanent or periodic HOT FLASHES – on the face, head FEVER – shivers, in the morning, at night SWEATING – the character: excessive, periodic, permanent BODY WEIGHT – if he has lost, gained weight – if his stomach girth has enlarged, association with dietary habits OEDEMA – if it is present, happened before, in which body area and how long it was present If he complains of: NOSE BLEEDING occurring suddenly, after exertion, during colds, without apparent reason 20 Ask about BOWEL MOVEMENT frequency – do not rely on patient’s complaint of diarrhea because the patient may not understand the meaning of this word ● whether there is pain, tenesmus while relieving stool, ask about melaena (coffee dregs) This symptom is significant only if the patient has not eaten blackberries nor taken certain medications (medicinal charcoal). ● fresh blood in stool should draw doctor’s attention ● ask about additional contents in stool: mucus, pus, worms and remains of undigested food. Disorders in URINATION - frequency, nocturnal urination, burning, urgency, urine flow, urinary incontinence, whites, urethrorrhoea (males) - Ask about: pain in the lumbar region, if positive- its radiation (to the pubic symphysis, to the urethra) and accompanying symptoms. Pain may be the result of nephropathy or accompany the lumbar vertebrae dysfunction Obtain information about THE MUSCLE AND SKELETAL SYSTEMS - ask about pain in the joints, joint rigidity, localization, accompanying symptoms (edema, redness, tenderness), - muscle pain, muscle rigidity, weakness, tingling sensations Assess SKIN sensations with the patient: ● itching ● rush ● fistulae Ask about SLEEP – difficulties in falling asleep. Ask if he wakes up rested, if he has problems with falling asleep, find the reasons for the abnormalities reported. 21 On taking history, do not ignore patient’s complaints of GENERAL MALAISE, anxiety, apathy, which may be symptomatic of many diseases. Enquire about VISUAL DISTURBANCES and symptoms including visual acuity, using glasses or contact lenses, eyeball movements, redness, lacrimation, itching, double vision, spots. Ask about HEARING (AUDITION) tinnitus, otorrhoea. Ask about disorders of THE REPRODUCTIVE ORGANS. Men usually complain of impotence and premature ejaculation. Women complain of dysmenorrhoea, whites, pain in the hypogastrium, pruritus of the vulva. Make sure if the periods are regular, when they started (or ended). Whether the periods are regular, how long they last, if they are excessive, painful. Ask about pregnancy, labor, whether the labor was spontaneous or instrumental (caesarean section, forceps) miscarriages. In the case of patients with numerous incidental sexual intercourses, condom usage should be enquired about, especially in homosexuals (AIDS). Ask about PAST DISEASES a) childhood diseases (measles, pertussis, scarlet fever, mumps, rubella) b) adult diseases (tuberculosis, diabetes, typhoid fever, tonsillitis, jaundice), past surgeries Ask about the HOUSING CONDITIONS - city - country – if it is dry, sunny or humid and dark, old or new housing estate – if there are any conveniences, how many members of the household Ask the patient about stimulants: - if he smokes, how much per day and since when, - if he drinks alcohol and how much, - ask about coffee, tea and other stimulants Obtain family history; ask about the parents’ age and health condition, reason of death if needed. Information concerning the health condition of the siblings, children or even cousins may be contributory. 22 Ask about the incidence of any diseases in the family: diabetes, heart diseases, hypertension, stroke, nephropathy, tuberculosis, neoplasms, arthritis, allergy, mental diseases, alcoholism, drug addiction and the symptoms present in a given patient. Ask about patient’s OCCUPATION - whether the patient is educated - jobs performed; kind of work – physical, intellectual - risk factors associated with patient’s job 25 Nutrition Obese Slim Emaciated Body structure: Leptosomic Asthenic Pyknic Athletic BODY MASS INDEX BMI = M/H2 M – real body weight [ kg] H – height [m] normal F - 22-25 M -22-26 SKIN EXAMINATION Colour Cyanosis Redness Xanthosis Pallor Browning Vascularization Telangiectasias Petechiae Cutaneous effusions Bloodstains Collateral circulation 26 Hydratation Dry Hydrated Temperature Increased Decreased Skin surface Rough Smooth Skin elasticity Tensed Elastic Loose Scars Infiltration Birthmarks Rush Pilosity Type F M Nails Normal Convex Concave Wrinkled Agnail Oedemas yes no Generalized Local Body regions Face Around ankles Calves The sacral region 27 THE HEAD AND NECK The cranium Symmetrical Tower skull Platycrania Wide Tenderness palpable percussion tumours scars The face Symmetrical Deformed Palpable trifacial neuralgia yes no The eyes Palpebral fissurae symmetrical yes no Eyeballs setting Normal Exophthalmos Mobile yes no Grafe’s sign Mobius’ sign Stellwag’s sign The pupil Wide Narrow Deformed yes no Reaction to: light yes no 30 THE NECK (inspection, palpation) Long Short Normal mobility yes no Skin scars yes no ulceration yes no Enlarged thyroid gland yes no Jugular veins filled collapsed Examination of the thyroid gland Fig.3. Examination of the thyroid gland – palpation a – the doctor is standing behind the patient, who is sitting b – the doctor is in front of the patient; his right hand is palpating the left lobe, his left hand is resting on the neck and his fingers are stabilizing the lobe Enlarged yes no Symmetrical yes no 31 Consistency rigid soft Murmurs over the thyroid gland yes no EXAMINATION OF THE SUPERFICIAL LYMPH NODES – If they are enlarged (palpable) Fig.4. Lymph nodes 32 Occipital yes no Cervical yes no Subclavicular yes no Axillary anterior yes no median yes no posterior yes no Inguinal yes no Ulnar yes no Look at the figure, asses the size, answer the questions: Are they tense? yes no Are they mobile? yes no Are they tender on palpation? yes no EXAMINATION OF THE THORAX (inspection, palpation, percussion, auscultation) Fig.5. Topographic lines on the anterior wall of the thorax. From left: right anterior axillary line, right midclavicular line, sternal line (median), left midclavicular line, left anterior axillary line Fig.6. Topographic lines on the posterior wall of the thorax. Vertebral and scapular lines are marked. 