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Biomedical subjects

A J Labovitz

Publications and source records attributed to A J Labovitz.

At least 37 records · Page 2Linked to original sources
PubMed1991

Evaluation of pulmonary venous flow by transesophageal echocardiography in subjects with a normal heart: comparison with transthoracic echocardiography.

Nineteen normal subjects and five patients with atrial fibrillation underwent transesophageal and transthoracic echocardiographic studies to evaluate the normal pulmonary venous flow pattern, compare right and left pulmonary venous flow and assess the effect of sample volume location on pulmonary venous flow velocities. Best quality tracings were obtained by transesophageal echocardiography. Anterograde flow during systole and diastole was observed in all patients by both techniques. Reversed flow during atrial contraction was observed with transesophageal echocardiography in 18 of the 19 subjects in normal sinus rhythm, but in only 7 subjects with transthoracic echocardiography. Two forward peaks during ventricular systole were clearly identified in 14 subjects (73%) with transesophageal echocardiography, but in none with the transthoracic technique. The early systolic wave immediately followed the reversed flow during atrial contraction and was strongly related to the timing of atrial contraction (r = 0.78; p less than 0.001), but not to the timing of ventricular contraction, and appeared to be secondary to atrial relaxation. Conversely, the late systolic wave was temporally related to ventricular ejection (r = 0.66; p less than 0.001), peaking 100 ms before the end of the aortic valve closure and was unrelated to atrial contraction time. Quantitatively, significantly higher peak systolic flow velocities were obtained in the left upper pulmonary vein compared with the right upper pulmonary vein (60 +/- 17 vs. 52 +/- 15 cm/s; p less than 0.05) and by transesophageal echocardiography compared with transthoracic studies (60 +/- 17 vs. 50 +/- 14 cm/s; p less than 0.05). Increasing depth of interrogation beyond 1 cm from the vein orifice resulted in a significant decrease in the number of interpretable tracings.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Prevalence and clinical implications of atrial spontaneous contrast in patients undergoing transesophageal echocardiography.

The prevalence of atrial spontaneous contrast was evaluated in 150 consecutive patients undergoing transesophageal echocardiography. Spontaneous contrast was observed in 29 patients (19%). It was seen in the left atrium in 24 patients, in the right atrium in 4 patients and in both atria in 1 patient. Spontaneous atrial contrast was not seen in the absence of an associated cardiac abnormality. Univariate analysis showed a significant relation between the presence of spontaneous contrast and significant mitral regurgitation (p less than 0.05), the presence of mitral valve prostheses (p less than 0.001), atrial fibrillation (p less than 0.0001) and left atrial size (p less than 0.001). Multivariate analysis showed that the presence of atrial fibrillation, prosthetic mitral valve and atrial size were independent factors for the presence of spontaneous contrast. However, of the 29 patients with spontaneous contrast, 13 (45%) were in sinus rhythm and in only 4 (16%) was the left atrial size greater than 60 mm. Left atrial thrombus was detected in 9 of the 150 patients. Although spontaneous contrast was noted in 5 (55%) patients with left atrial thrombus and in only 20 (14%) patients without left atrial thrombus (p less than 0.001), none of the 3 patients who had right atrial thrombus had spontaneous contrast in that chamber. Overall, 7 (58%) of the 12 patients with right or left atrial thrombi had no evidence of spontaneous contrast. Multivariate analysis showed that atrial fibrillation was the only independent clinical predictor of left atrial thrombus. Thus, spontaneous echocardiographic contrast is a common phenomenon observed in approximately 20% of the patients undergoing transesophageal echocardiography.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Spontaneous echocardiographic contrast in the descending aorta.

The visualization of echocardiographic spontaneous contrast is a common phenomenon in patients undergoing transesophageal echocardiographic studies. Its pathophysiology is not well understood, but it has been related to the presence of a low flow state in the cardiac chambers. We report the presence of spontaneous contrast in the descending aorta of four patients, a location not previously described in the absence of aortic dissection. In two patients, spontaneous contrast was noted in both the left atrium and the descending aorta. In one patient with moderate left ventricular dysfunction, spontaneous contrast was noted in the descending aorta and in the left ventricle. In the remaining case, no cardiac or aortic abnormalities were observed and this represents the first time that spontaneous contrast has been identified in a patient with an echocardiographically normal heart. The occurrence of spontaneous contrast has been considered an abnormal echocardiographic finding, since it has always been described in patients with clinical symptoms and cardiac abnormalities. The fact that spontaneous contrast can be visualized in patients with very mild structural cardiac abnormalities or none at all, warrants further investigation, especially when therapeutic or prognostic implications are considered.

