Elongation as a new shape index for the left ventricle

This study was done to quantify the shape of the left ventricle (LV). It was proposed that the shape of the LV is intimately related to its performance and that its elongation (ELO) is a sensitive measure of this performance. The performance was tested against classical cardiovascular parameters.

Using echocardiography and Simpson's rule, the endocardial surface area of the LV was calculated noninvasively with a simple experimental-mathematical model at enddiastole and endsystole. ELO as shape index was derived from the endocardial surface area of the LV with a simple formula. The endocardial surface area of the LV and ELO were determined in volunteers, in patients with mild heart failure and in patients with severe heart failure.

The normal value of endocardial surface area of LV at enddiastole is 138.3 cm2 while the normal value at endsystole is 99 cm2. The endocardial surface area of the LV is significantly bigger in patients with mild heart failure than in volunteers (p < 0.01) while the parameters ELO, ejection fraction and Doppler measurements are similar. The normal values of ELO at diastole and systole are 12 and 25 respectively. The value of ELO at endsystole is lower only in patients with severe heart failure. This means a more spherical shape and poor systolic function of the LV.

ELO is usefull as quantitative and qualitative index of left ventricular shape. ELO could be integrated and applied with new diagnostic tools such three-dimensional and contrast echocardiography.