Patients with nonischemic dilated cardiomyopathy (DCM) presenting with syncope have a one-year sudden death rate as high as 45%. As a result, the evaluation and treatment of these patients has been necessarily aggressive, including electrophysiologic studies (EPS), which can diagnose life-threatening ventricular arrhythmias as well as bradyarrhythmias due to sinus node dysfunction and heart block. However, as compared to patients with ischemic heart disease, EPS in patients with DCM is notoriously insensitive and may under diagnose these life-threatening conditions. Because of this, some investigators have suggested defibrillator therapy for patients with syncope, dilated cardiomyopathy and negative EPS in spite of an absence of data to support this approach. A recently published series from the University of Michigan seems to support this approach.

The study, published in the Journal of the American College of Cardiology (JACC 1999;33:1964-1970), prospectively evaluated a small number (n=14) patients with DCM presenting with syncope and having negative EPS. Seven of 14 (50%) were documented as having appropriate ICD therapy for ventricular tachyarrhythmias at a follow-up of 24±13 months. In comparison, 8 of 19 patients from a control population with DCM presenting with documented cardiac arrest had appropriate ICD therapy for ventricular tachyarrhythmias. The difference between the groups was not significant, suggesting there might be a similar benefit to ICD therapy in both populations.

Comparison between the 2 groups also demonstrated that the time to first appropriate shock was 10±14 months in the syncope group as compared to 48±47 months in the cardiac arrest group (p=0.06). Of note, no patients in the syncope group with left ventricular ejection fractions >35% had appropriate shocks. In addition, all 6 patients with NYHA class III heart failure had appropriate shocks.

Other issues regarding ICD therapy were also addressed. The 4 of the 14 patients with syncope died of progressive heart failure, a comparable overall survival to the cardiac arrest group. Seven of 14 (50%) received inappropriate ICD therapy for atrial fibrillation. In addition, only 1 of the 14 patients in the syncope group received a significant amount of bradycardia pacing, suggesting little use of the pacemaker functions for these devices.

While the data presented in the manuscript suggests that ICD therapy is appropriate for patients with DCM and syncope of indeterminate cause, a careful evaluation of the results is prudent and necessary. The study size was quite small and as such the results can be misleading. Clearly, the study alone cannot be justification for ICD implantation in this population. Larger multicenter trials will be necessary to definitively evaluate this potential indication for ICD therapy. While these results must be approached with caution, they do offer cause for optimism in a population with a high mortality, the majority of which arises from sudden cardiac death.

Patients with nonischemic dilated cardiomyopathy (DCM) presenting with syncope have a one-year sudden death rate as high as 45%. As a result, the evaluation and treatment of these patients has been necessarily aggressive, including electrophysiologic studies (EPS), which can diagnose life-threatening ventricular arrhythmias as well as bradyarrhythmias due to sinus node dysfunction and heart block. However, as compared to patients with ischemic heart disease, EPS in patients with DCM is notoriously insensitive and may under diagnose these life-threatening conditions. Because of this, some investigators have suggested defibrillator therapy for patients with syncope, dilated cardiomyopathy and negative EPS in spite of an absence of data to support this approach. A recently published series from the University of Michigan seems to support this approach.

The study, published in the Journal of the American College of Cardiology (JACC 1999;33:1964-1970), prospectively evaluated a small number (n=14) patients with DCM presenting with syncope and having negative EPS. Seven of 14 (50%) were documented as having appropriate ICD therapy for ventricular tachyarrhythmias at a follow-up of 24±13 months. In comparison, 8 of 19 patients from a control population with DCM presenting with documented cardiac arrest had appropriate ICD therapy for ventricular tachyarrhythmias. The difference between the groups was not significant, suggesting there might be a similar benefit to ICD therapy in both populations.

Comparison between the 2 groups also demonstrated that the time to first appropriate shock was 10±14 months in the syncope group as compared to 48±47 months in the cardiac arrest group (p=0.06). Of note, no patients in the syncope group with left ventricular ejection fractions >35% had appropriate shocks. In addition, all 6 patients with NYHA class III heart failure had appropriate shocks.

Other issues regarding ICD therapy were also addressed. The 4 of the 14 patients with syncope died of progressive heart failure, a comparable overall survival to the cardiac arrest group. Seven of 14 (50%) received inappropriate ICD therapy for atrial fibrillation. In addition, only 1 of the 14 patients in the syncope group received a significant amount of bradycardia pacing, suggesting little use of the pacemaker functions for these devices.

While the data presented in the manuscript suggests that ICD therapy is appropriate for patients with DCM and syncope of indeterminate cause, a careful evaluation of the results is prudent and necessary. The study size was quite small and as such the results can be misleading. Clearly, the study alone cannot be justification for ICD implantation in this population. Larger multicenter trials will be necessary to definitively evaluate this potential indication for ICD therapy. While these results must be approached with caution, they do offer cause for optimism in a population with a high mortality, the majority of which arises from sudden cardiac death.

Staten Island Office Relocated 

Effective October 1, the outpatient offices of the Arrhythmia Service in Staten Island have been relocated to 11 Ralph Place, Suite 201. The new office phone number at this site is (718) 981-0396. The Arrhythmia Service offers outpatient consultative services as well as pacemaker and defibrillator follow-up from this new office.

A full range of inpatient services including consultations, diagnostic electrophysiology studies, radiofrequency catheter ablations, tilt table testing and pacemaker and defibrillator implantations continue to be available in Staten Island through the Arrhythmia Service at the St.Vincent's Campus of the Sisters of Charity Hospital Center, 345 Bard Avenue.

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