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Biomedical subjects

E D Mundth

Publications and source records attributed to E D Mundth.

At least 19 recordsLinked to original sources

Forward ejection fraction: a new index of left ventricular function in mitral regurgitation.

Previous studies have shown that a normal LVEF is not a reliable index of LV function in MR. We hypothesized that the forward EF, which is the forward stroke volume (measured by Fick or thermodilution) divided by end-diastolic volume (measured by contrast ventriculography) may be a useful index of LV function, since it represents LV emptying into the aorta. This index was examined in 54 patients with chronic MR who had normal EF (greater than or equal to 50%). There were significant correlations between the forward EF and the end-diastolic volume index (r = -0.69, p less than 0.001), end-systolic volume index (r = -0.64, p less than 0.001), cardiac index (r = 0.43, p less than 0.01), and the ratio of systolic pressure-to-end-systolic volume (r = 0.65, p less than 0.001). Patients were divided into two groups according to the forward EF: group I (n = 34) had forward EF less than or equal to 35%; and group II (n = 20) had forward EF greater than 35%. Of the 32 patients who subsequently underwent mitral valve replacement, 24 patients were in group I and eight patients were in group II. At a mean follow-up of 35 months, four patients died; all of them were in group I. Improvement in functional class occurred in 75% of surgical survivors (80% in group I and 63% in group II, p = NS). These preliminary data suggest that forward EF may be a useful index of LV performance in patients with MR who have normal EF.

Adolescent

The use of rest and exercise radionuclide ventriculography in risk stratification in patients with suspected coronary artery disease.

The study examined the value of rest and exercise radionuclide ventriculography in risk stratification in patients with suspected coronary artery disease. There were 604 patients, 474 men and 130 women, aged 55 +/- 11 years (mean +/- standard deviation). At a follow-up of 18 +/- 10 months, there were 43 hard cardiac events: 27 patients died of cardiac causes and 16 had nonfatal acute myocardial infarctions. Univariate and multivariate survival analysis of the 10 most important clinical and exercise variables identified the exercise left ventricular ejection fraction as the most important predictor of death and total cardiac events (chi 2 = 18.1 and 29.6, respectively). The exercise heart rate was a significant, independent, but much weaker predictor of cardiac death and total events (chi 2 = 8.4 and 3.9, respectively), while exercise tolerance was a significant independent predictor of cardiac death only (chi 2 = 6.4). Actuarial life table analysis showed that the risk for future cardiac events increased in stepwise fashion as the exercise ejection fraction decreased. Thus, the exercise left ventricular ejection fraction is a useful prognosticator in patients with suspected coronary artery disease. This finding has important implications in patient management.

Actuarial Analysis

Determinants of outcome following left ventricular aneurysmectomy.

UNLABELLED: The determinants of outcome after left ventricular aneurysmectomy are not well understood. We analyzed preoperative follow-up information on 38 patients who had undergone left ventricular aneurysmectomy. At a mean follow-up of 39 months (range 6 to 68), 25 patients (66%) improved by at least one functional class (New York Heart Association) (Group I), and 13 patients (Group II) either died (n: 8) or had persistent congestive heart failure (n: 5). Patients in Group I had significantly higher left ventricular ejection fraction before surgery than patients in Group II (38 +/- 12% vs. 29 +/- 14%, P less than 0.04). The volume of the aneurysm at end-diastole was smaller among patients in Group I than Group II (42 +/- 32 ml vs. 73 +/- 47 ml, P less than 0.04). The contractile indices of the nonaneurysm segment, contractile segment ejection fraction, basilar half ejection fraction, and basilar fractional area shortening were not significantly different between the two groups. There was no difference between the two groups in the preoperative left ventricular end-diastolic pressure, cardiac index, pulmonary artery wedge pressure, pulmonary artery pressure, extent of coronary artery disease, number of bypass grafts inserted, or aortic cross-clamp times. CONCLUSION: 1) The ejection fraction and volume of the aneurysm are more important predictors of outcome after left ventricular aneurysmectomy than the contractile indices of the nonaneurysmal left ventricle and 2) symptomatic improvement occurs in 66% of patients after left ventricular aneurysmectomy.

Adult

Clinical and echocardiographic evaluation of the St. Jude cardiac valve prosthesis: follow-up of 126 patients.

