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Biomedical subjects

A J Labovitz

Publications and source records attributed to A J Labovitz.

At least 19 recordsLinked to original sources
PubMed1992

Mitral valve replacement: randomized trial of St. Jude and Medtronic-Hall prostheses.

To better define the merits of the bileaflet and tilting-disc valves, we prospectively randomized 102 patients (mean age, 57 years; range, 11 to 85 years) to receive either the St. Jude (n = 55) or the Medtronic-Hall (n = 47) mitral valve prosthesis between September 1986 and May 1991. The two groups were not different with respect to preoperative New York Heart Association class, incidence of mitral stenosis and insufficiency, angina score, extent of coronary artery disease, ventricular function, completeness of revascularization, or cross-clamp or bypass time. The hospital mortality (14.5% versus 10.6%, St. Jude versus Medtronic-Hall) and late mortality (7.3% versus 2.1%) were not significantly different. Follow-up was complete in 84 of 89 hospital survivors (94%) with a mean of 26 months (range, 1 to 60 months). The linearized rates of valve-related events and the 3-year actuarial survival demonstrated no significant differences between both cohorts. Comparison of the clinical outcome and echocardiographic parameters obtained at the time of follow-up demonstrated no significant differences between the two prostheses. These data indicate that the Medtronic-Hall and St. Jude mitral prostheses are similar with respect to their rates of valve-related complications and hemodynamic profiles. This study suggests that there is no difference between the St. Jude and Medtronic-Hall prostheses with regard to early clinical performance or hemodynamic results and therefore does not support the preferential selection of either prosthesis.

Adolescent↗
PubMed1992

Quantitation of mitral regurgitation by transesophageal echocardiography with Doppler color flow mapping: correlation with cardiac catheterization.

Eighty consecutive patients who underwent both left ventriculography and single-plane transesophageal echocardiography with Doppler color flow mapping were studied to compare the two techniques in the assessment of mitral regurgitation. Only the mosaic aspect of the regurgitant jet was included in the measurements. Values for inter- and intraobserver variability for the maximal regurgitant area measurements were 10 +/- 9% and 9 +/- 8%, respectively. The best correlation between angiography and Doppler color flow imaging was obtained with the maximal regurgitant area (r = 0.90). A maximal regurgitant area less than 3 cm2 predicted mild mitral regurgitation with a sensitivity of 96%, specificity of 100% and a predictive accuracy of 98%, whereas a maximal regurgitant area greater than 6 cm2 predicted severe mitral regurgitation with a sensitivity of 91%, a specificity of 100% and a predictive accuracy of 98%. A strong, although inferior, correlation was found for the maximal regurgitant area/left atrial area ratio (r = 0.81). A ratio less than 20% predicted mild mitral regurgitation with 94% accuracy, whereas a ratio greater than 35% predicted severe mitral regurgitation with 85% accuracy. Thus, single-plane transesophageal echocardiography with Doppler color flow mapping is an exquisitely sensitive technique for the diagnosis of mitral regurgitation. Minimal degrees of mitral regurgitation can be detected in approximately 62% of patients in whom no mitral regurgitation is detected by angiography. The mosaic maximal regurgitant area is a simple and easily obtainable Doppler echocardiographic index that provides an accurate estimation of mitral regurgitation severity.

Cardiac Catheterization↗
PubMed1992

Anterior wall left ventricular aneurysm repair. A comparison of linear versus circular closure.

To determine the efficacy of ventricular closure techniques, we reviewed our experience with 62 patients who survived the repair of aneurysms of the anterior wall of the left ventricular from 1984 through 1989. Forty of these patients underwent aneurysm repair by standard linear closure and 22 by a circular closure technique. After a mean follow-up interval of 3 years, there were no demonstrable differences in angina class, New York Heart Association functional classification, or survival. In 41 surviving patients, postoperative left ventricular dimensions and function were satisfactorily evaluated by standard echocardiographic measurements. No significant differences were found in postoperative long-axis left ventricular systolic diameter or in short-axis systolic or diastolic areas. There was a significantly larger long-axis diastolic diameter in the circular closure group; however, there was no difference in this parameter when the ratios of postoperative to preoperative lengths were compared. Further intragroup comparisons demonstrated an increase in short-axis areas postoperatively within the circular closure group in contrast to a decrease in patients in the linear closure group; these changes were not statistically significant. There was no significant difference in postoperative ejection fraction between the two closure groups, although minor reductions were found in the circular closure group. These data demonstrate no significant difference between the linear and circular closure techniques with respect to standard echocardiographic parameters, functional classification, and survival.

