Measurement of left ventricular dimensions and function in patients with dilated cardiomyopathy

Studies on medical therapy in heart failure are focused on changes of left ventricular (IM) dimensions and function. These changes may be small, requi ring a large study group. We measured IV parameters (IV volumes, IV ejectio n fraction (LV-EP), and left ventricular mass (LVM)) with two-dimensional e chocardiography (2D-echo) and magnetic resonance imaging (MRI) in 50 patien ts. Based on the difference between the measurements, we determined the var iance of the results and calculated the sample sizes needed to detect chang es of baseline values. For the calculated and measured parameters we found significant differences between the two techniques: LV-EF and LVM were high er in 2D-echo, and IV dimensions were comparable. The sample size to detect relevant changes from baseline with MRI was significantly (P < 0.01) small er than in 2D-echo. We conclude that NM is superior in clinical studies on left ventricular dimensional and functional changes, since measurements are more reproducible and the required sample size is substantially smaller, t hereby reducing costs. (C) 2001 Wiley-Liss, Inc.