The Annals of Thoracic Surgery, Vol 35, 159-169, Copyright © 1983 by The Society of Thoracic Surgeons
Early assessment of rest and exercise left ventricular function following coronary artery surgery
EH Austin, HN Oldham Jr, DC Sabiston Jr and RH Jones
Radionuclide assessment of rest and exercise left ventricular function was
performed in 14 patients before, eight days after, and three months after
coronary artery bypass grafting (CABG). Resting function was unaltered
after operation, although mild increases in heart rate and end-diastolic
volume were observed on the eighth postoperative day. In contrast, exercise
function was significantly improved at both postoperative time periods.
Exercise ejection fraction was 0.54 +/- 0.10 before operation, 0.73 +/-
0.12 at eight days, and 0.64 +/- 0.13 at three months. Before CABG, the
exercise-induced increase in stroke volume was achieved by an increase in
end-diastolic volume, whereas eight days after CABG this increase was
achieved by an increase in contractility (systolic blood
pressure/end-systolic volume). By three months, both contractility and
end-diastolic volume increased with exercise. Thus, improvement in left
ventricular function during exercise can be documented as early as eight
days after coronary revascularization. This change may be less pronounced
after three months of convalescence, but considerable improvement in
ventricular function persists compared to preoperative assessment.
