Europace Advance Access originally published online on March 19, 2007
Europace 2007 9(5):270-274; doi:10.1093/europace/eum015
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VENTRICULAR ARRHYTHMIA
Comparison of ventricular arrhythmia burden, therapeutic 
nterventions, and survival, in patients < 75 and patients 
75 years of age treated with mplantable cardioverter defibrillators
1 Cardiovascular Division, University of Akdeniz, Antalya, Turkey; 2 Cardiovascular Division, University of Minnesota Medical School, Minneapolis, MN, USA; 3 Central Minnesota Heart Center, St Cloud, MN, USA
Aim: Implantable cardioverter defibrillators (ICD) reduce arrhythmic mortality in a wide range of patients with poor left ventricular (LV) function. However, whether ICD therapy is equally effective in younger and older patients remains uncertain. To address this question, we compared ICD-documented ventricular tachyarrhythmia burden in patients < 75 years of age (Group 1) and 
75 years of age (Group 2).
Methods: Data were obtained from 208 consecutive ICD-treated patients: 159 Group 1 (mean age 59 ± 12), and 49 Group 2 (mean age 79 ± 3). Demographic and clinical features including presenting arrhythmias, LV ejection fraction, and nature of heart disease were similar. Medications were comparable except that amiodarone use was more frequent in Group 2.
Results: The numbers of combined ventricular tachycardia (VT) and ventricular fibrillation (VF) episodes per month were 0.4 ± 2 and 0.3 ± 2 for groups 1 and 2, respectively (P = 0.7). Individually, VT episodes per month were 0.4 ± 2 and 0.3 ± 2 (P = 0.7) and VF episodes per month were 0.003 ± 0.01 and 0.03 ± 0.2 (P = 0.2) for the two groups, respectively. The mean duration and average cycle length of arrhythmias were 3.1 ± 20.4 s and 275 ± 119 ms in Group 1, and 6 ± 45 s and 285 ± 114 ms in Group 2 (P values, 0.6 and 0.8). The mean time between the ICD implantation and the first episode of a device-treated arrhythmia was comparable in the two groups. Thirty-six patients died during follow-up; 22 (14%) Group 1 and 14 (29%) Group 2 (P = 0.02), almost exclusively on a non-sudden cardiac basis. Thus, despite higher ultimate mortality in older patients, both the nature and characteristics of spontaneous arrhythmia recurrence, and the time to first apparently beneficial therapy, were similar during follow-up in the two groups.
Conclusion: In terms of reversing potentially life-threatening arrhythmias, the rationale for ICD therapy is comparable in older and younger individuals.
Key Words: Ventricular arrhythmia burden, Elderly, Implantable cardioverter defibrillators
* Corresponding author: Tel: +612 625 4401; fax: +612 624 4937. E-mail address: bendi001{at}umn.edu
Manuscript submitted 3 September 2006. Accepted after revision 30 December 2006.