Question 1

A patient is undergoing ventricular pacing via a transvenous pacing lead.The nurse notes a pacing artifact,but it is not followed by a QRS on the electrocardiogram (ECG)monitoring.Which nursing intervention may correct this situation?

Accepted Answer

The patient is experiencing "loss of capture," which most often can be attributed either to displacement of the pacing electrode or to an increase in threshold as a result of drugs,metabolic disorders,electrolyte imbalances,or fibrosis or myocardial ischemia at the site of electrode placement.In many cases,increasing the output milliamperes (mA)may elicit capture.For transvenous leads,repositioning the patient to the left side may improve lead contact and restore capture.

Question 2

What parameter must be assessed frequently in the patient with an intraaortic balloon in place?

Accepted Answer

One complication of intraaortic balloon support is lower extremity ischemia resulting from occlusion of the femoral artery by the catheter itself or by emboli caused by thrombus formation on the balloon.Although ischemic complications have decreased with sheathless insertion techniques and the introduction of smaller balloon catheters,evaluation of peripheral circulation remains an important nursing assessment.The presence and quality of peripheral pulses distal to the catheter insertion site are assessed frequently along with color,temperature,and capillary refill of the involved extremity.Signs of diminished perfusion must be reported immediately.

Question 3

Which mechanism is responsible for the augmentation of coronary arterial blood flow and increased myocardial oxygen supply seen with the intraaortic balloon pump?

Accepted Answer

The blood volume in the aorta below the level of the balloon is propelled forward toward the peripheral vascular system,which may enhance renal perfusion.Subsequently,the deflation of the balloon just before the opening of the aortic valve creates a potential space or vacuum in the aorta,toward which blood flows unimpeded during ventricular ejection.This decreased resistance to left ventricular ejection,or decreased afterload,facilitates ventricular emptying and reduces myocardial oxygen demands.

Question 4

A patient has an implantable cardioverter defibrillator (ICD)for chronic ventricular tachydysrhythmias.What action should the nurse take when the patient's rhythm deteriorates to ventricular fibrillation?

Accepted Answer

If the dysrhythmia deteriorates into ventricular fibrillation,the implantable cardioverter defibrillator is programmed to defibrillate at a higher energy.If the dysrhythmia terminates spontaneously,the device will not discharge.

Question 5

Which hemodynamic alteration is the most common cause of a decrease in cardiac output in the postoperative cardiovascular patient?

Accepted Answer

In most patients,reduced preload is the cause of low postoperative cardiac output.To enhance preload,volume may be administered in the form of crystalloid,colloid,or packed red blood cells.

Question 6

A patient is connected to an external temporary pulse generator.What does the sensitivity control regulate?

Accepted Answer

The sensitivity control regulates the ability of the pacemaker to detect the heart's intrinsic electrical activity.Sensitivity is measured in millivolts (mV)and determines the size of the intracardiac signal that the generator will recognize.

Question 7

Which dosage of dopamine results in stimulation of beta1 receptors and increased myocardial contractility?

Accepted Answer

At low dosages of 1 to 2 mcg/kg/min,dopamine stimulates dopaminergic receptors,causing renal and mesenteric vasodilation.Moderate dosages result in stimulation of beta1 receptors to increase myocardial contractility and improve cardiac output.At dosages greater than 10 mg/kg/min,dopamine predominantly stimulates alpha receptors,resulting in vasoconstriction that often negates both the beta-adrenergic and dopaminergic effects.

Question 8

What is the rationale for administrating a fibrinolytic agent to a patient experiencing acute ST-elevation myocardial infarction (STEMI)?

Accepted Answer

The administration of a fibrinolytic agent results in the lysis of the acute thrombus,thus recanalizing,or opening,the obstructed coronary artery and restoring blood flow to the affected tissue.After perfusion is restored,adjunctive measures are taken to prevent further clot formation and reocclusion.

Question 9

A patient is admitted with left-sided heart failure and a blood pressure of 220/118 mm Hg.Which drug will be most effective in decreasing the blood pressure and reducing afterload?

Accepted Answer

Sodium nitroprusside (Nipride)is a potent,rapidly acting venous and arterial vasodilator,particularly suitable for rapid reduction of blood pressure in hypertensive emergencies and perioperatively.It also is effective for afterload reduction in the setting of severe heart failure.The drug is administered by continuous intravenous infusion,with the dosage titrated to maintain the desired blood pressure and systemic vascular resistance.

Question 10

What is the most common complication of fibrinolytic therapy?

Accepted Answer

The most common complication related to thrombolysis is bleeding.

Question 11

Adenosine is an antidysrhythmic agent that is given primarily what reason?

