Geometry or function for the prediction of prognosis following revascularization in ischaemic cardiomyopathy: beyond the ejection fraction: reply

We appreciate the insightful comments of Shah regarding geometry and function for prognostic assessment in ischaemic cardiomyopathy.1 We agree with him about the prognostic importance of end-systolic volume (ESV). As Shah points out, in our investigation, there was a trend towards larger baseline ESV before revascularization in patients with cardiac death (P= 0.052).2 For the purposes of responding to Shah's query, we assessed the prognostic value of ESV following revascularization. Larger ESV on follow-up echocardiography was a univariate predictor (P= 0.003) of cardiac death. However, neither baseline nor follow-up ESV was an independent predictor of outcome on multivariate analysis. Wall motion scores, ejection fraction (EF) improvement, and digoxin use in follow-up remained as the only independent predictors of outcome. While we recognize the prognostic importance of ventricular volumes, a smaller ESV has not always predicted improved outcome, most notably in the STICH trial where surgical reduction in ventricular volume did not improve outcome.3 Additionally, accurate, reproducible measurement of ESV utilizing two-dimensional echocardiography and the biplane method of discs is a challenging exercise. Jacobs et al.4 showed that the interobserver variability in the measurement of ESV was 24% compared with 14% for EF. Jacobs et al. also showed that the limits of agreement between two-dimensional echocardiography and magnetic resonance imaging for the determination of ESV was two times larger than that for EF. In our study, the interobserver variability for the measurement of ESV was 22% compared with 12% for EF (absolute difference of 3.8 EF points).