MS - Ch. 26: Dysrhythmias and Conduction Problems

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 is caring for a client who is being discharged after insertion of a permanent pacemaker. Which question by the client indicates a need for clarification?

"I should ask for a handheld device search when I go through airport security." At security gates at airports, government buildings, or other secured areas, the client with a permanent pacemaker should show a pacemaker ID card and request a hand (not handheld device) search. The client should obtain and carry a physician's letter about this requirement.

The nurse is providing discharge instructions for a client with a newly implanted cardiac defibrillator. What statement made by the client indicates the need for further teaching?

"I will report if I feel lightheaded and dizzy at my next doctor's appointment." The clients with newly implanted devices are told to treat lightheadedness and dizziness as an emergency so these symptoms should be reported as an emergency. Handheld security devices should be avoided because of the electromagnetic interference. Magnetic resonance imaging studies may deactivate the device so they need to be avoided. The CPR training is recommended for family as an emergency backup.

A nurse is performing discharge teaching with a client who has an implantable cardioverter defibrillator (ICD) placed. Which client statement indicates effective teaching?

"I'll keep a log of each time my ICD discharges." The client stating that he should keep a log of all ICD discharges indicates effective teaching. This log helps the client and physician identify activities that may cause the arrhythmias that make the ICD discharge. He should also record the events right before the discharge. Clients with ICDs should avoid contact sports such as football. They must also avoid magnetic fields, which could permanently damage the ICD. Household appliances don't interfere with the ICD.

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." 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 nursing student asks the nurse to describe the difference between sinus rhythm and sinus bradycardia on the electrocardiogram strip. What is the nurse's best reply?

"The only difference is the heart rate." All characteristics of sinus bradycardia are the same as those of normal sinus rhythm except for the rate, which will be below 60 in sinus bradycardia. The P waves will be shaped differently in other dysrhythmias. The QRS is the same voltage for sinus rhythms. The P-R interval is prolonged in atrioventricular blocks.

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 knows that what PR interval presents a first-degree heart block?

0.24 seconds 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 is assigned the following client assignment on the clinical unit. For which client does the nurse anticipate cardioversion as a possible medical treatment?

A client with atrial dysrhythmias The nurse is correct to identify a client with atrial dysrhythmias as a candidate for cardioversion. The goal of cardioversion is to restore the normal pacemaker of the heart, as well as, normal conduction. A client with a myocardial infarction has tissue damage. The client with poor perfusion has circulation problems. The client with heart block has an impairment in the conduction system and may require a pacemaker.

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 nurse provides evening care for a client wearing a continuous telemetry monitor. While the nurse is giving the client a back rub, the client 's monitor alarm sounds and the nurse notes a flat line on the bedside monitor system. What is the nurse's first response?

Assess the client and monitor leads. The nurse should assess the client and monitor leads first. It is important that the nurse "treat the client, not the monitor." Ventricular asystole may often appear on the monitor when leads are displaced. The other interventions are not necessary.

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 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?

Atrial flutter 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.

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 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 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'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.

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.

The licensed practical nurse is monitoring the waveform pattern on the cardiac monitor of the client admitted following a myocardial infarction. The nurse notes that every other beat includes a premature ventricular contraction (PVC). The nurse notes which of the following in the permanent record?

Bigeminy The nurse is correct to note bigeminy on the permanent record when every other beat is a PVC. Couplets are two PVCs in a row. Multifocal PVCs originate from more than one location. R-on-T phenomenon occurs when the R wave falls on the T wave.

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 tachydysrhythmias 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.

After evaluating a client for hypertension, a health care provider orders atenolol, 50 mg P.O. daily. Which therapeutic effect should atenolol have in treating hypertension?

Decreased cardiac output and decreased systolic and diastolic blood pressure As a long-acting, selective beta1-adrenergic blocker, atenolol decreases cardiac output and systolic and diastolic blood pressure; however, like other beta-adrenergic blockers, it increases peripheral vascular resistance at rest and with exercise. Atenolol may cause bradycardia, not tachycardia.

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?

Delayed conduction, producing a prolonged PR interval 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 who has premature ventricular contractions. What sign or symptom is observed in this client?

Fluttering Premature ventricular contractions usually cause a flip-flop sensation in the chest, sometimes described as "fluttering." Associated signs and symptoms include pallor, nervousness, sweating, and faintness. Symptoms of premature ventricular contractions are not nausea, hypotension, and fever.

The nurse reads an athletic client's electrocardiogram. What finding will be consistent with a sinus bradycardia?

Heart rate of 42 beats per minute (bpm). The heart rate of 42 bpm is slow but normal when it occurs in athletes with a sinus bradycardia. The PR interval is prolonged at 0.24 seconds, indicating a heart block. The QR interval is prolonged and indicates ventricular delay. The ratio of P to QR should be 1:1 in sinus bradycardia.

Which nursing intervention must a nurse perform when administering prescribed vasopressors to a client with a cardiac dysrhythmia?

Monitor vital signs and cardiac rhythm 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.

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.

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 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 dysrhythmia is common in older clients?

Sinus bradycardia Sinus bradycardia and atrial fibrillation are common dysrhythmia'a in older clients. Sinus tachycardia, sinus arrhythmmai, and ventricular tachycardia are not common dysrhythmias in older clients.

A client has been diagnosed with atrial fibrillation and has been prescribed warfarin therapy. What should the nurse prioritize when providing health education to the client?

The need to have regular blood levels drawn One drawback of warfarin therapy is the need to have blood levels drawn on a regular basis. The medication does not need to be taken on an empty stomach, and the client does not have to sit upright. Adequate fluid intake is useful in a general way, but the need for fluids is not increased by taking warfarin.

The nurse is proving discharge instructions for a client with a new arrhythmia. Which statement should the nurse include?

Your family and friends may want to take a CPR class. Having friends and family learn to perform CPR will help the client manage the arrhythmia. Monitoring pulse rate at home also helps the client manage the condition. Antiarrhythmic medication should be taken on time. Lightheadedness and dizziness should be reported to the provider.

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?

atropine sulfate 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 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.

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.