Understanding Heart Rhythms and Dysrhythmias, Exams of Advanced Calculus

Download Understanding Heart Rhythms and Dysrhythmias and more Exams Advanced Calculus in PDF only on Docsity! Advanced – Dysrhythmias Exam Questions with Verified Answers 2024 Update. Excitability - Correct answer the ability of non-pacemaker heart cells to respond to an electrical impulse that begins in pacemaker cells. Depolarization - Correct answer occurs when the normally negatively charged cells within the heart muscle develop a positive charge. Conductivity - Correct answer the ability to send an electrical stimulus from cell membrane to cell membrane. As a result, excitable cells depolarize in rapid succession from cell to cell until all cells have depolarized. Ex: the wave of depolarization causes the deflections in the ECG waveforms that are recognized as the P wave and QRS complex. Contractility - Correct answer the ability of atrial and ventricular muscle cells to shorten their fiber length in response to electrical stimulation, causing sufficient pressure to push blood forward through the heart. In other words, this is the mechanical activity of the heart. AV Node - Correct answer where impulses slow down or are delayed before proceeding to the ventricles. This delay is reflected in the PR segment on the ECG. This slow conduction provides a short delay, allowing the atria to contract and the ventricles to fill. SA Node - Correct answer the heart's primary pacemaker. It can spontaneously and rhythmically generate electrical impulses at a rate of 60-100 beats per min and therefore has the greatest degree of automaticity. Purkinje Cells - Correct answer composed of the bundle of HIS, bundle branches, and these fibers. Responsible for the rapid conduction of electrical impulses throughout the ventricles, leading to ventricular depolarization and the subsequent ventricular muscle contraction. Semi-Reclined - Correct answer While obtaining a 12-lead ECG, remind the patient be as as still as possible in a ________________________ position, breathing normally. Clea, Dry, Moist - Correct answer For continous ECG monitoring, be sure to __________________ skin and clip hairs/shave. Ensure that the electrode placement is _____________ and the gel on each electrode is ______________ and fresh. P Wave - Correct answer a deflection on an ECG representing atrial depolarization. When the electrical impulse is consistently generated form the SA node, this wave has a consistent shape in a given lead. If an impulse is then generated from a different (ectopic) focus, such as atrial tissue, the shape of this wave changes in the lead, indicating that an ectopic focus has fired. PR Segment - Correct answer the isoelectric line from the end of the P wave to the beginning of the QRS complex, when the electrical impulse is traveling through the AV node, where it is delayed. PR Interval - Correct answer measured form the beginning of the P wave to the end of the PR segment. Represents the time required for atrial depolarization, the impulse delay in the AV node, and the travel time to the Purkinje files. Normally measures from 0.12-0.20 seconds (five small blocks). QRS Complex - Correct answer represents ventricular depolarization on ECG lead. ST Segment - Correct answer an isoelectric line and represents early ventricular repolarization. Changes may be a result of myocardial injury, ischemia, infarction, conduction abnormalities or medications. T wave - Correct answer ventricular repolarization, usually positive, rounded, and slightly asymmetric. May change as a result of myocardial ischemia, potassium/calcium imbalances, medications, or ANS effects. U wave - Correct answer if this is present, it follows the T wave a may result from slow depolarization of ventricular Purkinje fibers. An abnormal U wave may suggest an electrolyte abnormality (Hypokalemia). QT Interval - Correct answer represent the total time required for ventricular depolarization and depolarization. Measured from the beginning of the Q wave to the end of the T wave. Varies with the patient's age and gender and changes with the heart rate, lengthening with slower heart rates and shortening with faster rates. Artifact - Correct answer an