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Biomedical subjects

A B Levine

Publications and source records attributed to A B Levine.

At least 37 records · Page 2Linked to original sources
PubMed1996

Exercise training in patients with heart failure. A randomized, controlled trial.

OBJECTIVE: To assess the benefit of exercise training in patients with heart failure caused by left ventricular systolic dysfunction and to further describe the physiologic changes associated with exercise training in these patients. DESIGN: Randomized, controlled trial. SETTING: Urban outpatient clinic. PATIENTS: 40 men with compensated heart failure who were receiving standard medical therapy were randomly assigned to an exercise-training group or to a control group that did not exercise. Fifteen of the 21 patients assigned to exercise training and 14 of the 19 patients assigned to the control group completed the study. INTERVENTION: Patients assigned to exercise training participated in a program of three exercise sessions per week for 24 weeks. MEASUREMENTS: Symptom-limited exercise tests with gas exchange analysis done just before randomization, at week 12, and at week 24. RESULTS: At week 24, the following changes (mean +/- SE) were seen in patients in the exercise group and patients in the control group, respectively; exercise duration, 2.8 +/- 0.6 minutes and 0.5 +/- 0.5 minutes; peak oxygen consumption (VO2), 231 +/- 54 L/min and 58 +/- 38 L/min; peak ventilation, 12 +/- 3 L/min and -4 +/- 3 L/min; peak heart rate, 10 +/- 4 beats/min and -2 +/- 4 beats/min; and peak power output, 20 +/- 6 W and 2 +/- 5 W. Differences between the increases occurring in the exercise group and the changes occurring in the control group were significant (P < 0.05). Among patients in the exercise group, 85% of the increase in peak VO2 occurred by week 12, and 46% of the increase in peak VO2 was caused by the increase in peak heart rate. CONCLUSION: Exercise training does not appear to be contraindicated in patients with compensated heart failure. Exercise training improved exercise tolerance, as measured by increases in peak VO2, exercise duration, and power output. This improved exercise tolerance was caused in part by an increase in peak heart rate.

Adult↗
PubMed1996

Reinnervation of the transplanted human heart as evidenced from heart rate variability studies.

This study evaluated heart rate variability (HRV) after cardiac transplantation in humans in an attempt to test the hypothesis that cardiac reinnervation occurs in the post-transplant period. HRV was measured using 24-hour Holter recordings performed on 37 ambulant patients 1 to 122 months after cardiac transplantation. All patients were free of histologic rejection and were taking no medication likely to influence HRV. Time and frequency domain were analyzed and circadian rhythm of hourly average heart rate was calculated. HRV increased with time after the transplant. Compared with patients in the early post-transplant period, patients > 36 months after transplant had lower 24-hour heart rates (86 vs 93 beats/min), an increased average of all 5-minute SDs of NN intervals (17.6 vs 11.3), and higher low-and high-frequency power. Ten of the 27 patients > 3 years after transplantation had evidence of functional cardiac reinnervation. Compared with patients who had no reinnervation, these patients had increased circadian variability with lower nocturnal heart rates (76 vs 91 beats/min) and greater sympathetic activity during daytime (natural logarithm sympathetic power -0.36 vs -1.45) and nighttime (natural logarithm sympathetic power -0.43 vs -1.98). Despite lower nocturnal heart rates, there was no HRV evidence for an increase in parasympathetic activity. Thus, patients late after cardiac transplantation have HRV evidence for an increase in sympathetic control of the heart.

Adult↗
PubMed1996

Clinical status of patients removed from a transplant waiting list rivals that of transplant recipients at significant cost savings.

We retrospectively contrasted the medical outcome of patients removed from the heart transplant consideration list because of clinical improvement with that of transplant recipients. Of 60 patients awaiting transplantation, 18 were removed from the list (group A), and 42 required transplant or died (group B). Group A significantly improved regarding exercise oxygen uptake, ejection fraction, and hemodynamics. For more than 2 years after transplantation or "delisting," both groups had comparable symptoms (New York Heart Association class I to II) and cardiovascular mortality (1 of 18 for group A vs 3 of 32 for group B) but lower hospitalizations for group A (0.5 +/- 0.6 of 27 months per patient) versus group B (2.8 +/- 2.1 of 23 months per patient) (p = 0.0002). Despite two patients who had been removed from the list requiring transplantation, savings for delisting exceeded $2.2 million. Thus medical therapy allows transplant recipient list removal with clinical improvements sustained for 1 to 3 years at significant cost savings.

