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Biomedical subjects

W Frishman

Publications and source records attributed to W Frishman.

At least 55 records · Page 3Linked to original sources
PubMed1981

Dynamic responses to continuous use of prazosin and hydralazine in patients with refractory heart failure.

The hemodynamic effects of oral doses of prazosin and hydralazine were studied in the same group of patients with chronic congestive heart failure. Prazosin, 3 to 10 mg, and hydralazine, 75 to 100 mg, were given by mouth every 6 hr and the responses to the first and the fifth consecutive dose were compared. The first dose of prazosin was followed by a predominant effect of left ventricular filling pressure and concomitantly by reduction of left ventricular afterload. Hydralazine acted primarily on left ventricular afterload with no significant effect on the filling pressure. A marked difference was noted in respect to the dynamic responses to continuous therapy with these two drugs. While the initial hemodynamic effect of prazosin was markedly attenuated in most of the cases after the fifth consecutive oral dose, the response to hydralazine was augmented by continuous therapy. These findings suggest that the reported hemodynamic tachyphylaxis seen with prazosin does not occur with hydralazine when given to the same patients with chronic congestive heart failure. Our study also indicates the importance of prolonged monitoring for the assessment of the hemodynamic effect of prazosin and hydralazine in patients with severe chronic congestive heart failure.

Aged↗
PubMed1981

Clinical relevance of intrinsic sympathomimetic activity of beta blockers.

beta-Blockers are effective in the symptomatic relief of angina pectoris by decreasing myocardial oxygen demand during effort and emotional stress. Agents with ISA such as pindolol produce effective beta-blockade during effort or emotional stress while conferring significant protection from myocardial depression and bradycardia at rest. In addition, agents with ISA have been shown to depress respiratory function to a lesser extent and to induce fewer peripheral vascular side effects than compounds devoid of this property. These potential effects of ISA may be counterbalanced by the consideration that ISA may be undesirable in angina occurring at rest or at low exercise levels. Additional well-controlled trials in patients with angina and resting bradycardia or impaired left ventricular function are needed to further document the clinical importance of ISA.

Adrenergic beta-Agonists↗
PubMed1981

Efficacy of sublingual nifedipine in the acute treatment of systemic hypertension.

The effects of sublingual nifedipine, a calcium antagonist vasodilator, were assessed in 43 patients with moderate to severe hypertension in an emergency room setting. Following a no-response placebo treatment period, the patients with supine diastolic blood pressure of less than 110 mm Hg (group A, n equals 17) received 10 mg of sublingual nifedipine, and the patients with supine diastolic blood pressure of much greater than or equal to 110 mm Hg (group B, n equals 26) received a 20-mg sublingual dose. In group A, systolic blood pressure decreased from 172.4 plus or minus 18.6 mm Hg to 140.0 plus or minus 14.6 mm Hg; diastolic pressure from 108.8 plus or minus 3.3 mm Hg to 87.6 plus or minus 9.9 mm Hg (P less than 0.001)., In group B, systolic blood pressure decreased from 203.8 plus or minus 22.1 mm Hg to 160.0 plus or minus 23.6 mm Hg; diastolic pressure from 127.7 plus or minus 11.3 mm Hg to 96.7 plus or minus 14.1 mm Hg (P less than 0.001). Heart rate increased significantly only in the 20-mg dose group, from 76 plus or minus 2 to 89 plus or minus 6 beats/min (P less than 0.005). Th effects of sublingual nifedipine were seen in one to five minutes, and the maximal effect in 20 to 30 minutes, with return to placebo baseline in four to five hours. Adverse reactions were minimal in both treatment groups. Nifedipine is an effective and safe hypotensive drug in the rapid management of moderate to severe hypertension and seems to be an effective nonparenteral agent for treatment of hypertensive emergencies.

Acute Disease↗
PubMed1980

Application of transesophageal echocardiography to continuous intraoperative monitoring of left ventricular performance.

Transesophageal M mode echocardiography was used for continuous monitoring of left ventricular dimensions in 21 patients (11 with valvular and 10 with coronary heart disease) undergoing open heart surgery. Echocardiograms were recorded in six stages of the procedure and simultaneous measurements of cardiac output (with dye dilution) and atrial pressures were made. Measurements of left ventricular diameters with the transesophageal technique correlated excellently with the corresponding measurements obtained with the standard parasternal method. In patients with volume overload, surgical correction was accompanied by a decrease in diastolic dimension, velocity of circumferential fiber shortening, mid wall stress and end-diastolic stiffness, and an increase in cardiac output. Pericardial and chest wall closures generally caused a significant decrease in cardiac output, and correlated with a decrease in diastolic diameter and an increase in the stiffness constant of the left ventricle. Thus, the decrease in cardiac output may have been due to decreased distensibility of the ventricular cavity secondary to mechanical restriction by the pericardium and chest wall. Pericardial opening caused a significant delay in septal motion that was reversed by closing the pericardium. This study confirms the validity of transesophageal echocardiography and its usefulness in monitoring changes in ventricular function during cardiac surgery.

Adult↗
PubMed1980

The demonstration of vegetations by echocardiography in bacterial endocarditis. An indication for early surgical intervention.

