Ventricular tachycardia and fibrillation in normal hearts.

Although ventricular tachyarrhythmias usually occur in the setting of definable heart disease, up to 15% of ventricular tachycardias and 10% of ventricular fibrillation occur in patients without heart disease. Of the various clinical entities comprising these idiopathic ventricular tachyarrhythmias, a few well-defined clinical syndromes have been described, such as idiopathic right ventricular outflow tract tachycardia, idiopathic left posterior fascicular ventricular tachycardia, and the right bundle branch block and ST segment elevation syndrome of idiopathic ventricular fibrillation. Many advances have been made in the past few years in our understanding and treatment of idiopathic ventricular tachyarrhythmias, and these advances are the subject of this review.