Identification of patients at high risk for sudden cardiac death.

Ventricular arrhythmias play an important role in the pathophysiologic aspects of sudden cardiac death. To increase the precision in predicting sudden cardiac death, ventricular arrhythmias can be classified into 3 groups: benign, potentially malignant and malignant. Benign ventricular arrhythmias pose negligible risk of sudden cardiac death; they usually present as palpitations and are not associated with heart disease. The frequency of ventricular premature depolarizations is usually moderate and repetitive forms are usually moderate and repetitive forms are usually absent in benign ventricular arrhythmias. Potentially malignant ventricular arrhythmias pose a moderate risk of sudden cardiac death; they present as palpitations or are discovered on routine screening and are associated with significant heart disease. The frequency of ventricular premature depolarizations usually is moderate, and repetitive forms are present. It is not known whether treatment with antiarrhythmic drugs will decrease the mortality associated with potentially malignant ventricular arrhythmias. Malignant ventricular arrhythmias pose a high risk of sudden cardiac death; they may present as palpitations, syncope or cardiac arrest and have a strong association with heart disease. The frequency of ventricular premature depolarizations is moderate to high, repetitive forms are present and intermittent sustained ventricular arrhythmias occur. Patients who have malignant ventricular arrhythmias and respond to antiarrhythmic drug treatment are proven to have a much lower mortality than those who do not.