Actuarial Analysis↗
PubMed1991

Comparison of transthoracic and transesophageal echocardiography for assessment of left-sided valvular regurgitation.

To compare transthoracic and transesophageal echocardiography in the clinical assessment of left-sided valvular regurgitation, 118 patients who underwent both transesophageal and transthoracic echocardiographic studies within a 24-hour period were included in this study. Presence or absence of aortic regurgitation was identified concordantly by both techniques in 93 patients (79%). Complete agreement between both techniques was found in 88 patients (75%). Presence or absence of mitral regurgitation was identified concordantly by both techniques in 89 patients (75%). Complete agreement in grade was found in only 74 patients (63%). Twenty-nine patients (25%) had mitral regurgitation detected by transesophageal echocardiography, but not by transthoracic echocardiography. Four of these patients (14%) had significant (2 to 3+) mitral regurgitation. Differences between transesophageal and transthoracic echocardiography do not appear to be clinically important in patients with aortic regurgitation. In mitral regurgitation, significant differences exist between these 2 techniques, with transesophageal echocardiography being much more sensitive.

Aortic Valve↗
PubMed1991

Atrial septal aneurysm and stroke: a transesophageal echocardiographic study.

The prevalence and morphologic characteristics of atrial septal aneurysms identified by transesophageal echocardiography in 410 consecutive patients are described. Two groups of patients were compared: Group I consisted of 133 patients referred for evaluation of the potential source of an embolus and Group II consisted of 277 patients referred for other reasons. An atrial septal aneurysm was diagnosed by transesophageal echocardiography in 32 (8%) of the 410 patients. Surface echocardiography identified only 12 of these aneurysms. Atrial septal aneurysm was significantly more common in patients with stroke (20 [15%] of 133 vs. 12 [4%] of 277) (p less than 0.05); right to left shunting at the atrial level was demonstrated in 70% of patients in Group I and 75% of patients in Group II by saline contrast echocardiography. Four patients in Group I had an atrial septal defect with additional left to right flow. There was no difference between the two groups in aneurysm base width, total excursion or left atrial or right atrial excursion. However, Group I patients had a thinner atrial septal aneurysm than did Group II patients. It is concluded that an atrial septal aneurysm occurs commonly in patients with unexplained stroke, is more frequently detected by transesophageal echocardiography than by surface echocardiography and is usually associated with right to left atrial shunting. Treatment (anticoagulant therapy vs. surgery) of atrial septal aneurysm identified in stroke patients can be determined only by long-term follow-up studies.

Adult↗
PubMed1991

Attenuation of myocardial ischemia during coronary occlusion by ultrashort-acting beta adrenergic blockade.

To assess the effect of the ultrashort-acting beta blocker esmolol on ischemia induced by acute coronary occlusion, we studied 16 patients undergoing coronary angioplasty. Doppler echocardiography and ECG monitoring were performed continuously before, during, and after balloon occlusion in the drug-free state and during esmolol infusion. Fourteen of the 16 patients had ST segment elevation during balloon inflation. However, maximal ST segment elevation (2.1 +/- 1.5 mm vs 1.7 +/- 1.3 mm, p less than 0.001) and duration of ST segment elevation (68 +/- 20 seconds vs 54 +/- 19 seconds, p less than 0.05) were both significantly reduced during esmolol infusion. Furthermore, the decrease in ejection fraction seen during drug-free balloon occlusions was significantly blunted during esmolol infusion. In the baseline state ejection fraction decreased from 55% to 38% (p less than 0.05) during coronary occlusion compared with a decrease from 52% to 49% (p = NS) during esmolol infusion. In addition, esmolol appeared to delay the onset of segmental wall motion abnormalities after coronary occlusion, occurring at a mean of 40 seconds after balloon inflation versus a mean of 31 seconds in the absence of beta blockade (p less than 0.05). Thus the use of ultrashort-acting beta blockade appears to diminish the extent and delay the onset of myocardial ischemia during acute coronary occlusion.

Adrenergic beta-Antagonists↗
PubMed1991

Ultra short-acting intravenous beta-adrenergic blockade as add-on therapy in acute unstable angina.

