In this report we briefly describe a patient with a dual chamber implantable cardioverter defibrillator in the context of severe ischemic cardiomyopathy who developed persistent atrial fibrillation. After appropriate anticoagulation and under mild sedation the patient was successfully cardioverted to sinus rhythm after a programmed ventricular synchronized defibrillation using his defibrillator. Programmed internal cardioversion of persistent atrial fibrillation in patients who have an implantable cardioverter defibillator without atrial defibrillation capabilities could be an effective and safe therapeutic option. Unlike external electrical cardioversion, this strategy does not interfere with the implantable cardioverter defibrillator, is more effective, and obviates the need of general anesthesia. This strategy should be further evaluated in clinical trials.
Case reportA 73-year-old Caucasian man presented to the outpatient clinic for evaluation of a recent episode of implantable cardioverter defibrillator (ICD) shock therapy. He had been implanted a dual chamber ICD (Model 1871, Vitality DR, Guidant Corp.) for secondary prevention due to resuscitated sustained ventricular tachycardia, not related to a correctable cause, in the context of severe ischemic cardiomyopathy. His past medical history was significant for coronary artery disease (old myocardial infarction and coronary artery bypass surgery), hypertension, diabetes mellitus, and hyperlipidemia. The patient's medications included metoprolol, ramipril, glimepiride, aspirin, and simvastatin.Interrogation of the stored events revealed that the recent episode of shock was an appropriate defibrillation (21 J biphasic shock) of ventricular arrhythmia (cycle length 330 ms) that classified into the VF zone. However, electrocardiographic examination and evaluation of the current electrograms revealed the presence of atrial fibrillation (AF) with a ventricular response of 84 beats/min (Figures 1, 2). The duration of AF was unknown while no event of inappropriate shock attributed to AF was detected. All hematological and biochemical studies including thyroid function tests were within normal limits. An echocardiographic study showed left ventricular (LV) dilatation with global systolic dysfunction (ejection fraction: 0.20) and evidence of increased filling pressures. The left atrial (LA) anteroposterior diameter was 41 mm and the LA diastolic volume 36 ml.Taking into account the severely impaired left ventricular systolic function as well as the absence of LA enlargement