35 Percussion sound Vesicular yes no Tympanic resonance yes no Dull yes no Mobility of the lower lung lines yes no (Auscultation) Basic respiratory murmurs Vesicular yes no Normal yes no With prolonged inspiration phase yes no Exacerbated yes no Bronchial yes no Accessory murmurs Dry rales yes no Wheezes yes no Whirring rales yes no Moist rales yes no Resonant Dull Pleural friction rub murmur yes no EXAMINATION OF THE MAMMARY GLAND Female mammary gland examination Symmetrical Asymmetrical Flattening observable yes no Depressions observable yes no Skin appearance Oedematous yes no 36 Orange skin yes no Ulceration yes no Nipples Prominent Pulled into Tenderness on palpation yes no Palpable tumours yes no Mark points in the figure Fig.8. Topographic regions of the breast – left mammary gland 1 – upper lateral quadrant, 2 – lower lateral quadrant, 3 – lower medial quadrant, 4 – upper medial quadrant, 5 – axillary tail of the breast, 6 – nipple area, central portion of the breast Nodules - if present, pay attention to ● location, ● size ● shape ● consistency ● tenderness ● mobility 37 If exerting pressure on the breast causes leakage yes no Male mammary glands Symmetrical yes no Enlarged yes no Enlarged nipples yes no HEART (Inspection) The area of the heart Prominent Normal Apex beat Visible Invisible Parasternal raising yes no Dynamic aorta Visible Invisible (Palpation) Apex beat Palpable Covered with the pulp of 1,2,3....fingers yes no Impalpable Heart area tremor Palpable Impalpable 40 Sounds: Sound 1 Sound 2 Sound 3 Sound 4 Intervals between the sounds yes no Murmurs yes no Systolic Diastolic Pericardial friction rub yes no EXAMINATION OF THE ARTERIES (Inspection, palpation, auscultation) Fig.12. Arteries available on palpation (a) and auscultation (b) (The aorta, the carotid arteries, the radial arteries, the ulnar arteries, the superficial femoral arteries, the popliteal arteries, the tibial arteries, the dorsal foot arteries are partially available on palpation.) 41 Pulsation of arteries Visible Invisible (Palpation ) Arteries The wall of the artery rectilinear serpentine fine hardened elastic rigid Pulse palpable yes no Equal on both symmetrical arteries yes no (Auscultation) the carotid artery , the thyroid gland level murmurs yes no the subclavian artery, below the middle of the clavicle murmurs yes no the renal arteries, the epigastrium and lumbar region murmurs yes no VEINS (Inspection, palpation) Jugular veins Filled yes no Collapsed yes no Venous pulse positive Venous pulse negative Veins of the lower limbs Clots yes no 42 THE ABDOMINAL CAVITY (examined in patient supine position or upright and bending over) Fig.13. Topography of the anterior abdominal wall 1 – the epigastric area 2 – the right subcostal area, 3 – the left subcostal area, 4 – the umbilical area, 5,6 – the abdominal lateral area, 7 –the pubic area, 8, 9 – the inguinal area (Inspection ) The symmetry of the abdomen yes no The shape of the abdomen Protuberating in the level of the thorax above the level of the thorax lower than the level of the thorax The umbilicus Protruding Pulled into Signs of umbilical inflammation Umbilical hernia The peristalsis – visible yes no Pulsation in epigastrium yes no 45 positive negative Abdominal masses positive negative (Auscultation) Peristaltic murmurs Present No murmurs THE URINARY ORGAN The kidney (Inspection) Protruding in the renal area Visible Invisible Oedema in the renal area Present No oedema (Palpation) Palpable lower pole of kidney Right yes no Left yes no Right kidney tenderness yes no Left kidney tenderness yes no (Percussion) Goldflam’s sign Right - positive negative Left - positive negative 46 The urinary bladder (palpation, percussion) Palpable over the pubic symphysis yes no Palpable after urination yes no THE ORGAN OF MOTION The extremities Symmetrical yes no Joint mobility presence yes no Congenital malformations yes no Joint oedemas yes no Joint deformations yes no Joint tenderness on palpation yes no Mobility restriction yes no which joints .......... Vertebral column Deformed yes no Scoliosis Lordosis Kyphosis Mobility restriction yes no In this part of the textbook, the schemes of the anamnesis and physical examination have previously been presented. The neuromuscular system and psychological examination have been omitted since we do not have the appropriate didactic equipment. The information concerning the patient, i.e. patient’s medical documentation – is called the CASE HISTORY. It is just the beginning of the process; CLINICAL REASONING is still ahead of the students. We present aims and principles of clinical reasoning, which is supported by the appropriate examples. Further stages of education of the medical profession, e.g. applying appropriate accessory laboratory tests and instrumental examinations, establishing the final diagnosis and planning the therapy are presented to the students during the successive years of the medical studies in the form of lectures and practical classes in the Clinical Departments. 47 References 1. Bates Barbara, Nicley S. Lynn.: Wywiad i badanie fizykalne. Kieszonkowy przewodnik. SPRINGER PWN, Warszawa 1997 2. Chlebowski Jakub: Choroby wewnętrzne. PZWL, Warszawa 1954 3. Droszcz Wacław: Diagnostyka chorób układu oddechowego. PZWL, Warszawa 1987 4. Harrison T.R.: Podstawy Medycyny Wewnętrznej. CZELEJ Lublin wydanie XIV, 2000 5. Orłowski Witold: Zasady ogólnej diagnostyki lekarskiej. PZWL, Warszawa 1994 6. Szczeklik Edward: Diagnostyka ogólna chorób wewnętrznych. PZWL, Warszawa 1966 7. Tatoń Jan: Ogólna Diagnostyka Internistyczna PZWL, Warszawa 1991 50 - Orientative, comparative auscultation (points of orientative percussion of chest) - Detailed auscultation: • supraclavicular fossae • anterior intercostal spaces in medial, intermedial and lateral parts of each space • in midaxillary line in its superior, medial and inferior parts • supraspinous areas • interscapular area symmetrically in its superior, medial and inferior parts • infrascapular areas Physiological respiratory murmurs: - vesicular murmur - bronchial murmur Pathological respiratory sounds: - rales • dry rales - sibilant rales (wheezes) - whirring rales • moist rales - coarse rales - medium rales - fine rales - crepitating - pleural friction rub (pleural crackle) 6. Heart examination Inspection - apex beat – limited bulge of the chest’s wall, visible during the heart contraction near its apex. In healthy people with the correct construction of the chest, it appears in the fifth left intercostal space, 1,5 cm medially to the left midclavicular line. It is most