Comparison between the mothod using angle correction algorithm in measuring left ventricular mass and anatomic M-mode measurement

Abstract

Objectives: Echocadiographic measurement of left ventricular (LV) mass is more sensitive method to detect LV hypertrophy than ECG. But it is too sophisticated to be able to achieve an acceptable quality control. This study is to find out a practical algorithm to overcome the angle deviation, which is one of the most annoying problems. Methods: For 15 healthy subjects whom the best quality M-mode measurements of LV mass at the short axis view were possible, obvious angle deviations were applied by examiner`s preference. LV masses were calculated using the values acquired from (1) the best quality images, (2) obvious angle deviated images, (3) correction by anatomical M-mode, (4) correction by cosine function of angle between vertical line on the posterior wall and the interrogation line at the parasternal long axis view, and (5) correction using the angle with septal wall. Regarding method (1) as the reference, the other methods were compared. Results: Angle deviation were 18.2 4.9o and 31.5 11.4o from the vertical line on the posterior wall and septal wall (p<0.0001). LV masses(g) were significantly different from method (1) except method (4)(p=0.227)(169.3 45.4g, 205.6 61.7g, 152.5 41.2g, 174.3 51.7g, and 119.5 39.2g for method (1)~(5), respectively). Correlation coefficients with method (1) were 0.953, 0.913, 0.958, and 0.148 for method (2) ~ (4), respectively. Bland-Altman plot showed that method (4) is better than any other methods. Conclusion: Simple correction algorithm using cosine function of deviated angle vertical line on the posterior wall is feasible and better or at least comparable to the anatomical M mode.