Comparison of myocardial temperatures with multidose cardioplegia versus single-dose cardioplegia and myocardial surface cooling during coronary artery bypass grafting.

Myocardial hypothermia with multidose cardioplegia has not been compared with single-dose cardioplegia and myocardial surface cooling with a cooling jacket in patients having coronary artery bypass grafting. In this study, 20 patients with three-vessel disease undergoing coronary bypass at 28 degrees C with bicaval cannulation, caval tapes, and pulmonary artery venting (4.9 +/- 0.7 grafts per patient) were prospectively randomized equally into group I (multidose cardioplegia) and group II (single-dose cardioplegia with a cooling jacket). The initial dose of cardioplegic solution was 1000 ml. Group I then received 500 ml of cardioplegic solution every 20 minutes, delivered into the aortic root and available grafts. In group II, after the cardioplegic solution had been administered, a cooling jacket covering the right and left ventricles was applied. In both groups temperatures were recorded every 30 seconds at five ventricular sites: (1) right ventricular epicardium; (2) right ventricular myocardium or cavity, 7 mm; (3) left ventricular epicardium; (4) left ventricular myocardium or cavity, 15 mm; and (5) septum, 20 mm. Group mean temperatures at each site at various times were compared within each group and between the two groups by analysis of variance. Aortic crossclamp time was 60.3 +/- 12.1 minutes in group I and 52.8 +/- 7.3 minutes in group II (p = 0.12); cardiopulmonary bypass time was 103.7 +/- 11.1 minutes in group I versus 87.7 +/- 12.7 minutes in group II (p less than 0.01). One minute after the cardioplegic solution was initially given, temperatures between groups at each site were not statistically different, but left ventricular epicardial temperatures within both groups were significantly higher than in the other four sites. Nineteen minutes after administration of the cardioplegic solution, temperatures in group I at all sites were higher than in group II. Similarly, throughout the entire period of aortic crossclamping, mean temperatures (except left ventricular myocardial site), maximum temperatures, and percentage of time all temperatures were 15 degrees C or higher were greater in group I than in group II. The following conclusions can be reached: 1. Initial myocardial cooling with 1000 ml of cardioplegic solution is not significantly limited by coronary artery disease but is suboptimal (16 degrees or 17 degrees C) in the inferior left ventricular epicardium because of continual warming from the aorta and subdiaphragmatic viscera. 2. Without myocardial surface cooling, excessive external myocardial rewarming to 18 degrees to 22 degrees C occurs within 20 minutes at all sites after delivery of the cardioplegic solution.(ABSTRACT TRUNCATED AT 400 WORDS)

Mitral valve replacement versus reconstruction. An analysis of indications and results of mitral valve procedures in a consecutive series of 80 patients.

Case histories of 80 patients undergoing mitral valve procedures over a 2 year period were analyzed to determine the preoperative and intraoperative factors favoring reconstruction. Of 34 patients undergoing valve reconstruction, 31 (90 per cent) were women, and the average age of patients undergoing reconstruction was 41 versus 51 for patients who underwent replacement. Absence of calcification on fluoroscopic study and at operation favored reconstruction, as did the finding of good leaflet mobility by preoperative echocardiograms and operative assessment. Pure lesions, i.e., stenosis or insufficiency, favored reconstruction. In this regard, the use of new annuloplasty techniques has facilitated the surgeon's ability to reconstruct regurgitant mitral valves. No operative deaths and excellent functional and clinical results obtained in 80 per cent of patients undergoing mitral reconstruction justify the aggressive application of this technique in properly selected patients.

Electrophysiologic delineation of the specialized atrioventricular conduction system in two patients with corrected transposition of the great arteries in situs inversus (I,D,D).

Electrophysiologic delineation of the atrioventricular conduction system at surgery is described in two patients with corrected transpostion of the great arteries in situs inversus. Intra-atrial electrograms were recorded in one patient from sites immediately adjacent to the coronary sinus located in the left-sided right atrium. The intraventricular portion of the atrioventricular conduction system was identified in both patients along the posterior and inferior margin of the ventricular septal defect, in contrast to the superior and anterior location found in corrected transposition of the great arteries in situs solitus. In contrast to the superior and anterior location found in corrected transposition of the great arteries in situs solitus. The course of the conduction system in the hearts of these two patients and a possible relationship to the cardiac loop and dual origin of the atrioventricular node is discussed. These cases illustrate the usefulness of segmental diagnosis of congenital heart disease and of electrophysiologic identification of the specialized atrioventricular conduction system at surgery.

Combined valvular aortic stenosis, hypertrophic subaortic stenosis and coronary artery disease: successful surgical correction.

A 51 year old woman with angina pectoris due to combined valvular aortic stenosis, hypertrophic subaortic stenosis and coronary artery disease is described. The diagnosis was first suspected following echocardiography. Discussed is the importance of excluding associated coronary artery disease and hypertrophic subaortic stenosis in patients with valvular aortic stenosis. A pre- and post-PVC aortic pressure response is described pathognomonic of coexistent valvular and hypertrophic subaortic stenosis. The patient underwent successful surgical correction of all three lesions.

An analysis of direct and indirect measurements of left atrial filling pressure.

Left ventricular function may be assessed by direct catheter measurements of left atrial pressure or by indirect measurements of pulmonary artery wedge pressure or pulmonary artery end-diastolic pressure. Controversy exists as to how closely the indirect measurements correlate with true left atrial pressure and to which is the most accurate. To clarify this probelm, we studied 43 patients undergoing cardiac surgical procedures with cardiopulmonary bypass. Both left atrial catheters for direct measurement and Swan-Ganz catheters were placed at the time of surgery. All patients were monitored continuously for 48 hours and hourly measurements were recorded. The resultant 1,620 left atrial pressure and pulmonary artery wedge pressure figures and 1,860 left atrial pressure and pulmonary artery end-diastolic wedge pressure measurements were subjected to computer analysis. The following conclusions have been found: (1) Pulmonary artery wedge pressure is a better indirect measure of left atrial pressure than is pulmonary artery end-diastolic wedge pressure (pooled correlation coefficient 0.629); (2) direct left atrial pressure measurement is more reliable and has fewer complications than indirect measurements; (3) there is no consistent correlation between left atrial pressure and central venous pressure (pooled correlation coefficient 0.3). A discussion of our results and the problems associated with left atrial catheters and Swan-Ganz catheters is presented.

Saphenous vein graft from aorta to coronary vein with production of continuous murmur. A complication of coronary artery bypass surgery.

A saphenous vein graft was inadvertently placed from the aorta to the coronary vein adjacent to the proximal left anterior descending coronary artery in a 53-year-old man with symptomatic coronary artery disease. The post-operative finding of a continuous murmur led to cardiac catheterization and successful surgical correction. The postoperative finding of a continuous murmur must alert the clinician to this possible technical error.