Role of 123-Iobenguane Myocardial Scintigraphy in Predicting Short Term Left Ventricular Functional Recovery and Indication to ICD Implantation after Coronary Revascularization: A Work Hypothesis

Abstract

AIM: 123I-Iobenguane myocardial scintigraphy (MIBG), which identifies sympathetic nervous system dysfunction, has been shown to be an effective predictor of sudden cardiac mortality in patient with congestive heart failure (CHF) and could be a useful instrument to early identify adverse clinical events. Methods: patients with CHF, a New York Heart Association classification (NYHA) of II or III and a left ventricular ejection fraction (LVEF) ≤ 35% were eligible for cardiac defibrillator (ICD) placement under current LVEF-based criteria in the guidelines. All patients listed for ICD underwent a MIBG before the implantation, in order to assess the prognostic value of an early cardiac MIBG to predict appropriate ICD indication. Results: 11 patients (100% males; age 65.1±8.9 years) with mean LVEF 29.1±4.9% entered the study. All patients had a coronary artery disease (CAD) treated by coronary artery bypass graft (CABG) in six cases, by a percutaneous coronary angioplasty (PTCA) in seven and both procedures in two patients. In all subjects the heart/mediastinum (H/M) ratio was calculated <1.6 (mean 1.27±0.13) and the mean wash-out rate (WR) was 4.88±3.80%. The LVEF improved at follow-up from 29.1±4.9% to 30.9±6.2% and in three patients proved to be >35%. An ICD was implanted in six patients (54.5%). The sensitivity, specificity, postive and negative predictive value of an H/M ratio ≤ 1.25 at MIBG was calculated in 75%, 75%; 85,7%, 60%. Conclusion: MIBG might be a promising method for excluding a 3-month left ventricular functional recovery.