Computer analysis of left ventricular dynamic geometry in man.

Analysis of left ventricular performance in 20 normal patients was undertaken using biplane cineangiography and a semiautomatic computer image processing system. The analysis included evaluation of volumes, ejection fraction, regional shortening, patterns of ejection and filling and, when simultaneous left ventricular pressure was recorded stroke work, stroke power, wall stress and internal myocardial work. All of these data were calculated from digitized images stored permanently on digital magnetic tape, and can be reproduced without reanalysis of the cine film. Normal left ventricular function is described by an end-diastolic volume index of 82 +/- 3 ml, an ejection fraction of 60 +/- 2 percent, left ventricular mass index of 97 +/- 6 g/m2, peak first derivative of volume (dV/dt) of 485 +/- 28 ml/sec, anterior shortening of 48 +/- 2.3 percent, inferior shortening of 33 +/- 1.7 percent, lateral shortening of 29 +/- 1.5 percent, anterior mean shortening velocity (Vcf, in percent of end-diastolic length [L]/sec) of 1.5 +/- 0.1 L/sec, inferior Vcf of 1.1 +/- 0.06 L/sec and lateral Vcf of 0.94 +/- 0.2 L/sec, stroke work of 1.33 +/- 0.21 joules, mean stroke power of 3.7 +/- 0.62 joules/sec, integrated left ventricular pressure (tension-time index) of 2,866 +/- 340 mm Hg-sec, and integrated stress (stress-time index) of 7,260 +/- 765 (X 10(3)) dynes sec/cm2. Internal myocardial work was calculated from the strain energy. More internal work was expended in circumferential than logitudinal shortening (circumferential, 0.69 +/- 0.1 joules; longitudinal, 0.41 +/- 0.08, P less than 0.01), because hoop stress was greater than meridian stress (hoop, 201 +/- 20 dynes/cm3 X 10(3); meridian, 126 +/- 13, P less than 0.001). This analysis of left ventricular performance provides a reliable means for identifying abnormal ventricular function and may be more sensitive than any one measurement alone. The use of digital image processing makes this complex functional analysis of left ventricular performance feasible.