DYS prepU
To evaluate a client's atrial depolarization, the nurse observes which part of the electrocardiogram waveform? P wave PR interval QRS complex T wave
Correct response: P wave Explanation: The P wave depicts atrial depolarization, or spread of the electrical impulse from the sinoatrial node through the atria. The PR interval represents spread of the impulse through the interatrial and internodal fibers, atrioventricular node, bundle of His, and Purkinje fibers. The QRS complex represents ventricular depolarization. The T wave depicts the relative refractory period, representing ventricular repolarization.
Two nursing students are reading EKG strips. One of the students asks the instructor what the P-R interval represents. The correct response should be which of the following? "It shows the time needed for the SA node impulse to depolarize the atria and travel through the AV node." "It shows the time it takes the AV node impulse to depolarize the atria and travel through the SA node." "It shows the time it takes the AV node impulse to depolarize the ventricles and travel through the SA node." "It shows the time it takes the AV node impulse to depolarize the septum and travel through the Purkinje fibers."
Correct response: "It shows the time needed for the SA node impulse to depolarize the atria and travel through the AV node." Explanation: The PR interval is measured from the beginning of the P wave to the beginning of the QRS complex and represents the time needed for sinus node stimulation, atrial depolarization, and conduction through the AV node before ventricular depolarization. In a normal heart the impulses do not travel backward. The PR interval does not include the time it take to travel through the Purkinje fibers.
The nurse receives a telephone call from a client with an implanted pacemaker who reports a pulse of 68 beats per minute, but the pacemaker rate is set at 72 beats per minute. What is the nurse's best response? "Please come to the clinic right away so that we may interrogate the pacemaker to see if it is malfunctioning." "Don't worry. The pacemaker's rate is often higher than the client's actual heart rate." "This is okay as long as you are not having any symptoms." "Try walking briskly for about 5 minutes to see if that gets your heart rate to increase."
Correct response: "Please come to the clinic right away so that we may interrogate the pacemaker to see if it is malfunctioning." Explanation: A client experiencing pacemaker malfunctioning may develop bradycardia as well as signs and symptoms of decreased cardiac output. The client should check the pulse daily and report immediately any sudden slowing or increasing of the pulse rate, which may indicate pacemaker malfunction. The client needs to be evaluated to avoid cardiac output problems. Walking will not keep the heart rate at a safe level.
The client asks the nurse to explain what is meant by a ventricular bigeminy cardiac rhythm. What is the best response by the nurse? "It is when the heart conduction is primarily from the atrioventricular node." "The rhythm has a normal beat, then a premature beat pattern." "The rhythm is regular but fast." "The heart rate is between 150 to 250 bpm."
Correct response: "The rhythm has a normal beat, then a premature beat pattern." Explanation: Bigeminy is a rhythm in which every other complex is a premature ventricular contraction (PVC). In trigeminy, every third complex is a PVC. The rhythm is not regular and the rate should not be 150-250 bpm.
A client with a second-degree atrioventricular heart block, Type II is admitted to the coronary care unit. How will the nurse explain the need to monitor the client's electrocardiogram (ECG) strip to the spouse? "The small box will transmit the heart rhythm to the central monitor all the time." "When your spouse needs help, an alarm will go off at the desk." "The box is recording the heart's electrical activity, and a physician will review the tracing later." "The heart's electrical activity will be recorded when the heart rate exceeds 60 beats per minute."
Correct response: "The small box will transmit the heart rhythm to the central monitor all the time." Explanation: In telemetry, a small box transmits the client's heart rhythm to the central unit for constant monitoring. Telemetry has nothing to do with the client needing help. A Holter monitor is a device that records the heart's electrical activity and for later review by a physician. The telemetry transmits the heart rhythm regardless of the client's heart rate.
After performing an ECG on an adult client, the nurse reports that the PR interval reflects normal sinus rhythm. What is the PR interval for a normal sinus rhythm? 0.05 and 0.1 seconds. 0.12 and 0.2 seconds. 0.15 and 0.3 seconds. 0.25 and 0.4 seconds.
Correct response: 0.12 and 0.2 seconds. Explanation: The PR interval is measured from the beginning of the P wave to the beginning of the QRS complex. It measures the time needed for conduction through the AV node before ventricular depolarization. The normal range in adults is 0.12 to 0.2 seconds.
The nurse is working on a telemetry unit. When the nurse is interpreting a client's heart rhythm, the nurse counts each large block on graph paper as how many seconds? 0.2 0.1 0.3 0.4
Correct response: 0.2 Explanation: Each small block on the graph paper equals 0.04 second, and five small blocks form a large block, which equals 0.2 second.