frequently visible and palpable, regular, covered with a pulp of the middle finger and it is compatible with heart beat rate and pulse; its left line is simultaneously the left line of the cardiac dullness. - heartbeat 51 - pulsation in the epigastric fossa (pathological sign) - filled jugular veins Palpation - apex beat - fremitus - pleural friction rub Percussion - absolute cardiac dullness (soft percussion) • superior line: upper edge of the fourth left rib ●left line: 1,5 cm medially from the midclavicular line, almost upright • right line: along the left sternal line • lower line: in the fifth left intercostal space, 1,5 cm medially to the left midclavicular line - relative cardiac dullness (strong percussion) • superior line: in place of attachment of the third ribs to the sternum or in the third in- tercostal space, then it heads downwards and it runs on the fourth rib in the left half of the chest, nearby the left midclavicular line • left line: from the fourth rib on the right midclavicular line in the left half of the chest upright and down to the fifth intercostal space or the sixth rib • right line: in the left sternal line or along the right sternal line Auscultation While auscultating, pay attention to heart beat rate and regularity of heart sounds. Assess the sound volume, sonority and accentuation, intervals between the first and second sounds and between the second and the following one. Search for split and bifurcated sounds, accidental sounds and murmurs. Projection of the valves: - mitral valve: attachment of the fourth left costal cartilage to the sternum - aortic valve: on the sternum, at the attachment of the third rib to the sternum 52 - pulmonary valve: in the second left intercostal space by the sternum - tricuspid valve: its projection crosses the sternum from the third left attachment to the fifth right attachment of the costal cartilages to the sternum Points of heart valve auscultation (following the order of auscultating): - mitral valve: on the heart apex - aortic valve: in the second right intercostal space by the sternum - pulmonary valve: in the second left intercostal space by the sternum - tricuspid valve: at the attachment of the fifth right costal cartilage to the sternum Heart sounds - sound I (low, long), appears at the beginning of ventricular systole. It is the result of vi- brations caused by sudden closing of left and right atrio-ventricular valves - sound II (high, short), audible after the end of ventricular contraction. Caused by vibra- tions of closing semilunar aortic and pulmonary valves, immediately after ventricular di- astole (may be bifurcated - physiology) - sound III (soft, low), appears after about 1/3 of diastolic time. It is probably the result of vibration of ventricular walls due to rapid filling with blood at the beginning of the dias- tole - sound IV appears exactly before sound I, when the pressure in the atria is high or if the walls of the ventricles are rigid because of their hypertrophy. Filling the ventricles during contraction of the atria causes the sound. Rarely is it audible in physiological conditions. All the audible sounds in the area of the heart between the beginning of sound I and sound II are called systolic, while those following the beginning of sound II and before sound I are called diastolic. 55 THE EXAMINATION OF ABDOMEN ORGANS Liver examination Liver percussion should determine the organ borders. The upper liver border is the same as lower right lung border, whereas it fuses with cardiac dullness to the left side. The lower liver border runs: between the tenth rib and the eleventh rib in the right axillary line, just below the costal chest border in the middle clavicular line, in the medial line– in the middle of the distance between the xiphoid and umbicullus, between the parasternal line and middle clavicular left line – just below the costal chest border. Liver palpation is performed with the right hand placed flat under right costal chest border, parallel to the long body axis, then applying pressure at the depth of inspiration in an attempt to move under the costal border in the right middle clavicular line and towards its right side. In normal conditions, the lower liver border is not touched. During the respiration, the lower liver border is slightly moving down and upwards. If the liver edge can be detected on palpation, some additional features have to be determined as there are various abnormalities related with specific diseases: ● Liver border the location and the course of liver edge to determine: - whether it is sharp or round, - whether it is smooth or knobby, - the mobility of the edge, - tenderness or pain. ● Liver surface - smooth, - even, - painful The gallbladder under normal conditions cannot be palpated. An enlarged gallbladder is felt as a pear-shaped formation that is connected to the liver and mobile on respiration. The strongest pain on palpation is related with inflamed gallbladder with accompanying Chełmoński's sign, which involves eliciting pain sensation during inspiration at the time of slapping patient’s right costal border. 56 Spleen examination The spleen is located under the left chest costal border and reaches the spine with is posterior border at the level of thoracic vertebrae X, and reaching the medial axillary line with its anterior border between the ninth rib and the eleventh rib. The long spleen axis runs obliquely along rib X from the posterior and upper side forward and downwards. Spleen percussion: is performed in semi lateral position i.e. the intermediate position between lying on the back and on the right side. The silent percussion of the inferior and anterior (directly adjacent to the chest wall) sides of spleen is performed. Spleen palpation: is performed with the right hand placed under the left costal margin perpendicularly to the margin while asking the patient to breathe deeply. During deep inspiration and expiration, the fingertips are inserted below the costal margin and the attention is paid to the spleen border, which emerges over the fingertips in the case of spleen enlargement. Under normal conditions the spleen cannot be palpated. In case of the enlargement of the spleen, special attention is paid to: ● spleen size – minor enlargement from several centimeters, as in infectious diseases, lymphatic leukemia, hemolytic anemia; marked enlargement may reach the pubic symphysis, as in myeloid leukemia; ● spleen surface – smooth, uneven, soft, hard ● spleen tenderness – spontaneous, i.e. in spleen infarction Pancreas examination The pancreas is located at the level of lumbar vertebrae I –II. The pancreas head is lodged within the curve of the duodenum; its corpus runs across the descending aorta and its tail reaches the left kidney. The physical exam of pancreas is difficult as the access is limited and it is not available for percussion or palpation. The examination of the gut The GI physical examination is commonly started from the sigmoid colon. The fingers are placed in the left iliac fossa, perpendicularly to the long sigmoid axis, and on superficial 57 and deep palpation the sigmoid can be felt as a cylinder of a few centimeter-diameter. The upper region of the colon is examined including the consecutive parts of the spleen flexure, transverse colon and hepatic flexure down towards the caecum. Usually, each consecutive region is not palpable, as it is dependent on the intestine luminal distention, its wall tension and the abdominal wall tension. 60 • systematic and detailed collection of the information/ data (including detached or/and atypical disease syndromes), when there are many possible and equally important hypotheses and no “dominant” diagnosis (e.g., diagnosing the fever of unknown origin). • following an established algorithm; e.g., diagnosing anemia or the presence of fluid in the pleural cavity that is accompanied by an isolated medical problem) 3. Clinical thinking (following the scheme) – problem-solving approach The diagnostic process should be organized and analyzed logically as presented below: 1. Eliciting information from the patient (history – syndromes, physical examination – signs, results of available accessory investigations) 2. List of activating data – all the abnormal results obtained from subjective and objective examinations, including medications tat have been received, results of the accessory investigations, risk factors, finally, patient’s demands; it is the doctor who decides, which syndromes can be classified as abnormal. 3. List of medical problems – the principles: • a set of data, which (according to the diagnostician) seem to be associated with the same pathology (what are the causes that their real relation has not been checked) • one or several activating data contribute to solving the problem • if a syndrome (activating data) can have several sources, it should become a distinct problem • each drug, risk factor or patient’s requirement should be regarded as a separate problem 4. Analysis of the listed problems – creating diagnostic hypotheses - an attempt to explain patient’s ailments qualified as "problems" by assigning them to a given pathology, disease. 5. Planning actions – sort and order of accessory investigations aiming at confirmation or rejection of the diagnostic hypothesis. General note: It seems that the critical point in analyzing a clinical case is to convert the activating data into medical problems. It is obvious that a student, having an initially narrow clinical knowledge, will be incapable of associating the activating data with problems and, as a result, the list of clinical problems will follow the list of activating data (as many clinical problems are considered activating data). On the other hand, an experienced doctor, who knows and is able to identify a set of syndromes that accompany a certain disease, will be able to link all the activating data with one medical problem, which shows perfectly well how important both 61 the knowledge and clinical experience (based on diagnosing disease syndromes) is. It markedly contributes to the advancement of the diagnostic process. 4. Example of a clinical case analysis A 43-year-old patient has visited the outpatient clinic: Anamnesis (history) Main complaints: 2-weeks history of aggravating pain in the precordial pit, mainly in the morning and after an irritation. Patient noticed occurrence of an increased appetite – meals bring relief to the pain, nothing in common with exertion. That morning an onset of a severe pain made the patient visit a doctor. No vomiting. Regular bowel movements (once in 24 hours), no abnormalities, no melaena stools. The described disorders occurred for the first time in his life. He has been treated for hypertension (the highest measured BP value was 200/120); actually receiving metoprolol (50 mg q. 12 hr, orally). He was treated with acetylsalicylic acid for abdominal pain (300 mg q. 8-24 hr, 2 wks). Besides: • has smoked 30 cigarettes a day for 25 years • family history: father after infarction at the age of 58, mother suffering from peptic ulcer • drives for a living, married, with 2 children Physical examination: body temperature - 36.8 C weight – 80 kg height - 1.76 m nodes: NAD (no abnormalities detected) C.V.S.: heart rate 96/min., regular; heart sounds loud, normal accentuation; BP110/70 mmHg; R.S.: respiratory rate - 26/min., pectoral/vocal fremitus symmetrical, vesicular resonance, vesicular murmur – normal; Abd: hard, marked tenderness in the epigastrium, Blumberg sign positive, no abdominal masses on palpation, tympanic resonance over the whole abdominal cavity - diminished hepatic dullness, peristalsis detectable, smooth-edged liver protruding 2 cm below the costal arch, Goldflam’s and Chełmoński’s signs negative. Extremities: peripheral pulse compatible with heart beat, palpable on peripheral arteries. 62 Activating data: Anamnesis: 1. Abdominal pain 2. Hypertension 3. Metoprolol 4. Acetylsalicylic acid 5. Nicotinism 6. Father – ischemic heart disease (IHD) 7. Mother– peptic ulcer Physical examination: 8. Tenderness in the abdominal area – Blumberg sign - positive 9. Board-hard abdomen 10. Tachypnoe 11. Diminished hepatic dullness Problem list with assigned activating data: 1. Acute abdomen: 1, 8, 9, 10 and 11 2. Hypertension: 2 3. Medications: 3, 4 4. Nicotinism: 5 5. Family history: 6, 7 Problem analysis: No doubt, the main problem that needs immediate diagnosing seems to be the set of syndromes called „acute abdomen” syndromes. With such accompanying signs, a disease of upper alimentary tract may be suspected, e.g. duodenal ulcer, with perforation (the first of the possible diagnostic hypotheses) due to treatment with non-steroid anti-inflammatory drugs (NAID) may have occurred. Proceeding: One of a readily available examination is an X-ray of the abdominal cavity, in which the air under the dome of the diaphragm can be detected. This radiological syndrome could confirm the diagnostic hypothesis and substantiate initiation of the treatment – surgical 65 1%, 3%, 5%, 10% II. A 50-year-old woman with a positive mammography result, performed after reading an article about breast cancer prevention is seeking medical advice. What is the probability that she really suffers from mastopathy, if breast cancer incidence (hypothetic data) in this age group reaches 1%, mammography sensitivity- 90%, specificity- 80%? 