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D J Mehlman

Publications and source records attributed to D J Mehlman.

30 records · Page 2Linked to original sources
PubMed1979

A prospective study of mitral valvular prolapse in young men.

A cardiac history, a physical examination, an electrocardiogram, phonocardiograms in the supine and standing positions, and an M-mode echocardiogram were obtained in 100 randomly selected, presumably healthy, male medical students (mean age, 26 years). Four percent met standard echocardiographic criteria for mitral valvular prolapse. No midsystolic clicks or late systolic murmurs were appreciated in this group, and none complained of chest pain or palpitations. To elucidate further the clinical implication of the echocardiographic pattern of mitral valvular prolapse, 24-hour ambulatory ECGs, multistage exercise tests, and scintiscans of myocardial perfusion at rest and after exercise (using radioactive 13nitrogen-labelled ammonium) were obtained, with normal results. The absence of life-threatening arrhythmias and exercise-induced abnormalities in these four asymptomatic subjects without abnormal physical findings suggests that the echocardiographic pattern of mitral valvular prolapse in such individuals may represent a variant of normal which does not require extensive evaluation.

Adult↗
PubMed1978

A guide to the radiographic identification of prosthetic heart valves.

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.

Heart Valve Prosthesis↗
PubMedDate not supplied

Plaque and structural characteristics of the descending thoracic aorta using transesophageal echocardiography.

The in vivo acoustic and structural characteristics of atherosclerosis in the descending thoracic aorta have not been well delineated. We prospectively evaluated the descending thoracic aorta of 147 patients (35 women and 112 men; age, 61 +/- 14 years) who underwent clinically indicated transesophageal echocardiography. Patients with suspected disease of the aorta were excluded. Thirty-eight patients (26%) had protruding plaques (men, 25%; women, 29%). Six patients had mobile intimal densities with the mobile area ranging up to 1 cm2. As expected, aortic lumen area was decreased (plaque-free, 3.53 cm2; plaque, 3.19 cm2; p less than 0.05) and wall area was increased (plaque-free, 1.51 cm2; plaque, 1.92 cm2; p less than 0.05) in the regions of the plaque. However, total arterial area was not increased (plaque-free, 5.04 cm2; plaque, 5.09 cm2; difference not significant) in a compensatory manner as observed in other arterial beds. Plaque gray scale was less than the gray scale of plaque-free wall (plaque-free, 141.2; plaque, 122.7; p less than 0.05) when compared at the same level of the descending thoracic aorta or with a second aortic plaque-free level (plaque-free, 150.4; plaque, 122.7; p less than 0.05). Standard deviation of gray scale level was similar between plaque and normal regions. Unsuspected protruding plaques in the descending thoracic aorta occurred in one quarter of the patients referred for routine transesophageal examination. Plaques tended to have lower echogenicity and were differentiated from plaque-free walls within patients. Plaque formation did not result in increased total arterial area. These data suggest that the degree or character of compensatory atherosclerotic remodeling in the highly elastic descending thoracic aorta may differ from other arterial beds.

Aorta, Thoracic↗
PubMedDate not supplied

Structural evaluation of porcine heart valve prostheses with radiofrequency ultrasound.

BACKGROUND: Bioprosthetic heart valve use is limited by progressive degeneration. Early degenerative changes are often occult, making assessment of tissue integrity difficult. Ultrasound tissue characterization may detect alterations in tissue structure and allow early detection of leaflet degeneration. METHODS: Using a modified echocardiographic unit (Acuson), radiofrequency (RF) integrated backscatter amplitude (IBA) (integral/RF/dt) was measured in 38 leaflets from nine explanted and six control porcine valves. Regions of interest in each leaflet were studied using four ultrasound frequencies. Radiographic gray scale mean and leaflet thickness were measured at each region of interest. Percent collagen and mineral were calculated for each region of interest using color-image processing of histologic sections and compared to IBA. RESULTS: IBA values for control vs. explanted leaflets were (mean value+/-standard deviation): 8.2+/-4.69 dB vs. -4.7+/-4.64 dB at 7.0 MHz; -5.8+/-4.34 dB vs. -3.1+/-5.34 dB at 5.0 MHz; -3.8+/-3.38 dB vs. -2.1+/-3.18 dB at 3.5 MHz; and -9.0+/-4.58 dB vs. -7.1+/-4.25 dB at 2.5 MHz. Collagen content was 27.7+/-8.50% vs. 33.2+/-10.90%, mineral content was 0.1+/-0.10% vs. 2.1+/-4.30%, and radiographic gray scale mean was 150.6+/-1.96 vs. 145.3+/-5.14 for control vs. explanted leaflets, respectively. For control and explanted leaflets IBA, collagen content, mineral content, and radiographic gray scale mean were different (control vs. explanted P<0.05). Leaflet thickness was also noted to be different between the two groups. IBA was different among explanted leaflets with low, medium, and high mineral content. CONCLUSION: IBA was found to be a useful technique to differentiate normal from explanted porcine prosthetic valves in vitro. This method may be useful in the serial assessment of bioprosthetic leaflet degenerative properties in vivo.

Adult↗