The nurse knows that what PR interval presents a first-degree heart block? 0.24 seconds 0.14 seconds 0.16 seconds 0.18 seconds
Correct response: 0.24 seconds Explanation: In adults, the normal range for the PR is 0.12 to 0.20 seconds. A PR internal of 0.24 seconds would indicate a first-degree heart block.
The nurse cares for a client with a dysrhythmia and understands that the P wave on an electrocardiogram (ECG) represents which phase of the cardiac cycle? Atrial depolarization Early ventricular repolarization Ventricular depolarization Ventricular repolarization
Correct response: Atrial depolarization Explanation: The P wave represents atrial depolarization. The QRS complex represents ventricular depolarization. The T wave represents ventricular repolarization. The ST segment represents early ventricular repolarization, and lasts from the end of the QRS complex to the beginning of the T wave.
A client presents to the emergency department via ambulance with a heart rate of 210 beats/minute and a sawtooth waveform pattern per cardiac monitor. The nurse is most correct to alert the medical team of the presence of a client with which disorder? Asystole Premature ventricular contraction Atrial flutter Ventricular fibrillation
Correct response: Atrial flutter Explanation: Atrial flutter is a disorder in which a single atrial impulse outside the SA node causes the atria to contract at an exceedingly rapid rate. The atrioventricular (AV) node conducts only some impulses to the ventricle, resulting in a ventricular rate slower than the atrial rate, thus forming a sawtooth pattern on the heart monitor. Asystole is the absence of cardiac function and can indicate death. Premature ventricular contraction indicates an early electric impulse and does not necessarily produce an exceedingly rapid heart rate. Ventricular fibrillation is the inefficient quivering of the ventricles and indicative of a dying heart.
The nurse is monitoring a patient in the postanesthesia care unit (PACU) following a coronary artery bypass graft, observing a regular ventricular rate of 82 beats/min and "sawtooth" P waves with an atrial rate of approximately 300 beat/min. How does the nurse interpret this rhythm? Atrial fibrillation Atrial flutter Ventricular tachycardia Ventricular fibrillation
Correct response: Atrial flutter Explanation: Atrial flutter occurs because of a conduction defect in the atrium and causes a rapid, regular atrial rate, usually between 250 and 400 bpm and results in P waves that are saw-toothed. Because the atrial rate is faster than the AV node can conduct, not all atrial impulses are conducted into the ventricle, causing a therapeutic block at the AV node. This is an important feature of this dysrhythmia. If all atrial impulses were conducted to the ventricle, the ventricular rate would also be 250 to 400 bpm, which would result in ventricular fibrillation, a life-threatening dysrhythmia. Atrial flutter often occurs in patients with chronic obstructive pulmonary disease, pulmonary hypertension, valvular disease, and thyrotoxicosis, as well as following open heart surgery and repair of congenital cardiac defects (Fuster, Walsh et al., 2011)
A client's electrocardiogram (ECG) tracing reveals a atrial rate between 250 and 400, with saw-toothed P waves. The nurse correctly identifies this dysrhythmia as Atrial flutter Atrial fibrillation Ventricular fibrillation Ventricular tachycardia
Correct response: Atrial flutter Explanation: The nurse correctly identifies the electrocardiogram (ECG) tracing as atrial flutter. Atrial flutter occurs in the atrium and creates impulses at a regular atrial rate between 250 and 400 times per minute. The P waves are saw-toothed in appearance. Atrial fibrillation causes a rapid, disorganized, and uncoordinated twitching of atrial musculature. The atrial rate is 300 to 600, and the ventricular rate is usually 120 to 200 in untreated atrial fibrillation. There are no discernible P waves. Ventricular fibrillation is a rapid, disorganized ventricular rhythm that causes ineffective quivering of the ventricles. The ventricular rate is greater than 300 per minute and extremely irregular, without a specific pattern. The QRS shape and duration is irregular, undulating waves without recognizable QRS complexes. Ventricular tachycardia is defined as three or more PVCs in a row, occurring at a rate exceeding 100 beats per minute.
A nurse is caring for a client who has been admitted to have a cardioverter defibrillator implanted. The nurse knows that implanted cardioverter defibrillators are used in which clients? Clients with recurrent life-threatening bradycardias Clients with sinus tachycardia Clients with ventricular bradycardia Clients with recurrent life-threatening tachydysrhythmias
Correct response: Clients with recurrent life-threatening tachydysrhythmias Explanation: The automatic implanted cardioverter defibrillator (AICD) is an internal electrical device used for selected clients with recurrent life-threatening tachydysrhythmias. Therefore, options A, B, and C are incorrect.