Aged↗
PubMed1990

Color Doppler echocardiographic evaluation of patients with a flail mitral leaflet.

Chordal rupture with a subsequent flail mitral valve leaflet is now the most common cause of pure mitral regurgitation. To describe the Doppler color flow findings in flail mitral leaflet and the determinants of these findings, Doppler color flow mapping and conventional Doppler echocardiography were performed in 31 consecutive patients presenting with a flail mitral leaflet. In the 23 patients with a posterior flail leaflet, a distinctive highly eccentric and turbulent jet directed toward the posterior wall of the aorta was noted. In the eight patients with an anterior flail leaflet, a jet directed toward the posterolateral left atrial wall was noted. Maximal regurgitant jet area was significantly larger in patients with a flail anterior leaflet (13.1 +/- 3.0 cm2) than in those with a flail posterior leaflet (5.8 +/- 3.0 cm2, p = 0.0001). Maximal jet area to left atrial ratio was also significantly higher in those with a flail anterior leaflet (0.56 +/- 0.16) than in those with a flail posterior leaflet (0.27 +/- 0.17, p = 0.0006). When systolic left atrial velocities encoded as red were incorporated into the maximal jet area measurement, 7 of the 8 patients with an anterior flail leaflet had a jet area greater than 8 cm2, consistent with severe mitral regurgitation, compared with 13 of the 23 patients with a flail posterior leaflet. There was no correlation between jet area or jet area to left atrial ratio and any hemodynamic variable. Patients with acute mitral regurgitation exhibited a trend toward smaller jet areas, but this did not reach statistical significance. Regurgitant fraction calculated from pulsed Doppler recording of mitral and aortic flow was consistent with moderately severe or severe mitral regurgitation in all cases and averaged 70%. Thus, patients with a flail mitral valve leaflet have distinctive Doppler color flow findings. A highly eccentric and turbulent jet directed posteriorly to the aorta may contribute to a systematic underestimation of severe mitral regurgitation by conventional Doppler color flow criteria. The use of pulsed Doppler ultrasound to calculate regurgitant fraction in patients with a flail mitral valve leaflet may be helpful in reliably assessing the degree of mitral regurgitation.

Acute Disease↗
PubMed1990

Diastolic function in patients undergoing coronary angioplasty: influence of degree of revascularization.

To assess the early effects of successful coronary angioplasty on Doppler-derived left ventricular filling patterns and the significance of the extent of revascularization on these variables, 31 patients undergoing coronary angioplasty were examined within 24 h before and after the revascularization procedure. After angioplasty, the peak early to late velocity ratio increased from 0.89 +/- 0.2 to 1.05 +/- 0.3 (p less than 0.0001) and the one-third filling fraction increased from 42 +/- 10% to 48 +/- 10% (p less than 0.0001). The percent atrial contribution to filling decreased from 45 +/- 7% to 41 +/- 8% (p less than 0.01), and the pressure half-time and the isovolumetric relaxation time shortened from 55 +/- 15 to 43 +/- 13 ms (p less than 0.001) and from 100 +/- 14 to 82 +/- 17 ms (p less than 0.0001), respectively. When comparing patients with complete (n = 23) and incomplete (n = 8) revascularization, the same changes in the Doppler variables were observed. However, the mean rate of acceleration of early filling increased significantly after angioplasty only in those patients with complete revascularization. These data indicate that the left ventricular diastolic filling pattern is modified significantly as early as 24 h after successful coronary angioplasty. Improvement in impaired relaxation appears to be the most likely explanation for these changes, although increased myocardial stiffness in patients with incomplete revascularization is an alternative hypothesis.

Aged↗
PubMed1990

Comparison of hemodynamic pressure half-time method and Gorlin formula with Doppler and echocardiographic determinations of mitral valve area in patients with combined mitral stenosis and regurgitation.

