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Biomedical subjects

J L Weiss

Publications and source records attributed to J L Weiss.

At least 109 records · Page 6Linked to original sources
PubMed1982

Nifedipine in unstable angina: a double-blind, randomized trial.

We assessed the efficacy of adding nifedipine to the conventional treatment of unstable angina in 138 patients in a prospective, double-blind, randomized, placebo-controlled trial. There was no difference between the two groups in the dose of conventional antianginal medication or in age, prior myocardial infarction, ejection fraction, or other risk factors. Failure of medical treatment (defined as sudden death, myocardial infarction, or bypass surgery within four months) occurred in 43 of 70 patients given placebo and in 30 of 68 given nifedipine. Kaplan-Meier survival-curve analysis of the number and time dependence of treatment failures demonstrated a benefit of nifedipine over placebo (P = 0.03). The benefit was particularly marked in patients with ST-segment elevation during angina (P = 0.02). Side effects (transient hypotension or diarrhea) required withdrawal of the drug from four patients given nifedipine and from one given placebo. We conclude that the addition of nifedipine to conventional therapy is safe and effective in unstable angina.

Adult↗
PubMed1982

Catenoidal shape of the interventricular septum in idiopathic hypertrophic subaortic stenosis: two dimensional echocardiographic confirmation.

A catenoid is a curved surface with the property of net zero curvature at all points. Morphologic observations have suggested that the interventricular septum in idiopathic hypertrophic subaortic stenosis has a catenoid shape, (that is, concave to the left in the transverse plane and convex to the left in the sagittal plane). To determine if such a septal configuration is present in living patients, six patients with clinically diagnosed idiopathic hypertrophic subaortic stenosis were studied with phased array two dimensional echocardiography, and left ventricular wall segment curvature, thickness and motion were compared with values in six patients with left ventricular hypertrophy secondary to long-standing systemic hypertension, and in six normal subjects. A curvature thickness index was determined from the echocardiographic image for systole and diastole as: curvature thickness index equals segment thickness times the sum of curvatures in the transverse and sagittal planes. In all six patients with idiopathic hypertrophic subaortic stenosis the septum had a catenoidal configuration and showed significantly less (p less than 0.05) septal change in the curvature thickness index during the cardiac cycle than it did in the control groups. In contrast, the left ventricular free wall had significantly greater (p less than 0.05) change of curvature thickness index over the cardiac cycle in patients with idiopathic hypertrophic subaortic stenosis. The hyperkinetic free wall motion seemed to account in part for systolic anterior motion of the anterior mitral leaflet as part of the displacement of the entire mitral apparatus. The catenoid shape of the septum observed in idiopathic hypertrophic subaortic stenosis may account for asymmetric hypertrophy and septal immobility, because a ventricular segment with net zero curvature would develop internal tension but have isometric contraction.

Adolescent↗
PubMed1981

Ventricular size and shape by two-dimensional echocardiography.

The evaluation of cardiac size and shape has been aided by the recent development of high resolution real-time two-dimensional echocardiography, which permits dynamic cross-sectional evaluation of all or a large portion of the left ventricle throughout the cardiac cycle. This review addresses itself to the determination of left ventricular size and shape by two-dimensional echocardiography. A method is described for accurate volume determination in the intact, isolated, ejecting canine heart. By combining the two-dimensional echocardiogram with knowledge of transducer position and orientation with respect to the heart, it is possible to reconstruct a three-dimensional representation of a chamber and thereby measure volume without reliance on major geometric assumptions. Because of the unique ability of two-dimensional echocardiography to produce a cross-sectional image of the beating heart in a large number of planes, it is suitable for the determination of cardiac shape and architecture. The recognition of early regional cardiac dilatation in acute myocardial infarction is described. Changes in ventricular shape brought about by the dynamic alterations lend themselves well to two-dimensional echocardiographic study. The pivotal nature of the interventricular septum renders it susceptible to changes in the functional state of both ventricles. That the interventricular septum may mediate ventricular interaction acutely is suggested by the acute effects of right ventricular loading in man using the Mueller maneuver. Leftward septal displacement and flattening of the septum during the early maximal Mueller maneuver is evidenced by a substantial increase in the radius of curvature of the septal segment, without a change in the left ventricular free wall. This septal flattening occurs in diastole and persists during systole. Diastolic events thus appear to influence systolic shape. Changed septal shape may be an important mechanism of, and evidence for, ventricular interdependence in normal man.

Animals↗
PubMed1981

Clinical recognition of giant left ventricular aneurysm.