To assess the efficacy and safety of the ultra short-acting beta-blocking agent, esmolol, in acute unstable angina, we administered esmolol to 21 patients who had persistent angina despite conventional medical therapy. Following a baseline Doppler echocardiographic examination, esmolol was titrated to reduce the rate-pressure product by at least 20%. Once the patients had been receiving a maintenance dosage for 30 minutes, Doppler echocardiographic studies were repeated. Mean esmolol dose at target response was 17 +/- 16 mg/min, with the dosage range of 8 to 24 mg/min. Esmolol was effective in alleviating anginal chest pain in 18 of the 21 patients. Seven patients eventually underwent percutaneous transluminal coronary angioplasty (PTCA) and eight had coronary bypass surgery. The remainder were discharged receiving medical therapy including oral beta-blockade. During esmolol therapy, heart rate and blood pressure decreased significantly (86 +/- 14 to 68 +/- 12 beats/min and 125 +/- 16 to 103 +/- 20 mm Hg, both p less than 0.001). Cardiac output decreased from 5.4 +/- 1.3 to 4.5 +/- 1.1 L/min (p less than 0.001) secondary to a decrease in heart rate as stroke volume remained unchanged. Left ventricular ejection fraction increased from 47 +/- 12 to 49 +/- 13 with esmolol therapy, although this change was not statistically significant. Both the one third filling fraction as well as E/A ratio (ratio of early-to-late diastolic filling velocities) increased with esmolol therapy (35 +/- 8% to 38 +/- 8% and 0.73 +/- 0.2 to 0.85 +/- 0.23, both p less than 0.005), indicating improvement in left ventricular diastolic function.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1991

The effects of high (sodium meglumine diatrizoate, Renografin-76) and low osmolar (sodium meglumine ioxaglate, Hexabrix) radiographic contrast media on diastolic function during left ventriculography in patients.

Although a majority of studies indicate superior hemodynamic and clinical profiles of low osmolar compared with high osmolar contrast media, the effect of these agents on diastolic left ventricular function has not been examined. We prospectively examined hemodynamic, electrocardiographic, and echocardiographic indices of left ventricular function in patients undergoing contrast ventriculography with a high osmolar, ionic, monomeric contrast, diatrizoate (Renografin-76) compared with a low osmolar, ionic, dimeric contrast, ioxaglate (Hexabrix). Thirty patients were randomized to each group. There were no clinical differences between the two groups. The decrease in systemic pressures was significantly greater with diatrizoate after left ventriculography (-38.5 +/- 3.5 versus -18.2 +/- 2.3, p less than 0.001) and selective left coronary angiography (-29.5 +/- 2.4 versus -17.4 +/- 2.6, p less than 0.001). In addition, left ventricular end-diastolic pressure increased significantly more with diatrizoate (7.3 +/- 0.9 versus 2.7 +/- 0.8 mm Hg for ioxaglate, p less than 0.001). QT interval prolongation occurred in both patient groups. Diatrizoate decreased systemic vascular resistance, and increased cardiac output and left ventricular ejection fraction more than ioxaglate, while simultaneously increasing left ventricular end-diastolic volume and altering the peak atrial filling velocity. Negative dp/dt (p less than 0.05), but not Tau, computed by the logarithmic or derivative methods, was reduced by diatrizoate. These data indicate that significant alteration of diastolic filling patterns occurs with high osmolar compared with low osmolar contrast agents. Although the clinical significance of this observation is currently unknown, these data further support the reported hemodynamic superiority of the low osmolar, dimeric contrast agent ioxaglate during contrast angiography.

Contrast Media↗
PubMed1991

Effects of aging on left ventricular structure and function.

To better characterize the cardiac structural and functional changes that are associated with aging, Doppler-echocardiography was performed on 23 young (mean age, 25 years) and 30 old (mean age, 70 years) healthy normotensive subjects. Left ventricular cavity dimensions and wall thickness were determined and left ventricular mass index was calculated from M-mode echocardiograms. Stroke volume was calculated from Doppler-measured aortic flow. Diastolic filling was evaluated by pulsed Doppler echocardiography of mitral inflow. Posterior wall thickness (1.0 vs 0.8 cm, p less than 0.05) and relative wall thickness (0.42 vs 0.35, p less than .05) were significantly greater in the elderly subjects compared with the younger subjects. Left ventricular mass index increased on average 0.25 gm/m2/yr but was not significantly increased in the elderly compared with the younger subjects (89 vs 77 gm/m2). Shortening fraction and stroke volume did not differ between the two groups. Diastolic filling was dramatically altered with aging, and the elderly subjects demonstrated a doubling of percent atrial contribution (37% vs 19%, p less than 0.0001) and halving of peak early-to-peak atrial velocity ratio (0.85 vs 1.77, p less than .01).