Mitral valve area determined by the Gorlin formula in patients with combined mitral stenosis and regurgitation underestimates the true orifice size. Recent data suggest Doppler ultrasound and two-dimensional echocardiography more accurately estimate the mitral valve area in patients with mixed mitral valvular disease. This study assessed the accuracy of an alternate method, the hemodynamic pressure half-time method, for mitral valve area determination in such patients. In 22 patients, 28 separate mitral valve areas were calculated by the hemodynamic pressure half-time method, the Gorlin formula, and the Gorlin formula corrected for mitral regurgitation, and were compared with results calculated by the Doppler pressure half-time method. Six patients were studied both before and after balloon mitral valvuloplasty. In addition, mitral valve areas calculated by all four methods were compared with results obtained by planimetry in 15 patients with technically optimal echocardiograms. The mitral valve areas determined by hemodynamic pressure half-time corretated closely with the valve areas determined by Doppler (r = 0.90), whereas mitral valve areas determined by the Gorlin formula (both without and with correction for mitral regurgitation) did not correlate as well with the Doppler-estimated valve areas (r = 0.47 and r = 0.56, respectively). Correlation between the Doppler-derived mitral valve areas and the planimetered valve areas was also good (r = 0.84), as was that between the mitral valve areas calculated by hemodynamic pressure half-time and those calculated by planimetry (r = 0.78).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Safety and utility of transesophageal echocardiography in the critically ill patient.

We studied the safety and utility of transesophageal echocardiography in the evaluation of critically ill patients in the intensive care unit setting. Sixty-two studies were performed in four different intensive care units on 61 patients with a mean age of 58 +/- 14 years (range 25 to 78 years). Indications for the study included suspected aortic pathologic conditions (18 patients), cardiac source of embolus (16 patients), postmyocardial infarction complications (6 patients), and suspected infective endocarditis (5 patients). Studies were performed at bedside with the use of small amounts of intravenous sedatives. The probe was passed successfully in 61 of 62 attempts. Diagnoses that were missed by surface echocardiography, including aortic dissection, left atrial thrombus, ruptured papillary muscle, and prosthetic valve vegetation were clearly identified by transesophageal echocardiography, which facilitated appropriate management in these cases. In cases in which no pathologic condition was identified, transesophageal echocardiography was useful in ruling out intracardiac shunt, in assessing left ventricular function, and in excluding significant valvular pathologic conditions. No serious complications were recorded, and the procedure was, in general, very well tolerated.

Adult↗
PubMed1990

Aortic valve decalcification.

Ultrasonic decalcification of the aortic valve was performed in 22 elderly patients with critical aortic stenosis (aortic valve areas less than 0.8 cm2) as an alternative to prosthetic valve replacement. All of the patients had symptoms. The mean New York Heart Association class was 3.3 +/- 0.9. Adequate decalcification with restoration of leaflet mobility was achieved in all patients, including seven with bicuspid aortic valves. Leaflet perforation occurred and was successfully repaired in five patients. Ten patients underwent concomitant myocardial revascularization. There were two operative deaths (9%) and three late deaths. Echocardiograms were obtained preoperatively, postoperatively, and at 6 months. The mean aortic valve area increased significantly from 0.72 +/- 0.17 to 1.42 +/- 0.31 cm2 (p less than 0.001) and the peak gradient decreased from 74 +/- 34 to 25 +/- 13 mm Hg (p less than 0.001). At 6 months the aortic valve area (1.29 +/- 0.48 cm2) and peak gradient (31 +/- 12 mm Hg) continued to be significantly better than the preoperative measurements (p less than 0.001), but the 6-month aortic valve area was slightly decreased and the gradient increased when compared with the immediate postoperative values (p less than 0.02). The prevalence of mild to moderate aortic insufficiency increased from 50% of the patients preoperatively to 87% at 6 months (p less than 0.05). Two patients subsequently required aortic valve replacement for restenosis and aortic insufficiency. Ultrasonic decalcification is effective in relieving aortic stenosis, but subsequent restenosis and insufficiency may limit its application.

Aged↗
PubMed1989

Immediate and short-term effects of aortic balloon valvuloplasty on left ventricular diastolic function and filling in humans.

