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Biomedical subjects

A J Labovitz

Publications and source records attributed to A J Labovitz.

118 records · Page 7Linked to original sources
PubMed1985

Value of multiple echocardiographic views in the evaluation of aortic stenosis in adults by continuous-wave Doppler.

Fifty-two adults referred for evaluation of aortic stenosis (AS) were studied using continuous-wave and pulsed Doppler echocardiography. Three windows were used to determine which approach (apical, right parasternal or suprasternal) yielded optimal results. Doppler-derived peak aortic valve gradients were compared with the peak gradients measured at cardiac catheterization in 23 patients. High-velocity jets were best recorded from the cardiac apex and less frequently from the right parasternal and suprasternal areas. However, gradients from the right parasternal area correlated best with cardiac catheterization findings, although recordings could be made from this window in only 49% of the patients. Velocities from the suprasternal window were significantly (p less than 0.01) lower than those from the apex or right parasternal areas. Gradient underestimation from the suprasternal window tended to increase with age of the patient (p less than 0.01). When the maximal Doppler derived gradient from any window was compared with catheterization measurements, the correlation coefficient was 0.86. Gradients derived from Doppler velocities accurately predicted severe (more than 50 mm Hg) gradients at catheterization. Thus, Doppler echocardiography is useful in evaluation of AS when several windows are used for optimal assessment of aortic valve gradient.

Adult↗
PubMed1985

Frequency of mitral valve dysfunction from mitral anular calcium as detected by Doppler echocardiography.

Doppler echocardiography is useful for detecting and quantifying mitral regurgitation (MR) and mitral stenosis (MS). To determine the prevalence of these abnormalities in patients with mitral anular calcium (MAC), 51 consecutive patients who had an echocardiographic diagnosis of MAC were examined by Doppler ultrasound. Transmitral flow was evaluated to determine the presence of MR or left ventricular inflow obstruction (MS) by continuous and pulsed-wave Doppler echocardiography. The severity of these hemodynamic abnormalities was quantitated by previously described techniques. Eleven patients (22%) had mild MR, 17 (33%) had moderate to severe MR and 4 (8%) had significant MS. Clinical findings such as a systolic murmur, evidence of congestive heart failure, and dyspnea on exertion were not helpful in distinguishing patients with no or mild MR from those who had moderate to severe MR. M-mode measured left atrial size was significantly larger (p less than 0.05) in patients with moderate to severe MR. This study suggests that MR is often associated with MAC, that MS is not a rare finding with MAC, and that Doppler echocardiography can quantitate these lesions in the elderly when symptoms are not specific and physical findings are inconclusive or absent.

Aged↗
PubMed1985

The effects of Valsalva maneuver on global and segmental left ventricular function in presence and absence of coronary artery disease.

To determine the effects of the Valsalva maneuver on global and regional left ventricular function, single-plane left ventriculograms were performed in the 30-degree right anterior oblique projection in 50 patients during normal breath holding and during the late strain phase of the Valsalva maneuver. Thirty-one patients had significant coronary artery disease (greater than 70% luminal narrowing in a major coronary artery). Ventriculograms were analyzed for determination of ejection fraction, end-diastolic, and end-systolic volumes. Regional wall motion was analyzed by a chord method of calculating segmental fractional shortening. Ejection fraction increased significantly in the entire group of patients (62 +/- 16% to 70 +/- 19%, p less than 0.0001), while both end-diastolic (105 +/- 33 cc to 88 +/- 34 cc, p less than 0.0001) and end-systolic volumes (43 +/- 29 cc to 30 +/- 29 cc, p less than 0.0001) showed striking reductions with Valsalva maneuver. Patients without significant coronary disease usually exhibited global augmentation in left ventricular function, while those with coronary disease often exhibited only segmental improvement. This augmentation appeared to be dependent on the patency of the supplying coronary vessel.

Adult↗
PubMed1985

The effects of sampling site on the two-dimensional echo-Doppler determination of cardiac output.