Adult↗
PubMed1991

Effects of electrophysiologic testing of the automatic implantable cardioverter-defibrillator on left ventricular systolic function and diastolic filling.

We investigated the effects of electrophysiologic testing of the automatic implantable cardioverter-defibrillator (AICD) on left ventricular systolic function and diastolic filling in 12 patients. Ventricular tachycardia or ventricular fibrillation was induced by programmed electrical stimulation and alternating-current, respectively. Patients were studied before and immediately after, 10 minutes after, and 1 hour after defibrillation by the AICD using M-mode, two-dimensional, and pulsed Doppler echocardiography. Immediately after defibrillation, increases were found in the peak early filling velocity (70 +/- 10 cm/sec to 84 +/- 24 cm/sec, p less than 0.01), peak early-to-atrial filling velocity ratio (1.05 +/- 0.21 to 1.29 +/- 0.26, p less than 0.005), and maximum rate of diastolic chamber enlargement (82 +/- 26 mm/sec to 102 +/- 44 mm/sec, p less than 0.05). These changes were not evident at 10 minutes and 1 hour. Cardiac output and ejection fraction were unchanged after defibrillation. Heart rate and diastolic filling time were unchanged. We conclude that electrophysiologic testing of the AICD does not impair left ventricular function in the immediate to 1-hour period after defibrillation. Left ventricular systolic function is unchanged and diastolic filling is enhanced.

Cardiac Pacing, Artificial↗
PubMed1991

Pathophysiology of isolated systolic hypertension in elderly patients: Doppler echocardiographic insights.

Systemic hemodynamics were evaluated with aortic pulsed wave Doppler echocardiography in 79 elderly subjects with isolated systolic hypertension participating in the Systolic Hypertension in the Elderly Program (SHEP) and were compared with the values in 39 normal age-matched subjects. Cardiac output was elevated (4.50 +/- 1.13 L/min versus 3.94 +/- 1.12 L/min, p less than 0.05) in patients with isolated systolic hypertension in comparison with values in normal elderly subjects. Systemic vascular resistance did not differ between both groups (2140 +/- 536 dyn.sec/cm-5 versus 2011 +/- 553 dyn.sec/cm-5, p = NS). The mean acceleration of blood during left ventricular ejection was similar in patients with isolated systolic hypertension in comparison with normals (12.6 +/- 5.6 m/sec2 versus 11.5 +/- 3.5 m/sec2, p = NS). Patients with isolated systolic hypertension had significantly decreased arterial compliance, as measured by the stroke volume-to-pulse pressure ratio (0.77 +/- 0.26 cm3/mm Hg versus 1.11 +/- 0.30 cm3/mm Hg, p less than 0.0001). The prevalence of aortic and mitral regurgitation as well as valvular and annular calcification did not differ between analyzed groups. Isolated systolic hypertension in elderly patients appears to be multifactorial, with reduced arterial compliance and increased cardiac output both playing a role.

Aged↗
PubMed1991

Effect of mitral regurgitation on pulmonary venous velocities derived from transesophageal echocardiography color-guided pulsed Doppler imaging.