The effect of aortic balloon valvuloplasty on left ventricular diastolic function and filling was investigated in 44 adult patients with severe aortic stenosis. Two-dimensional and Doppler echocardiography was performed in all patients before and 24 h after valvuloplasty. In 19 patients (short-term group) repeat studies were performed at 3 (n = 2) and 6 (n = 17) months. Left ventricular relaxation, chamber stiffness and filling were assessed in 16 patients (immediate post-valvuloplasty group) before and immediately after valvuloplasty by simultaneous micromanometer left ventricular pressure tracings and echocardiograms. Immediately after valvuloplasty, relaxation was slightly impaired in the immediate post-valvuloplasty group, as reflected by the isovolumic relaxation time constant (56 +/- 26 to 68 +/- 39 ms; p less than 0.01) and maximal negative dP/dt (2,063 +/- 640 to 1,767 +/- 495 mm Hg/s; p less than 0.001). The chamber stiffness constants and diastolic filling dynamics were unchanged immediately after valvuloplasty. Twenty-four hours after valvuloplasty, patients without mitral regurgitation (n = 24) showed increases in the peak early filling velocity (72 +/- 31 to 83 +/- 28 cm/s; p less than 0.05) and peak early to atrial filling velocity ratio (0.8 +/- 0.6 to 1.0 +/- 0.7; p less than 0.05). However, in patients with mitral regurgitation (n = 20), the diastolic filling dynamics were not significantly changed. In the short-term group at the 3 to 6 month follow-up period, patients without mitral regurgitation (n = 12) showed striking increases compared with pre-valvuloplasty values in the peak early filling velocity (66 +/- 21 to 93 +/- 31 cm/s; p less than 0.02), peak early to atrial filling velocity ratio (0.6 +/- 0.2 to 0.9 +/- 0.4; p less than 0.02) and early time-velocity integral (9 +/- 4 to 16 +/- 6 cm; p less than 0.002). In patients with mitral regurgitation (n = 7) decreases occurred in the peak early filling velocity (123 +/- 32 to 106 +/- 28 cm/s; p less than 0.05) and peak early to atrial filling velocity ratio (1.5 +/- 0.7 to 1.1 +/- 0.6; p less than 0.05). Functional class in hospital improved after valvuloplasty (3.1 +/- 1.0 to 2.6 +/- 0.9; p less than 0.001) and correlated modestly with the percent decrease in Doppler-derived peak gradient (rs = 0.41, p less than 0.02) and mean gradient (rs = 0.36, p less than 0.05), but did not correlate with changes in aortic valve area, left ventricular ejection fraction or diastolic filling variables.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1989

Exercise capacity during the first year after cardiac transplantation.

Few data are available examining the influence of perioperative clinical parameters on exercise capacity after cardiac transplantation. Accordingly, 40 patients were studied by metabolic exercise testing early (1 to 3 months) and late (6 to 12 months) after cardiac transplantation. Various clinical parameters, including congestive heart failure class, length of hospital stay, age, cold ischemic time and histologic evidence of rejection were correlated with exercise capacity after transplantation. As expected, peak exercise capacity correlated inversely with both age and length of hospital stay. There was no correlation with preoperative congestive heart failure class or heart rate at rest. Interestingly, there was a statistically significant correlation between cold ischemic time and exercise capacity after transplantation. In addition, increased episodes of rejection during the first 6 months after transplantation resulted in statistically lower exercise capacity at 6 to 12 months after the operation. Thus, ischemic damage during transport of the donor organs and subclinical damage during early rejection may affect clinical status after heart transplantation and may only be apparent during increased physical demand such as exercise.

Adult↗
PubMed1989

Usefulness of Doppler echocardiography in the diagnosis of congestive heart failure.

One hundred fifty-one consecutive patients with a diagnosis of congestive heart failure (CHF) referred for echocardiography were prospectively evaluated to (1) define the frequency of normal left ventricular systolic function in a referral-based population with CHF; (2) establish cardiac mechanisms responsible for symptomatology in these patients; and (3) assess the ability to clinically differentiate these subsets of patients based on routine history and physical examination. Of the 151 total patients, 51 (34%) had normal left ventricular systolic function (left ventricular ejection fraction greater than or equal to 55%). Primary valvular disease was present in 4 of these 51 patients (8%), and Doppler echocardiographic evidence of abnormal left ventricular filling (diastolic dysfunction) was evident in 10 (20%). In addition, no predefined resting abnormality was noted in 34 (66%) of them. Despite this finding, 51% of all patients with normal left ventricular systolic function were being treated with digoxin therapy in the absence of atrial arrhythmia. Clinical differentiation of this group of patients from those with abnormal left ventricular systolic function was difficult and may have accounted for this apparently inappropriate treatment. Thus, evaluation of left ventricular function and of causative mechanisms of CHF before initiation of long-term treatment is mandatory.

Adult↗
PubMed1989

The effect of premature ventricular contraction on left ventricular relaxation, chamber stiffness, and filling in humans.

