Arrhythmias in heart failure--therapeutic challenges

Electrophysiologic disorders are common at all stages of heart failure due to myocardial mechanical factors, neuroendocrine disturbances, electrolyte abnormalities, or ischemia, and also because of cardiovascular drugs. The prevalence of various forms of heart block, bradycardias, and arrhythmias in heart failure is largely unknown, as is their relationship to the etiology of the syndrome. Complex and multiform ventricular premature beats and nonsustained ventricular tachycardia are common, and their frequency is broadly related to the severity of heart failure. Supraventricular arrhythmias are also common features of the syndrome. The heart failure syndrome has an ominous prognosis. Approximately half the patients die suddenly, but the causal relationship between preexisting arrhythmias and sudden death is not known. Equally vital is knowledge of the influence of drug therapy on the arrhythmias of heart failure, but at present this is scarce and needs further study.