Intraatrial conduction delay associated with an epicardial implantable cardioverter-defibrillator

The implantable cardioverter-defibrillator (ICD) has become an important mode of therapy for patients at risk for sustained ventricular arrhythmias. While the survival benefit of these devices is clear, adverse consequences are coming to light. The authors report a case of dramatic intraatrial conduction delay associated with repeated ICD shocks, resulting in pacemaker syndrome in a patient who had received both an ICD and a dual-chamber pacemaker. This and other conduction disturbances may become more common as experience with ICDs grows, and may demand adjunctive or alternative therapies to prevent frequent shocks.