Size and function of the human left and right ventricles during growth

Summary

Volume parameters of 63 left (LV) and 50 right ventricles (RV) were calculated from bi-plane angiocardiograms of infants, children and adolescents. Seventeen of the LV were from patients who were normal or had only minor abnormalities, 26 were from patients with atrial septal defect and left-to-right shunt less than 170% and 20 were from patients with pulmonary stenosis and pressure gradients less than 50 mmHg. Sixteen of the RV were from patients who were normal, 6 from patients with slight aortic regurgitation, 17 from patients with aortic stenosis or coarctation and pressure gradients less than 30 mmHg and 11 from patients with patent ductus arteriosus and left-to-right shunt less than 60%. The ejection fraction (EF) of RV [0.626±0.050 (SD)] was smaller than that of LV (0.711±0.064). There was no significant correlation (p>0.05) with body surface area (BSA) (LV: r=−0.055; RV: r=−0.063) or heart rate (HR) at rest (LV: r=0.197; RV: r=0.179). However, EF correlated significantly with the endsystolic volume (ESV) (normalized for BSA^1.22) (LV: r=−0.82; RV: r=−0.72), but not with the normalized enddiastolic volume (EDV) (LV: r=−0.05; RV: r=−0.22).

For LV as well as RV, EDV and ESV, stroke volume and LV mass were proportional to BSA^1.22. In contrast, the cardiac output, being the same for RV and LV, increased in proportion to BSA. There was, however, a significant correlation (r=0.465; p<0.001) between cardiac index (CI) and HR at rest. At 100 beats/min CI was 4.57±0.88 litre/min/m².

The evaluation of the spatial position of LV and RV yielded a significant descent (about 18°) of both ventricular apices relative to their respective semilunar valves during the period of growth. In patients with atrial septal defect (mean shunt 86%), the apex of the normal LV was shifted posteriorly by 20°.

These data may contribute to our understanding of the physiology of normal circulation and heart function during the period of growth.