Evaluation of the Ability of Echocardiography to Measure Acute Alterations in Left Ventricular Volume

Measurement of acute serial changes in left ventricular volume is often desirable. Although left ventricular volumes estimated echocardiographically correlate well with results of angiographic methods, the sensitivity with which echocardiography can detect acute alterations in volume is unknown. Accordingly, the effect on transverse left ventricular dimension of interventions known to alter left ventricular volume (tilting and administration of nitroglycerin and phenylephrine) was studied in six normal subjects. Tilting significantly reduced end-diastolic dimension (from 48 ± 1.7 to 41.8 ± 1.5 mm,P < .01) and end-systolic dimension (from 32.2 ± 0.6 to 27.5 ± 0.8 mm,P < .001). Nitroglycerin also reduced end-diastolic dimension (from 44.8 ± 2.3 to 39.8 ± 2.1 mm,P < .02) and end-systolic dimension (from 30.2 ± 1.3 to 26.5 ± 1.2,P < .005). In contrast, phenylephrine increased end-diastolic dimension (from 42.3 ± 2.6 to 45.6 ± 2.6 mm,P < .025) but did not significantly alter end-systolic dimension (from 28.9 ± 2.0 to 31.8 ± 2.9 mm). Mean rate of circumferential fiber shortening (mean Vcf) was not altered significantly by tilting or by phenylephrine, but was increased by nitroglycerin (from 1.3 ± 0.1 to 1.7 ± 0.1 circ/sec,P < .005). In addition, a study of eight patients with chronic rheumatic mitral valve disease showed that there was a positive correlation between the percentage change in R-R intervals and the percentage change in transverse diastolic dimension (y = .22x - 10,r = 0.68). These results indicate that the anticipated changes in left ventricular volume are readily detected by echocardiography. Thus, this noninvasive technique may be uniquely valuable in situations in which it is desired to make serial measurements of left ventricular volume.