No abstract

The validity of cardiac output values from injections of indicator into a peripheral vein was tested. Dye dilution curves resulting from injections of Coomassie Blue dye alternately from peripheral and central sites were obtained in 20 subjects. Peripheral injections in which the dye was not flushed into the circulaton were in a large percentage of cases unreadable. In those which could be read the area under the curve was larger and the cardiac output on the average 8.5% lower than the values obtained from paired flushed injections. Curves from flushed peripheral injections had larger time components and lower concentration of indicator than those from paired central injections. There was no systematic difference in the cardiac output values derived from the two sites. In man, contamination of the primary curve by recirculation of dye does not seem to cause significant error when the indicator is flushed into the venous system in the manner described.

Aortocoronary vein grafts were placed in seven patients to bypass severe proximal stenosis in nine coronary arteries. Routine postoperative angiography showed patent grafts in all patients and substantial increase of proximal occlusive disease, diffusely or at the points of narrowing, in six of nine arteries (four patients), with complete obstruction of four of the six vessels. Two of the four patients experienced improvement in angina which was sustained despite the advanced proximal disease. The third patient suffered a late postoperative myocardial infarction and the fourth had recurrence of angina, both probably as a result of the increased proximal disease. The possibility is considered that a successful vein graft, by diverting flow from the poststenotic segment, may accelerate its occlusion and that consequences of advancing occlusive disease may not be prevented by vein-grafting surgery. Additional Indexing Woi Direct revascularization Myocardial infarction Patient selection for surgery rds: Coronary atherosclerosis Coronary blood flow Coronary arteriography Angina T HE RESULTS of aortocoronary bypass surgery have proven so far satisfactory' but the long-term benefits will be affected by closure of grafts or by the natural progression of the underlying coronary atherosclerosis.

Transvenous pacemakers offer advantages but may also lead to complications not seen with transthoracic pacemakers. We have seen two patients in whom at autopsy large right atrial thrombi were found around the catheter. The first patient had signs of increasing right heart failure and oliguria and died 48 hours after implantation of the pacemaker, which functioned normally throughout. At autopsy 80% of the right atrium was filled by a thrombus. This thrombus had caused inadequate filling of the right atrium and seemed responsible for the deterioration and death of the patient. The second patient died suddenly 2 months after insertion of the pacemaker after suprapubic prostatectomy. At autopsy a well-organized thrombus encircled the catheter between the junction of the azygos vein and the superior vena cava to the tricuspid valve. The thrombus may have caused signs of right heart failure before death. Since right atrial thrombi may be detected by angiography and treated by surgery, it is important to be aware of this rare complication of transvenous pacing.