Abstract 20231: Effect of Coronary Ischemic Burden on Therapies for Ventricular Tachyarrhythmia (VT) and Death in Patients with an Implantable Cardioverter Defibrillator (ICD)
Background: The effect of coronary ischemic burden on arrhythmic outcomes and death in ICD recipients has not been fully defined. We examined patients in the prospective Ontario ICD Database registry (Feb 2007-Mar 2009), to determine if coronary disease burden is associated with increased mortality and appropriate therapy from an ICD.
Methods: We followed 3165 ICD recipients (65±11 yrs, 81% men) prospectively for occurrence of appropriate device therapies, either antitachycardia pacing (ATP) or shock for VT, or death. We examined outcomes in patients who had high (presence of reversible ischemia by myocardial perfusion imaging, CCS class 2–4 angina, ≥50% stenosis left main, or ≥70% stenosis in ≥2 vessels) or intermediate (≥70% stenosis in 1 vessel, prior PCI or CABG, and not high risk) ischemic burden, compared to those with low (no reversible ischemia, no coronary stenosis, and no angina) ischemic burden.
Results: Ischemic burden was high (n=1406, 44.4%), intermediate (n=1059, 33.5%), or low (n=700, 22.1%). In total, 208 deaths, 231 appropriate device shocks and 576 appropriate therapies (ATP or shock) occurred during 2,407 person-years follow-up. High ischemic burden was a significant univariate predictor of increased mortality (hazard ratio [HR] 2.48, 95%CI; 1.63–3.79, p<0.001), and reduced appropriate therapy (HR 0.74, 95%CI; 0.60–0.92, p=0.006), but was not associated with appropriate shock (HR 0.94, 95%CI; 0.67–1.32, p=0.72). In multivariable analysis adjusted for age, sex, heart failure, atrial fibrillation, diabetes, hypertension, smoking, cerebrovascular disease, medications, hemoglobin, sodium, creatinine, QRS duration, and LVEF, high ischemic burden remained a significant predictor of mortality with HR 1.62 (95%CI; 1.00–2.62, p=0.048). However, the association of high ischemic burden with the occurrence of appropriate therapy (HR 0.77, 95%CI; 0.59–1.01, p=0.056) was attenuated, and the association with appropriate shock (HR 0.97, 95%CI; 0.63–1.49, p=0.89) remained non-significant. Intermediate ischemic burden was not associated with arrhythmic endpoints or mortality.
Conclusions: Greater coronary ischemic burden was associated with increased risk of death, but not appropriate ATP or device shock in ICD recipients.
- © 2010 by American Heart Association, Inc.