[Challenges and opportunities for the control of ventricular arrhythmia]

Sudden cardiac death continues to be a significant health care problem. Patients with prior myocardial infarction, severe left ventricular dysfunction, and nonsustained ventricular tachycardia are at high risk for sudden death. Identification of patients prone to sudden cardiac death is still unresolved, although a number of strategies have been applied over the past two decades based on the degree of left ventricular dysfunction, frequency of spontaneous ventricular arrhythmias, and ventricular late potentials. It has been recognized that patients with myocardial infarction and depressed left ventricular function have enhanced sympathetic relative to vagal tone controlling cardiac rhythm and rate. This can be measured as depressed heart rate variability and baroreflex sensitivity. Other markers of risk have been explored, QT dispersion, post-extrasystolic heart rate turbulence and T wave alternans. Development of the automatic ICD has been one of the most spectacular achievements of the last 20 years in cardiology. The ICD reduces sudden death in postmyocardial infarction patients. Nevertheless, a clearer delineation is needed of the subsets of patients in whom an optimal medical regimen might be the best option for preventing sudden death.