Patients with heart failure have a high incidence of both symptomatic and asymptomatic arrhythmias.
About 10 per cent of patients have syncope or presyncope resulting from ventricular tachycardia. However Holter monitoring reveals that up to 70 per cent of patients have asymptomatic episodes of nonsustained ventricular tachycardia, which indicate a poor prognosis independent of the severity of left ventricular dysfunction.