M-mode echocardiography overestimates left ventricular mass in patients with normal left ventricular shape: a comparative study using three-dimensional echocardiography.

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.