Clinical significance and management of arrhythmias in the heart failure patient.

Congestive heart failure (CHF) is a common manifestation of hypertension, coronary artery disease, and dilated cardiomyopathy. The Framingham study showed that the incidence of CHF increases twofold with each decade of age. The presence of CHF increases the age-adjusted death rate 5.5-fold for women and 8-fold for men, and it increases the sudden death rate 5.5-fold in both men and women. Ventricular arrhythmias are a common accompaniment of CHF. Ambient ventricular premature complexes occur in most of these patients, and nearly one half of all CHF patients will have nonsustained ventricular tachycardia on a 24-h ambulatory electrocardiographic (Holter) recording. In addition, low left ventricular ejection fraction (LVEF) predicts inducible sustained ventricular tachycardia on electrophysiologic study. One-year mortality increases with worsening New York Heart Association (NYHA) Functional Class and decreasing LVEF. As the overall yearly mortality increases, the proportion of patients who die of arrhythmias decreases. The precise mechanism of death is frequently difficult to assess. Nonarrhythmic causes of death include CHF, shock, electromechanical dissociation, and myocardial rupture. Arrhythmic causes are most commonly due to ventricular tachycardia/ventricular fibrillation. Bradycardic events (asystole or heart block) are usually associated with progressively worsening CHF. Noncardiac causes that may confuse classification include pulmonary embolus and cerebrovascular accident. Because many patients have ischemic heart disease as the etiology of the CHF, a recurrent ischemic event can likewise make classification difficult. Overall, approximately one half of all deaths in CHF are arrhythmic and one half are nonarrhythmic.