Abstract 2302: Prediction of Sudden Death in Patients With Chronic Heart Failure: A Prospective Comparative Study of Cardiac I-123 Metaiodobenzylguanidine Imaging and Signal-Averaged Electrocardiogram
Background: The identification of patients at risk for sudden death in patients with chronic heart failure (CHF) still remains an important goal. Cardiac I-123 metaiodobenzylguanidine (MIBG) imaging and signal-averaged electrocardiogram (SAECG) provide prognostic information in CHF patients. The aim of this study was to prospectively investigate whether cardiac I-123 MIBG imaging and SAECG would predict sudden death in CHF patients.
Methods: At the entry, I-123 MIBG imaging and SAECG were performed in 104 consecutive CHF outpatients (NYHA class: 2.1±0.6, ischemic origin: 52%) whose radionuclide left ventricular ejection fraction (LVEF) was less than 40% (29.5±7.5%). The cardiac MIBG heart to mediastinum ratio (H/M) and 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% (the mean control WR +2 SD). The duration of filtered QRS complex (fQRSd), the root mean square voltage for the last 40ms of filtered QRS complex (RMS40), and the duration of low amplitude signals < 40μV in the terminal portion of filtered QRS complex (LAS40) were obtained by SAECG. Abnormal SAECG was defined as fQRSd > 130ms and at least one of the following: RMS40 < 15μV and/or LAS40 > 40ms.
Results: With a mean follow-up of 65±30 months, 17 of 104 patients died suddenly. At Cox analysis, out of the variables including clinical, echocardiographic, hemodynamic, biochemical, MIBG and SAECG parameters, WR (p=0.0020), H/M(delayed) (p=0.0057), plasma noradrenaline (p=0.0134), LVEF (p=0.0178), H/M(early) (p=0.0362), and plasma uric acid (p=0.0498) showed a significant association with sudden death, while there were no associations between SAECG parameters and sudden death, and there was no significant difference in sudden death-free rate between patients with and without abnormal SAECG. Multivariate analysis revealed that WR was the only independent predictor of sudden death (p=0.0318, hazard ratio 1.039 [95%CI 1.003 to 1.076]). Patients with abnormal WR had a significantly higher risk of sudden death than those with normal WR (log rank p=0.0079; risk ratio 3.13 [95%CI 2.21 to 4.43]).
Conclusion: Cardiac MIBG WR would predict the risk of sudden death in CHF patients, although SAECG might not.