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Does the abnormal signal-averaged electrocardiogram predict future appropriate therapy in patients with implantable
Majid Haghjoo1, Arash Arya, Mozhgan Parsaie
1Department of Pacemaker and Electrophysiology, Rajaie Cardiovascular Medical and Research Center, School of Medicine, Iran University of Medical Sciences, P.O. Box 15745-1341, Tehran 1996911151, Iran. majid.haghjoo@gmail.com
Insights
The signal-averaged electrocardiogram (SAECG) generally does not predict appropriate implantable cardioverter-defibrillator (ICD) therapy for ventricular tachyarrhythmias. However, SAECG may be useful in specific patient subgroups, such as those with coronary artery disease and monomorphic ventricular tachycardia.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- Signal-averaged electrocardiogram (SAECG) has prognostic value post-myocardial infarction and in nonischemic cardiomyopathy.
- The predictive capability of SAECG for appropriate implantable cardioverter-defibrillator (ICD) therapy remains under-investigated.
Purpose of the Study:
- To determine if SAECG can identify patients with ICDs who will receive appropriate therapy for ventricular tachyarrhythmias.
- To evaluate the role of SAECG in predicting appropriate ICD therapy.
Main Methods:
- Prospective study of 83 consecutive ICD patients with recorded SAECGs between August 2002 and August 2004.
- Follow-up in an outpatient ICD clinic with collection and analysis of interrogated electrograms.
Main Results:
- Over 9 months, 32% of patients received appropriate ICD therapy.
- No significant difference in SAECG findings between patients with and without appropriate ICD therapy (P = .41).
- Left ventricular ejection fraction was the sole predictor of appropriate therapy (P = .02), except in a subgroup with coronary artery disease and monomorphic ventricular tachycardia where abnormal SAECG was also a predictor (P = .02).
Conclusions:
- SAECG does not generally predict ventricular tachyarrhythmia recurrence or appropriate ICD therapy.
- SAECG findings should not typically influence decisions regarding ICD implantation.
- An exception exists for patients with coronary artery disease and monomorphic ventricular tachycardia, where SAECG may have predictive value.
Background:
Several studies have documented the prognostic significance of the signal-averaged electrocardiogram (SAECG) both after myocardial infarction and nonischemic cardiomyopathy. However, whether the SAECG can identify patients with implantable cardioverter-defibrillator (ICD) who receive appropriate therapy has not been hitherto completely investigated.
Methods:
Between August 2002 and August 2004, 83 consecutive ICD patients who had had SAECGs recorded were enrolled in this study. All patients were followed up in the outpatient ICD clinic, and interrogated electrograms were collected.
Results:
Over 9.0 +/- 2.8 months of follow-up, 27 (32%) patients had appropriate ICD therapy for ventricular tachycardia or fibrillation; 15 (55.6%) patients had abnormal; and the remaining 12 (44.4%) had normal SAECGs. Of the 56 patients with no appropriate therapy, 27 (48.2%) and 29 (51.8%) patients had abnormal and normal SAECGs, respectively. There were no statistically significant differences between the 2 groups in SAECG findings (P = .41). A Cox regression analysis showed that the left ventricular ejection fraction was the only predictor of appropriate therapy (P = .02). Subgroup analysis of the patients with coronary artery disease and spontaneous monomorphic ventricular tachycardia indicated that left ventricular ejection fraction (P = .03) and abnormal SAECG (P = .02) were predictors of appropriate therapy.
Conclusions:
Our data demonstrate that except for the subgroup of patients with coronary artery disease presenting with monomorphic ventricular tachycardia, the SAECG did not predict ventricular tachyarrhythmia recurrence and, hence, appropriate ICD therapy. Thus, SAECG findings should generally not be a factor in decision for ICD implantation.
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