Various arrhythmias are found in different clinical situations, such as premature complexes in health individuals, supraventricular tachyarrhythmias in patients with Wolff-Parkinson-White syndrome, atrioventricular block, and ventricular fibrillation in cardiopathic conditions, especially in patients with ischemic disease. Topics discussed in this volume include: malignant ventricular arrhythmias; sudden death; automatic implantable cardioverter defibrillators; syncope; current indications for pacing therapy; radiofrequency catheter ablation; flutter; and atrial fibrillation.