Chapter 26: Caring for Clients with Cardiac Dysrhythmias

The nursing student asks the nurse how to tell the difference between ventricular tachycardia and ventricular fibrillation on an electrocardiogram strip. What is the best response?

"Ventricular fibrillation is irregular with undulating waves and no QRS complex. Ventricular tachycardia is usually regular and fast, with wide QRS complexes." Ventricular fibrillation is irregular with undulating waves and no QRS complex, while ventricular tachycardia is usually regular and fast with wide QRS complexes. The rhythms look different on the electrocardiogram strip. The QRS is wide and bizarre or undefined in ventricular fibrillation. The P-R interval is not present in the ventricular dysrhythmias.

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?

0.12 and 0.2 seconds. 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, caring for a client who develops dizziness and a second-degree heart block, Mobitz Type 1. What will be the initial nursing intervention?

Administer an IV bolus of atropine. Atropine 0.5 mg given rapidly as an intravenous bolus every 3 to 5 minutes to a maximum total dose of 3.0 mg is the medication of choice in treating symptomatic second-degree heart block. The client may need to be sent to the cardiac catheterization lab for a temporary pacemaker, but atropine should be tried first. Cardioversion is used to treat a fast heart rate. Reviewing the medication record will not help the client initially.

A client is brought to the ED and determined to be experiencing symptomatic sinus bradycardia. The nurse caring for this client is aware the medication of choice for treatment of this dysrhythmia is the administration of atropine. What guidelines will the nurse follow when administering atropine?

Administer atropine 0.5 mg as an IV bolus every 3 to 5 minutes to a maximum of 3.0 mg. Atropine 0.5 mg given rapidly as an intravenous (IV) bolus every 3 to 5 minutes to a maximum total dose of 3.0 mg is the medication of choice in treating symptomatic sinus bradycardia. By this guideline, the other listed options are inappropriate.

A client is scheduled for an elective electrical cardioversion for a sustained dysrhythmia lasting for 24 hours. Which intervention is necessary for the nurse to implement prior to the procedure?

Administer moderate sedation IV and analgesic medication as prescribed. Before an elective cardioversion, the client should receive moderate sedation IV as well as an analgesic medication or anesthesia. In contrast, in emergent situations, the client may not be premedicated. Digoxin is usually withheld for 48 hours before cardioversion to ensure the resumption of sinus rhythm with normal conduction. If the cardioversion is elective and the dysrhythmia has lasted longer than 48 hours, anticoagulation performed for a few weeks before cardioversion may be indicated. The client is instructed not to eat or drink for at least 4 hours before the procedure.

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 flutter 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).

Which dysrhythmia has an atrial rate between 250 and 400, with saw-toothed P waves?

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 shape. Atrial fibrillation causes a rapid, disorganized, and uncoordinated twitching of atrial musculature. Ventricular fibrillation is a rapid, disorganized ventricular rhythm that causes ineffective quivering of the ventricles. 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's experiencing sinus bradycardia with a pulse rate of 40 beats/minute. The client's blood pressure is 80/50 mm Hg and the client reports dizziness. Which medication does the nurse anticipate administering to treat bradycardia?

Atropine I.V. push atropine is used to treat symptomatic bradycardia. Dobutamine is used to treat heart failure and low cardiac output. Amiodarone is used to treat ventricular fibrillation and unstable ventricular tachycardia. Lidocaine is used to treat ventricular ectopy, ventricular tachycardia, and ventricular fibrillation.

The nurse is providing discharge instructions to a client after a permanent pacemaker insertion. Which safety precaution will the nurse communicate to the client?

Avoid undergoing magnetic resonance imaging (MRI). A client with a pacemaker should avoid undergoing an MRI because the magnet could disrupt pacemaker function and cause injury to the client. Disruption is less likely to occur with newer microwave ovens. The client must avoid vigorous arm and shoulder movement only for the first 6 weeks after pacemaker implantation. Airport metal detectors don't harm pacemakers; however, the client should notify airport security guards that he has a pacemaker because its metal casing and programming magnet could trigger the metal detector.

