M-Mode Echocardiography Overestimates Left Ventricular Mass in Patients with Normal Left Ventricular Shape: A Comparative Study Using Three-Dimensional Echocardiography

Abstract

Aims: We sought to evaluate whether left ventricular (LV) mass (M) determined by M-mode echocardiography is overestimated compared with LVM calculated by three-dimensional (3D) echocardiography (E) in patients with normal LV shape. Methods and Results: A total of 112 studies in 56 patients (60±13 years) with hypertension ( n =25) or aortic stenosis ( n =31) and 30 control subjects (57±14 years) evaluated for cardiac sources of embolism were analyzed. LVM by M-mode and 3DE was highly correlated ( r =0.85; p <0.001). However, there were broad limits of agreement (−58 to 110 g) demonstrating large variability between the methods. M-mode overestimated 3DE LVM by a mean of 15±24% ( p <0.001) with overestimation in controls and the different patient groups. Variability was unrelated to increasing quartiles of LVM values. Using technique-specific partition values for normal LVM, the agreement between M-mode and 3DE for the detection of LV hypertrophy was 83% (Kappa=0.59; p <0.001). Conclusion: Although M-mode and 3DE correlate well for the calculation of LVM, there is a systematic difference between the two techniques leading to overestimation of LVM by the 1D technique. Thus, previously published cutoff values for normal LVM derived from M-mode may not apply for 3DE. However, the use of technique-specific partition values allows stratification of patients for the presence of LV hypertrophy with reasonable agreement.