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Dive into the research topics where David J. Mehlman is active.

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Featured researches published by David J. Mehlman.


American Journal of Cardiology | 1990

A possible mechanism for neurologic ischemic events in patients with atrial septal aneurysm

Miguel Zabalgoitia-Reyes; Cesar J. Herrera; Dipeshkumar K. Gandhi; David J. Mehlman; David D. McPherson; James V. Talano

Abstract A trial septal aneurysm (ASA) is a congenital malformation of the atrial septum that has been associated, among other conditions, with transient ischemic attacks and strokes. 1–5 The nature of this relation is unclear. Embolic events have been attributed to thrombus formation in or at the base of the aneurysmal sac. 5,6 However, the possibility of an associated functionally patent foramen ovale leading to a paradoxical embolus from a right-to-left shunting also has been suggested. 2–4 To help clarify this issue, we analyzed the morphologic and functional characteristics of the atrial septum in patients with ASA by the use of transesophageal contrast echocardiography.


Circulation | 1990

Functional chiral asymmetry in descending thoracic aorta.

Lee J. Frazin; Gregory M. Lanza; Michael J. Vonesh; Fouad Khasho; Caryn Spitzzeri; Sandra McGee; David J. Mehlman; K. B. Chandran; James V. Talano; David D. McPherson

To determine whether rotational blood flow or chiral asymmetry exists in the human descending thoracic aorta, we established the ability of color Doppler ultrasound to detect rotational flow in a tornado tube model of a vortex descending fluid column. In a model of the human aortic arch with a pulse duplicator, color Doppler was then used to demonstrate that rotational flow occurs first in the transverse arch and then in the proximal descending thoracic aorta. With the use of color Doppler esophageal echocardiography, 53 patients (age range, 25-78 years; mean age, 56.4 years) were prospectively examined for rotational flow in the descending thoracic aorta. At 10 cm superior to retro-left ventricular position, 22 of 38 patients (58%) revealed rotational flow with obvious diastolic counterclockwise rotation but less obvious systolic clockwise rotation. At 5 cm superior to retro-left ventricular position, 29 of 46 patients (63%) revealed rotational flow with a tendency toward systolic clockwise and diastolic counterclockwise rotation. At the retro-left ventricular position, 47 of 53 patients (89%) revealed rotational flow, usually of a clockwise direction, occurring in systole. Our data suggest that aortic flow is not purely pulsatile and axial but has a rotational component. Rotational flow begins in the aortic arch and is carried through to the descending thoracic aorta, where flow is chirally asymmetric with systolic clockwise and diastolic counterclockwise components. These data demonstrate an aortic rotational flow component that may have physiological implications for organ perfusion.


The New England Journal of Medicine | 1971

Serum alpha 1-fetoglobulin with gastric and prostatic carcinomas.

David J. Mehlman; Bernadine H. Bulkley; Peter H. Wiernik

THE presence of serum alpha1-fetoglobulin in adults is accepted as diagnostic of primary hepatoma or embryonal testicular tumor.1 Recently, we encountered a patient with gastric and prostatic carci...


American Journal of Cardiology | 1992

Comparison of transesophageal and transthoracic echocardiography for diagnosis of right-sided cardiac lesions

Cesar J. Herrera; David J. Mehlman; Renee S. Hartz; James V. Talano; David D. McPherson

Abstract Two-dimensional transthoracic echocardiography (TTE) is an established method for the evaluation of cardiac or paracardiac structural abnormalities such as tumors, vegetations and thrombi. 1–4 Cardiac structural resolution can be limited with TTE owing to anatomic interference. With transesophageal echocardiography (TEE), regions of the heart previously difficult to visualize are now readily studied. These regions include the vena cavae, right ventricular outflow tract, pulmonic valve and pulmonary trunk. The usefulness of TEE as compared with TTE in assessing right-sided cardiac pathology has not been clearly determined. We compared both techniques with the objectives of studying their diagnostic ability for the evaluation of right-sided cardiac lesions, and comparing data obtained with those from other confirmatory techniques.


American Journal of Cardiology | 1999

Echocardiographic prevalence of mitral and/or aortic regurgitation in patients exposed to either fenfluramine-phentermine combination or to dexfenfluramine

Madhu K Kancherla; Hani Salti; Todd A. Mulderink; Michele Parker; Robert O. Bonow; David J. Mehlman

We evaluated the prevalence of valvular regurgitation in patients who have taken anorectic medications. Two-dimensional echocardiograms with color flow Doppler were recorded in 200 consecutive patients referred to a major metropolitan hospital for evaluation of cardiac function because of a history of anorectic medication use. Each patient filled out a questionnaire at the time of the visit or through telephone contact. Each echocardiogram was reviewed by 2 observers. The degree of valvular regurgitation was graded by a consensus of both observers. Significant valvular regurgitation was defined as at least moderate mitral regurgitation (MR) or at least mild aortic regurgitation (AR), as recommended by the Food and Drug Administration and Centers for Disease Control and Prevention. For all patients having taken anorectic drugs, there was a 5% prevalence of at least moderate MR, a 12% prevalence of at least mild AR, and a 16% prevalence of significant MR and/or AR. Patients with significant AR and/or MR were older than those without significant valvular regurgitation (49+/-12 vs 44+/-11 years, p = 0.03). Patients with significant MR and/or AR had a longer exposure duration (8 vs 6 months, p = 0.049) to anorectic drugs. There was no difference in weight loss between those with and without significant regurgitation (p = NS). The 2 largest subgroups were patients who took the fenfluramine-phentermine combination (n = 127) and those who took dexfenfluramine alone (n = 42). The prevalence of significant MR and AR was 5% and 9% for the fenfluramine-phentermine group and 0% and 14% for the dexfenfluramine group, respectively. There was also a high subthreshold level of MR and AR in these patients.


