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.