Role of drugs and devices in patients at risk of sudden cardiac death

The search for effective treatment for preventing sudden cardiac death (SCD) initially started with anti-arrhythmic agents in high-risk patients, but the use of randomized controlled trials clearly led to the conclusion that an approach based on anti-arrhythmic agents is not useful, and sometimes potentially harmful (the risk of arrhythmic death was increased up to 159% in CAST study). Today the approach to SCD prevention includes considering both the setting of patients who have already presented a cardiac arrest or a malignant ventricular tachyarrhythmias (secondary prevention of SCD) and the much broader setting of primary prevention in patients at variable degrees of identifiable risk. For secondary prevention of SCD, implantable cardioverter defibrillation is now the standard of care (the risk of overall mortality may be reduced by 20-31%), and anti-arrhythmic agents, specifically amiodarone, have only a complementary role (for reducing device activations or for preventing atrial fibrillation). For primary prevention of SCD in high-risk patients, cardioverter defibrillators have nowadays specific indications in patients with left ventricular dysfunction (often in combination with cardiac resynchronization therapy), where the risk of overall mortality may be reduced by 23-54%. For the large number of subjects who have some risk of SCD, but are not identified as at high risk of SCD, a series of drugs could exert a favorable effect (beta-blockers, angiotensin-converting enzyme inhibitors, angiotensin receptor blocker agents, statins, omega-3 fatty acids and aldosterone antagonists), and for some of them evidence is emerging, from subgroup analysis, of possible SCD prevention capabilities.