CH 28: Disorders of Cardiac Conduction and Rhythm
The client is diagnosed with a respiratory sinus dysrhythmia. Which electrocardiogram pattern correlates to this finding?
An increase in heart rate with inspiration and slowing with expiration
A nurse is monitoring a client with a consistent and regular heart rate of 128 beats/min. Which physiologic alteration would be consistent with this finding?
Decrease in ventricular filling time and blood pressure Consistently elevated heart rates initially cause blood pressure and cardiac output to increase. However, ventricular filling time, cardiac output, and blood pressure eventually decrease.
The nurse assesses the electrocardiogram for depolarization of the atria. What portion of the ECG will the nurse be assessing?
P wave above the baseline
Which client will the nurse prioritize to assess first?
The client with sinus arrest
Which cardiac drug classification decreases sympathetic outflow to the heart and is the is the cornerstone of therapy for catecholaminergic polymorphic ventricular tachycardia (CPVT)?
Beta-adrenergic blockers
A monitored hospitalized client with a pulmonary embolism has been in atrial fibrillation (AF) for 4 days. The nurse observes the rhythm spontaneously convert to a normal sinus rhythm. Which form of AF is this?
paroxysmal
A client is seen in the emergency department complaining of chest discomfort, productive cough, and a fever of over 101°F (38.3°C) for 3 days. The nurse performs an electrocardiogram and observes a rate of 110 beats per minute (bpm) with a normal P wave and a PR interval of 0.12 second preceding each QRS complex. What does the nurse determine the rhythm to be?
sinus tachycardia
A client who will be undergoing a Holter monitor examination would be given which instruction?
"Keep a diary of your activities and symptoms throughout the examination."
A client arrives at the emergency room with dizziness and a near syncopal episode. Vital signs include a heart rate of 46 beats/min and blood pressure of 86/50 mm Hg. The cardiac monitors show regular rhythm as above. The client states the health care provider has been running blood work to rule out hypothyroidism. Based on the rhythm, what does the nurse report the client has?
A symptomatic bradyarrhythmia
A nurse is monitoring a client with a consistent and regular heart rate of 128 beats/min. Which physiologic alteration would be consistent with this finding?
Decrease in ventricular filling time and blood pressure
Nursing students who are studying for their upcoming cardiac exam are discussing how the heart could possibly continue to beat once removed from the body. One of the students explains that this phenomenon is directly related to automaticity. What is automaticity?
Inherent spontaneous action-potential The heart has four inherent properties essential in the development and conduction of cardiac rhythms. The property of automaticity is the ability of certain cells in the myocardium to automatically or spontaneously initiate an electrical impulse called an action potential. In a normally functioning heart the rate is controlled by the sinoatrial (SA) node.
A client's electrocardiogram rhythm shows normal sinus rhythm followed by a complex of six premature ventricular contractions with a return to normal sinus rhythm. Which interpretation should the nurse document in the medical record?
Nonsustained ventricular tachycardia Ventricular tachycardia can be sustained, lasting more than 30 seconds and requiring intervention, or it can be nonsustained and stop spontaneously.
A client experiencing a sinus arrest would demonstrate which symptom or finding?
Prolonged periods of asystole demonstrated on an electrocardiogram
The nurse is interpreting an electrocardiogram of a 65-year-old woman. Which should the nurse recognize as representing ventricular depolarization?
QRS complex
What is the correct sequence for the generation of electrical impulses in the heart causing ventricular contraction?
SA node, AV node, bundle of His, bundle branches, and Purkinje fibers
A nurse educator is teaching a group of nurses at a long-term care facility about atrial fibrillation in light of its prevalence in older adults. Which statement by the nurses would the educator most want to correct?
The contraction of the ventricles and the atria can range from 400-600 beats per minute."
A nurse is caring for a client with an average heart rate of 56 beats/min. The client has no adverse symptoms associated with this heart rate and is receiving no treatment. Which activity modification should the nurse suggest to avoid further slowing of the heart rate?
"Avoid bearing down while having a bowel movement." Bearing down during a bowel movement stimulates the vagus nerve and results in a slowing of the heart rate. Vagal stimulation as well as some medications decreases the firing rate of the sinoatrial node and conduction through the atrioventricular node to cause a decrease in heart rate.
Which antiarrhythmic medication works by blunting the effect of sympathetic nervous system stimulation on the heart?
Beta-blockers, such as metoprolol
A 20-year-old college student, with no past medical history, arrives at the emergency room complaining of severe palpitations and dizziness that started this morning following a night of studying. The student is very upset that this is happening because the final exams are the following day. The cardiac monitor shows a heart rate of 110, regular rhythm with occasional premature ventricular complexes. The nurse explains to the student that this can happen in healthy hearts and is usually caused by stimulation of:
sympathetic nervous system
A client with a history of angina presents with uncharacteristic chest pain. The subsequent electrocardiogram (ECG) reveals T-wave elevation. This finding suggests an abnormality with which aspects of the cardiac cycle?
ventricular repolarization The T wave on an ECG corresponds to ventricular repolarization. Atrial depolarization is represented by the P wave and ventricular depolarization by the QRS complex. The isoelectric or zero line between the P wave and the Q wave represents depolarization of the atrioventricular node, bundle branches, and Purkinje system.
A client who will be undergoing a Holter monitor examination would be given which instruction?
"Keep a diary of your activities and symptoms throughout the examination." While the client is wearing a Holter monitor (usually 48 hours), he or she will be instructed to maintain a diary of activities and symptoms so that the recorded electrocardiographic reading can be correlated with the diary events. The other options are not instructions appropriate for a Holter monitor examination.
Which antiarrhythmic medication works by blunting the effect of sympathetic nervous system stimulation on the heart?
Beta-blockers, such as metoprolol Class II drugs (e.g., propranolol, metoprolol, atenolol, timolol, and sotalol) are beta-adrenergic-blocking drugs that act by blunting the effect of sympathetic nervous system stimulation on the heart, thereby inhibiting calcium channel opening. These drugs decrease automaticity by depressing phase 4 of the action potential. They also decrease heart rate and cardiac contractility. These medications are effective for treating supraventricular dysrhythmias and tachydysrhythmias by counteracting the action on the arrhythmogenesis of catecholamines.
A client is seen in the emergency department complaining of chest discomfort, productive cough, and a fever of over 101°F (38.3°C) for 3 days. The nurse performs an electrocardiogram and observes a rate of 110 beats per minute (bpm) with a normal P wave and a PR interval of 0.12 second preceding each QRS complex. What does the nurse determine the rhythm to be?
sinus tachycardia Sinus tachycardia is a heart rate >100 bpm that has its origin in the sinoatrial node. A normal P wave and PR interval should precede each QRS complex. The mechanism of sinus tachycardia is enhanced automaticity, related to sympathetic stimulation or withdrawal of vagal tone. Sinus tachycardia is a normal response during any increase in metabolic activity such as fever, stress, and anxiety.
