Abstract 13358: Prediction of Sudden Death in Patients With Chronic Heart Failure: A Prospective Comparative Study of Cardiac I-123 Metaiodobenzylguanidine Imaging, QT dispersion and Signal-Averaged ECG: A 10-Year Follow up Study
Background: The identification of patients at risk for sudden cardiac death in chronic heart failure (CHF) still remains to be an important goal. Although it is shown that ICD therapy could prevent sudden cardiac death in CHF patients with severely reduced LV systolic function (LV ejection fraction <35%), it remains unclear which CHF patients with LVEF>35% would have the risk of sudden cardiac death. Cardiac I-123 metaiodobenzylguanidine (MIBG) imaging provides prognostic information in patients with CHF. However, no information is available on the comparison of the prognostic value between cardiac MIBG imaging and ECG parameters such as QT dispersion and abnormal signal-averaged ECG (SAE). We sought to investigate the prospective value of cardiac MIBG imaging, QT dispersion and SAE in CHF patients with mildly to moderately reduced LV systolic function (LVEF>35%) of the gray zone for the ICD therapy.
Method: At the entry, cardiac MIBG imaging, standard 12-lead ECG and SAE were performed in 60 consecutive stable CHF outpatients with radionuclide LVEF from 35% to 45% (38.3±2.8). The cardiac MIBG imaging was performed and washout rate (WR) was 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±2SD). 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.
Result: During the follow up period of 6.7±3.1 years (0.4–11.4), 9 (15%) of 60 patients died suddenly. At Cox regression analysis, WR was significantly and independently associated with sudden death (p=0.002), whereas neither abnormal SAE nor QT dispersion was associated with poor outcome. Patients with an abnormal WR had significantly higher risk of sudden death (32% vs 3%, p=0.017, hazard ratio: 12.5, 95% CI 1.6–100.0).
Conclusion: Cardiac MIBG WR, but not the ECG parameters of QT dispersion or SAE, is a powerful predictor of sudden death in patients with CHF and mildly to moderately reduced LV systolic function.
- © 2010 by American Heart Association, Inc.