A nurse provides morning care for a client in the intensive care unit (ICU). Suddenly, the bedside monitor shows ventricular fibrillation and the client becomes unresponsive. After calling for assistance, what action should the nurse take next?

Begin cardiopulmonary resuscitation In the acute care setting, when ventricular fibrillation is noted, the nurse should call for assistance and defibrillate the client as soon as possible. If defibrillation is not readily available, CPR is begun until the client can be defibrillated, followed by advanced cardiovascular life support (ACLS) intervention, which includes endotracheal intubation and administration of epinephrine. Electrical cardioversion is not indicated for a client in ventricular fibrillation.

The nurse in the intensive care unit (ICU) hears an alarm sound in the patient's room. Arriving in the room, the patient is unresponsive, without a pulse, and a flat line on the monitor. What is the first action by the nurse?

Begin cardiopulmonary resuscitation (CPR) Commonly called flatline, ventricular asystole (Fig. 26-19) is characterized by absent QRS complexes confirmed in two different leads, although P waves may be apparent for a short duration. There is no heartbeat, no palpable pulse, and no respiration. Without immediate treatment, ventricular asystole is fatal. Ventricular asystole is treated the same as PEA, focusing on high-quality CPR with minimal interruptions and identifying underlying and contributing factors.

A client has returned to the cardiac care unit after having a permanent pacemaker implantation. For which potential complication should the nurse most closely assess this client?

Bleeding at the implantation site Bleeding, hematomas, local infections, perforation of the myocardium, and tachycardia are complications of pacemaker implantations. The nurse should monitor for chest pain and bradycardia, but bleeding is a more common immediate complication. Malignant hyperthermia is unlikely because it is a response to anesthesia administration.

The nurse is caring for a client who has just undergone catheter ablation therapy. The nurse in the step-down unit should prioritize what assessment?

Cardiac monitoring Following catheter ablation therapy, the client is closely monitored to ensure the dysrhythmia does not reemerge. This is a priority over monitoring of LOC and pain, although these are valid and important assessments. Ablation does not involve the implantation of a device.

The nurse is analyzing a rhythm strip. What component of the ECG corresponds to the resting state of the client's heart?

T wave The T wave specifically represents ventricular muscle depolarization, also referred to as the resting state. Ventricular muscle depolarization does not result in the P wave, U wave, or QRS complex.

The nurse is observing the monitor of a patient with a first-degree atrioventricular (AV) block. What is the nurse aware characterizes this block?

Delayed conduction, producing a prolonged PR interval First-degree AV block occurs when all the atrial impulses are conducted through the AV node into the ventricles at a rate slower than normal. Thus the PR interval is prolonged (>0.20 seconds).

The nurse witnesses a client experiencing ventricular fibrillation. What is the nurse's priority action?

Defibrillation Advanced cardiac life support recommends early defibrillation for witnessed ventricular fibrillation. A cardioversion is used with a client who has a pulse. Atropine is used for bradycardia and dobutamine is an inotropic medication used to increased cardiac output.

The nurse recognizes which as being true of cardioversion?

Defibrillator should be set to deliver a shock during the QRS complex. Cardioversion involves the delivery of a "timed" electrical current. The defibrillator is set to synchronize with the ECG and deliver the impulse during the QRS complex. The synchronization prevents the discharge from occurring during the vulnerable period of repolarization (T wave), which could result in VT or ventricular fibrillation.

A client has been living with an internal, fixed-rate pacemaker. When checking the client's readings on a cardiac monitor the nurse notices an absence of spikes. What should the nurse do?

Double-check the monitoring equipment. One of the reasons for lack of pacemaker spikes is faulty monitoring equipment.

The nurse and the other members of the team are caring for a client who converted to ventricular fibrillation (VF). The client was defibrillated unsuccessfully and the client remains in VF. The nurse should anticipate the administration of what medication?

Epinephrine 1 mg IV push Epinephrine should be given as soon as possible after the first unsuccessful defibrillation and then every 3 to 5 minutes. Antiarrhythmic medications such as amiodarone and lidocaine are given if ventricular dysrhythmia persists.

