[Arrhythmia and anti-arrhythmia therapy as prognostic risks]

The incidence of sudden death is estimated to be 0.25%/year in the industrialized world. 30 to 40% of patients are known to be at major risk before they succumb sudden death. Etiology is usually coronary heart disease (75%), dilated and hypertensive cardiomyopathy as well as valvular disease. 75% of patients dying suddenly die from ventricular fibrillation. The most common mechanism of sudden cardiac death in heart failure is sustained ventricular tachycardia deteriorating into ventricular fibrillation, the initiating factors being single ventricular beats, ventricular pairs or nonsustained ventricular tachycardia (trigger mechanism). At least 50% of patients dying during Holter monitoring have been on antiarrhythmic treatment during the time of sudden death and this percentage is increased to 70% in patients dying from torsade de pointes ventricular tachycardia. The question that has arisen is whether suppression of such arrhythmias by antiarrhythmic agents will reduce the incidence of sudden cardiac death. Unfortunately, the patient group at highest risk - low ventricular ejection fraction and high incidence of nonsustained ventricular tachycardia episodes during 24 hour-monitoring and thus, the group most in need of arrhythmia suppression - has the lowest responder rate as well as the highest incidence of serious toxicity. Until the suppression of those arrhythmias by antiarrhythmic agents is demonstrated to improve prognosis in this patient group, routine use of antiarrhythmic agents cannot be recommended in this patient population.