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Biomedical subjects

B H Greenberg

Publications and source records attributed to B H Greenberg.

At least 19 recordsLinked to original sources
PubMed1991

Does the magnitude of mitral regurgitation determine hemodynamic response to vasodilation in chronic congestive heart failure?

Although it is usually assumed that direct-acting vasodilators improve cardiac function in patients with congestive heart failure (CHF) by altering left ventricular preload and afterload, several studies have suggested that most of the benefit occurs as a result of a reduction in associated mitral regurgitation (MR), which is present in the majority of patients with severe CHF. To test his hypothesis, the hemodynamic response to oral hydralazine was examined in CHF patients with competent mitral prostheses (group 1) and patients with CHF due to severe MR and left ventricular dysfunction (group 2). Both groups demonstrated significant increases in cardiac, stroke volume, and stroke work indices, although these were greater in group 2. Only group 2 experienced a significant reduction in left ventricular filling pressure. Thus, the presence of MR is not essential for hemodynamic improvement but is associated with significantly greater responses.

Adult↗
PubMed1991

Medical therapy for patients with aortic insufficiency.

The medical course and management of patients with aortic insufficiency depends on the severity of the valve lesion and acuity with which it develops. In this article a description of the basic pathophysiology of aortic insufficiency and the natural history of the disease is outlined. Recent information describing both the acute and long-term effects of vasodilator therapy is summarized. With this information, a rational approach to the medical management of aortic insufficiency is developed.

Acute Disease↗
PubMed1990

Vasodilatory effects of lidocaine on epicardial porcine coronary arteries.

To investigate the mechanism of lidocaine's effect to cause vasorelaxation, swine epicardial mid-right coronary arterial rings were placed under constant (5 g) tension in a muscle bath, precontracted with 35 mmol/l KCl and exposed to increasing concentrations of lidocaine (3-2,000 micrograms/ml). At a concentration of 10 micrograms/ml, mild vasoconstriction occurred, increasing tension 1.9 +/- 0.1% above baseline. Vasodilation began to occur at 30 micrograms/ml and was maximal at 2,000 micrograms/ml, reducing tension 97.5 +/- 0.2% below baseline. Vasodilation was not altered significantly by removal of endothelium or by pretreatment with propranolol or indometacin.

Animals↗
PubMed1990

Medical management of congestive heart failure.

The syndrome of congestive heart failure can result from a variety of cardiac disorders of which left ventricular dysfunction is the most common. The clinical presentation is determined by the interaction between cardiac dysfunction and a series of compensatory mechanisms that are activated throughout the body. Therapy for this disorder is best approached through an understanding of this complex relationship and an appreciation for the influence of preload, afterload, and contractility on cardiac performance. Recent important advances in therapy include the use of combined diuretic therapy, a better understanding of the value of the digitalis glycosides, and evidence that angiotensin-converting enzyme (ACE) inhibitors can relieve symptoms and prolong life. More intensive therapy earlier in the course of congestive heart failure appears to have some clinical benefit. The use of ACE inhibitors during this phase may delay progression of the underlying left ventricular dysfunction. Future therapy will be influenced by the results of ongoing trials that are testing both new agents and expanded indications for drugs that are currently available.

Cardiac Output↗
PubMed1989

Mechanical characteristics of the failing left ventricle.

Overall cardiac performance depends on both the systolic and diastolic function of the left ventricle (LV). Determinants of LV systolic function include preload, afterload, and contractility. In patients with congestive heart failure (CHF), abnormalities of systolic and diastolic function often coexist. In addition, compensatory changes that develop in response to low cardiac output and high ventricular pressures can affect the mechanical characteristics of the LV. Therapy of CHF is aimed at improving myocardial contractility and reducing both preload and afterload. Agents that can relieve volume overload and those that decrease intrinsic LV chamber stiffness (and increase compliance) will improve diastolic function.

Biomechanical Phenomena↗
PubMed1988

Left ventricular response to submaximal and maximal exercise in asymptomatic aortic regurgitation.

