[Right ventricular function before and 6 months after aortocoronary bypass. A radioisotope angiographic study]

The aim of the present paper is the study of the changes induced on right ventricular function after myocardial revascularization with aortocoronary bypass graft. Two-three days before and 6 months after operation gated radionuclide ventriculography has been performed in 25 patients with previous myocardial infarction (MI), anterior in 16 patients and inferior in 9. At postoperative examination, right ventricular ejection fraction (EF) was slightly but significantly reduced (p less than 0.01), while peak ejection and filling rates were unchanged. Symmetric parameters of left ventricular function did not show changes at post-operative control, except a clear-cut rise of left ventricular peak filling rate (p less than 0.05). Before operation, in patients with previous anterior MI, left ventricular EF was slightly less and right ventricular EF slightly more than in patients with previous inferior MI; after operation right ventricular EF significantly decreased (p less than 0.01) only in patients with previous anterior MI. No correlation has been demonstrated in pre- postoperative changes of the observed parameters, neither between the two groups of previous MI nor between right and left ventricular cavity. Six months after myocardial revascularization, left ventricular performance, as examined with radionuclide angiography, was practically unchanged except for improvement of diastolic function, while right ventricular performance was moderately impaired, more in patients with previous anterior MI than in those with previous inferior MI.