The effect of mitral regurgitation on pulmonary venous flow velocity was studied in 66 patients undergoing transesophageal echocardiography. Nine patients were studied intraoperatively before and after surgery, so that 75 pulmonary venous flow tracings were analyzed. Fifty-four patients had no significant (0 to 1+) mitral regurgitation and 21 had significant (2 to 3+) mitral regurgitation. Comparison of both groups revealed significant differences in the pulmonary venous flow pattern. In patients with no significant mitral regurgitation, the peak systolic velocity was higher (55 +/- 16 vs. -4 +/- 16 cm/s; p less than 0.0001) and the peak diastolic velocity was lower (43 +/- 13 vs. 59 +/- 17 cm/s; p less than 0.01) when compared with values in patients with significant mitral regurgitation. Consequently, the peak systolic/diastolic velocity ratio was significantly higher in the patients without significant mitral regurgitation (1.4 +/- 0.5 vs. 0.4 +/- 1.3; p less than 0.0001). The same trend was noted with respect to the systolic and diastolic velocity integrals. As the degree of mitral regurgitation increased, the peak diastolic velocity and diastolic velocity integral increased, whereas the peak systolic velocity and systolic velocity integral decreased. In patients with severe mitral regurgitation, the systolic flow became reversed (retrograde). The sensitivity of reversed systolic flow for severe mitral regurgitation was 90% (9 of 10), the specificity was 100% (65 of 65), the positive predictive value was 100% (9 of 9), the negative predictive value was 98% (65 of 66) and the predictive accuracy was 99% (74 of 75).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗
PubMed1991

Superiority of transesophageal echocardiography in detecting cardiac source of embolism in patients with cerebral ischemia of uncertain etiology.

The diagnostic yield of transesophageal and transthoracic echocardiography for identifying a cardiac source of embolism was compared in 79 patients presenting with unexplained stroke or transient ischemic attack. There were 35 men and 44 women with a mean age of 59 years (range 17 to 84); 52% had clinical cardiac disease. Both transthoracic and transesophageal echocardiograms were performed using Doppler color flow and contrast imaging. Transesophageal echocardiography identified a potential cardiac source of embolism in 57% of the overall study group compared with only 15% by transthoracic echocardiography (p less than 0.0005). Compared with transthoracic echocardiography, transesophageal echocardiography more frequently identified atrial septal aneurysm associated with a patent foramen ovale (9 versus 1 of 79 patients, p less than 0.005), left atrial thrombus or tumor (6 versus 0 of 79 patients, p less than 0.05) and left atrial spontaneous contrast (13 versus 0 of 79 patients, p less than 0.0005). All cases of left atrial thrombus or spontaneous contrast were identified in patients with clinically identified cardiac disease. In the 38 patients with no cardiac disease, transesophageal echocardiography identified isolated atrial septal aneurysm and atrial septal aneurysm with a patent foramen ovale more frequently than transthoracic echocardiography (8 versus 2 of 38 patients, p less than 0.05). The two techniques had a similar rate of identifying apical thrombus and mitral valve prolapse. Overall, transesophageal echocardiography identified abnormalities in 39% of patients with no cardiac disease versus 19% for transthoracic echocardiography (p less than 0.005). Thus, transesophageal echocardiography identifies potential cardiac sources of embolism in the majority of patients presenting with unexplained stroke.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral Infarction↗
PubMed1991

Echocardiographic evaluation of cardiac structure and function in elderly subjects with isolated systolic hypertension.

One hundred four participants in the Systolic Hypertension in the Elderly Program (SHEP) trial (mean age 71 +/- 6 years) were examined by Doppler echocardiography to gain information on the cardiac structural and functional alterations in isolated systolic hypertension. Participants had a systolic blood pressure greater than 160 mm Hg with diastolic blood pressure less than 90 mm Hg and were compared with 55 age-matched normotensive control subjects. Left ventricular mass index was significantly higher in the participants than in the normotensive subjects (103 +/- 28 versus 87 +/- 23 g/m2, p = 0.0014) and 26% of the participants met echocardiographic criteria for left ventricular hypertrophy compared with 10% of normotensive subjects. Left atrial index was also greater in participants than in normotensive subjects (2.26 +/- 0.32 versus 2.11 +/- 0.24 cm/m2, p = 0.005) and 51% of participants had left atrial enlargement. Doppler measures of diastolic filling were significantly different between the two groups, with peak atrial velocity higher (76 +/- 17 versus 69 +/- 17 cm/s, p = 0.02) and ratio of peak early to atrial velocity lower (0.76 +/- 0.23 versus 0.86 +/- 0.22, p = 0.0124) in participants. There was no correlation between left ventricular mass index and Doppler measures of diastolic function, but relative wall thickness correlated significantly with peak atrial velocity (r = 0.22, p = 0.016) and peak early to peak atrial velocity ratio (r = 0.24, p = 0.007). There was no difference in M-mode ejection phase indexes of systolic performance (shortening fraction and peak velocity of circumferential fiber shortening) between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