interference seen on the monitor or rhythm strip, which may look like a wandering or fuzzy baseline. It can be caused by patient movements, loose or defective electrodes, improper grounding, or faulty ECG equipment such as broken worse or cables. Some can mimic lethal dysrhythmias such as ventricular tachycardia or ventricular fibrillation. ASSESS PATIENT TO DIFFERENTIATE ARTIFACT FROM ACTUAL LETHAL RHYTHMS. DO NOT RELY ONLY ON THE ECG MONITOR. Normal Sinus Rhythm - Correct answer the rhythm originating from the SA node that meets these ECG criteria: -Rate: 60-100bpm -Rhythm: atrial and ventricular rhythms regular -P waves: present, consistent configuration, one P wave before each QRS complex -PR Interval: 0.12-0.20 seconds and constant -QRS Duration: 0.04-0.10 second and constant 60-100, normal, one, 0.12-0.20, .04-.10 - Correct answer Normal Sinus Rhythm is the rhythm originating from the SA node that meets these ECG criteria: Trigeminy - Correct answer ___________________ is a repeated three-beat pattern, usually occurring as two sequential normal complexes followed by a premature complex and a pause, with the same pattern repeating itself in triplets. Quadrigeminy - Correct answer _______________________ is a repeated four-beat pattern, usually occurring as three sequential normal complexes followed by a premature complex and a pause, with the same pattern repeating itself in four-beat pattern. Sinus Tachycardia (ST) - Correct answer Increased rate of SA node discharge as a result of sympathetic nervous system stimulation or vagal (parasympathic) inhibition, which increases the heart rate. The rate of SA node discharge > 100 bpm. Initially- increases cardiac output and blood pressure (compensation for decreased CO/BP). However, continued increases in heart rate decrease coronary perfusion time, diastolic filling time, and coronary perfusion pressure while increasing myocardial oxygen demand. Symptoms: -fatigue, weakness, shortness of breath -orthopnea, decreased O2 sats, decreased BP, decreased cerebral perfusion, decreased urine output -T wave inversion or ST-segment elevation or depression in response to myocardial ischemia. -anxiety, pain, stress, fever, anemia, hypoxemia, hyperthyroidism. -drugs such as epinephrine, atropine, caffeine, alcohol, nicotine, cocaine, aminophylline, and thyroid medications may increase HR. -a compensatory response to decreased CO or BP as occurs in dehydration, hypovolemic shock, myocardial infarction, infection, and heart failure. - Correct answer What are possible causes for sinus tachycardia? Sinus Bradycardia - Correct answer excessive vagal (parasympathetic) stimulation to the heart causes a decreased rate of sinus node discharge. May result from carotid sinus massage, vomiting, suctioning, Valsalva maneuvers, ocular pressure, pain, hypoxia, inferior wall MI, and administration of drugs such as beta-adrenergic blocking agents, calcium channel blockers, and digitalis. Increases coronary perfusion time, but it may decrease coronary perfusion pressure. However, myocardial oxygen demand is decreased. Symptoms: -asymptomatic -syncope ("blackouts" or fainting) -confusion -dizziness/weakness -hypotension -diaphoresis (excessive sweating) -shortness of breath -chest pain Treatment: -medications (atropine 0.5mg IV) -IV fluids (increase intravascular volume) -oxygen Glucagon - Correct answer If beta-blocker overdose is suspected in causing a patient to be in sinus bradycardia, administration of what may help by increasing the HR and blood pressure? Temporary Pacing - Correct answer a nonsurgical intervention for sinus bradycardia that provides a timed electrical stimulus to the heart when either the impulse initiation or the conduction system of the heart is defective. The electrical stimulus then spreads throughout the heart ro depolarize the cells, which should be followed by contraction and cardiac output. This is used for patients with symptomatic bradydysrhythmias who do not respond to atropine or for patients with asystole. There are two types: transcutaneous and transvenous. Permanent Pacemaker - Correct answer inserted to treat conduction disorders that are not temporary, including complete heart block. These are usually powered