1%, 4%, 8%, 32% The same situation, a woman underwent the mammography as a result of a breast nodule discovered on palpation. What is the estimated breast cancer probability if the sensitivity and specificity of this symptom reach 70%; what is breast cancer probability based on a positive mammography result? 1%, 10%, 20%, 30% 66 Krzysztof ChiŜyński1, Janusz Kawiński2, Sławomir Ceranka1 The electrocardiographic examination, performance and analysis 1 Department of Invasive Cardiology, I Chair of Cardiology and Cardiac Surgery, Medical University of Łódź 2 Department of Cardiology, I Chair of Cardiology and Cardiac Surgery, Medical University of Łódź An electrocardiogram (ECG) is a recording of the cardiac electrical activity as a graph or a series of wave lines on a moving strip of graph paper or displayed on a monitor. I/. History of electrocardiography • 1887 – an English physiologist Augustus D. Waller, who worked in St. Mary’s Hospital in Paddington, London published the first electrocardiogram of a human being, which was performed using a capillary electrometer. • 1895-1901 – a Dutch physiologist Willem Einthoven developed the technique of recording the activity of the heart; he introduced the term “electrocardiography” and assigned the letters P, Q, R, S and T to five basic deflections. In 1924 he was awarded the Nobel Prize for his discovery. II/. Electrophysiological grounds of ECG Electrocardiogram is a concise record of the changes of potentials during depolarization and repolarization of myocardial cells. Electric changes at the level of a single cardiomyocyte are as shown in figure 1. 67 Fig. 1. Functional potential – diagram Knowledge of these phenomena is essential to understand the characteristic picture of ECG curve (waves, intervals, segments). Resting potential The interior of a myocardial cell is electrically negative in relation to its exterior and the potential of its interior is about –90 mV. The state in which intracellular negative ions predominate over the positive charge outside is called the 'cell polarization' and it is defined as the resting membrane potential. The resting membrane potential is maintained by sodium ions at a higher concentration outside the cell and accumulation of potassium ions inside cardiomyocytes. The cell membrane is impermeable for sodium ions during the resting state. They do not penetrate the cell by passive diffusion driven by the gradient of concentrations. In the resting state, cell membrane is however, permeable for potassium ions and the existing difference of these ion concentrations between the cell interior and the extracellular space directs the diffusion outside, counteracting the potential difference. The difference of the potential between the cell interior and the intercellular space is maintained enzymatically – actively by Na+ K+ ATP-ase, which transports these ions against the gradient of concentrations and the potentials of electric 70 • left anterior fascicle • left posterior fascicle • septal – left branch extension Right bundle branch – along the right side of the interventricular septum. Within the action potential of stimulation – conduction system • in phases 0, 1, 2 and 3 to the level of membrane potential (-55 ÷ - 60 mV) – the myocardial cell does not react to any stimuli – absolute refractory period • from –55 ÷ -60 mV to about –90 mV – relative refractory period • directly after obtaining full excitability near the end of T wave, a stimulus weaker than is normally required can depolarize cardiac cells. This short portion of repolarization is called the supernormal period. Also in the second half of phase 3 there comes to vulnerable period of repolarization (vulnerable phase) during which a stimulus may produce severe arrhythmias – the ventricular tachycardia or ventricular fibrillation. IV/. ECG Leads A lead – is an electric circuit consisting of a galvanometer connected through electrodes with two points of electric field. In everyday life a lead is regarded as a single ECG curve (although it is a certain mental shortcut). Two groups of leads are distinguished: bipolar and unipolar. In case of bipolar leads both electrodes are attached at the points of potentials which are measured. When unipolar leads are registered, a positive electrode is located at the site of the investigated potential (the tracing electrode, while the negative one - at the site distant from the investigated tissue of zero potential / reference electrode). Standard complete ECG specifies 12 separate leads: - 3 limb leads, bipolar (classic) – determined as: I, II, III - 3 limb leads, unipolar – determined as: aVR, aVL, aVF 71 - 6 precordial, unipolar leads – determined as: V1-V6 The diagram of classic limb bipolar leads (Einthoven’s) are presented in figure 3. Fig.3 Einthoven’s triangle diagram These leads record the difference of potentials between the body areas located in the same distance (approximately) from the heart. In a stationary ECG, the electrodes are attached to forearms and lower leg, whereas during exercise test or 24 h Holter monitoring all the electrodes are attached to the chest. The colours of the lead endings and the places of attachment of the electrodes are the following: • N – black (right lower leg or the region of right anterior superior iliac spine) • R – red (right forearm or the region of right shoulder) • L – yellow (left forearm or the region of left shoulder) • F – green (left lower leg or the region of left anterior superior iliac spine) The measurement of the difference of the potentials (in mV) is performed between these electrodes: • lead I – the difference of potentials between the electrodes placed on “left arm” and “right arm” (LA-RA) • lead II - the difference of potentials between the electrodes “left foot” and “right arm” (LF-RA) 72 • lead III - the difference of potentials between the electrodes “left foot” and “left arm” (LF-LA) (in American literature these are