Canine left ventricular volume and mass during thoracotomy by two-dimensional echocardiography: Increased ventricular mass after ischemia and reperfusion

Left ventricular end-diastolic volume ( V c) and mass ( M c) were studied in 10 dogs by two-dimensional echocardiography after thoracotomy and construction of a pericardial well filled with sound-conducting gel. Five selected LV sections were obtained in vivo by two-dimensional ultrasound. After X-ray angiography and thermal dilution cardiac outputs, 9 of the 10 hearts were fixed by glutaraldehyde coronary perfusion while filling pressures were maintained equal to LVEDP and RVEDP in vivo. Silastic casts of the left ventricle were used to measure cavity volume ( V c) by displacement, and LV mass was determined by weighing ( V pm). Study of postmortem casts with a Simpson's rule algorithm revealed that volume calculations with two of six possible pairs of orthogonal sections were congruent with the line of identity vs cast displacement volume. Optimum results in vivo were obtained from averaged data based on these section pairs (from three echo sections) as V c = 0.94 V c + 0.2 ( r = 0.88). LV mass was given by M c = 0.95 M pm + 6.6 ( r = 0.90). Systolic volume, stroke volume, and ejection fraction were less satisfactory, reflecting difficulties with long axis sections during systole in the open chest. To examine the suitability of these methods for physiologic studies, LV mass was measured before and after 30 min of normothermic ischemic arrest and reperfusion in six dogs. LV mass increased from 109 ± 7 (SE) g before ischemia to 153 ± 13 g after ischemia ( P < 0.01). Two-dimensional echocardiography thus demonstrates unique potential for experimental cardiovascular physiology.