Scintigraphic perfusion abnormality and fragmented qrs predicts cardiac death in patients with non-ischemic left ventricular dysfunction

Background and aim: Recently, importance of fragmented QRS (fQRS) is recognized in patients with various cardiovascular diseases. Several reports showed that fQRS reflects myocardial scar and predicts outcome in patients with non-ischemic cardiomyopathy. Furthermore, some reports showed that Impaired myocardial perfusion on myocardial perfusion imaging (MPI) reflects myocardial fibrosis and is an important variable in predicting outcomes in patients with dilated cardiomyopathy. The aim of this study is to evaluate relationship between myocardial perfusion imaging (MPI) and fQRS and whether combination of MPI, and fQRS predicting outcome among patients with non-ischemic left ventricular dysfunction (LVD). Methods: We performed 201Tl myocardial scintigraphy and evaluated clinical parameters in 104 patients (61.5±14 years, 78 men) with LVEF<50% on echocardiography. fQRS included ≥ 1 notches in the R or S wave in at least 2 contiguous leads corresponding to a major coronary artery territory in case of QRS duration <120 msec or ≥ 2 notches in case of QRS duration≥120msec on standard 12-leads electrocardiogram. We calculated total defect score (201Tl-TDS) based on 17 segments model of SPECT images on a 5-point scale (0: normal to 4: defect) and assessed TDS (0 to 85). Thereafter patients were observationally followed-up. Cardiac death was reviewed retrospectively. Results: During 2.5±2.1 years of follow-up, cardiac death occurred in 11 patients. LVEF was significantly lower (p=0.033), Tl-TDS was significantly higher (p=0.022) in patients with f-QRS (n=55) than those in without f-QRS (n=49). Furthermore, Tl-TDS was significantly higher in patients with fQRS in ≥ 2 major coronary artery territories (n=28) than those in with fQRS in 1 territory (n=27, p<0.0001). Tl-TDS was one of the few clinical parameters related to presence of fQRS. Patients with fQRS showed significantly lower survival than those without fQRS by Kaplan-Meier analysis (Log-rank test p=0.017). 201Tl-TDS cut-off value was 18 for cardiac death (AUC 0.78, p< 0.0001). In patients with fQRS, patients with Tl-TDS≥18 showed significantly lower survival than those with TDS<18 by Kaplan-Meier analysis (Log-rank test p<0.0001). In multivariate analysis, presence of both fQRS and Tl-TDS≥18 was strongest predictor for cardiac death in patients with LVD (OR: 23.44, 95% CI: 4.34-203.9, p<0.0001) Conclusion: This study indicated that presence of fQRS related to severity of impaired myocardial perfusion on MPI and presence of both fQRS and impaired myocardial perfusion predicts poor prognosis in patients with non-ischemic LVD.