by a lithium battery and have an average life span of 10 years. After the battery power is depleted, the generator must be replaced by a procedure done with the patient under local anesthesia. Atrial Dysrhythmias - Correct answer The focus of impulse generation shifts away from the sinus node to the atrial tissues. The shift changes the axis (direction) of atrial depolarization, resulting in a P-wave shape that differs from normal P waves. The most common are: -Supraventricular Tachycardia (SVT) -Premature Atrial Complexes (PAC) -Atrial Fibrillation Premature Atrial Complexes (PAC) - Correct answer a type of atrial dysrhythmia that occurs when atrial tissue becomes irritable. This ectopic focus fires an impulse before the next sinus impulse is due. The premature P wave may not always be clearly visible because it can be hidden in the preceding T wave. Examine the T wave closely for any changes and compare with other T waves. This is usually follow by a pause. Cause of atrial irritability: stress, fatigue, anxiety, inflammation, infection, caffeine, nicotine, or alcohol, drugs (epinephrine, sympathomimetics, amphetamines, digitalis, or anesthetic agents). May also result from myocardial ischemia, hyper metabolic states, electrolyte imbalance, or atrial stretch. Symptoms: typically asymptomatic, possible heart palpitations. Management: -stress reduction -treat underlying cause (i.e. heart failure) -avoid caffeine/alcohol -if occur frequently... administer prescribed antidysrhythmic drugs. Supraventricular Tachycardia - Correct answer the rapid stimulation of atrial tissue at a rate of 100-280 beats/minute in adults. P waves may not be visible, especially if there is a 1:1 conduction with rapid rates, because the P waves are embedded in the preceding T wave. May occur in healthy young people, especially women. Usually caused by a re- entry mechanism in which one impulse circulates repeatedly throughout the atrial pathway, re-stimulating the atrial tissue at a rapid rate. Cardiovascular deterioration may occur with a decrease in blood pressure. Symptoms: palpitations, chest pain, weakness, fatigue, shortness of breath, nervousness, anxiety, hypotension, and syncope. Treatment: -catheter ablation (preferred) -vagal maneuvers (induce vagal stimulation of the cardiac conduction system - carotid sinus massage, vasalva maneuvers) -beta blockers, calcium channel blockers Atrial Fibrillation - Correct answer multiple rapid impulses from many atrial foci depolarize the atria in a totally disorganized manner at a rate of 350-600x/minute; ventricular response to usually 120-200 bpm. The result is a chaotic rhythm with no clear P waves, no atrial contractions, loss of atrial kick, and an irregular ventricular response. The rapid and irregular ventricular rate decreases ventricular filling and reduces cardiac output. This alteration in cardiac function allows for blood to pool, placing the patient at risk for clotting concerns such as DVT or PE. Risk Factors: -HTN, heart failure, coronary artery disease *ATRIAL FIBROSIS AND LOSS OF MUSCLE MASS*, previous ischemic stroke, transient ischemic attack (TIA), thromboembolic event, diabetes mellitus, heart failure, mitral valve disease Signs & Symptoms: irregular apical pulse, poor perfusion, fatigue, weakness, SOB, dizziness, anxiety, syncope, palpitations, chest discomfort/pain, and hypotension. Some patients may be asymptomatic. Thrombus Formation - Correct answer Atrial fibrillation can lead to _________________ ____________________ in the atria putting patients at risk for pulmonary embolisms and DVTs. -Antidysrhythmic Drugs (slow ventricular conduction or to convert the AF to NSR) - calcium channel blockers, beta-blockers, digoxin -Anticoagulants (benefits of preventing stroke v. risk of bleeding) -heparin, warfarin, lovenox (prevent strokes associated with AF) -Percutaneous radio frequency catheter ablation - Correct answer What does treatment look like for atrial fibrillation? Ventricular Dysrhythmias - Correct answer potentially more life threatening than atrial dysrhythmias because the left ventricle pumps oxygenated blood throughout the body to perfuse vital organs and other tissues. The most common or life-threatening include: