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Biomedical subjects

B R Alter

Publications and source records attributed to B R Alter.

10 recordsLinked to original sources
PubMed1985

Interventional therapy for the treatment of acute myocardial infarction: thrombolysis with and without angioplasty. A brief review of the literature and the experience at a community hospital.

Thrombolytic therapy is a feasible, practical, and important approach to the treatment of the patient with an acute myocardial infarction. Data have conclusively demonstrated improvement in both postinfarction indices of left ventricular function and overall survival statistics. Definitive treatment for the underlying coronary lesion may be done acutely with percutaneous transluminal coronary angioplasty or the patient may undergo elective bypass surgery or coronary angioplasty at a later time, depending on the clinical circumstances. Direct intracoronary infusion of the thrombolytic agent is the most effective route of administration. However, if it is not possible for the patient to be taken to a cardiac catheterization laboratory, the intravenous route may be used. Further development of newer thrombolytic agents will undoubtedly make this mode of therapy standard and routine for the patient with acute myocardial infarction.

Adult↗
PubMed1983

The effects of intraventricular gradients on left ventricular ejection dynamics.

The generation of abnormal gradients between the apical cavity and the subaortic valvular region of the left ventricle in patients with hypertrophic cardiomyopathy (HCM) has traditionally been equated to a dynamic obstruction to left ventricular outflow. To examine this concept in more detail, left ventricular ejection dynamics were studied during cardiac catheterization in 30 patients with HCM and 29 patients with no evidence of cardiovascular disease. Using multisensor catheterization techniques, ascending aortic flow velocity and micromanometer left ventricular and aortic pressures were simultaneously recorded during rest (n = 47). Dynamic left ventricular emptying was also analyzed with frame-by-frame angiography (n = 46). The temporal distribution of left ventricular outflow was independently derived from both flow velocity and angiographic techniques. The HCM patients were subdivided into three groups: I, intraventricular gradients at rest (n = 9); II, intraventricular gradients only with provocation (n = 12); III, no intraventricular gradients despite provocation (n = 9). Expressed as a precentage of the available systolic ejection period (%SEP), the time required for ejection of the total stroke volume was (mean +/- 1 S.D.): Group I, 69 +/- 17% (flow), 64 +/- 6% (angio); Group II, 63 +/- 14% (flow), 65 +/- 6% (angio); Group III, 61 +/- 16% (flow), 62 +/- 4% (angio); control group, 90 +/- 5% (flow) 86 +/- 10% (angio). No significant difference was observed between any of the three HCM subgroups, but, compared with the control group, ejection was completed much earlier in systole independent of the presence or absence of intraventricular gradients. The presence of coexisting mitral regurgitation in 12 of the HCM patients did not alter these results. This study demonstrates that 'outflow obstruction', as traditionally defined by the presence of an abnormal intraventricular pressure gradient and systolic anterior motion of the mitral valve, does not impede left ventricular outflow in HCM. In a pure fluid dynamic sense, we believe that outflow obstruction does not exist in this disease entity.

Angiography↗
PubMed1981

Pacemaker-induced hypotension.

We report a case of hypotension and decreased cardiac output resulting from artificial ventricular pacemaker rhythm. Hemodynamic deterioration was associated with loss of normal time relationships between atrial and ventricular contraction and paradoxical fall in systemic vascular resistance despite a low output state. The therapeutic implications of this unusual response are discussed.

Aged↗
PubMed1980

Dynamics of left ventricular ejection in obstructive and nonobstructive hypertrophic cardiomyopathy.

The purpose of this study was to examine the dynamics of left ventricular ejection in patients with obstructive and nonobstructive hypertrophic cardiomyopathy (HCM). 30 patients with HCM and 29 patients with no evidence of cardiovascular disease were studied during cardiac catheterization. Using a single multisensor catheter, electromagnetically derived ascending aortic flow velocity and high fidelity left ventricular and aortic pressures were recorded during rest (n = 47) and provocative maneuvers (n = 23). Dynamic ventricular emptying during rest was also analyzed with frame-by-frame angiography (n = 46). Left ventricular outflow was independently derived from both flow velocity and angiographic techniques. The HCM patients were subdivided into three groups: (I) intraventricular gradients at rest (n = 9), (II) intraventricular gradients only with provocation (n = 12), and (III) no intraventricular gradients despite provocation (n = 9). During rest, the percentage of the total systolic ejection period during which forward aortic flow existed was as follows (mean +/- 1 SD): group I, 69 +/- 17% (flow), 64 +/- 6% (angio); group II, 63 +/- 14% (flow), 65 +/- 6% (angio); group III, 61 +/- 16% (flow), 62 +/- 4% (angio); control group, 90 +/- 5% (flow), 86 +/- 9% (angio). No significant difference was observed between any of the HCM subgroups, but compared with the control group, ejection was completed much earlier in systole independent of the presence or absence of intraventricular gradients. These results suggest that "outflow obstruction," as traditionally defined by the presence of an abnormal intraventricular pressure gradient and systolic anterior motion of the mitral valve, does not impede left ventricular outflow in HCM.

Blood Flow Velocity↗
PubMed1977

Traumatic right coronary artery-right ventricular fistula with retained intramyocardial bullet.

A case of traumatic right coronary artery-right ventricular fistula secondary to a gunshot wound is presented. In addition, the bullet was retained within the interventricular septum. The diagnostic approach, surgical findings and operative procedure of this and other reported cases are discussed. Several key points are emphasized. First, extended follow-up is necessary after trauma to the heart since fistulas may develop years after the initial injury. Second, surgery is generally indicated for fistulas although some data are presented suggesting that small to moderate fistulas may be treated medically. Third, if surgery is undertaken, very careful operative technique must be utilized to locate and close the fistula. Surgical treatment of choice may be coronary arterial ligation with a distal bypass graft if necessary. Postoperative evaluation is mandatory because fistulas may recur. Indications for removal of a foreign body within the myocardium are also discussed.

Adult↗