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Biomedical subjects

E L Alderman

Publications and source records attributed to E L Alderman.

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

The clinical spectrum of coronary artery disease and its surgical and medical management, 1974-1979. The Coronary Artery Surgery study.

Data from the National Heart, Lung, and Blood Institute's Coronary Artery Surgery Study (CASS) are used to describe the types of persons who undergo coronary angiography for possible coronary artery bypass surgery, the reasons patients receive coronary bypass surgery, and operative mortality results, as well as changing trends in the therapy assigned. The review is designed to provide background material for those assessing coronary artery bypass technology.

Adrenergic beta-Antagonists↗
PubMed1982

Determinants of coronary surgery in a consecutive patient series from geographically dispersed medical centers. The coronary artery surgery study.

The Coronary Artery Surgery Study registry enrolled 24,959 patients from 1974 through 1979. Of these patients, 12,556 had anginal chest pain symptoms and significant angiographic coronary disease (greater than or equal to 70% lesion in a major vessel or greater than or equal to 50% in the left main coronary artery) and were considered coronary bypass surgery candidates. Stepwise linear discriminant-function analysis of clinical and angiographic determinants of therapeutic assignment revealed that myocardial jeopardy (a composite score of the relationship of proximal lesions to retained wall motion in anterior and inferior segments) was the most important determinant. Site-to-site variability, another important predictor of therapeutic assignment, was assessed after adjusting for differing patient populations and was found to be significant (p less than 0.001). Other significant predictors were angina severity, the number of operable vessels, change in activity level, unstable angina and the presence of a left main lesion. Temporal changes (between 1974 and 1979) in the use of beta-blocking drugs and in therapeutic assignment of patients with left main lesions and one-vessel disease suggested altered decision-making in response to the reporting of major coronary surgery trials. We conclude that the dominant factors in therapeutic assignment for patients with completed arteriographic evaluations reflect considerations of jeopardized myocardium and continuing diversity of opinion about the importance of therapeutic and prophylactic indications for coronary surgery.

Actuarial Analysis↗
PubMed1980

Left ventricular response to isometric exercise in patients with denervated and innervated hearts.

Patients with cardiac denervation resulting from allograft transplantation have been observed to increase their diastolic and systolic blood pressure during isometric exercise without concomitant cardioacceleration. To determine the mechanism for the blood pressure increase, heart rate, blood pressure, and ventricular volumes (measured using fluoroscopy of tantalum midwall myocardial markers) were recorded before and after a 50% maximal voluntary contraction. Seven cardiac transplant recipients (denervated heart) and seven nontransplant patients (innervated heart) were studied. Innervated and denervated heart patients increased systolic blood pressure by 16% and 21% and total peripheral resistance by 20% and 12%, respectively. The percentage responses were not significantly different between groups, except for heart rate, which increased 17% in innervated heart patients and 2% in denervated heart patients (p less than 0.05). Neither group had enhanced contractility or increases in cardiac output, suggesting that the blood pressure increases resulted in both groups from increased peripheral resistance.

Adult↗
PubMed1980

Evaluation of methods for quantitating left ventricular segmental wall motion in man using myocardial markers as a standard.

Radiopaque markers were implanted in the left ventricular myocardial midwall in 58 patients and studied in the 30 degrees right anterior oblique projection by computer-aided fluoroscopy. Marker motion was used as a standard of segmental wall motion against which the accuracy of five methods for measuring left ventricular wall motion was assessed: two methods using hemiaxial measurements in rectangular coordinates, two using radial measurements in polar coordinates (all with frame-by-frame axial reindexing) and one using radial measurements in fixed external polar coordinates. The latter method showed significantly less error (25.9%, p less than 10(-6)) in measuring midwall marker motion than the other four methods (range 42.5--47.5%) in the group as a whole and in subgroups that had abnormalities of posterior, apical and anterior wall motion. This method also had the best correlation of marker motion and motion of adjacent endocardial border (of the overall left ventricle and the posterior, apical, and anterior walls separately) as visualized by ventriculography in 29 patients. The bulk of the reduction in error using this method was due to the use of a fixed external reference system, with a small additional increment of error removed by proper selection of the polar origin at a point 69% of the distance from the anterolateral edge of the aortic valve to the ventricular apex at end-systole.

Coronary Artery Bypass↗
PubMed1980

Hemodynamic and clinical comparison of the Hancock modified orifice and standard orifice bioprostheses in the aortic position.

