¶ … Implantable Cardiac Devices Heart disease remains one of the leading causes of death in the United States but there are a number of different implantable cardiac devices (ICDs) available today, including pacemakers, defibrillators and cardiac resynchronization devices, that can help people with heart disease or failure go on to lead normal lives by regulating their heart beats through a series of electric shocks. To determine the facts about these devices, this paper provides a review of the literature to explain the respective indications for these devices as well as their differences. Finally, a summary of the research and important findings concerning these implantable cardiac devices are provided in the conclusion.

Review and Discussion

Indications for each of the following: Pacemaker, ICD (defibrillator) & Cardiac Resynchronization Devices

Pacemaker. According to Gregoratos et al. (1), this type of ICD is indicated for patients suffering from abnormalities of atrioventricular (AV) conduction which may be asymptomatic; however, in some cases, patients will experience serious symptoms due to ventricular arrhythmias, bradycardia, or both). Consequently, Gregoratos and his associates (1) report that indications for pacemaker implants are related to the presence or absence of bradycardia-attributable symptoms. In addition, Gregoratos et al. (1) note that physician discretion concerning permanent pacing is required in cases of AV block following valve surgery. In sum, the American Heart Association (2) reports that pacemakers are indicated for:

Patients whose hearts beat too slow or fast;

Patients who hearts do not beat regularly; and,

Patients who suffer from a block in the heart's electrical pathways.

ICD (defibrillator). According to Perry (3), ICDs are the...

The 2012 ACCF/AHA/HRS Guidelines for Implantable Defibrillator and Cardiac Resynchronization Therapy for Cardiac Rhythm Abnormalities (4) reports that these devices are indicated for patients in the following circumstances:
Level of Evidence: A With left ventricular ejection fraction (LVEF) ? 35% due to prior myocardial infarction (MI) who are at least 40 days post-MI and are in New York Heart Association (NYHA) Functional Class II or III;

With LV dysfunction due to prior MI who are at least 40 days post-MI, have an LVEF ? 30%, and are in NYHA Functional Class I; and,

Who are survivors of cardiac arrest due to ventricular fibrillation (VF) or hemodynamically unstable sustained ventricular tachycardia (VT) after evaluation to define the cause of the event and to exclude any completely reversible causes.

Level of Evidence: B

With nonischemic dilated cardiomyopathy (DCM) who have an LVEF ? 35% and who are in NYHA Functional Class II or III;

With nonsustained VT due to prior MI, LVEF < 40%, and inducible VF or sustained VT at electrophysiological study;

With structural heart disease and spontaneous sustained VT, whether hemodynamically stable or unstable;

With syncope of undetermined origin with clinically relevant, hemodynamically significant sustained VT or VF induced at electrophysiological study;

Assuming patients are on chronic, optimal medical therapy and have a reasonable expectation of survival with good functional status for > 1 year (4).

Cardiac Resynchronization Devices

According to the American Heart Association (5), cardiac resynchronization therapy (CRT) is used to treat various arrhythmias;…