Cardiac arrhythmias are very common in the setting of
heart failure, with atrial and ventricular arrhythmias often present in the same patient. The risk and the benefit of antiarrhythmic
therapies are still a matter of debate. Class I
antiarrhythmic drugs should be avoided in patients with
heart failure, cardiac
ischemia, or previous
myocardial infarction. Beta-blocker agents reduce morbidity and decrease mortality in patients suffering from moderate to severe
heart failure.
Amiodarone may be beneficial in patients with advanced
heart failure and increased resting heart rates. This class III
drug may be effective to suppress episodes of
atrial fibrillation but can also be beneficial in reducing ventricular response by slowing atrioventricular conduction during chronic
atrial fibrillation.
Implantable cardioverter-defibrillators (ICDs) markedly reduce
sudden cardiac death in patients with
ventricular tachycardia or
ventricular fibrillation. In patients with advanced
heart failure, however, the ICD may not markedly extend survival. Recently analyzed data from the Canadian
Implantable Defibrillator Study (CIDS), Antiarrhythmics Versus
Implantable Defibrillators (AVID) registry, Multicenter Unsustained
Tachycardia Trial (MUSTT), and Multicenter Automatic
Defibrillator Implantation Trial (MADIT) have consistently shown that it is the sickest patient who benefits the most from ICD
therapy. Patients with markedly depressed ejection fraction (<30%), poor New York Heart Association functional class, and advanced age have been identified as those who really need ICD
therapy. Studies of
implantable cardioverter-defibrillators in patients with moderate to severe
heart failure have been launched and will provide necessary answers to the question of whether a reduction in
sudden death will translate into a reduction of all-cause mortality. For patients resuscitated from sustained
ventricular tachycardia or
ventricular fibrillation, an ICD or, in some cases,
amiodarone should be considered.
Catheter or surgical ablation can be considered for selected patients with
ventricular tachycardia.