Cardiac Output, Low↗
PubMed1996

Evaluation of the prethrombotic state in pregnancy and in women using oral contraceptives.

The purpose of this study was to determine the effects of pregnancy and oral contraceptive use on in vivo coagulation by measurement of plasma levels of prothrombin fragment 1 + 2 and thrombin antithrombin III complex. Fifty-four women with uncomplicated singleton gestations, 34 women using oral contraceptives and 45 non-pregnant controls were the subjects of this study. Levels of prothrombin fragment 1 + 2 and thrombin-antithrombin III complex were measured using enzyme linked immunoassays. In uncomplicated pregnancies, levels of prothrombin fragment 1 + 2 and thrombin antithrombin III complex increased significantly with advancing gestational age. Women using oral contraceptives had significantly higher levels of prothrombin fragment 1 + 2 and thrombin antithrombin III complex compared to non-pregnant controls. The significant increase in levels of prothrombin fragment 1 + 2 and thrombin-antithrombin III complex throughout gestation and in women using oral contraceptives provided evidence of thrombin activation during these clinical conditions.

Antithrombin III↗
PubMed1996

Intraabdominal bleeding following laparoscopic adnexal surgery. A report of three cases.

BACKGROUND: The incidence of major complications from laparoscopy is reported to be 0.6-2.5%. The literature reviewing laparoscopic adnexal surgery reports few cases of intraoperative or postoperative complications. CASES: We describe three cases of intraabdominal bleeding following laparoscopic oophorectomy and salpingo-oophorectomy and salpingo-oophorectomy. In two of the three cases, postoperative exploratory laparotomy failed to identify the source of bleeding. CONCLUSION: Possible causes of postoperative bleeding are loosening of clips from an automated stapling device and delayed bleeding from vessels tamponaded by the pneumoperitoneum. Many complications of operative laparoscopy probably are underreported and, when present, may occur outside a health care facility since many of these cases are performed on an ambulatory basis. Some patients will acquire medical and/or surgical intervention.

Abdominal Injuries↗
PubMed1996

Reversal of end-stage heart failure is predicted by long-term therapeutic response rather than initial hemodynamic and neurohormonal profile.

BACKGROUND: Long waiting list periods for heart transplantation have led to clinical improvements for some patients resulting in their removal from the waiting list. This study sought to determine what characteristics differentiated those patients with a good clinical outcome from those who continued to need a transplant. METHODS: The initial and final serial (every 3 months) right heart catheterization data of 60 patients awaiting transplantation were retrospectively analyzed, and the patients were divided into two groups: group A, patients who were taken off the list in follow-up because of improvement (n = 18 of 60), and group B who continued to require transplantation or died (n = 42 of 60). RESULTS: For Group A, there were significant declines in right atrial pressure (9 +/- 4 to 4 +/- 3 mm Hg, initial versus final, p = 0.001), systolic pulmonary arterial pressure (51 +/- 17 to 34 +/- 6 mm Hg, p = 0.0001), with an increase in electron in ejection fraction (20% +/- 4% to 34% +/- 10%, p = 0.005). The change in cardiac output and norepinephrine level was not statistically significant. For Group B, there were no changes in the initial and final values of right atrial pressure, systolic pulmonary arterial pressure, pulmonary capillary wedge pressure, or norepinephrine levels. A significant rise in ejection fraction from 17% +/- 22% +/- 8%, p = 0.003 did occur. The majority of patients in group A (12 of 18) had idiopathic dilated cardiomyopathy. In contrast, an ischemic etiology was found in the majority of group B patients (25 of 42). CONCLUSIONS: This study shows that transplant waiting list outcome cannot be predicted from a patient's initial hemodynamic or neurohormonal presentation. Rather, those patients capable of reversing their hemodynamic derangements with therapy over time are most likely to sustain a favorable clinical outcome. It appears that patients with idiopathic rather than ischemic cardiomyopathy respond more favorably to medical interventions with improved prognosis.

Adult↗
PubMed1994

Cardiovascular responses of cardiac transplant patients to arm and leg exercise.