The noninvasive diagnosis of left ventricular aneurysm has markedly improved with gated blood pool scintigraphy. However, in patients with giant anterior ventricular aneurysms, the gated blood pool scintigram performed in two standard views (anterior and 40 degree left anterior oblique) may incorrectly suggest ischemic cardiomyopathy. We retrospectively identified five patients who underwent resection of a ventricular aneurysm over a 2 1/2 year period and who had preoperative scintigraphic studies that appeared to show severe diffuse left ventricular dysfunction. contrast ventriculography demonstrated preserved wall motion in septal, inferior and lateral segments not seen by gated blood pool scintigraphy and showed extraordinarily large anterior aneurysms. M-mode or two-dimensional echocardiograms showed intact posterior wall function in all patients, suggesting severe regional myocardial disease rather than global dysfunction. Two-dimensional echocardiography showed additional segments with preserved function as well as discrete aneurysms in all patients. We conclude that gated blood pool scintigraphy, when performed in two standard views, may fail to correctly diagnose some patients with very large anterior wall aneurysms. M-mode echocardiography, two-dimensional echocardiography and additional scintigraphic views that visualize the posterior portions of the left ventricle improve noninvasive diagnosis of patients with resectable giant left ventricular aneurysms.

Aged↗
PubMed1981

The predictive value of a strongly positive stress test in patients with minimal symptoms.

The ability of a strongly positive stress test to predict left main coronary artery disease in people with suspected coronary artery disease but with minimal or no angina was investigated in 40 such patients. Nine had a history of myocardial infarction but no angina. Thirty-one had mild angina or a history of mild angina. The stress electrocardiograms were analyzed according to criteria known to be associated with left main coronary artery disease in moderately or severely symptomatic patients; (1) early S-T segment changes (stage I or II of exercise), (2) 2 mm or more S-T segment depression, (3) downsloping S-T segments, (4) associated exercise-induced hypotension, (5) prolonged S-T segment changes after the test (greater than or equal to 8 minutes) and (6) anterior and inferior S-T segment depression. The prevalence of left main coronary artery disease was 35 percent and that of any severe coronary artery disease 75 percent. The criterion of anterior and inferior electrocardiographic changes with exercise was most predictive of left main coronary artery disease (P less than 0.01 by chi 2). Exercise electrocardiography is useful in the prediction of left main or other severe coronary artery disease even when performed in patients who have minimal angina or in those who are asymptomatic after myocardial infarction.

Adult↗
PubMed1981

Diagnosis and management of postoperative pericardial effusions and late cardiac tamponade following open-heart surgery.

The clinical and laboratory findings of 28 patients identified as having late pericardial effusions were examined. Eleven of these patients were asymptomatic; 9 patients had moderate symptoms including fatigue, malaise, weight gain, and dyspnea on exertion, and 8 patients with similar symptoms had evidence of cardiac tamponade. Ten patients underwent right heart catheterization in the intensive care unit; normal hemodynamics were confirmed in 4 and cardiac tamponade in 6 patients. Pericardiocentesis was effective in decompressing cardiac tamponade in 7 of 8 patients. One patient required operative subxiphoid drainage after unsuccessful pericardiocentesis. In addition, 5 patients with moderate clinical symptoms and pericardial effusions, who did not have cardiac tamponade, underwent pericardiocentesis because of a need for chronic anticoagulant therapy. The remaining patients were managed successfully by observation, discontinuation of warfarin when possible, fluid restriction, and diuretic therapy. All but 1 patient was symptomatically improved. A diagnostic and therapeutic schema is presented as an aid to early recognition of this troublesome and potentially lethal complication.

Adult↗
PubMed1981

Transseptal pressure gradient with leftward septal displacement during the Mueller manoeuvre in man.

Septal displacement is postulated as an important mediator of ventricular interdependence. During acute right ventricular loading with the Mueller manoeuvre the septum flattens and shifts leftward. To investigate the mechanism of this septal deformation, we measured transseptal pressures in nine patients during Mueller manoeuvres with simultaneous right and left ventricular micromanometers, and left ventricular configuration with two-dimensional echocardiograms. Data were analysed throughout diastole and at end-systole during control and maximum Mueller manoeuvre (-40 to -80 mmHg airway pressure). Leftward septal displacement during the Mueller manoeuvre was evidenced by an increase in septal radius of curvature at end-diastole persisting through end-systole. The left ventricular free wall radius of curvature was unchanged. During the Mueller manoeuvre, the left ventricular cavity area decreased significantly in the cross-sectional view. All Mueller manoeuvres were associated with a decrease in left-to-right ventricular transseptal pressure gradient throughout diastole. There was no significant change in the gradient at end-systole; septal flattening persisted, however, despite a pronounced left to right pressure gradient. Thus, diastolic septal flattening during right ventricular loading is associated with a decreased transseptal pressure gradient but does not require right ventricular diastolic pressure to exceed left ventricular diastolic pressure. The persistence of flattening in systole suggests that once septal shift occurs during diastole, other forces during systole maintain the deformity despite a large intracavitary transseptal gradient.