A patient converts from normal sinus rhythm at 80 beats/min to atrial fibrillation with a ventricular response at 166 beats/min. Blood pressure is 162/74. Respiratory rate is 20/min with normal chest expansion and clear lungs bilaterally. IV heparin and Cardizem are given. The nurse caring for the patient understands that the primary goal of treatment is what? Decrease SA node conduction Control ventricular rate Improve oxygenation Maintain anticoagulation
Correct response: Control ventricular rate Explanation: Treatment for atrial fibrillation is to terminate the rhythm or to control ventricular rate. A rapid ventricular response reduces the time for ventricular filling, resulting in a smaller stroke volume. Control of rhythm is the initial treatment of choice followed by anticoagulation with heparin and then Coumadin.
The nurse is assessing a patient with a probable diagnosis of first-degree AV block. The nurse is aware that this dysrhythmia is evident on an ECG strip by what indication? Variable heart rate, usually fewer than 90 bpm Irregular rhythm Delayed conduction, producing a prolonged PR interval P waves hidden within the QRS complex
Correct response: Delayed conduction, producing a prolonged PR interval Explanation: First-degree AV block may occur without an underlying pathophysiology, or it can result from medications or conditions that increase parasympathetic tone. It occurs when atrial conduction is delayed through the AV node, resulting in a prolonged PR interval.
The nurse is caring for a client with atrial fibrillation. What procedure would be recommended if drug therapies did not control the dysrhythmia? Defibrillation Maze procedure Pacemaker implantation Elective cardioversion
Correct response: Elective cardioversion Explanation: Atrial fibrillation also is treated with elective cardioversion or digitalis if the ventricular rate is not too slow. Defibrillation is used for a ventricular problem. A Maze procedure is only a distractor for this question. Pacemakers are implanted for bradycardia.
Which nursing intervention must a nurse perform when administering prescribed vasopressors to a client with a cardiac dysrhythmia? Keep the client flat for one hour after administration Administer every five minutes during cardiac resuscitation Document heart rate before and after administration Monitor vital signs and cardiac rhythm
Correct response: Monitor vital signs and cardiac rhythm Explanation: The nurse should monitor the client's vital signs and cardiac rhythm for effectiveness of the medication and for side effects and should always have emergency life support equipment available when caring for an acutely ill client. The side effects of vasopressor drugs are hypertension, dysrhythmias, pallor, and oliguria. It is not necessary to place a client flat during or after vasopressor administration. When administering cholinergic antagonists, documentation of the heart rate is necessary.
The emergency department nurse is caring for a patient who has gone into cardiac arrest. The nurse is performing external defibrillation. Which of the following is a vital step in the procedure? Gel pads are placed anteriorly, over the apex, and posteriorly for better conduction. No one is to be touching the patient at the time shock is delivered. Continue to ventilate the patient via endotracheal tube during the procedure. Second shock cannot be administered for 1 minute to allow recharging.
Correct response: No one is to be touching the patient at the time shock is delivered. Explanation: In external defibrillation, both paddles may be placed on the front of the chest, which is the standard paddle placement. Whether using pads or paddles, the nurse must observe two safety measures. First, maintain good contact between the pads or paddles and the patient's skin to prevent leaking. Second, ensure that no one is in contact with the patient or with anything that is touching the patient when the defibrillator is discharged, to minimize the chance that electrical current will be conducted to anyone other than the patient. Ventilation should be stopped during defibrillation.
A healthy adult client is seeing a health care provider for an annual physical examination. While the nurse is taking the client's vital signs, the client states, "Occasionally, my heart skips a beat." The nurse believes that the client is experiencing what condition? Premature atrial complex Atrial flutter Sinus tachycardia Ventricular fibrillation
Correct response: Premature atrial complex Explanation: A premature atrial complex (PAC) is a single ECG complex that occurs when an electrical impulse starts in the atrium before the next normal impulse of the sinus node.
Which ECG waveform characterizes conduction of an electrical impulse through the left ventricle? P wave QRS complex PR interval QT interval
Correct response: QRS complex Explanation: The QRS complex represents ventricular depolarization. The P wave is an ECG characteristic reflecting conduction of an electrical impulse through the atria. The PR interval is a component of an ECG tracing reflecting conduction of an electrical impulse through the AV node. The QT interval is an ECG characteristic reflecting the time from ventricular depolarization to repolarization.