Bioprosthetic aortic valve replacement in patients with a small aortic root has been associated with postoperative transvalvular gradients. A modified orifice Hancock xenograft bioprosthesis has been developed and is purported to increase significantly the effective orifice area (as evaluated by in vitro testing) compared to the standard orifice Hancock bioprosthesis. To assess the in vivo differences, we compared 481 patients with standard orifice prostheses with 156 patients with modified orifice prostheses. Postoperative catheterization was performed in 24 patients with modified orifice (valve diameters 19 to 25 mm) with 14 with standard orifice valves (valve diameters 21 to 25 mm). Actuarial rates of survival, valve failure, endocarditis, and thromboembolism did not differ significantly between the two subgroups. Peak aortic valve gradients on the whole were less in the modified orifice subgroup than in the standard origice subgroup (12 +/- 1 torr versus 20 +/- 6 torr [mean +/- SEM]), but the difference was not statistically significant (p greather than 0.05). The calculated in vivo aortic valve areas were slightly, but insignificantly, greater in the modified orifice subgroup than in the standard orifice subgroup (p greater than 0.05). These in vivo data partially corroborate the in vitro findings of increased effective orifice area and internal-to-external diameter ratio for the modified orifice bioprosthesis. The hemodynamic differences between the two valve types are small, however, and the putative clinical advantages inherent in the use of the modified orifice bioprosthesis remain to be completely defined.

Aortic Valve↗
PubMed1979

Effect of intrathoracic pressure on left ventricular performance.

Left ventricular dysfunction is common in respiratory-distress syndrome, asthma and obstructive lung disease. To understand the contribution of intrathoracic pressure to this problem, we studied the effects of Valsalva and Müller maneuvers on left ventricular function in eight patients. Implantation of intramyocardial markers permitted beat-by-beat measurement of the velocity of fiber shortening (VCF) and left ventricular volume. During the Müller maneuver, VCF and ejection fraction decreased despite an increase in left ventricular volume and a decline in arterial pressure. In addition, when arterial pressure was corrected for changes in intrapleural pressure during either maneuver it correlated better with left ventricular end-systolic volumes than did uncorrected arterial pressures. These findings suggest that negative intrathoracic pressure affects left ventricular function by increasing left ventricular transmural pressures and thus afterload. We conclude that large intrathoracic-pressure changes, such as those that occur in acute pulmonary disease, can influence cardiac performance.

Cardiac Output↗
PubMed1979

Reliability and reproducibility of interpretation of 99mtechnetium pyrophosphate myocardial scintigrams.

The interpretations of 156 99mtechnetium pyrophosphate myocardial scintigrams by four observers were analyzed in order to determine the reliability and reproducibility of the subjective process of reading scintigrams. The scintigrams were scored on an integral scale from 0 to 4, depending upon the degree of myocardial radionuclide accumulation, and the site and nature of uptake were specified. Exact agreement upon score was generally poor but approximate concurrence of interpretation was good (90.4 and 92.5% inter- and intra-observer agreement, respectively). There was somewhat less agreement on scintigrams with the higher scores of 3 and 4 (83.3 and 78.0%, respectively). A high level of concurrence upon the differentiation between diffuse and localized uptake, and upon the site of uptake, was found. We conclude that only approximate rather than exact agreement of individual readers' interpretations can be expected in this subjective technique, that scintigrams with higher degrees of radionuclide accumulation produce slightly greater observer disagreement, and that variability of interpretation could account for some of the diagnostic inaccuracy of 99mtechnetium pyrophosphate myocardial scintigraphy.

Angina Pectoris↗
PubMed1979

Effects of digitalis on normal and abnormal left ventricular segmental dynamics.

To study the effects of digoxin on regional left ventricular performance, continuous ventricular dynamics were assessed in nine patients with stable coronary disease. Computer-assisted analysis of the fluoroscopic motion of surgically implanted mid wall myocardial markers was used. The markers define six minor ventricular radii and outline the left ventricle. One and one-half hours after administration of 1 mg of intravenous digoxin, mean velocity of circumferential fiber shortening for all segments increased 19 percent, from 0.67 +/- 0.06 to 0.78 +/- 0.06 circumference/sec (P less than 0.01) and ejection fraction increased 4.5 percent, from 0.50 +/- 0.03 to 0.53 +/- 0.03 (P less than 0.05). Segmental velocity of circumferential fiber shortening, total segmental shortening and early segmental systolic shrtening increased in 83 percent to 91 percent of normal segments, depending on which index was used. Only 45 to 55 percent of initially abnormal segments benefited from digoxin. In general, segmental dyssynergy increased even when net ventricular function was enhanced. These results suggest that in pateints with chronic left ventricular contraction abnormalities due to coronary disease, deterioration of performance in abnormal regions after administration of digoxin may result from increased stress imposed by increased afterload and by improved segmental dynamics in more normal areas.