To investigate the influence of single spontaneous premature ventricular ectopic beats on left ventricular contraction, relaxation, chamber stiffness, and filling, we examined 21 patients with simultaneous micromanometer left ventricular pressure tracings and echocardiograms. Instantaneous left ventricular diameter and mitral valve inflow velocity were obtained by using of M-mode and pulsed Doppler echocardiography, respectively. The isovolumic relaxation time constants (TL and TD) were calculated by mean of a zero (TL) and variable (TD) asymptote pressure. The chamber stiffness constants were derived from the diastolic pressure-diameter (kd) and pressure-volume (kv) relationships. The extrasystolic beat was associated with marked impairments of relaxation, systolic function, and diastolic filling as seen by an increased TL (53 to 71 msec; p less than 0.001), TD (59 to 89 msec; p less than 0.005), time from maximum negative dp/dt to the lowest diastolic pressure (147 to 170 msec; p less than 0.05), and decreased number of elasped TDs (3.1 to 2.4; p less than 0.05), end-systolic pressure-diameter ratio (2.4 to 1.7; p less than 0.001), maximum positive dp/dt (1904 to 1326 mm Hg/sec; p less than 0.001), shortening fraction (31% to 21%; p less than 0.001), and peak early filling velocity (59 to 49 cm/sec; p less than 0.001). Chamber stiffness constants were unchanged. Relaxation and chamber stiffness were unchanged during the postextrasystolic beat as reflected by TL, TD, maximum negative dp/dt, and kd and kv.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Noninvasive assessment of diastolic and systolic properties of ibopamine in patients with congestive heart failure.

The acute effect of a single oral 100 mg dose of ibopamine on systolic and diastolic left ventricular function in nine patients with congestive heart failure was assessed by quantitative M-mode and pulsed Doppler echocardiography. Echocardiography was performed at baseline and 30, 60, and 120 minutes after ingestion of drug. Indices of systolic and diastolic left ventricular function were derived from digitized tracings of the septal and posterior endocardial surfaces and transmitral and aortic valve velocity profiles. Ibopamine significantly improved systolic function as reflected by a decrease in the preejection period to left ventricular ejection time ratio from 0.57 +/- 0.16 at baseline to 0.47 +/- 0.15 (p less than 0.05) 30 minutes after ingestion of drug. The maximum improvements in stroke volume and cardiac output after ibopamine were from 63 +/- 35 to 72 +/- 40 ml (p less than 0.05) and 4.6 +/- 1.7 to 5.4 +/- 2.1 L/min (p = 0.05), respectively. The contribution of atrial systole to total diastolic filling increased from 32 +/- 10% at baseline to 37 +/- 12% (p less than 0.05) after 30 minutes and persisted for at least 120 minutes. The distribution of diastolic filling was significantly altered after ingestion of ibopamine as reflected by a decrease in the ratio of the time-velocity integrals of left ventricular filling during early diastole and atrial systole (Ei/Ai) from 2.44 +/- 1.08 at baseline to 1.98 +/- 0.97 (p less than 0.05) 30 minutes after drug. The decrease in the Ei/Ai persisted for at least 120 minutes. The duration of the effect of ibopamine on diastolic filling persisted longer than its effect on augmenting systolic function. The positive effect of ibopamine on systolic function makes it a promising drug in the treatment of congestive heart failure.

Adult↗
PubMed1989

The effects of successful PTCA on left ventricular function: assessment by exercise echocardiography.

To assess the usefulness of exercise echocardiography in the follow-up of patients after percutaneous transluminal coronary angioplasty (PTCA), we studied 56 patients at rest and immediately following exercise with two-dimensional echocardiography. Sixty-nine of 73 stress/echo studies (94%) were suitable for interpretation. Seventeen patients (group I) with significant coronary artery disease (CAD) were studied before and after PTCA. Sixteen patients with coronary disease not undergoing PTCA (group II) and 23 individuals without significant coronary disease (group III) served as age-matched controls. Left ventricular ejection fraction did not change significantly in group I patients prior to PTCA (56 +/- 7 versus 54 +/- 12, p = ns) or in group II patients (52 +/- 10 versus 56 +/- 15, p = ns), rest versus immediate after exercise measurements. Following angioplasty, left ventricular ejection fraction increased in group I patients from 55 +/- 7 to 65 +/- 8, p less than 0.001 from rest to exercise, and to a similar extent in group III individuals (55 +/- 6 to 66 +/- 8, p less than 0.001). Electrocardiographic (ECG) evidence of ischemia (greater than 1 mm ST segment depression) was found in 13 of 17 group I patients prior to PTCA and in 8 of 16 group II patients (CAD). None of the 25 normal patients and four of the group I patients following PTCA had abnormal ECG changes with exercise. New exercise-induced echocardiographic wall motion abnormalities were found in 12 of 17 group I patients prior to PTCA and in none of the group I patients following PTCA.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon↗