How to calculate left ventricular mass in routine practice? An echocardiographic versus cardiac magnetic resonance study.

Background: An accurate assessment of left ventricular (LV) mass is important for the detection of LV hypertrophy.

Aims: To assess the accuracy of four echocardiographic imaging modalities for assessing LV mass compared with cardiac magnetic resonance (CMR).

Methods: We prospectively studied 40 consecutive patients, who underwent an echocardiographic examination using four imaging modalities (M-mode fundamental imaging [FI], M-mode harmonic imaging [HI], two-dimensional [2D] FI and 2D HI) and CMR (our gold standard for LV mass measurement). All echocardiographic measurements were performed by two independent observers.

Results: All echocardiographic modes significantly overestimated LV mass compared with CMR (P≤0.04), except 2D FI (P=0.25). This overestimation was significantly higher with HI (up to 15.5%) compared with FI (up to 5.7%; P≤0.04). Significant correlations were observed between the different echocardiographic methods and the two observers. The interobserver agreement over LV mass measurement was lower with FI (intraclass coefficient [ICC] range, 0.66-0.73) than with HI (ICC range, 0.72-0.82), and the best agreement was obtained with 2D HI (ICC, 0.82). Good agreement between CMR and all echocardiographic methods was observed among the smallest LV diameters (ICC range, 0.62-0.85), but not among the largest LV diameters (ICC range, 0-0.22).

Conclusions: HI overestimates LV mass compared with FI and CMR; this leads to overestimation of prevalence of LV hypertrophy in a population of hypertensive patients. HI improves interobserver reproducibility of LV mass measurement compared with FI, leading to a significant decrease in the number of patients required for clinical trials evaluating LV mass regression. Accuracy of LV mass measurement by echocardiography is affected by LV geometry.