A cardiac care nurse is caring for a client who is experiencing positive chronotropy. What effect should the nurse prepare for?

Increased heart rate Stimulation of the sympathetic system increases heart rate. This phenomenon is known as positive chronotropy. It does not influence dysrhythmias.

The nurse is assessing a client who had a pacemaker implanted 4 weeks ago. During the client's most recent follow-up appointment, the nurse identifies data that suggest the client may be socially isolated and depressed. What nursing diagnosis is suggested by these data?

Ineffective coping related to pacemaker implantation Depression and isolation may be symptoms of ineffective coping with the implantation. These psychosocial symptoms are not necessarily indicative of issues related to knowledge or decisions. Further data would be needed to determine a spiritual component to the client's challenges.

A patient is 2 days postoperative after having a permanent pacemaker inserted. The nurse observes that the patient is having continuous hiccups as the patient states, "I thought this was normal." What does the nurse understand is occurring with this patient?

Lead wire dislodgement Phrenic nerve, diaphragmatic (hiccupping may be a sign), or skeletal muscle stimulation may occur if the lead is dislocated or if the delivered energy (mA) is set high. The occurrence of this complication is avoided by testing during device implantation.

The nurse is writing a plan of care for a client with a cardiac dysrhythmia. What would be the priority goal for the client?

Maintain adequate cardiac output. For client safety, the most appropriate goal is to maintain cardiac output to prevent worsening complications as a result of decreased cardiac output. A resting rate of less than 70 bpm is not appropriate for every client. Chest pain is more closely associated with acute coronary syndrome than with dysrhythmias. Nursing actions cannot normally influence the physical structure of the heart.

A client is undergoing preoperative teaching before his cardiac surgery and the nurse is aware that a temporary pacemaker will be placed later that day. What is the nurse's responsibility in the care of the client's pacemaker?

Monitoring for pacemaker malfunction or battery failure Monitoring for pacemaker malfunctioning and battery failure is a nursing responsibility. The other listed actions are physician responsibilities.

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?

No one is to be touching the patient at the time shock is delivered. 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 client with an ICD calls his cardiologist's office and talks to the nurse. He is concerned because he feels he is being defibrillated too often. The nurse tells the client to come to the office to be evaluated because the nurse knows that the most frequent complication of ICD therapy is what?

Oversensing of dysrhythmias Inappropriate delivery of ICD therapy, usually due to oversensing of atrial and sinus tachycardias with a rapid ventricular rate response, is the most frequent complication of ICD. Infections, failure to capture, and premature battery failure are less common.

To evaluate a client's atrial depolarization, the nurse observes which part of the electrocardiogram waveform?

P wave 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.

The nurse is assessing vital signs in a patient with a permanent pacemaker. What should the nurse document about the pacemaker?

Pacer rate After a permanent pacemaker is inserted, the patient's heart rate and rhythm are monitored by ECG.

The nursing educator is presenting a case study of an adult client who has abnormal ventricular depolarization. This pathologic change would be most evident in what component of the ECG?

QRS complex The QRS complex represents the depolarization of the ventricles and, as such, the electrical activity of that ventricle.

Which ECG waveform characterizes conduction of an electrical impulse through the left ventricle?

QRS complex 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.

The nurse is caring for a client who has had an ECG. The nurse notes that leads I, II, and III differ from one another on the cardiac rhythm strip. How should the nurse best respond?

Recognize that the view of the electrical current changes in relation to the lead placement. Each lead offers a different reference point to view the electrical activity of the heart. The lead displays the configuration of electrical activity of the heart. Differences between leads are not necessarily attributable to equipment malfunction or dysrhythmias.

The nurse is caring for a client with refractory atrial fibrillation who underwent the maze procedure several months ago. The nurse reviews the result of the client's most recent cardiac imaging, which notes the presence of scarring on the atria. How should the nurse best interpret this finding?

Recognize this as a therapeutic goal of the procedure. The maze procedure is an open heart surgical procedure for refractory atrial fibrillation. Small transmural incisions are made throughout the atria. The resulting formation of scar tissue prevents reentry conduction of the electrical impulse. Consequently, scar formation would constitute a successful procedure. There is no indication for repeating the procedure or implanting a pacemaker.

