Abstract 1650: Prognostic Value of Cardiac I-123 Metaiodobenzylguanidine Imaging in Patients With Chronic Heart Failure: A Prospective 10-year Follow Up Comparative Study with QT dispersion, Signal-Averaged Electrocardiogram and Heart Rate Variability
Backgruond: We previously reported that Cardiac I-123 metaiodobenzylguanidine (MIBG) imaging might provide prognostic information in patients with chronic heart failure (CHF). However, no information is available on the comparison of the prognostic values between cardiac I-123 MIBG imaging and ECG parameters, such as QT dispersion, abnormal signal-averaged ECG (SAE) and heart rate variability (HRV) in CHF patients.
Methods: In 106 CHF outpatients with radionuclide LVEF<40% (30±8%), the cardiac MIBG washout rate (WR) were calculated from the chest anterior view images obtained at 20 and 200 min after isotope injection. Abnormal WR was defined as WR>27%. In addition, QTc dispersion was obtained using the Bazzet’s formula. The abnormality on SAE was defined as filtered QRS duration>130ms and the RMS voltage for the last 40ms<15μV or the shortest duration of <40μV in the terminal portion >40ms. The time and frequency domain parameters of HRV were calculated from 24 hour Holter recordings. Thereafter, they were followed up for >10 years.
Results: During the follow up period, 28 of 106 patients had cardiac death including 18 sudden deaths. At multivariate Cox analysis, WR was a significant predictor of cardiac death (p<0.001) and sudden death (p=0.004), while neither of QTc dispersion, abnormal SAE or HRV parameters was associated with poor outcome. Kaplan-Meier analysis revealed that patients with abnormal WR had a significantly higher risk both of cardiac death (43% vs 10%, p<0.0001) and sudden death (27% vs 6%, p=0.0003) than those with normal WR.
Conclusions: WR in cardiac MIBG imaging would predict the risk of cardiac death in CHF patients, although ECG parameters might not.