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Infarct size and recurrence of ventricular arrhythmias after defibrillator implantation
J De Sutter1, R Tavernier, C Van de Wiele
1Department of Cardiology, University Hospital Gent, Belgium. johan.desutter@rug.ac.be
Insights
Infarct size predicts ventricular arrhythmia recurrence and hospitalizations after implantable cardioverter defibrillator (ICD) implantation in coronary artery disease (CAD) patients. Larger infarcts identified by perfusion imaging indicate higher risk for these adverse events.
Area of Science:
- Cardiology
- Medical Imaging
- Electrophysiology
Background:
- Implantable cardioverter defibrillators (ICDs) are crucial for managing life-threatening ventricular arrhythmias (VA) in coronary artery disease (CAD) patients.
- Infarct size is a known predictor of mortality post-ICD implantation.
- The predictive value of infarct size for VA recurrence and hospitalization after ICD implantation remains unclear.
Purpose of the Study:
- To assess if infarct size, measured by perfusion imaging, can identify patients at higher risk of VA recurrence and hospitalization after ICD implantation.
- To evaluate the relationship between infarct size and specific adverse events, including electrical storm.
Main Methods:
- A study of 56 patients with CAD and life-threatening VA undergoing ICD implantation.
- Thallium-201 stress-redistribution perfusion imaging was performed before ICD implantation to calculate infarct size using a defect score (DS).
- Follow-up assessed documented VA episodes, appropriate ICD therapies, and cardiac hospitalizations for electrical storm, heart failure, or angina.
Main Results:
- After a mean follow-up of 470 days, 39% of patients experienced VA recurrence.
- Independent predictors for VA recurrence included presenting with ventricular tachycardia (VT) and a defect score (DS) ≥ 20.
- Patients with DS ≥ 20 had significantly more cardiac hospitalizations, particularly for electrical storm.
Conclusions:
- The extent of myocardial scarring, quantified by perfusion imaging's defect score, is an independent predictor of VA recurrence and cardiac hospitalization post-ICD implantation in CAD patients.
- Perfusion imaging can stratify patients into high- and low-risk groups for adverse events after ICD implantation.
- A defect score of 20 or higher identifies patients at increased risk for VA recurrence and electrical storm requiring hospitalization.
Abstract:
Infarct size as determined by perfusion imaging is an independent predictor of mortality after implantable cardioverter defibrillator (ICD) implantation in patients with coronary artery disease (CAD) and life-threatening ventricular arrhythmias (VA). However, its value as a predictor of VA recurrence and hospitalisation after ICD implantation is unknown. Therefore, the objective of this study was to evaluate whether infarct size as determined by perfusion imaging can help to identify patients who are at high risk for recurrence of VA and hospitalisation after ICD implantation. We studied 56 patients with CAD and life-threatening VA. Before ICD implantation, all patients underwent a uniform study protocol including a thallium-201 stress-redistribution perfusion study. A defect score as a measurement of infarct size was calculated using a 17-segment 5-point scoring system. Study endpoints during follow-up were documented episodes of appropriate anti-tachycardia pacing and/or shocks for VA and cardiac hospitalisation for electrical storm (defined as three or more appropriate ICD interventions within 24 h), heart failure or angina. After a mean follow-up of 470+/-308 days, 22 patients (39%) had recurrences of VA. In univariate analysis, predictors for recurrence were: (a) ventricular tachycardia (VT) as the initial presenting arrhythmia (86% vs 59% for patients without ICD therapy, P=0.04), (b) treatment with beta-blockers (36% vs 68%, P=0.03) and (c) a defect score (DS) > or = 20 (64% vs 32%, P=0.03). In multivariate analysis, VT as the presenting arrhythmia (chi2=5.51, P=0.02) and a DS > or = 20 (chi2=4.22, P=0.04) remained independent predictors. Cardiac hospitalisation was more frequent in patients with a DS > or = 20 (44% vs 13% for patients with DS < 20, P=0.015) and this was particularly due to more frequent hospitalisations for electrical storm (24% vs 3% for patients with DS < 20, P=0.037). The extent of scarring determined by perfusion imaging can separate patients with CAD into high- and low-risk groups for recurrence of VA and cardiac hospitalisation after ICD implantation.