One hundred twenty-six patients with a St. Jude valve prosthesis were followed up clinically and studied by combined M-mode echocardiography and phonocardiography. Fifty patients underwent aortic valve replacement, 58 underwent mitral valve replacement and 18 underwent a combination of the two. The early postoperative mortality rate was 8% for aortic, 6.9% for mitral and 6% for combined valve replacement. Follow-up ranged from 2 to 46 months (mean +/- SD 28 +/- 9). The late postoperative mortality rate was 5%; in patients who survived, improvement in New York Heart Association functional class occurred in 97%. Major thromboembolic events occurred in two patients and anticoagulation-related complications occurred in three patients. Valve-related complications occurred in 14 patients and included bacterial endocarditis (6 patients), paravalvular leak (5 patients), severe hemolysis (1 patient), thrombosis of valve (1 patient) and possible mechanical valve failure (1 patient). In 7 of these 14 patients, repeat surgery was required and 5 patients survived. Abnormal echocardiographic findings in these seven patients included a shortened aortic closure (A2) to mitral valve opening interval, increased left atrial and left ventricular size and initial diastolic rounding of the St. Jude valve motion in the patient with the thrombosed valve. It is concluded that the St. Jude valve prosthesis is associated with favorable functional results and a low complication rate for a mean follow-up period of 28 months. Combined M-mode echocardiography and phonocardiography may be useful in assessing patients with suspected complications related to the St. Jude cardiac valve.

Adult

Rest and redistribution thallium-201 myocardial scintigraphy to predict improvement in left ventricular function after coronary arterial bypass grafting.

To examine the value of rest and redistribution thallium-201 imaging in predicting improvement in left ventricular (LV) ejection fraction (EF) after coronary artery bypass grafting (CABG), 26 patients with coronary artery disease (CAD) and abnormal LV function were studied. Nineteen patients had pathologic Q waves preoperatively. Rest and redistribution thallium-201 images and radionuclide ventriculograms were obtained before and after CABG, and the thallium scintigrams were evaluated both quantitatively and qualitatively. The patients were divided according to the preoperative thallium scintigrams into 2 groups: Group I (16 patients) had either normal resting thallium-201 images or reversible resting perfusion defects, and Group II (10 patients) had fixed resting perfusion defects. The resting EF was less than 50% preoperatively in all patients. Fourteen patients (54%) showed improvement in EF postoperatively. Three patients (2 in Group I and 1 in Group II) showed new postoperative perfusion defects, and none of the 3 showed improvement in LV function. Of the remaining 14 patients in Group I, 12 (86%) showed improvement in LV function, compared with 2 of 9 patients in Group II (p less than 0.01). Improvement in LV function was observed in 8 of the 19 patients (42%) with abnormal Q waves. Nitroglycerin intervention radionuclide ventriculograms were obtained in 20 patients before CABG. Of the 6 patients who showed improvement in LV function with nitroglycerin, 4 also showed improvement postoperatively. Postoperative improvement in LV function was also observed in 6 of the 14 patients who did not improve with nitroglycerin. Thus, rest and redistribution thallium imaging is useful in identifying patients whose LV function will improve after CABG. Normal rest thallium-201 images or reversible resting defects correctly identified 12 of 14 patients (86%) who showed improvement in LV function postoperatively. Nitroglycerin-intervention ventriculography and abnormal Q waves were less useful in this differentiation.

Adult

Measurement of ejection fraction by thermal dilution techniques.

The reproducibility, accuracy, and clinical applicability of ventricular ejection fraction derived by a thermal dilution technique were assessed in 22 dogs and 18 patients. Results obtained by the thermal technique were compared to simultaneous results obtained by radionuclide angiography. Right ventricular ejection fraction, measured in 9 dogs (1014 determinations) and 8 patients (744 determinations) was reproducible +/- 5%. Left ventricular ejection fraction, measured in 10 patients, was reproducible +/- 5%. Correlation between thermal and radionuclear measurements varied from 0.86 to 0.93 (all P less than 0.02). We conclude that, because of its low cost, ease of use, and accuracy, thermally derived ejection fraction determinations can be helpful in hemodynamic monitoring of critically ill patients.

Angiography

Use of computed tomography to assess mediastinal complications after median sternotomy.

Thirty computed tomographic (CT) scans from 27 patients who had undergone median sternotomy were reviewed. A control group of 15 asymptomatic patients was studied either early (within 21 days) or late (46 days to 22 years) after sternotomy. Twelve patients with symptoms ranging from sternal click to obvious mediastinitis also were studied within 30 days of sternotomy. The CT findings were correlated with the patient's clinical course. Imperfect sternal closure (sternal step-offs and gaps) was found in 10 of the 15 asymptomatic patients. Focal retrosternal fluid collections, air, and hematomas were seen in more than 75% of the asymptomatic patients. Retrosternal abscess, presternal abscess, and sternal disruption were noted in 3 symptomatic patients. Computed tomography correctly diagnosed the extent of mediastinal abscess in all patients. In the 3 patients in whom there was a discrepancy between the CT scan and the clinical findings, the scan ultimately was shown to be correct. These results indicate that computed tomography is a valuable tool in diagnosing wound problems after sternotomy because it accurately depicts the extent and depth of the wound infection.

Adult

Complications of median sternotomy: computed tomographic evaluation.

