The cases of 100 consecutive patients who underwent coronary artery bypass grafting with coronary sinus (retrograde) cardioplegia (group R) without the antegrade-retrograde approach were reviewed. To evaluate the safety and the efficacy of this technique, another 100 consecutive patients who underwent a similar procedure but with conventional aortic root (antegrade) cardioplegia (group A) were used as a comparison. The two groups were similar with respect to age, male to female ratio, associated medical problems, extent of coronary artery disease, mean preoperative ejection fraction (0.56 +/- 0.13 versus 0.53 +/- 0.18), pump time (113.1 +/- 43 versus 111.7 +/- 38 minutes), aortic cross-clamp time (57.4 +/- 20 versus 60.8 +/- 23 minutes), number of grafts per patient, level of hypothermia, complication rate, rate of postoperative myocardial infarction (4% versus 3%), and mortality rate (2% versus 2%). Hemodynamic measurements were made 6 hours after operation in 59 patients in group R and 47 patients in group A. The cardiac index, left ventricular stroke work index, and right ventricular stroke work index were better in group R but not significantly so (p greater than 0.05). However, only 27% of patients in group R required a temporary pacemaker, and only 9% needed inotropic agents after 6 hours of operation in contrast to 51% and 42%, respectively, in group A (p less than 0.05). There were no complications from catheter intubation. In group R, right ventricular wall temperature (11 degrees +/- 3.6 degrees C) was higher than the septal (10.8 degrees +/- 3.2 degrees C) and left ventricular wall temperatures (9.1 degrees +/- 2.8 degrees C) (p greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)