THE PROARRHYTHMIC POTENTIAL OF IMPLANTABLE CARDIOVERTER-DEFIBRILLATORS

The implantable cardioverter-defibrillator (ICD) is remarkably effecti ve in preventing sudden cardiac death in high-risk patients, but it al so has the capacity to provoke or worsen cardiac arrhythmias. Tachyarr hythmias or bradyarrhythmias may result from the delivery of antitachy cardia or antibradycardia therapies by tiered-therapy defibrillators. This proarrhythmia, although rarely fatal, increases the morbidity ass ociated with defibrillator therapy. Proarrhythmia is related as much t o suboptimal programming as to technical limitations of the device. Th e proarrhythmic potential of ICD therapy can be minimized by tailoring the ''electrical prescription'' according to characteristics of the c linical arrhythmia and individual ICD idiosyncrasies.