A nurse is providing health education to a client scheduled for cryoablation therapy. The nurse should describe what aspect of this treatment?

Using a cooled probe to eliminate the source of dysrhythmia Cryoablation therapy involves using a cooled probe to create a small scar on the endocardium to eliminate the source of the dysrhythmias. Endocardium resection involves peeling away a specified area of the endocardium. Electrical ablation involves using shocks to eliminate the area causing the dysrhythmias. Radio frequency ablation uses high-frequency sound waves to destroy the area causing the dysrhythmias.

A patient with hypertension has a newly diagnosed atrial fibrillation. What medication does the nurse anticipate administering to prevent the complication of atrial thrombi?

Warfarin Because atrial function may be impaired for several weeks after cardioversion, warfarin is indicated for at least 4 weeks after the procedure. Patients may be given amiodarone, flecainide, ibutilide, propafenone, or sotalol prior to cardioversion to enhance the success of cardioversion and prevent relapse of the atrial fibrillation (Fuster, Rydén et al., 2011).

The nurse is caring for a client who is displaying a third-degree AV block on the EKG monitor. What is the priority nursing intervention for the client?

alerting the healthcare provider of the third-degree heart block The client may experience low cardiac output with third-degree AV block. The healthcare provider needs to intervene to preserve the client's cardiac output. Monitoring the blood pressure and heart rate are important, but not a priority. The identification of a code status during a heart block is not appropriate. IV fluids are not helpful if the heart is not perfusing.

A client tells the nurse "my heart is skipping beats again; I'm having palpitations." After completing a physical assessment, the nurse concludes the client is experiencing occasional premature atrial complexes (PACs). The nurse should instruct the client to

avoid caffeinated beverages. If premature atrial complexes (PACs) are infrequent, no medical interventions are necessary. Causes of PACs include caffeine, alcohol, nicotine, stretched atrial myocardium (e.g., as in hypervolemia), anxiety, hypokalemia (low potassium level), hypermetabolic states (e.g., with pregnancy), or atrial ischemia, injury, or infarction. The nurse should instruct the client to avoid caffeinated beverages.

A client reports light-headedness, chest pain, and shortness of breath. They physician orders tests to ascertain what is causing the client's problems. Which test is used to identify cardiac rhythms?

electrocardiogram An electrocardiogram is used to identify normal and abnormal cardiac rhythms.

The nurse assesses a client with a heart rate of 120 beats per minute. What are the known causes of sinus tachycardia?

hypovolemia The causes of sinus tachycardia include physiologic or psychological stress (acute blood loss, anemia, shock, hypovolemia, fever, and exercise). Vagal stimulation, hypothyroidism, and digoxin will cause a sinus bradycardia.

A client asks the nurse what causes the heart to be an effective pump. The nurse informs the client that this is due to the:

inherent rhythmicity of cardiac muscle tissue. Cardiac rhythm refers to the pattern (or pace) of the heartbeat. The conduction system of the heart and the inherent rhythmicity of cardiac muscle produce a rhythm pattern, which greatly influences the heart's ability to pump blood effectively.

The nurse analyzes a 6-second electrocardiogram (ECG) tracing. The P waves and QRS complexes are regular. The PR interval is 0.18 seconds long, and the QRS complexes are 0.08 seconds long. The heart rate is calculated at 70 bpm. The nurse correctly identifies this rhythm as

normal sinus rhythm. The electrocardiogram (ECG) tracing shows normal sinus rhythm (NSR). NSR has the following characteristics: ventricular and atrial rate: 60 to 100 beats per minute (bpm) in the adult; ventricular and atrial rhythm: regular; and QRS shape and duration: usually normal, but may be regularly abnormal; P wave: normal and consistent shape, always in front of the QRS; PR interval: consistent interval between 0.12 and 0.20 seconds and P:QRS ratio: 1:1.

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 Sinus bradycardia is a dysrhythmia that proceeds normally through the conduction pathway but at a slower than usual (less than 60 beats/minute) rate.