Improvement by oral metoprolol of exercise-induced ischemic dysfunction in patients with coronary heart disease

The effect of metoprolol on global left ventricular function during exercise was analyzed with nuclear ventriculography in 17 patients with ischemic heart disease. All had stable angina pectoris and ST-segment depression of more than 0.1 mV during treadmill exercise when not taking metoprolol. Each patient was stressed with supine bicycle exercise to the same load on a maintenance dose of metoprolol (100 mg X 2/day) and on a second occasion without the drug, the two being separated by 7 days. The mean heart rate and systolic blood pressure were significantly reduced both at rest and exercise with metoprolol. There was no significant difference of rest left ventricular ejection fraction with or without metoprolol. At exercise, however, every patient showed improvement of left ventricular function, the average left ventricular ejection fraction increasing by 14% (+/- 6) relative to the same exercise without metoprolol (p less than 0.001). We conclude that chronic metoprolol treatment in patients with ischemic heart disease can ameliorate left ventricular dysfunction induced by exercise and may thereby reduce myocardial ischemia.

Does complete revascularization by the conventional method truly provide the best possible results? Analysis of results and comparison with revascularization of infarct-prone segments (systematic segmental myocardial revascularization): the Sheba Study

Myocardial revascularization is usually considered "complete" if all stenosed major coronaries are bypassed. Attempts were made to compare the results of this method with an approach by which each of the following five left ventricular infarct-prone segments is revascularized if ischemic: anteroseptal, anterolateral, posterosuperior, posteroinferior, and diaphragmatic. Two subsets of patients were studied. A total of 366 patients (Group A) who underwent aortacoronary bypass operations from 1980 to 1982 were followed up for a mean of 16.3 (6 to 43) months and were retrospectively divided into two groups: Group A1 (120 patients) had incomplete segmental revascularization (mean of 3.4 grafts per patient) and Group A2 (246 patients) had complete segmental revascularization (4.0 grafts per patient) (p less than 0.0001). Groups A1 and A2 were identical in all clinical and angiographic parameters: unstable angina, 60%; previous myocardial infarction, 70%; left main stenosis, 10%; and ejection fraction less than 30%, 2%. Overall operative mortality was 2.3%. Results in Groups A1 and A2, respectively, were as follows: operative mortality, 5.8% versus 0.8% (p less than 0.005); perioperative myocardial infarction, 6.9% versus 0.8% (p less than 0.0005); 35 month survival rate, 93.3% versus 97.9% (p less than 0.02); total freedom from symptoms, 54.1% versus 68.3% (p less than 0.025). In addition, 151 patients operated on in 1984 (Group B) were studied prospectively with regard to operative mortality and perioperative myocardial infarction, and the results were identical to those in Group A. Compared to conventional complete revascularization, complete segmental revascularization provides better results.

The effects of varying lengths and powers of CO2 laser pulses transmitted through an optical fiber on atherosclerotic plaques

We have studied the changes induced in atherosclerotic arteries by a CO2 laser beam delivered through a silver halide optical fiber. We found that the crater depth and diameter correlate with the total energy delivered and with the mode of delivery. Short-duration high-power pulses caused shallower and narrower craters and less damage to the arterial wall compared to the same energy delivered as low-power pulses of long duration. Thus, high-power pulses for short periods may be an effective and safe procedure for evaporization of atherosclerotic plaques.

Hemodynamic effects of nifedipine in hypertension in the presence of elevated angiotensin-II and beta-adrenergic blockade

The hemodynamic effects of the slow release form of a calcium channel blocker, nifedipine retard, in essential hypertension patients after angiotensin II (AII) infusion were studied using nuclear ventriculography. Sublingual nifedipine lowered blood pressure that had been acutely raised by an infusion of AII to its baseline level. When used for 4 weeks, nifedipine retard maintained its blood-pressure-lowering effects without a change in heart rate, both when used alone and when used in addition to beta-adrenergic blockers. In the patients with untreated essential hypertension, nifedipine counteracted the lowering effect of AII on left ventricular ejection fraction (LVEF), which was 67.5 +/- 8.9% at recumbency, 61.2 +/- 6.6% (+/- SD) during AII infusion, and 72.1 +/- 7.5% 30 minutes after sublingual nifedipine. These acute effects seem to result from a marked reduction in total peripheral resistance (TPR) and are accompanied by a rise in cardiac index (CI). The TPR, in dynes/sec/cm-5, was 1376.9 +/- 275.8 at recumbency, 2000.7 +/- 358 during AII infusion, and 1228.6 +/- 289 30 minutes after sublingual nifedipine. The corresponding figures for CI in liters/M2 BSA, were 4.02 +/- 0.77, 3.03 +/- 0.64, and 4.32 +/- 0.79. In patients receiving beta-blocker therapy (propranolol or atenolol) with inadequate control of blood pressure, similar results were obtained in LVEF (69.7 +/- 8.87% at recumbency, 63.7 +/- 11.9% during AII infusion, and 72.2 +/- 6.05% 30 minutes after sublingual nifedipine). The initial TPR was much higher than that of untreated essential hypertensive patients. Nevertheless, the increase obtained during AII infusion was counteracted by sublingual nifedipine. CI was decreased by AII.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential regulation of effector responses of cell mediated immunity in experimental salmonellosis

Delayed type hypersensitivity (DTH) and protective cell mediated immunity showed different profiles with respect to time following intraperitoneal immunization with live Salmonella enteritidis. Whereas the DTH response decreased with time the Protection Index increased. The decline in DTH response was found to be associated with suppressor cells generated by intraperitoneal immunization and could be prevented by cyclophosphamide treatment prior to immunization. It was concluded that the two effector responses of cell mediated immunity were under differential regulation.

