Angiology

Adult male and female Sprague-Dawley rats were subjected to an isopro terenol-induced myocardial infarction. Six weeks before the induction of myo cardial infarction, some of the animals had been orchiectomized or ovari ectomized. The animals were autopsied at regularly timed intervals on days 1, 2, 3, 8, and 15 after myocardial infarction. The gonadectomized animals mani fested less severe untoward changes, survived in greater numbers, and experi enced superior repair of their damaged hearts. Circulating levels of enzymes (e.g., CPK, GOT, GPT, and LDH), lipids, glucose, and BUN rose and fell during the acute necrosis and repair phases with distinct differences between the intact and castrated animals. Reciprocal changes in the weight of the adrenal and thymus glands, coupled with dynamic changes in circulating corticosterone levels, reflected marked temporal changes in the spectrum of adrenal steroids being secreted, as well as gonadal hormone mediated changes affecting adreno cortical function. The implications of these findings are that adrenocortical, androgenic, and estrogenic hormones condition the nature of the patho physiologic response to acute myocardial infarction in rats.

Exercise electrocardiography and selective coronary arteriography was per formed in 24 consecutive patients with complete bundle branch block. The criteria for a positive exercise electrocardiogram (E-ECG) were a 1 mm depres sion or elevation in the J point from the control state, as well as in the ST segment measured at 0.04 seconds from the J point.

Eleven of 12 patients with complete left bundle branch block had a positive E-ECG. Nine of them had normal coronary arteriograms, except one with less than 50% lesions in two arteries. Two patients had severe three-vessel disease. Only one patient had a true negative exercise test. No patient had a false negative test.

Nine of 12 patients with complete right bundle branch block had a positive E-ECG. One of these 9 had minimal nonobstructive disease, while the other 8 had severe two- or three-vessel coronary artery disease. Three of the 12 right bundle branch block patients had a negative E-ECG. Two of them had a true negative exercise test, and one a false negative test.

Because of a high incidence of probably false positive results, E-ECG appears to be unreliable in detecting coronary artery disease in patients with complete left bundle branch block. But it can provide useful information in the non- invasive evaluation of coronary artery disease in patients with complete right bundle branch block.

A total of 142 saphenous vein bypass patients who underwent pre- and postoperative treadmill stress tests were analyzed. The double product at the onset of ischemia improved in 15 of 25 females (68%) and 67 of 117 males (58%). In patients with a history of preoperative angina, 103 of 132 (78%) were relieved after operation, but only 81 of 132 (61%) improved their double product. In those with preoperative angina during treadmill stress testing, 48 of 79 (61%) improved. In patients without preoperative angina on treadmill stress testing, 40 of 65 (62%) improved their double product. When ST depression developed at a workload of 4 METS on the preoperative treadmill stress test, 54 of 87 (62%) improved. When ST depression developed at 6 METS, 20 of 34 (58%) improved their double product at the point of ischemia.

The patient's sex, angina during treadmill stress testing, and the workload associated with ischemia did not help identify those who would benefit from bypass surgery. Treadmill stress testing does demonstrate the disparity be tween symptomatic and functional improvement and provides an important parameter for evaluation of aortocoronary bypass.