Ventricular tachycardia can be eradicated by surgicalremoval of the focus of the arrhythmia, but this operation carries considerable risk and is reserved for very serious problems.
The AV node or His bundle may be destroyed by electrical energy delivered through a catheter electrode placed close to the AV conduction system. This procedure effectively prevents the AV conduction of atrial arrhythmias. A ventricular pacemaker is then needed to prevent ventricular bradycardia. Pacemakers of another sort can also be used to interrupt repetitive paroxysms of tachycardia. Steerable electrode catheters can be used to deliver radiofrequency energy to any part of the heart responsible for the generation or continuation of tachycardias. Atrial tachycardia, AV nodal tachycardia and the abnormal pathways responsible for WPW syndrome can be successfully treated. The catheter ablation techndique is very successful and safe.
Implantable automatic cardioverterdefibrillator Serious ventricular arrhythmias (ventricular fibrillation or rapid ventricular tachycardia with hypotension) carry a mortality within 1 year of up to 40%. Antiarrhythmic drug therapy, particularly with amiodarone, may reduce the mortality. An important alternative therapy is the implantable cardioverter-defibrillator (ten), which can recognize ventricular tachycardia or fibrillation and automatically deliver a defibrillating shock to the heart. It is relatively small and is powered by lithium batteries sufficient to provide energy for about 100 shocks each of 25-30 J. The device is usually implanted behind the rectus abdominis muscle and is connected to the heart by several wires and electrodes. When an arrhythmia develops that requires treatment, the device takes about 15 s to recognize the arrhythmia and charge its capacitors. It then delivers the defibrillating discharge. The shock may be painful, particularly if the patient is still fully conscious. The use of this device has cut the sudden death rate in patients with serious ventricular arrhythmias to between 1 and 2% in the first year. However, because of its expense it is not widely available.