called: L1, L2, L3 – from English – limb) Unipolar limb leads (in Goldberger modification) are obtained using a positive (active) electrode (one pole) attached to one of the three extremities (right arm, left arm or left foot) whereas the central terminal is made by connecting the other two extremity electrodes and the second pole of the lead far from the investigated tissue of zero potential. These leads serve for measuring the absolute potential at a given point. The three extremity electrodes are attached as follows to obtain the three augmented (unipolar) leads: • lead aVR – the positive electrode is attached to the “right arm” (RA) • lead aVL – the positive electrode is attached to the “left arm” (LA) • lead aVF – the positive electrode is attached to the “left foot” (LF) the “zero electrode” is an attachment of the remaining two electrodes (and its electric potential is zero). ATTENTION! All limb leads (bi- and unipolar) are in the frontal plane and classic lead I belongs both to frontal and transverse (horizontal) plane; precordial (unipolar) leads are in the transverse plane. Precordial unipolar leads (Wilson’s) are recorded from 6 typical attachments of the electrodes on the chest (fig. 4): • V1 – red – right side of the sternum in the fourth intercostal space • V2 – yellow – left side of the sternum in the fourth intercostal space • V3 – green – midway between V2 and V4 • V4 – brown – midclavicular line in the fifth intercostal space • V5 – black – anterior axillary line at the same level as V4 75 • HRA – recording potentials from high right atrium (RA) • EpH - recording potentials from the region of the bundle of His • CS - recording potentials from the coronary sinus • RVA - recording potentials from right ventricular apex • other leads – dependently on definite needs in the course of the examination Fig. 6. ECG (a record from numerous endocardiac leads) V/. Analysis of ECG curve Before starting an adventure with the analysis of real ECG records, the essentials of an electrocardiographic ABC must be known. The beginnings may be difficult but...the end crowns the work. This is an example of normal electrocardiogram (fig. 7) 76 Fig.7. Normal ECG 1/. Waves, segments, intervals (fig. 8) Fig. 8. Waves, segments and intervals in ECG The ECG curve consists of repeatable elements that are PQRST complexes. Each complex includes: 77 a/ waves – each deflection of ECG curve up or down the isoelectric line; the following waves are distinguished: - P wave – a record of atrial depolarization - Q, R, S waves – the QRS complex – a record of ventricular depolarization - T wave – a record of fast ventricular repolarization - U wave – a record of (most probably) Purkinje’s fibres repolarization - J point is also distinguished; it is a junction between QRS complex and ST segment b/ segments – the sections of the ECG between the waves: - PQ (PR!) segment – it begins with the end of the P wave and ends with the onset of the QRS complex, represents the onset of atrial repolarization and electrical impulses conduction from atria to ventricles, through atrio-ventricular node, the bundle of His and Purkinje network; - ST segment - begins with the end of the QRS complex and ends with the onset of the T wave, represents the early part of slow repolarization of ventricles, - TP segment – begins with the end of the T wave and ends with the onset of the following P wave, represents the time during which electrical activity of the heart is absent. ATTENTION! This TP segment determines the level of isoelectric line (0 mV). c/ intervals – include waves and complexes: - PQ (PR!) interval – it begins with the onset of P wave and ends with the onset of the QRS complex, represents depolarization and the onset of repolarization of the atria and the time of the conduction of impulses from the atria to the ventricles. - QT interval – it begins with the onset of QRS complex and ends with the end of T wave, represents the duration of electrical activity of the ventricules (their depolarization and repolarization). ATTENTION! It is one of the most important fragments of ECG curve, particularly in the assessment of the risk of sudden cardiac death! 80 ATTENTION! In case of not typically calibrated ECG record, the following formula should be used to get the real amplitude of the given ECG wave: mm) (10 amplitude signaln calibratio normal amplitude signaln calibratio measured amplitude wavereal x)( amplitude wavemeasured = and thus: amplitude signaln calibratio measured 10 x amplitude wavemeasured x = 4/. ECG standards It should be remembered that the values of the time of duration and the height of particular ECG components are not constant but different in particular leads in which they are estimated. Usually these measurements are performed in ECG limb lead II (classic) a/ height standards (amplitude) of particular waves: - P wave – 1-2,5 mm (0,1-0,25 mV) - Q wave – 0-3 mm (0-0,3 mV) - R wave – 6-20 mm (0,6-2,0 mV) - S wave – 0-8 mm (0-0,8 mV) - T wave – 2,5-6 mm (0,25-0,6 mV) b/ duration standards of waves, segments and intervals: - P wave - ≤ 110 ms - QRS complex – 60-90 ms - PQ (PR) segment – 40-100 ms - PQ (PR) interval – 110-200 ms (at HR ≤ 90/min) 81 - QT interval – max. 360-410 ms(at HR~ 60/min) min. 280-330 ms (at HR~ 90/min) - T wave – 120-160 ms 5/ Description of ECG components a/. P wave – represents depolarization of the right and left atrium. Its ascending part reflects depolarization of the right atrium and the descending part of the left atrium. Normal sinus P wave is always positive in lead III (and V6) and negative – in lead aVR; the inclination angle of P wave electrical axis in the frontal plane is 00 to +700. P waves can be: tall – they occur in subjects with right atrial hypertrophy (e.g. chronic obstructive pulmonary disease, organic heart diseases), in sympathetic system preponderance, in coronary heart disease and hyperthyroidism wide (sometimes bifurcated) – in conditions leading to left atrial hypertrophy, e.g. mitral stenosis, mitral regurgitation, arterial hypertension negative – it is always an abnormal phenomenon and indicates that the stimulus has been originated not in the sinus node but in other pacemaker cells invisible: - hidden in QRS complex (e.g. during A-V nodal rhythm or atrio-ventricular nodal re- entry tachycardia – AVNRT) - periodically buried in QRS complexes or T waves (e.g. in A-V III0 block) - occur in the form of f waves (slight, irregular