Fate of nonobstructive aneurysmatic coronary artery disease: angiographic and clinical follow-up report

The incidence of coronary aneurysmatic dilatation without coronary stenosis is rare, and the clinical course of such an entity is unknown. We present five adult patients, four men and one woman, with such an anatomic finding. The age range was 44 to 60 years. In four patients the aneurysmatic dilatations involved multiple coronary sites. The clinical course in all five patients was suggestive of coronary insufficiency. Despite no obstructive disease, two of the patients developed transient ischemic ECG changes accompanied by chest pain, and another two patients demonstrated ischemic exercise nuclear ventriculography response. In time, all five patients developed acute myocardial infarction and recatheterization revealed complete occlusion of a previously nonstenosed aneurysmatic vessel. More information is needed in order to guide therapy. However, prevention of thrombus formation and close follow-up is highly recommended.

Two-dimensional echocardiography in discrete subaortic stenosis

Thirty-seven patients with discrete subaortic stenosis (DSS) underwent 2-dimensional echocardiography (2-D echo) and cardiac catheterization. The peak systolic pressure gradients ranged from 0 to 150 mm Hg. Thirty-two patients had membranous DSS and 5 had fibromuscular DSS. Of 37 patients with DSS, 2-D echo diagnosed the presence and type in 35; in 2, a membrane was demonstrated by angiography. Of the 35 patients accurately diagnosed by 2-D echo, angiography corroborated the diagnosis in 33, but failed to show the membrane in 2. Subsequent cardiac surgery confirmed the accuracy of the echocardiographic diagnosis in these 2 patients. In all patients with membranous DSS, the anterior insertion of the membrane was demonstrated. In 9 of them the posterior insertion was demonstrated by tilt of the transducer but the anterior insertion disappeared. In 4 patients both insertions were demonstrated simultaneously and in 3 patients the membrane was demonstrated as a continuous line. In 4 of the 5 patients with fibromuscular DSS, both insertions of the lesion were demonstrated simultaneously. However, 2-D echo was unsuccessful in assessing the severity of obstruction. In only 1 patient did demonstration of the whole subaortic membrane as a continuous line below the aortic valve correlate with severe obstruction. Thus, the presence and type of DSS, but not the degree and severity, can be accurately and reliably diagnosed by means of 2-D echo.

Correlation between echocardiography and cardiac catheterization in assessing the severity of aortic stenosis

The severity of aortic stenosis was assessed by echocardiography in 81 consecutive adult patients, 40 of whom underwent cardiac catheterization. The patients' mean age was 54 +/- 16.4 years. A good correlation was found between the severity of aortic stenosis assessed by cross-sectional echocardiography and cardiac catheterization. Aortic valve separation of 7 mm or less occurred only in severe aortic stenosis whereas a separation of 12 mm ruled out any significant aortic stenosis. A separation of 8-11 mm constituted a 'grey' area between mild and severe aortic stenosis. Cross-sectional echocardiography provides a reliable method for crude evaluation of aortic stenosis.

Systolic closure of aortic valve in patients with prosthetic mitral valves

Systolic closure of the aortic valve was found in 10 of 36 patients who underwent mitral valve replacement. Eight patients had early systolic closure, and two had mid-systolic closure. The left ventricular outflow tract dimension on M-mode and two dimensional echocardiograms, left ventricular posterior wall and septal thickness, left ventricular dimensions in systole and diastole, aortic valve opening, and mitral to aortic valve distance were not significantly different between patients with and without systolic closure of the aortic valve. Two of the 10 patients with systolic aortic valve closure were catheterised and in neither was there a gradient between the left ventricle and the aorta. The two patients with mid-systolic closure, however, were the patients who had the narrowest left ventricular outflow tract which could cause significant distortion of blood flow. Systolic closure of the aortic valve in patients with mitral valve replacement is probably not caused by left ventricular outflow tract obstruction, though abnormalities in laminar flow from the left ventricular outflow tract may be involved.

Bilateral congenital coronary artery fistula

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Correlation between cardiac catheterization and echocardiography in assessing the severity of mitral stenosis

During a 12-mth period 162 consecutive patients with mitral stenosis underwent examination by M-mode as well as cross-sectional echocardiography. The mitral valve area was measured by cross-sectional echocardiography ad the severity of mitral stenosis by M-mode echocardiography. Out of the total, 69 patients underwent left and right heart catheterization and in 53 of these the mitral valve area was calculated. A correlation of r=0.92 for the mitral valve area was found between sector scan echocardiography and cardiac catheterization, whereas the correlation between M-mode echocardiography and catheterization yielded a result of only r=0.38. Thus the assessment of the severity of mitral stenosis by cross-sectional echocardiography is a reliable alternative to cardiac catheterization.

Toxicological effects of dichlorvos (DDVP) on brain and liver acetylcholinesterase (AChE) activity of Tilapia mossambica, Peters

Acetylcholinesterase (AChE) activity of T. mossambica in relation to the interacting effects of aging and sub-lethal concentrations of Dichlorvos was studied. The enzyme activity of brain and liver decreased with increasing size (and age) and DDVP-exposed fish showed considerable inhibition of brain and liver AChE. The degree of enzyme inhibition followed a positive correlation with the insecticide concentration and the time of exposure. Brain exhibited a higher degree of enzyme inhibition in all age groups of fish as compared to liver. Small fish were more susceptible to the insecticide with respect to AChE activity. When transferred to clean water most of the exposed fish recovered their AChE activity and the recovery was greater in liver than in brain. Small fish exhibited comparatively a high level of recovery in the AChE activity. The degree of recovery followed an inverse relationship with the time of exposure.