Accepted Answer

Adenosine occurs endogenously in the body as a building block of adenosine triphosphate (ATP).Given in intravenous boluses,adenosine slows conduction through the atrioventricular (AV)node,causing transient AV block.It is used clinically to convert supraventricular tachycardias and to facilitate the differential diagnosis of rapid dysrhythmias.

Question 12

A nurse is providing care to a patient on fibrinolytic therapy.Which of the following statements from the patient warrants further assessment and intervention by the nurse?

Accepted Answer

The nurse must continually monitor for clinical manifestations of bleeding.Mild gingival bleeding and oozing around venipuncture sites are common and not causes for concern.However,severe lower back pain and ecchymoses are suggestive of retroperitoneal bleeding.If serious bleeding occurs,all fibrinolytic heparin therapies are discontinued,and volume expanders,coagulation factors,or both are administered.

Question 13

Which of the following statements regarding beta-blockers is correct?

Accepted Answer

Knowledge of the effects of adrenergic-receptor stimulation allows for anticipation of not only the therapeutic responses brought about by beta-blockade but also the potential adverse effects of these agents.For example,bronchospasm can be precipitated by noncardioselective beta-blockers in a patient with chronic obstructive pulmonary disease secondary to blocking the effects of betA₂ receptors in the lungs.

Question 14

Through what mechanism does enalapril decrease blood pressure?

Accepted Answer

Enalapril is an angiotensin-converting enzyme (ACE)inhibitors that produces vasodilation by blocking the conversion of angiotensin I to angiotensin II.Because angiotensin is a potent vasoconstrictor,limiting its production decreases peripheral vascular resistance.In contrast to the direct vasodilators and nifedipine,ACE inhibitors do not cause reflex tachycardia or induce sodium and water retention.

Question 15

Which finding is a reliable indicator of reperfusion after fibrinolytic therapy?

Accepted Answer

Initially,when there is reperfusion,ischemic chest pain ceases abruptly as blood flow is restored.Another reliable indicator of reperfusion is the appearance of various "reperfusion" dysrhythmias.Premature ventricular contractions,bradycardias,heart block,ventricular tachycardia,and (rarely)ventricular fibrillation may occur.

Question 16

How does a percutaneous transluminal coronary angioplasty (PTCA)improve blood flow?

Accepted Answer

Percutaneous transluminal coronary angioplasty involves the use of a balloon-tipped catheter that,when advanced through an atherosclerotic lesion (atheroma),can be inflated intermittently for the purpose of dilating the stenotic area and improving blood flow through it.The high balloon-inflation pressure stretches the vessel wall,fractures the plaque,and enlarges the vessel lumen.

Question 17

A transvenous pacemaker is inserted through the right subclavian vein and threaded into the right ventricle.The pacemaker is placed on demand at a rate of 70.What is the three letter code for this pacing mode?

Accepted Answer

The original code is based on three categories,each represented by a letter.The first letter refers to the cardiac chamber that is paced.The second letter designates which chamber is sensed,and the third letter indicates the pacemaker's response to the sensed event.A VVI pacemaker paces the ventricle when the pacemaker fails to sense an intrinsic ventricular depolarization.

Question 18

Noninvasive emergency pacing is best achieved via the use of which type of temporary pacing?

Accepted Answer

Transcutaneous cardiac pacing involves the use of two large skin electrodes,one placed anteriorly and the other posteriorly on the chest,connected to an external pulse generator.It is a rapid,noninvasive procedure that nurses can perform in the emergency setting and is recommended for the treatment of symptomatic bradycardia.

Question 19

The possibility of microshock when handling a temporary pacemaker can be minimized by which intervention?

Accepted Answer

The possibility of "microshock" can be minimized by wearing gloves when handling the pacing wires and by proper insulation of terminal pins of pacing wires when they are not in use.The latter can be accomplished either by using caps provided by the manufacturer or by improvising with a plastic syringe or section of disposable rubber glove.The wires are to be taped securely to the patient's chest to prevent accidental electrode displacement.

Question 20

When analyzing the electocardiogram (ECG)strip of the patient with a pacemaker,the nurse notices there is a spike before each QRS complex.What is this phenomenon indicative of?

Accepted Answer

The pacing artifact is the spike that is seen on the electrocardiographic tracing as the pacing stimulus is delivered to the heart.A P wave is visible after the pacing artifact if the atrium is being paced.Similarly,a QRS complex follows a ventricular pacing artifact.With dual-chamber pacing,a pacing artifact precedes both the P wave and the QRS complex.

Quiz 15: Cardiovascular Therapeutic Management

A patient is undergoing ventricular pacing via a transvenous pacing lead.The nurse notes a pacing artifact,but it is not followed by a QRS on the electrocardiogram (ECG) monitoring.Which nursing intervention may correct this situation?