oscillations of the isoelectric line – during atrial fibrillation) or F waves (tall, occurring regularly – during atrial flutter) 82 b/ PR (PR) segment and interval PR (PR) segment represents the onset of repolarization of the atria (which lasts until the onset of ST segment) and the time of progression of the impulse from the AV node through the bundle of His, bundle branches and Purkinje network. PQ (PR) interval represents the duration of both P wave and PQ segment and thus additionally the time of atrial depolarization If a detailed endocardiac ECG record is registered (during invasive electrophysiological study) – look at Fig. 11 – 4 subperiods can be distinguished within PQ (PR) interval - PA segment (0-40 ms) – duration of intra-atrial conduction - AH segment (<120 ms) - time of atrio-ventricular conduction - H segment (< 10 ms) – time of conduction in the bundle of His - HV segment (< 55 ms) - time of intra-ventricular conduction (within Purkinje network) Fig. 11. ECG (I, aVF, V1, V6 and endocardiac leads) 85 ATTENTION! - The presence of deep Q wave and short R wave in lead III may depend on high positioning of the diaphragm, that is why in the case of diagnostic doubts ECG should always be recorded at the pick of inspiration; if these were due to changes in position, then during deep inspiration the amplitude of Q wave will decrease (or Q wave will disappear) and of R wave – will increase. - A notch on the ascending arm of R wave, the so called delta wave represents the preexciation syndrome and indicates depolarization of part of the ventricular muscle through an additional atrioventricular pathway (Kent’s bundle, Mahaim’s fibres. - While analysing the QRS complex, ventricular activation time is also estimated, i.e. a negative vector or intrinsicoid deflection. It is the time from the onset of the QRS complex to the peak of the R wave (fig.13). Fig. 13. Determination of the negative vector This negative vector is an exponent of the conduction rate and the thickness of myocardium; it is different for the right (≤ 35 ms) and left (≤ 45 ms) ventricles. Prolongation of ventricular activation time is useful in diagnosing branch blocks as well as myocardial hypertrophy. d/. Junction point J 86 The name originates from English and means the junction between the QRS complex and the ST segment. In normal ECG, the J point should be on the isoelectric line (maximum 1 mm above or below this line). ATTENTION! Higher deviation of the J point in precordial leads (sometimes also in limb leads) with accompanying concave elevations of ST segment in these leads may be observed in healthy subjects and is called premature ventricular repolarization syndrome. It can lead to diagnostic mistakes and “over-diagnosis” of myocardial infarctions (STEMI – ST elevation myocardial infarction). e/. ST segment The ST segment represents early (slow) phase of repolarization of the right and left ventricles. In normal ECG records, ST segment is flat (isoelectric – max. – 0,5 depression, + 1 mm elevation); leads V1-V3 are an exception – where ST segment elevation can reach 2 mm. ST segment appearance can vary: - horizontally in isoelectric line (STANDARD!) - horizontal depression of ST segment (typical for myocardial ischaemia) - down sloping depression of ST segment (typical for myocardial ischaemia and overloading of the given ventricle) - slanting upwards depression of ST segment (may be the variant of the standard) - slagging depression of ST segment (over dosage of digitalis) - concave upwards elevation of ST segment (typical for premature ventricular repolarisation syndrome) - ST segment elevation, convex upwards (Pardee’s wave – characteristic in STEMI 87 The assessment of the ST segment is particularly important in the analysis of myocardial ischaemia; due to common prevalence of ischaemic heart disease and its share in morbidity and mortality in the Polish population, various ST segment appearance in this pathology is presented in fig. 14. Fig. 14 The shape of ST-T comlexes in ischaemia f/. T wave T wave represents the final (abrupt) phase of ventricular repolarization. In majority of leads the T wave is positive (deflected above the isoelectric line), negative in aVR lead (and often in V1, flat or shallow – negative in III, aVF, less frequently in a VI lead. Other variations of this shaping that particularly occur in pathological conditions are: - T wave flat (isoelectric) in physiological conditions found in leads: III, aVF, aVL - T wave negative – in physiological conditions found in aVR lead and often in lead V1; in pathological conditions it is typical of coronary heart disease - T wave two-humped - T wave biphasic (usually - +) - T wave sharply peaked, tall (characteristically in acute coronary heart disease and hyperkalemia) 90
300 grids (a’ 5 mm) will come out within 1 min (300x0,2 s = 60 s = 1 min) - thirdly – the number of these 300 grids divided by the number of 5 mm grids between the successive RR waves gives the heart rate. Fig. 15. The record of ECG (Lead II) Heart rate = 300/min: 4 = 75/min Of course, at the paper speed of 50 mm/s – because here 600 grids of 5 mm side is printed within one minute – to calculate heart rate, 600 should be inserted into the numerator of the above formula and it should be divided by the number of 5 mm grids between the successive R waves. Another way of calculating the rate is to divide the time unit by the length of a single cardiac cycle (RR interval). Considering the same example, 60 s (i.e. 1 min) should be divided by 0,8 s (4 grids of 5 mm side = 20 grids of the side of 1 mm = 20x40 ms = 800 ms = 0,8 s). min / 75 s 0,8 60 rateHeart == If (in this ECG) 1 evolution lasts 0,8 s and in 60 s there will be 75 cycles/min then in 1 s: 1: 0,8 = 1,25 cycles per second (that is 1,25 Hz). In everyday practice, a special cardiologic scale (fig.16) is used, which demonstrates the heart rate with satisfying precision [based on the distance between a few (2-6) successive RR intervals]. 91 Fig. 16. A photograph of a scale The last remark! While estimating irregular rhythm (e.g. during atrial fibrillation) the minimum, maximum and mean values must be given. 