A patient comes to the emergency department with reports of chest pain after using cocaine. The nurse assesses the patient and obtains vital signs with results as follows: blood pressure 140/92, heart rate 128, respiratory rate 26, and an oxygen saturation of 98%. What rhythm on the monitor does the nurse anticipate viewing? Sinus bradycardia Ventricular tachycardia Normal sinus rhythm Sinus tachycardia
Correct response: Sinus tachycardia Explanation: Sinus tachycardia occurs when the sinus node creates an impulse at a faster-than-normal rate. Causes include medications that stimulate the sympathetic response (e.g., catecholamines, aminophylline, atropine), stimulants (e.g., caffeine, nicotine), and illicit drugs (e.g., amphetamines, cocaine, Ecstasy).
The nurse documents that a client is having a normal sinus rhythm. What characteristics of this rhythm has the nurse assessed? Heart rate between 60 and 150 beats per minute. Impulse travels to the atrioventricular (AV) node in 0.15 to 0.5 seconds. The ventricles depolarize in 0.5 seconds or less. The sinoatrial (SA) node initiates the impulse.
Correct response: The sinoatrial (SA) node initiates the impulse. Explanation: The characteristics of normal sinus rhythm are heart rate between 60 and 100 beats per minute; the SA node initiates the impulse; the impulse travels to the AV node in 0.12 to 0.2 seconds; the ventricles depolarize in 0.12 seconds or less; and each impulse occurs regularly.
A patient who had a myocardial infarction is experiencing severe chest pain and alerts the nurse. The nurse begins the assessment but suddenly the patient becomes unresponsive, no pulse, with the monitor showing a rapid, disorganized ventricular rhythm. What does the nurse interpret this rhythm to be? Ventricular tachycardia Atrial fibrillation Third-degree heart block Ventricular fibrillation
Correct response: Ventricular fibrillation Explanation: The most common dysrhythmia in patients with cardiac arrest is ventricular fibrillation, which is a rapid, disorganized ventricular rhythm that causes ineffective quivering of the ventricles. No atrial activity is seen on the ECG. The most common cause of ventricular fibrillation is coronary artery disease and resulting acute myocardial infarction. Ventricular fibrillation is always characterized by the absence of an audible heartbeat, a palpable pulse, and respirations.
The nurse is caring for a client with second-degree atrioventricular block, Type I with symptomatic bradycardia. What is the most likely medication the nurse will administer? nadolol diltiazem atropine sulfate atenolol
Correct response: atropine sulfate Explanation: Atropine blocks acetylcholine at parasympathetic neuroeffector sites and blocks vagal stimulation. The client will be treated with an anticholinergic that blocks the effects of the vagal nerve. Atenolol and nadolol are beta blockers that are used for chest pain, myocardial infarction, and hypertension. Diltiazem is a calcium channel blocker used to treat angina or slow the heart rate.
A client with dilated cardiomyopathy is having frequent episodes of ventricular fibrillation. What medical treatment does the nurse anticipate the client will have to terminate the episode of ventricular fibrillation? internal cardioverter defibrillator insertion pacemaker insertion radiofrequency ablation electrophysiological study
Correct response: internal cardioverter defibrillator insertion Explanation: The implantable cardioverter defibrillator (ICD) is an electronic device that detects and terminates life-threatening episodes of tachycardia or fibrillation, especially those that are ventricular in origin. Patients at high risk of ventricular tachycardia (VT) or ventricular fibrillation who would benefit from an ICD are those who have survived sudden cardiac death syndrome, which usually is caused by ventricular fibrillation, or who have experienced spontaneous, symptomatic VT (syncope secondary to VT) not due to a reversible cause (called a secondary prevention intervention). Radiofrequency ablation destroys a small area of heart tissue that is causing rapid and irregular heartbeats, and is used to reduce pain. A cardiac electrophysiology study is an invasive procedure that tests the electrical conduction system of the heart to assess the electrical activity and conduction pathways of the heart.
A client is diagnosed with a dysrhythmia at a rate slower than 60 beats/minute with a regular interval between 0.12 and 0.20 seconds. What type of dysrhythmia does the client have? sinus bradycardia atrial bradycardia heart block none
Correct response: sinus bradycardia Explanation: Sinus bradycardia is a dysrhythmia that proceeds normally through the conduction pathway but at a slower than usual (less than 60 beats/minute) rate.
