Continuous assessment of left ventricular volume by ultrasonic analogue conversion system

Applicability of ultrasonic analogue conversion system devised by us for assessments of left ventricular volume was examined in patients with and without heart disease. The conversion system could sample the echoes from the endocardial surfaces of the interventricular septum and the posterior left ventricular wall. The conversion system could also calculate automatically the minor axis and volume of the left ventricle. End-diastolic, end-systolic, and stroke volumes calculated by the conversion system were close to those calculated from biplane ventriculograms and to those calculated from photographic records of B-mode echo-display. Change in left ventricular volume caused by respiration ranged up to 17.5%. Spontaneous variations in left ventricular volume during continuous monitoring was up to 7.5%. End-diastolic, end-systolic, and stroke volumes were reduced by sublingual administration of nitroglycerin. The results indicate applicability of the ultrasonic analogue conversion system for continuous assessments of left ventricular volume in man.