Cardiovascular effects of weight reduction in obese patients with angina pectoris

Beneficial effect of a low-fat low-calorie diet on myocardial energy metabolism in patients with angina pectoris

8 patients with exertional angina pectoris were treated for 3 months with a low-fat, low-calorie diet. Serum cholesterol was reduced by 28% and body-weight by 7.9 kg on average. The effect of the dietary intervention was assessed by a heart metabolic study during pacing-induced tachycardia. After dietary treatment coronary sinus blood-flow and myocardial oxygen consumption were considerably reduced, but pacing time before angina developed increased. Other improvements were a reduction in lactate release during pacing, a reduction in citrate release during recovery, a reduction in alanine output during rest and recovery, and a lower uptake of glutamate. The results suggest a beneficial effect of low-fat, low-calorie dietary treatment on myocardial energy metabolism in patients with exertional angina pectoris.

Multiple-lead QRS changes with exercise testing. Diagnostic value and hemodynamic implications

To evaluate the diagnostic potential and hemodynamic significance of exercise-induced multiple-lead QRS changes, we studied exercise test responses in 230 patients with chest pain syndromes undergoing Bruce protocol exercise tests. When increases in the R waves of multiple ECG leads (epsilon R) plus ST segment change greater than 1 mm were present, 74 of 75 patients (99%) had coronary disease; this was a higher percentage than that achieved with either measurement alone or when ST change was combined with increase in R in a single lead. Sixty-four of the 75 patients (85%) had multivessel disease, the most severe form of coronary artery disease. Left ventricular end-diastolic pressure (both at rest and after left ventriculography), presence and degree of resting ventricular asynergy, and ejection fraction were all significantly more abnormal in patients whose epsilon R increased, regardless of ST-segment change. Further, in patients who stopped exercise because of cardiac symptoms, exercise duration and the product of heart rate times blood pressure were significantly lower when epsilon R increased. Thus, the mechanism for the increase in epsilon R with exercise in patients with coronary artery disease appears to be related to abnormalities in left ventricular function.

Echocardiographic and hemodynamic correlates in Prinzmetal angina pectoris: a case report

In a patient suffering from Prinzmetal angina pectoris, ischemic attacks of the anterior left ventricular wall were associated with the following changes: fall in cardiac output; increased left ventricular diastolic pressure (LVDP) and volume; flattening of the septal motion; marked reduction of the mitral valve early diastolic amplitude and rate of opening; and marked reduction of the systolic closure velocity. It is suggested that LVDP rise depends, at least in part, on variations in left ventricular diastolic volume and segmental wall motion, and that disruption of the mitral valve motion derives from changes in LVDP and flow through the mitral orifice.

Evaluation of R wave amplitude changes versus ST-segment depression in stress testing

Exercise ECGs and coronary angiograms were reviewed in 266 patients (81 normals and 185 with significant coronary artery disease). Thirty-three false positive and 96 false negative ST responses to stress testing were purposely chosen to determine if the R wave could reduce the number of false ST responses. R wave amplitude changes were measured in the control and in the immediate postexercise period. An increase or no change in R wave was taken as evidence of an abnormal response, while a decrease in the R wave was a normal response. The sensitivity by ST segment was 48% and the specificity was 59%. These values were low because of the large number of false positive and negative ST responses in the study. It was our purpose to determine if these lowered values could be significantly improved by the R wave. Using R wave criteria, the sensitivity was 63% (P is less than 0.01) while the specificity was 79% (P is less than 0.01). The sensitivity and specificity of stress testing can be significantly improved using R wave changes.