Blood Pressure↗
PubMed1981

Combined administration of nitroglycerin and propranolol to patients with acute myocardial infarction.

Hemodynamic effects of combined nitroglycerin and propranolol administration were investigated in patients with acute myocardial infarction. After nitroglycerin infusion decreased the mean arterial pressure by 20 mm Hg for one hour, nitroglycerin was continued, and patients were given 0.033 mg/kg of propranolol every five minutes for a total dose of 0.1 mg/kg, or until there was a decrease in heart rate to less than 60 beats/min, an increase in left ventricular filling pressure (LVFP) to greater than 15 mm Hg, or a decrease in systolic arterial pressure to less than 85 mm Hg. Seven of eight patients with initial LVFP less than or equal to 15 mm Hg and three of seven with initial LVFP greater than 15 mm Hg received 0.1 mg/kg of propranolol. Propranolol significantly decreased heart rate. Although pressure time/minute decreased significantly, the magnitude of its decrease was small, suggesting only a minimal effect on myocardial oxygen demands. The LVFP increased after giving propranolol but remained less than the control value. Simultaneous administration of nitroglycerin likely prevented further increases, since LVFP increased after cessation of nitroglycerin infusion, and three patients subsequently had pulmonary edema. Propranolol administration resulted in a significant increase in peripheral vascular resistance and a decrease in cardiac output.

Blood Pressure↗
PubMed1979

Regional cardiac dilatation after acute myocardial infarction: recognition by two-dimensional echocardiography.

To assess the early topographic changes after acute transmural myocardial infarction, we studied 28 patients during the first two weeks after infarction by serial two-dimensional echocardiography. Regional end-diastolic segment lengths and wall thicknesses for anterior and posterior left ventricular walls were calculated. Eight patients showed infarct expansion, with disproportionate dilatation and transmural thinning in the infarcted zone, that was significantly different (P less than 0.005) from changes in non-infarcted regions. This regional expansion led to an overall left ventricular dilatation in these eight patients of 25 per cent compared to 5 per cent in the 20 patients without infarct expansion. Although the eight patients with regional expansion did not have significantly higher peak creatine kinase or Killip classification, they had a significantly greater eight-week mortality (four of eight versus none of 20, P less than 0.004). Thus, regional cardiac dilatation may be an early, lethal consequence of transmural infarcts, and appears to be an important mechanism of acute cardiac dilatation after myocardial infarction.

Acute Disease↗
PubMed1979

Current management of atrial myxoma with emphasis on a new diagnostic technique.

Sixteen patients aged 22-64 years have undergone removal of atrial myxoma at the Johns Hopkins Hospital. The first two patients had myxomas removed by closed surgical approach, and both died. Fourteen consecutive patients have undergone operation with the aid of cardiopulmonary bypass, and all survived. There has been one late death unrelated to myxoma. Current surgical approach is excision of the tumor and its stalk or base and resection of the portion of intra-atrial septum to ensure complete removal. Recently a new diagnostic technique of two-dimensional phased array real time echocardiography has been used in four patients, including a pregnant woman, to confirm the clinical diagnosis of atrial myxoma. This technique provides a two-dimensional view of both atria and ventricles in cross section or sagittal view. This noninvasive method is painless, is independent of cardiac function and carries no risk or radiation hazard. The two-dimensional echocardiogram is superior to the standard one-dimensional or M-mode echocardiogram for diagnosis of myxoma in that it can evaluate simultaneously both right and left atria, can detect smaller space-occupying lesions because of better resolution and can more readily determine the size of the lesion and its stalk, can evaluate the mobility of the tumor and can determine more accurately the extent of tumor obstruction. Because of these qualities, we have relied on two-dimensional echocardiography as the definitive diagnostic procedure for detection of atrial myxoma. Currently operation for atrial myxoma is performed without cardiac catheterization or angiocardiography.

Adult↗