The visualization of vegetations by M-mode echocardiography in patients with infective endocarditis has been suggested to imply a poor prognosis regarding the development of major systemic emboli, congestive heart failure and the need for early surgical intervention. The question of using the finding of vegetations by echocardiography as an indication for surgery is controversial. To answer this question, 30 patients with the clinical diagnosis of endocarditis were studied by echocardiography. In 17 of the 30 (57 per cent) vegetations were present (aortic eight, mitral four, both mitral and aortic five), whereas in 13 (43 per cent) no vegetations were visualized. Infecting organisms were similar in each group; Streptococcus viridans being the most common. The patients with echocardiographically demonstrable vegetations had a higher incidence of congestive heart failure compared to the patients without (14 of 17 versus six of 13, p less than 0.05), major emboli (eight of 17 versus two of 13, p = NS) and need for valve surgery (17 of 17 versus two of 13, p less than 0.001). Mortality was not significantly different in the two groups (six of 17 versus three of 13, p = NS). Urgent or emergency surgery was required in 16 of 17 patients with vegetations. Thus, the demonstration of vegetations by echocardiography identified a subset of patients with more severe disease in whom early operative intervention was required.

Adult↗
PubMed1980

Neurogenic hypertension related to vascular compression of the lateral medulla.

Neurogenic hypertension may be reproduced consistently in experimental animals, although its clinical significance is unclear. An ectatic loop of the posterior inferior cerebellar (PICA) compressed the left vagus nerve root entry-exit zone in two patients with long-standing hypertension. When this loop was mobilized for occipital-PICA bypass, the hypertension resolved. These observations suggest that neurovascular compression of the area encompassing the nucleus tractus solitarius may be a sufficient cause of neurogenic hypertension in humans. The structural and functional relationships of these areas of the brain stem and their role in modulating blood pressure are reviewed.

Adult↗
PubMed1980

Echocardiographic and surgical correlations in bacterial endocarditis.

The results of preoperative echocardiography were compared with the pathologic findings at the time of surgery in 24 patients undergoing valve surgery for endocarditis. Of the 32 valves involved by vegetations, 27 (84%) were identified preoperatively. Valve destruction was correctly predicted in 16 of 18 cases. Myocardial abscess formation was detected in only one of the five patients in whom it occurred. Overall, the echocardiograms satisfactorily predicted the pathologic anatomy in 20 cases. In the remaining four patients, the echocardiographic description was seriously incomplete or misleading. Thus, surgery can be recommended on the basis of the clinical and echocardiograhic findings for patients with endocarditis. Cardiac catheterization is reserved for patients in whom significant coronary artery disease or intracardiac shunts are suspected or in whom a satisfactory echocardiogram cannot be obtained.

Adult↗
PubMed1980

Hemodynamic performance of the Ionescu-Shiley valve prosthesis.

The hemodynamic performance of the Ionescu-Shiley bovine heterograft valve has been evaluated by intraoperative measurement of transvalvular gradients and cardiac outputs. Effective orifice areas (EOAs) were calculated and the data compared to those obtained by other investigators for other prostheses. In the aortic position, each valve, from 19 to 31 mm external diameter, produced a pressure gradient; mean EOA increased with increasing valve size, so that small (19 to 23 mm) valves were moderately stenotic and larger valves were only mildly stenotic. The presence of a mitral prosthesis produced larger transaortic valve gradients, probably as a result of aortic outflow obstruction by the mitral prosthesis. The Ionescu valve appears to be hemodynamically superior to other biological valves in the aortic position and comparable to most mechanical prostheses, although the data for comparison are scant. Each mitral valve produced a pressure gradient and, on the average, larger (29 mm) valves performed no better than smaller (25 mm). Mean EOAs for each valve size (25 to 29 mm) were adequate to provide satisfactory hemodynamics comparable to other available prosthetic valves. Mild obstruction of the left ventricular outflow by the prosthetic struts was seen to be related to the distance between ventricular septum and the struts. Most currently available prostheses seem to provide similar hemodynamics in the mitral position, and considerations such as thrombogenicity and durability may be relatively more important in the choice of a mitral valve substitute than in the choice of an aortic valve substitute.

Aortic Valve↗
PubMed1979

Echocardiographic findings in cardiogenic shock due to right ventricular myocardial infarction.

The echocardiographic findings in a patient with cardiogenic shock secondary to acute right ventricular myocardial infarction based on typical clinical, electrocardiographic, and hemodynamic features are described. The echocardiogram demonstrated a large RV/LV minor axis ratio caused by a volume overload of the right ventricle and an underfilled left ventricle. The interventricular septum showed abnormal movement, presumably due to right ventricular overload or severe disease of the left anterior descending coronary artery. Diminished septal systolic thickening, as seen in our patient, may be explained by extension of the infarct from the right ventricle to the adjacent part of the septum. Predominant right ventricular involvement can be a cause for a correctable hypotension in patients with acute myocardial infarction and should therefore be recognized early. The echocardiographic picture demonstrated in our patient, when considered in conjunction with the clinical status, can be useful for early diagnosis.

Echocardiography↗