In patients with chronic aortic regurgitation the quantitative changes in loading conditions and left ventricular performance from rest to submaximal exercise have not been related to the magnitude of change observed from rest to maximal exercise. Changes in end-diastolic volume index, as a measure of preload, and measures of contractile performance (ejection fraction and the systolic blood pressure/end-systolic volume index ratio) were assessed at rest, submaximal and maximal supine bicycle exercise using radionuclide angiography in 74 patients with chronic moderate to severe aortic regurgitation. With exercise, end-diastolic volume index decreased in a stepwise manner from 166 +/- 47 to 152 +/- 41 to 143 +/- 41 ml/m2 at rest, submaximal and maximal exercise, respectively. For the entire group, these changes were not associated with a significant change in ejection fraction but were associated with stepwise increases in systolic blood pressure to end-systolic volume index ratio. However, when patients were divided into 3 subgroups based on an increase (group I), minimal change (group II) or a decrease (group III) in ejection fraction from rest to maximal exercise, stepwise increases in systolic blood pressure to end-systolic volume index were again observed in groups I and II but not in group III. These changes were significantly greater in group I than in group II at submaximal and maximal exercise levels. Differences in ejection fraction response and end-diastolic and end-systolic volumes with exercise in the 3 groups were evident at the submaximal exercise level.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve Insufficiency↗
PubMed1987

Static exercise with congestive heart failure and the response to vasodilating drugs.

The hemodynamic response to static exercise in 28 patients with congestive heart failure (CHF) was compared with that in 8 control subjects. Static handgrip exercise at 50% of the maximal voluntary contraction was performed to fatigue. In patients with CHF, pulmonary arterial wedge pressure increased from 20 +/- 18 to 31 +/- 10 mm Hg (p less than 0.001) (mean +/- standard deviation) and systemic vascular resistance increased from 1,730 +/- 454 to 2,151 +/- 724 dynes s cm-5 (p less than 0.001). Although cardiac index did not change significantly, stroke volume index and stroke work index decreased from 24 +/- 6 to 20 +/- 6 ml/m2 (p less than 0.001) and 28 +/- 11 to 25 +/- 12 g-m/s2 (p less than 0.05), respectively. In control subjects, pulmonary arterial wedge pressure did not change significantly; cardiac index increased from 3.6 +/- 0.3 to 4.0 +/- 0.4 liters/min/m2 (p less than 0.05) and systemic vascular resistance increased slightly, from 1,011 +/- 186 to 1,106 +/- 180 dynes s cm-5 (p less than 0.05). The effects of arterial dilation with hydralazine on the response to static exercise were assessed in 10 of the patients with CHF. Compared with predrug exercise, cardiac index increased 68% (p less than 0.01), stroke volume index increased 76% (p less than 0.01) and systemic vascular resistance decreased 47% (p less than 0.01) after administration of hydralazine. Thus, static exercise can have adverse effects on cardiac performance in patients with CHF.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Beneficial effects of the calcium antagonist PN 200-110 in patients with congestive heart failure.

We studied the acute hemodynamic effects of PN 200-110, a newly available calcium antagonist, in 12 patients with severe congestive heart failure. Measurements of cardiac performance were obtained by a right heart catheter before and after administration of 5 and 15 mg of PN. Peak drug effects occurred 1-2 h following the administration of PN 200-110 and were dose related. The 15-mg dose reduced mean arterial pressure (MAP) from 90 +/- 11 to 75 +/- 6 mm Hg (mean +/- SD) (p less than 0.001) and decreased systemic vascular resistance (SVR) from 1,740 +/- 500 to 995 +/- 300 dynes X s X cm-5 (p less than 0.01). Stroke volume index (SVI) increased from 26 +/- 7 to 36 +/- 10 ml/m2 (p less than 0.001), and cardiac index (CI) rose from 2.1 +/- .3 to 2.8 +/- .6 L/m2 (p less than 0.01). Pulmonary arterial wedge pressure (PAW) changed insignificantly. Seven patients performed graded supine exercise at identical workloads before and after treatment. When peak exercise values were compared, the addition of PN 200-110 further reduced SVR from 1,282 +/- 461 to 936 +/- 356 dynes X s X cm-5 (p less than 0.01) and increased CI from 3.3 +/- 1.1 to 4.3 +/- 1.3 L/m2 (p less than 0.01). Only minor, self-limiting side effects were noticed during acute administration. Of the seven patients discharged on PN 200-110 and followed for at least 6 months, six reported substantial relief of symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Ejection fraction response to supine exercise in asymptomatic aortic regurgitation: relation to simultaneous hemodynamic measurements.