Effect of angina on the left ventricular diastolic pressure-volume relationship

The increased left ventricular end-diastolic pressure associated with myocardial ischemia was studied in 19 patients at cardiac catheterization. Single plane left ventriculograms were performed using high fedelity micromanometer tipped catheters before and immediately following rapid atrial pacing. Left ventricular diastolic properties were evaluated by constructing diastolic pressure-volume curves from the simultaneous pressure and volume data. In seven control patients, there was no significant change in left ventricular hemodynamics or the diastolic pressure-volume curve after atrial pacing. Twelve patients with significant coronary artery disease developed angina during pacing and had an increased left ventricular end-diastolic pressure (18 +/- 2 mm Hg, control, vs 30 +/- 2 mm Hg, angina, P less than .01) in the immediate post-pacing period. In these patients, the post-pacing ejection fraction was modestly decreased (0.63 +/- 0.03, control, vs 0.57 +/- 0.03, angina P less than 0.01), and left ventricular volumes at end systole (59 +/- 8 cc, control, vs 74 +/- 9 cc, angina, P less than 0.0125) were increased. The post-pacing diastolic pressure-volume curves in all 12 patients were shifted upward as compared with control so that for any given diastolic volume, pressure was higher during angina. The data indicate that the increased left ventricular diastolic pressure during myocardial ischemia is the result of both impaired left ventricular systolic performance and altered left ventricular diastolic properties.

Exercise vectorcardiography in diagnosis of ischaemic heart-disease

The changes in the cardiac electric field during exercise have been studied by conventional vectorcardiographic techniques. Criteria have been developed to distinguish the changes seen in patients with coronary-artery disease proven angiographically from the changes in patients with normal coronary arteriograms. These criteria were derived from a learning set of 105 patients. Vectorcardiograms were taken immediately before and immediately after a maximal treadmill exercise test. In this group of 105 patients--72 with abnormal coronary arteries and 33 with normal coronary arteries--vectorcardiography before and after exercise diagnosed correctly 86% of the abnormals and 82% of the normals. This gives a sensitivity of 86% and a specificity 82%. ST-segment analysis in the same group gave a sensitivity of 60% and a specificity of 85%. The same criteria applied blind to a second testing set of 92 patients gave a sensitivity of 84% and a specificity of 65%. In the same group ST-T analysis gave a sensitivity of 56% and a specificity of 78%. The sensitivity with these criteria compares favourably with the best results so far achieved with ST-segment analysis aided by computer. This technique can be easily used by the clinician and improves the diagnostic accuracy of exercise testing.

Left ventricular end-diastolic pressure volume relationships with experimental acute global ischemia

The mechanism of elevation of left ventricular end-diastolic pressure during acute global ischemia was evaluated by examiniation of the relative contributions of a decrease in contractility and an alteration of the pressure-volume relationship. The external circumference (mercury-in-silastic gauge) pressure relationship, as an index of the pressure-volume relationship, was studied in beta adrenergic and ganglionic blocked, open chest dogs on right heart bypass at constant heart rate ane aortic pressure. Ischemia of one and two hours' duration was produced by reducing total coronary blood flow in cannulated left and right coronary arteries until left ventricular end-diastolic pressure rose significantly. At a constant stroke work, left ventricular end-diastolic pressure rose from 5.0 +/- 0.5 to 15.0 +/- 0.5 cm H2O in the experiments of one hour of ischemia, and from 7.0 +/- 1.0 to 17.0 +/- 1.0 cm H2O in experiments of two hours of ischemia. Ischemia was followed by one hour of restoration of coronary blood flow. Ischemia produced a marked depression of ventricular function: stroke work, considered at a left ventricular end-diastolic pressure of 15 cm H2O, decreased from 21.0 +/- 3.0 to 3.5 +/- 0.5 gm-m, and from 15.0 +/- 2.0 to 2.5 +/- 0.5 gm-m, in the experiments of one and two hours, respectively. Neither ischemia nor reflow changed the pressure-volume relationship. Thus, the elevation of left ventricular end-diastolic pressure during ischemia in an otherwise normal canine myocardium is due to a decrease in systolic performance of the heart rather than to an alteration of the pressure-volume relationship.