Prediction and prevention of sudden cardiac death in heart failure

The 12 month SCD rate was almost 5% increasing to nearly 8% at two years. 5 The annual mortality in dilated cardiomyopathy (DCM) has been reported to range from 10-50% from referral centres, with up to 28% of deaths being classified as sudden. 6 w2 More recent studies of DCM patients on optimal medical treatment have reported considerably lower mortality rates of around 7% at two years. 7 Although patients with DCM were excluded from many early ICD studies, a number of recent randomised trials have included such patients and will provide crucial outcome data to guide patient management. 8, 9 The recently reported sudden cardiac death in heart failure trial (SCD-HeFT) demonstrated similar relative risk reductions in mortality in ischaemic and non-ischaemic patients (21% and 27%, respectively) suggesting that the use of ICDs in patients with severely depressed left ventricular (LV) function was beneficial regardless of the aetiology of heart failure. 9 The results were less conclusive in the cardiomyopathy trial (CAT) of patients with DCM: the study was terminated early with no reduction in all cause mortality at two and four years follow up, although the study was underpowered. 7 New York Heart Association class Mortality rates increase the higher the New York Heart Association (NYHA) class, but the proportion of patients dying suddenly (rather than from progressive pump failure) is highest among those with less severe heart failure (NYHA class II or III) (fig 3). ACE, angiotensin converting enzyme; ACS, acute coronary syndrome; BNP, B type natriuretic peptide; BP, blood pressure; CRT, cardiac resynchronisation therapy; EPS, electrophysiological study; HRV, heart rate variability; ICD, implantable cardioverter-defibrillator; LV, left ventricular; LVEF, left ventricular ejection fraction; MI, myocardial infarction; NSVT, non-sustained ventricular tachycardia; NYHA, New York Heart Association; SAECG, signal averaged ECG; SCD, sudden cardiac death; TWA, T wave alternans; VF, ventricular fibrillation; VT, ventricular tachycardia.