The change in ejection fraction during exercise is frequently employed as a measure of left ventricular functional reserve in patients with aortic regurgitation. However, little information is available about its relation to invasive measurements of cardiac performance. Therefore, simultaneous hemodynamic measurements and supine exercise blood pool scintigraphy were performed in 14 patients with severe, asymptomatic or minimally symptomatic aortic regurgitation associated with cardiomegaly but preserved left ventricular function at rest. Their hemodynamic measurements at rest were normal and their exercise capacity was excellent. When the patients were categorized into those patients whose ejection fraction increased or did not decrease by more than 0.05 (Group 1) and those whose ejection fraction decreased by more than 0.05 (Group 2), important differences were apparent. Echocardiographic, radionuclide and hemodynamic measurements at rest in the two patient groups were similar, but Group 1 exhibited a greater increase in cardiac index during supine exercise (2.8 +/- 0.4 to 10.0 +/- 1.8 versus 2.7 +/- 0.5 to 6.9 +/- 1.0 liters/min per m2; p less than 0.005) and a lesser increase in pulmonary capillary wedge pressure (13 +/- 4 to 19 +/- 7 versus 12 +/- 4 to 31 +/- 8 mm Hg; p less than 0.01). The severity of regurgitation decreased during exercise in all patients, but end-diastolic volume decreased and end-systolic volume decreased or was unchanged in Group 1, whereas end-diastolic volume was unchanged and end-systolic volume increased in Group 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

The relationship between functional class and cardiac performance in patients with chronic aortic insufficiency.

We have evaluated the relationship of New York Heart Association functional class (FC) assessment to rest and exercise hemodynamics and resting left ventricular (LV) functional data in 75 consecutive patients with isolated, chronic aortic insufficiency. Although there was a tendency for hemodynamic and angiographic variables to worsen as FC increased there was considerable overlap between patients assigned to the various groups. Statistically significant differences were seen only for resting left ventricular end-diastolic pressure (LVEDP) and pulmonary artery wedge (PAW) pressure which were higher in FC 3/4 patients than in FC 1 or 2 patients. The results of our study suggest that FC assignment cannot be used to accurately define underlying LV performance or hemodynamics in an individual patient with chronic aortic insufficiency. However, since severe abnormalities are unlikely to be present in asymptomatic patients, routine detailed frequent investigation does not seem warranted in this group. As FC worsens, the likelihood of left ventricular dysfunction increases. Thus, the presence of symptoms is an indication for more extensive evaluation.

Adult↗
PubMed1983

The preoperative evaluation in patients with endocarditis. Is cardiac catheterization necessary?

We retrospectively compared clinical assessment and cardiac catheterization to subsequent surgical findings with regard to specific valvular involvement, hemodynamic status, and presence of myocardial abscess in patients recommended for cardiac surgery for endocarditis. Of 105 consecutive patients with endocarditis, 19 met one or more of the following criteria suggesting the need for early surgery: congestive heart failure; systemic emboli; persistent infections or new conduction abnormalities. Of these 19 patients, seven had prosthetic cardiac valves. Clinical assessment was highly sensitive (95 percent) and specific (89 percent) for specific valvular involvement and was also highly sensitive and specific in evaluating myocardial abscess and congestive heart failure; however, clinical assessment could not identify the source of infection in one patient with multiple prosthetic valves, did not define the specific valve in one patient with right-sided endocarditis, and overestimated the severity of mitral regurgitation in one patient who had normal pressures and flows at catheterization. Catheterization incorrectly predicted multivalvular involvement in four patients. At catheterization, only one patient experienced evidence of clinical deterioration, and this was probably not related to the procedure. We conclude that although clinical assessment is correct in most patients, it may on occasion lead to an erroneous conclusion. Catheterization and angiograms are of value in the preoperative evaluation of patients with endocarditis, particularly in cases where the clinical assessment is ambiguous or uncertain. The procedures can be performed at low risk, and the information obtained may substantially influence management in some cases.

Adolescent↗
PubMed1982

Acute effects of alcohol in patients with congestive heart failure.

We evaluated the acute effects of moderate alcohol consumption in eight patients with New York Heart Association Functional Class III-IV congestive heart failure. Hemodynamic and echocardiographic variables were measured at baseline and then repeated at 30-minute intervals after ingestion of alcohol, 0.9 g/kg body weight, in the form of 80 proof vodka. Mean peak blood alcohol levels (+/- SE) at 60 minutes were 117 +/- 8 mg/dL. A significant reduction in mean arterial pressure, pulmonary artery and pulmonary artery wedge pressures, and systemic vascular resistance occurred over the first 90 minutes. Neither cardiac index, stroke volume index, stroke work index, nor echocardiographic variables were significantly changed. In patients with heart failure, a single moderate dose of alcohol reduces afterload by dilating arterial resistance vessels. No evidence of acute deterioration in cardiac performance was seen. In such patients occasional consumption of moderate dose alcohol can be safely tolerated.