Adult↗
PubMed1979

Long-term serial angiographic studies after coronary artery bypass surgery.

Twenty-six patients underwent repeat coronary angiography 5--8 years after saphenous vein coronary artery bypass surgery (SVCABG). These patients were selected from the first cohort of 117 patient who had SVCABG because they had obtained essentially complete relief of angina, and because all grafts were patent at initial angiography 11.2 months (mean) after surgery. Of the 39 grafts (1.5 grafts per patient) patent at 1 year, 34 (87.2%) were patent at reexamination 76 months (mean) (range 65--103 months) after SVCABG. Graft occlusion could not be predicted by the early angiographic appearance of the graft itself or its proximal or distal anastomosis. In some cases, narrowing or irregularity consistent with intimal hyperplasia appeared to progress, while in others it developed at late follow-up. Progressive narrowing occurred in 96% (22 of 23 grafted vessels) of the native coronary arteries proximal to the graft anastomosis. Progresssion to a stenosis greater than 75% or total occlusion was seen distal to the graft anastomosis in eight of 39 grafts (20%). Of 103 non-bypassed major vessels, 56% showed some progression of disease and half of these progressed to significant stenoses (greater than 75% luminal narrowing). There were no apparent predictors to indicate whether progression in nongrafted coronary arteries would occur preferentially in a previously stenotic or nonstenotic vessel, although 80% of vessels with initial stenoses greater than 75% progressed to total occlusion.

Adult↗
PubMed1979

Role of tachycardia as an inotropic stimulus in man.

We examined the inotropic effect of tachycardia in nine postsurgical aortocoronary bypass graft patients (with intact cardiac innervation) and nine cardiac allograft recipients (with denervated hearts). The changes in stroke volume (SV) and velocity of circumferential fiber shortening (VCF) which accompany sudden increases and decreases in atrial pacing frequency were determined by computer-aided fluoroscopic analysis of the motion of surgically implanted midwall myocardial markers. Because the first beat after a change in rate retains the frequency characteristics of the preceding rate, we compared the first posttachycardia beat with control beats and late tachycardia beats with the first tachycardia beat; afterload and preload for each pair of beats were similar. For an increase in heart rate of 50 beats/min, SV and VCF rose 79 and 64% from the first tachycardia beat to late tachycardia beats, and SV and VCF rose 8 and 35% from control beats to the first posttachycardia beat in the innervated group. Responses in the denervated group were not significantly different from those in the innervated group. The degree of the inotropic response was positively correlated with the magnitude of the increase in heart rate (r = 0.91). The decay in augmented contractility after decreasing the rate back to control levels fits an exponential relationship with a mean t((1/2)) of 1.7 s. Thus, in conscious man, increases in heart rate represent a positive inotropic stimulus, independent of other factors influencing ventricular performance and unaffected by neural innervation, and should be considered when changes in cardiac function are interpreted during serial studies or after drug administration.

Adolescent↗
PubMed1978

Cardiac sarcoidosis. Diagnosis with endomyocardial biopsy and treatment with corticosteroids.

A 27 year old woman was hospitalized for progressive dyspnea, fatigue and retrosternal chest pain. She had progressive cardiac enlargement with clinical and laboratory confirmation of a dilated cardiomyopathy. Transvenous percutaneous right ventricular endomyocardial biopsy yielded a specimen showing a noncaseating granuloma. The patient's dyspnea responded dramatically to steroid therapy with corresponding improvement in radiographic and echographic measures of ventricular performance. This case illustrates the problem of diagnosing cardiac sarcoidosis when there is no apparent evidence of other organ involvement.

Adult↗
PubMed1978

Diverticulum of the left ventricle in hypertrophic cardiomyopathy.

An unusual case of diverticulum of the left ventricle is presented. The most distinctive feature was the presence of a circumferential mid-ventricular contraction ring with histologic abnormalities similar to those described in patients with asymmetric septal hypertrophy. This abnormal ring of tissue obstructed emptying of the ventricular apex and isolated it from the rest of the ventricle. The obstructed apex assumed the appearance of a muscular diverticulum, and the residual portion of the ventricle was markedly diminished in volume. In addition, the abnormal mid-ventricular hypertrophy interfered with papillary muscle function, producing mitral valve prolapse and mitral regurgitation. The patient's age was equally unusual; she was 65 at the time of diagnosis, probably the oldest known patient with ventricular diverticulum. She was treated surgically by transapical myotomy and myectomy of the mid-ventricular contraction ring, in order to increase effective ventricular volume. The relationship of this entity to other types of ventricular deiverticula and aneurysms, and to hypertrophic cardiomyopathy, is discussed.

Aged↗