7/. Cardiac electric axis and its determination The heart is a peculiar generator of current, which is associated with the creation of the electric field. The electric field is spatial and thus its description using a vector requires a three-dimensional co-ordinate system. Mean vector of the ventricular system (QRS complex) is the resultant of the activation vectors of the interventricular septum, cardiac apex, inferior wall and free RV and LV walls (these in turn are the resultants of local summation vectors). However, in everyday practice, the projection of QRS complex vector on the frontal plane supplies sufficient information; thus when we speak about cardiac electrical axis we actually speak about its component in the frontal plane. In clinical practice, cardiac electrical axis can be determined in different ways: • the system of typical QRS deflections in leads I, II and III can be useful for characterizing particular intervals of the axis • based on the Einthoven’s triangle (fig. 17) 92 Fig. 17. Einthoven’s triangle This triangle is oriented in the space in such a way that its sides run the axis of classic leads: I (00), II (=600), III (+1200). The signs (+ and -) are marked on this triangle and point zero of the lead axis (in the middle of each side). To determine the direction of the straight line two points are always needed and thus the same number of classic leads is necessary to determine cardiac electric axis. Most frequently leads II and III are chosen. Then, the values of R waves (positive) and Q and S waves (negative) are summed. Next, the calculated values from the middle point of lead axes I and III are shifted into the proper direction (preserving the signs + and -). Finally, perpendicular lines are drawn through the ends of segments marked on the triangle sides and the points of their crossing determine the mean vector of QRS complex axis. • based on the circle of Carbera (1st way) (fig. 18) 95 QRS complex in aVF lead is positive, the cardiac axis will be in the range of right axis deviation (+900 to +1800). • in modern ECG equipment, the values of axes, P waves, QRS complexes and T waves are calculated on the record. Fig. 20. Examples of QRS axis: A – normal axis B – left axis deviation Fig. 20: record 2A – lead I – QRS complex is positive, lead aVF – also positive – cardiac axis in the range from 00 to +900, that is normal QRS axis, precisely +650 (as calculated by a program in ECG apparatus). record 2B: lead I – QRS complex is positive and aVF – negative – this means that the cardiac axis is in the range from 00 to –900, thus in the range of left axis deviation; it must be determined whether it is a pathological left axis deviation; cardiac axis is positive, in the range from 00 to –300, when QRS complex is positive in lead II – the axis is recorded as “left axis deviation” without an adjective pathological (as calculated by a program in ECG apparatus: -230) 96 ATTENTION! Determination of electrical axis is made easier by the following observation: • if the predominant QRS complex deflections in leads I and III are directed to each other – it is a right axis deviation, • if the predominant QRS complex deflections in leads I and III are directed apart, the electrical axis is deviated to the left. Interpretation of cardiac electrical axis deviation • in healthy subjects the electric axis deviation is in the range from 00 to +900 • left axis deviation (QRS complexes shaped divergently – “apart”) can be observed: when the diaphragm is positioned high (e.g. in pregnant or obese subjects), in left ventricular hypertrophy (e.g. in arterial hypertension, in organic heart diseases leading to left ventricular hypertrophy, in primary hypertrophic cardiomyopathy) and abnormal intraventricular conduction (block of the left branch of the bundle of His, left ventricular block) • right axis deviation (QRS complexes in leads I and III are directed to each other – deep S waves in lead I and tall R waves in lead III) occurs: when the diaphragm is positioned low (in tall, slim subjects), in right ventricular hypertrophy (in chronic cor pulmonale, in organic heart diseases burdening right ventricle, acute cor pulmonale (eg. pulmonary embolism) and in anomalous intraventricular conduction (right branch block of the bundle of His, left posterior fascicular block) Estimation of heart position in chest While assessing cardiac electrical axis, it should be remembered that it is not anatomical position of the heart in relation to chest walls that is being described, but the course of a minute QRS vector. However, in the heart of healthy subjects the direction of the vector is similar to the long anatomical axis; thus on the basis of QRS complexes shape (if other factors are not considered, e.g. left ventricular hypertrophy or left branch block of the bundle of His) the position of the heart in the chest may be indirectly concluded. 97 The estimation of heart position in chest may be carried out on the basis of the shape of dominating QRS complexes deflections in leads aVL and aVF (the picture of QRS complexes is similar to QRS complexes in leads I and III). In vertical position – in aVL lead, a deep S wave is predominant and in aVF lead is similar to QRS complex in V1 or V2 lead and in aVF – to V5-V6. In semivertical position – in aVL lead QRS complex has low amplitude and in aVF lead – tall R wave (QRS complex is similar to QRS complex in lead V5-V6) In horizontal position – in aVL lead, a tall R wave is predominant and in aVF lead – deep S wave (QRS complex in aVL lead is similar to QRS complex in lead V5 or V6, while in aVF lead – to V1 or V2) In semi horizontal position – in aVL lead, a tall R wave is predominant and in aVF lead – QRS complex has low amplitude (QRS complex in aVL lead is similar to QRS complex in V5 or V6) In indirect or oblique position – both in aVL and aVF leads QRS complexes are positive and similar to those in leadsV5, V6. Changes of heart position round its long axis – rotations These are determined in precordial leads on the basis of the R and S waves ratio. Usually in precordial leads V3 and V4 R wave appears to be equal to S wave. • the shift of “rightventricular” picture more to the right in the band of precordial leads (deep S wave up to V5, V6) proves the rotation of heart anatomical axis to the right – dextrogyration • the shift of “leftventricular” picture to the left (tall R wave also in V1-V2 – proves the rotation of heart anatomical long axis to the left – sinistrogyration • when the apex of the heart is close to the front – deeper Q waves are observed in all limb bipolar leads • when the apex of the heart is displaced backward – the presence of deep S wave is observed in all limb bipolar leads.