American Heart Journal | 1991

Pathologic and angiographic correlations of transesophageal echocardiography in prosthetic heart valve dysfunction

Farooq A. Chaudhry; Cesar J. Herrera; Paul F. DeFrino; David J. Mehlman; Miguel Zabalgoitia

To determine the diagnostic accuracy of transesophageal echocardiography (TEE) in prosthetic valve dysfunction, the pathologic and/or angiographic data from 37 valves were compared with that obtained by transesophageal and transthoracic echocardiography. Of the 21 prostheses with severe regurgitation, TEE identified all 14 mitral, the five aortic, and one of the two tricuspid valves; on the other hand transthoracic echocardiography identified 2 of the 14 mitral, the five aortic, and one of the two tricuspid valves. Of the 10 prostheses with flail cusp(s), nine (90%) were correctly identified by TEE and four (40%) were correctly identified by transthoracic echocardiography. All five prostheses with paravalvular regurgitation were detected through the esophageal window and one detected through the precordial window. TEE was unable to document the two prosthetic aortic stenoses, whereas the transthoracic examination correctly quantified the gradient in one but underestimated it in the other case. Seven patients underwent valve replacement on the basis of the clinical and TEE information alone. In assessing cause, origin, and severity of prosthetic mitral regurgitation, TEE is the method of choice. In selected cases, TEE can avoid angiography and facilitate optimal timing of reoperation. In selected aortic and tricuspid dysfunction, TEE may provide additional morphologic, but limited hemodynamic information.


Annals of Internal Medicine | 1976

Dilantin®, Agranulocytosis, and Phagocytic Marrow Histocytes

Min-Fu Tsan; David J. Mehlman; Robert S. Green; William R. Bell

Excerpt Agranulocytosis associated with Dilantin®*(diphenylhydantoin) therapy has been reported in five cases (1-5) and only two had bone-marrow aspiration during the acute stage (3-4). We report t...


Circulation | 1978

A guide to the radiographic identification of prosthetic heart valves.

David J. Mehlman; Leon Resnekov

To facilitate the radiographic identification of prosthetic heart valves, radiographic silhouettes of various aortic, mitral and tricuspid valve prostheses were analyzed and shematized. Forty different prosthetic valve models (heterograft and mechanical) were obtained from seven domestic manufacturers. Each prosthesis was positioned to approximate the aortic, mitral or tricuspid valve anulus plane. The valves were then radiographed and photographed as they would appear in posteronanterior and left lateral chest radiographs. The radiographic silhouettes were examined and a scheme was designed to enable easy, yet accurate, differentiation of the many heart valve prostheses. Illustrations of the various valve types are presented as they would appear in routine chest radiographs.


American Heart Journal | 1990

Transesophageal echocardiography in the awake elderly patient: Its role in the clinical decision-making process

Miguel Zabalgoitia; Dipeshkumar K. Gandhi; James L. Evans; David J. Mehlman; David D. McPherson; James V. Talano

To assess the impact on the management and safety of transesophageal echocardiography (TEE) in the elderly population, the results and limitations of this technique were retrospectively analyzed in 88 patients. TEE was indicated whenever the transthoracic approach was not diagnostic or was inconsistent with the clinical setting. The most frequent clinical indications were to investigate the source of emboli, assess valvular regurgitation, and identify valvular vegetations. In 72 patients (82%) TEE significantly influenced management decisions. In selected patients TEE avoided the use of more invasive diagnostic procedures. Adverse effects included occasional premature atrial or ventricular beats (11 patients), sinus bradycardia (six patients), and protracted nausea (one patient). We conclude that in elderly patients with cardiovascular diseases, TEE plays a significant role in the decision-making process without adding a significant risk.


American Journal of Cardiology | 1992

Value and limitations of transesophageal echocardiography in evaluating prosthetic or bioprosthetic valve dysfunction

Cesar J. Herrera; Farooq A. Chaudhry; Paul F. DeFrino; David J. Mehlman; Kevin M. Mulhern; Robert A. O'Rourke; Miguel Zabalgoitia

Optimal management of patients with prosthetic heart valves requires serial assessment of valve function. The addition of Doppler and color flow techniques to conventional transthoracic echocardiography (TTE) has increased our ability to evaluate prosthetic valve function. However, the sensitivity of TTE remains limited in a number of patients because of suboptimal precordial windows or because of ultrasound interference with the nonbiologic materials composing the prostheses.1–3 Transesophageal echocardiography (TEE) allows excellent imaging resolution of the cardiac anatomy without interposition of thoracic structures. Recently, TEE has been shown to increase the yield of undetected prosthetic valve abnormalities by TTE.4–8 However, most of the TEE information relates to biologic prostheses in the mitral position.5–8 Thus, the purpose of this study was to investigate the diagnostic accuracy of TEE in evaluating mechanical and biologic prostheses in both aortic and mitral positions, and the impact of the TEE information on the clinical outcome.

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David D. McPherson

University of Texas Health Science Center at Houston

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Miguel Zabalgoitia

University of Texas Health Science Center at San Antonio

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