Cardiac output was measured by two-dimensional echocardiographic Doppler technique in 55 adult patients in the intensive care unit. Doppler cardiac output determinations were measured from four sites (suprasternal long axis of the ascending aorta, suprasternal long axis of the descending aortic, apical left ventricular outflow tract, and parasternal long axis of the main pulmonary artery) and were compared to cardiac output determined by thermodilution for a total of 101 observations (r = 0.84). Mean cardiac output was 5.3 L/min (range 1.8 to 9.5 L/min) by Doppler technique and 5.1 L/min (range 1.6 to 8.9 L/min) as measured by thermodilution. Correlation of Doppler cardiac output with thermodilution cardiac output gave r values of 0.85, 0.83, 0.90, and 0.81 from the ascending aorta, descending aorta, left ventricular outflow tract, and pulmonary artery, respectively. Averaging of data in patients in whom more than one determination was possible resulted in improved correlation (r = 0.94). Thus, cardiac output can be measured with reasonable accuracy by Doppler from a variety of sampling sites and averaging of data from more than one site may improve these results.

Adult↗
PubMed1985

Noninvasive assessment of pacemaker hemodynamics by Doppler echocardiography: importance of left atrial size.

The relative decrease in cardiac output with ventricular pacing versus "physiologic" modes was measured noninvasively using Doppler echocardiography in 26 patients. Standard echocardiographic measurements of left ventricular size (diastolic diameter), left ventricular function (shortening fraction) and left atrial size were examined to determine which of these variables might best identify patients more likely to benefit from maintenance of atrioventricular (AV) synchrony. Decreases in relative cardiac output, expressed as reduction in the Doppler-derived flow velocity integral, with loss of AV synchrony ranged from 0 to 43% (mean decrease 21%). There was no correlation between left ventricular size or function and effect of pacing mode on relative cardiac output. There was, however, correlation between left atrial size and sensitivity to pacing mode. Patients with normal left atrial size were significantly more sensitive to loss of AV synchrony. In this subgroup, the decrease in flow velocity integral with ventricular pacing was 32 +/- 11% compared with only 11 +/- 13% in patients with left atrial enlargement. Thus, Doppler echocardiography is useful in assessing optimal pacing mode in the individual patient. Echocardiographically measured left atrial size may identify patients in whom physiologic pacing may be major benefit.

Adult↗
PubMedDate not supplied

Clinical utility of Doppler ultrasound in cardiac diseases.

During the past decade Doppler echocardiography has evolved to an extent that it has become a major noninvasive tool for cardiac evaluation in both acquired and congenital heart disease. This article describes current applications of Doppler techniques in the evaluation of cardiac anatomy and hemodynamics. The principles and methods employed in the use of Doppler echocardiography are described and illustrated for assessment and quantitation of flow velocities, pressure gradients, valve areas, valve regurgitation, stroke volume, cardiac output, cardiac shunts, and diastolic filling indices. The increasing accuracy of these applications has led to a substantial reduction in the need for invasive diagnostic methods, such as cardiac catheterization, especially in patients where frequent follow-up evaluations are indicated.

Blood Flow Velocity↗
PubMedDate not supplied

Two-dimensional, spectral Doppler, and color flow imaging in adults with acquired and congenital cor triatriatum.

Four adult patients ranging in age from 37 to 72 years with cor triatriatum diagnosed by two-dimensional, spectral Doppler, and color flow imaging are presented, including a previously undescribed "acquired" form after orthotopic heart transplantation and the oldest documented patient with cor triatriatum. The echocardiographic features of cor triatriatum with use of surface and transesophageal imaging are reviewed, with particular emphasis on the color flow findings. Color flow imaging has simplified the diagnosis and assessment of cor triatriatum, including the demonstration of other often-associated congenital cardiac anomalies.

Adult↗
PubMedDate not supplied

Determination of right ventricular ejection fraction by two-dimensional echocardiographic single plane subtraction method.

Right ventricular ejection fraction is a useful measurement for evaluating right ventricular function in various states, including coronary artery disease, chronic obstructive pulmonary disease, and both congenital and valvular heart diseases. The right ventricular geometry has made it difficult to evaluate right ventricular ejection fraction by simple echocardiographic methods. In this study 36 consecutive patients were examined by two-dimensional echocardiography within 4 hours of radionuclide-determined right ventricular ejection fraction to test a simplified method for calculating right ventricular ejection fraction by two-dimensional echocardiography. Echocardiographic measurements were independently determined in the subcostal and apical four-chamber views. Correlation with first pass radionuclide right ventricular ejection fraction was r = 0.89 and 0.84. Right ventricular ejection fraction could be calculated from one of two views in 92% of patients studied. This technique for determination of right ventricular ejection fraction offers a simple noninvasive method of evaluating right ventricular function.

Adolescent↗