Adult↗
PubMed1981

Mechanism for improved cardiac performance with arteriolar dilators in aortic insufficiency.

To determine how arteriolar dilation improves cardiac performance in aortic insufficiency, we evaluated the acute effects of hydralazine in 10 patients with chronic severe aortic insufficiency. Control measurements of intracardiac and intravascular pressures, cardiac output and left ventricular volumes were obtained at cardiac catheterization. Hydralazine, 0.3 mg/kg i.v. (maximal dose 20 mg), was administered and all measurements were repeated 30 minutes later. A reduction in systemic vascular resistance from 1264 to 710 dyn-sec-cm-5 was associated with significant increases in forward cardiac index (2.9 to 5.1 l/min/m2) and stroke volume index (37 to 55 ml/m2). Left ventricular end-diastolic pressure was reduced from 19 to 12 mm Hg. There was a significant reduction in mean arterial pressure (88 to 83 mm Hg) and a significant increase in heart rate (81 to 94 beats/min). Regurgitant stroke volume was reduced by more than 10 ml/m2 in seven patients and for the group was significantly reduced, from 65 to 53 ml/m2. Regurgitant fraction was reduced in all patients; the overall reduction from 0.64 to 0.48 was highly significant. Ejection fraction increased more than 0.10 in four patients, by 0.08 in an additional patient and for the group increased significantly from 0.50 to 0.57. Left ventricular end-diastolic volume decreased by more than 25 ml/m2 in four patients, by 19 ml/m2 in an additional patient and was decreased significantly, from 208 to 190 ml/m2, for the group. Arteriolar dilators improve cardiac performance in aortic insufficiency by reducing the amount of aortic regurgitation and, in some patients, by substantially improving systolic pump fraction. These data suggest a role for arteriolar dilators in the management of selected patients with aortic insufficiency.

Adult↗
PubMed1981

Results of long-term vasodilator therapy in patients with refractory congestive heart failure.

The long-term effects of vasodilator therapy with oral hydralazine and long-acting nitrates were studied in 34 patients with refractory heart failure. Seven patients who had marginal hemodynamic improvement despite optimal hydralazine therapy were not maintained on vasodilators, and eight who had a favorable hemodynamic response subsequently discontinued hydralazine therapy because of side effects. Of these 15 patients, four (27%) died and 11 remained in New York Heart Association functional class II or IV at a mean follow-up of 10 +/- 2 months (SEM). The 19 patients who received chronic therapy for 8 +/- 2 months were divided into nine late responders (47%), who improved to functional class I or II, and 10 late nonresponders (53%), who remained in functional class III or IV. Only one of the nine late responders (11%) died, compared with seven of the 10 late nonresponders (70%) (p less than 0.01). The actuarially determined survival at 1 year was 100% for late responders and 13 +/- 12% for late nonresponders (p less than 0.01). No clinical variable could distinguish late responders from late nonresponders. Hemodynamic variables measured before vasodilator therapy showed that late responders had a lower mean right atrial pressure (8 +/- 1 vs 17 +/- 3 mm Hg, p less than 0.01) and lower mean pulmonary artery wedge pressure (20 +/- 2 vs 30 +/- 2 mm Hg, p less than 0.005), higher stroke, volume index (27 +/- 2 vs 20 +/- 1 ml/m2, p less than 0.005) and higher stroke work index (32 +/- 4 vs 19 +/- 2 g-m/m2, p less than 0.01) than late nonresponders. There were no significant differences in the acute response to vasodilators between the two groups. We conclude that (1) a substantial portion of patients with refractory congestive heart failure either do not have a beneficial response to vasodilator therapy or discontinue it because of side effects; (2) about half of the patients who are maintained on chronic vasodilator therapy (or about one-fourth of the patients in whom therapy is initiated) had sustained clinical benefit; and (3) the initial hemodynamics, but not the clinical variables, are predictive of late mortality and late clinical response. Patients with evidence of more severe left ventricular dysfunction have an unfavorable course.

Administration, Oral↗