Complications of median sternotomy are infrequent (0.5%-5%) but have a very high mortality and morbidity. Conventional radiographic techniques are of limited value in assessing these complications. Twenty sternotomy patients without problems and 12 with clinical problems were studied with CT. In the control group, focal edema, focal hematomas, and minor sternal irregularities were universal. In the problem group, CT was able to distinguish the six patients without significant infection from the six with major infections. In the latter group, CT was of great value in determining whether the infection was limited to the presternal tissues, the anterior mediastinum, or both.

Abscess

Cardiac perforation with tamponade during cardiac catheterization.

Among 6,675 adult patients undergoing cardiac catheterization in our institution, three patients developed cardiac perforation and tamponade (incidence 0.04%). Two perforations involved the left atrium, and one the right atrium. Tamponade developed in the three patients. Hemodynamic confirmation of tamponade was available in two patients. Pericardiocentesis was performed in all three patients. Two patients required emergency surgery. All patients recovered.

Cardiac Catheterization

Pacemaker inhibition in cardiac surgery.

We described a noninvasive method of pacemaker inhibition for patients with pacemakers who are undergoing cardiac operation. It is a simple and effective way to attain complete cessation of electrical and mechanical activity of the pacemaker. Cold cardioplegic techniques are currently used to attain cardiac arrest and myocardial preservation. For patients with permanent pacemakers who require a cardiac operation, the addition of the method of pacemaker inhibition results in a decrease in the potential for myocardial injury and a quiet operative field, which facilitates the surgical techniques.

Cardiac Surgical Procedures

The effect of antithrombotic therapy on patency rates of saphenous vein coronary artery bypass grafts.

In an attempt to improve upon the reported long-term patency rates of 65% to 85% for saphenous vein coronary artery bypass grafts (CABG), a prospective randomized trial comparing warfarin, aspirin, and placebo treatment in post-CABG patients was carried out. From an initial group of 216 patients, 161 patients remained in the study, and vein graft patency was determined in 111 patients (220 grafts) from 1 to 47 months postoperatively. There was a trend toward better cumulative graft patency in patients given warfarin, but the results did not achieve statistical significance. Improved results with warfarin were most marked among patients who were restudied within 24 months of CABG operation, in most instances because of the development of recurrent angina pectoris. There were four major bleeding complications of warfarin therapy, including one death, over 2,108 patient-months. Since most of the occlusive changes in vein grafts appear in the first 6 to 12 months, any effect of antithrombotic therapy will be most evident in the early postoperative period, with greatly reduced impact with long-term administration. Results of this study suggest that short-term antithrombotic therapy deserves further assessment in prevention of vein graft occlusion in the first year or two following a CABG operation. This potential benefit must be evaluated in the context of the recognized bleeding complications of warfarin therapy.

Adult

Assessment of left ventricular function in patients with isolated severe disease of the left anterior descending artery: clinical, electrocardiographic, hemodynamic, and angiographic correlations.

The purpose of this study was to define the spectrum of left ventriculographic (LV) abnormalities in 60 patients with isolated Greater Than or Equal To 90% diameter narrowing of the left anterior descending artery (LAD). The patients were divided into three groups: Group I (26 patients) had normal left ventricular (LV) function with ejection fraction (EF) of Greater Than 60% and no akinetic-dyskinetic segment representing abnormal contracting segments (ACS) of the left ventricular wall; Group II (15 patients) had mild to moderate LV dysfunction with EF of 40-60% and an akinetic-dyskinetic segment of Less Than 30% of the end diastolic perimeter (0-30%; mean, 11.6%) and Group III (19 patients) had severe LV dysfunction with EF Less Than 40%, or an akinetic-dyskinetic segment of Greater Than or Equal To 30% (30-81%; mean, 41.5%) or both. The data obtained from the history, physical examination, electrocardiogram (ECG), chest x-ray studies, hemodynamic studies, left ventriculography, and coronary arteriography were entered and filed on a memory disc in an IBM 370-168 computer. Analysis of the results showed: 1) more severe LV dysfunction is associated with increased incidence of large hearts, gallops, decreased cardiac output, and occlusion of the LAD. 2) ECG evidence of infarction is also associated with higher incidence of the abnormalities of the indices of LV dysfunction. 3) LAD occlusion (versus stenosis) has a higher incidence of severe LV dysfunction and prior infarction. 4) The site of LAD disease did not predict the extent of left ventricular dysfunction. 5) Collaterals did not protect against severe LV dysfunction.

Adult

Surgican considerations in management of angina pectoris.

In deciding on the best form of treatment for patients with angina pectoris, a substantial number of important factors must be carefully and individually considered. These include symptomatic status, extent and location of occlusive coronary artery disease, left ventricular functional status, and risk factors. Relief of angina pectoris with revascularization surgery can be expected in 80% to 90% of patients, with an operative mortality well below 5% when preoperative left ventricular function is normal or only moderately depressed.

Angina Pectoris