This investigation compares the cardiovascular responses of normal (n = 10) and cardiac transplant (n = 14) subjects to peak arm and leg exercise. It also tests the hypothesis that the higher heart rate (fc) in normal subjects during light (30 W) submaximal arm versus leg exercise is due to cardiac innervation. In cardiac transplant patients, power output, oxygen consumption (VO2), fc and rate pressure product were 54%, 28%, 7%, and 8% lower during peak arm than leg exercise, respectively. In normal subjects, power output, VO2, fc and rate pressure product were 61%, 33%, 8%, and 11% lower during peak arm than leg exercise, respectively. In cardiac transplant patients there was no significant difference in absolute fc during submaximal arm and leg exercise. In normal subjects, absolute fc during arm and leg exercise was [mean (SD)] 97 (4) beats.min-1 and 92 (4) beats.min-1, respectively (P = 0.07). Plasma noradrenaline was increased more during arm than leg exercise in both cardiac transplant and normal subjects. Maximal leg testing is useful when determining the capacity of cardiac transplant patients to perform arm work. The higher absolute fc reported by other investigators for normal subjects during submaximal arm versus leg exercise may be mediated by cardiac innervation.

Arm↗
PubMed1994

Exercise training in a patient with congestive heart failure on continuous dobutamine.

We present a 53-yr-old man with congestive heart failure who underwent 32 wk of exercise training. The patient was on a continuous infusion of dobutamine for 10 months prior to exercise training, which was subsequently discontinued at wk 24 of exercise training. Symptom-limited graded exercise tests were performed at baseline, wk 12, wk 24, and wk 32 of exercise training. While on a continuous infusion of dobutamine, the patient's oxygen consumption and exercise duration were increased during the exercise training period. Additionally, the patient was able to maintain these changes for 8 wk while continuing to exercise after the discontinuation of the dobutamine therapy.

Dobutamine↗
PubMed1994

Cardiovascular responses to submaximal arm and leg exercise in cardiac transplant patients.

We examined whether an increase in stroke volume (SV) contributes to the increase in cardiac output that occurs when cardiac transplant patients (CT) exercise between 50% and 75% of maximum. Upright arm and leg exercise was performed by 13 CT and 10 normal controls. Cardiac output (CO2 rebreathing), expired air, and catecholamine measures were obtained at rest and at 50% and 75% of maximum. From rest to 50% of maximum both normals and CT increased heart rate (HR) and SV during arm and leg exercise. In normals, HR (arm = +17 +/- 2 min-1; leg = +21 +/- 3 min-1) was increased further at 75% of maximum but not SV (arm = 3 +/- 4 ml; leg = +2 +/- 8 ml). In CT, further increases in both HR (arm = +9 +/- 1 min-1; leg = +13 +/- 1 min-1) and SV (arm = +12 +/- 5 ml; leg = +12 +/- 3 ml) were observed at 75% of maximum. During leg exercise plasma norepinephrine was increased more in CT than in normals. Between 50% and 75% of maximum, an increase in SV is a more important mechanism for increasing cardiac output during upright arm and leg exercise in CT than in normals.

Arm↗
PubMed1992

Sonographic diagnosis of the large for gestational age fetus at term: does it make a difference?

We evaluated 406 women with late third-trimester ultrasound examinations to determine whether the sonographic diagnosis of a large for gestational age (LGA) fetus, defined as an estimated fetal weight at or above the 90th percentile, altered the management of labor and delivery. The sonographic prediction of LGA fetuses had a sensitivity, specificity, and positive predictive value of 50, 90, and 52%, respectively. Women without the sonographic diagnosis of an LGA fetus (N = 338) differed from those with the diagnosis (N = 68) in the frequency of diagnosed labor abnormalities (19 versus 30%, P = .03), use of epidural anesthesia (57 versus 74%, P = .01), and the incidence of cesarean deliveries (32 versus 53%, P = .004). To determine whether it was the sonographic prediction of an LGA fetus or the actual fetal weight that altered clinical management and perinatal outcomes, we stratified the study population into four groups and compared the true negatives with the false positives and the false negatives with the true positives. The incorrect sonographic diagnosis of an LGA fetus had a statistically significant effect on both the diagnosis of labor abnormalities (P = .04) and the incidence of elective cesareans (P = .04) in pregnancies with appropriate for gestational age birth weights.

Cesarean Section↗
PubMed1992

Maternal renal artery Doppler velocimetry in normotensive pregnancies and pregnancies complicated by hypertensive disorders.

Hypertensive disorders in pregnancy contribute to substantial maternal and perinatal morbidity and mortality. Clinically, these disorders are characterized by hypertension and proteinuria. However, these signs appear some time after the physiologic derangements have been initiated. The primary objectives of this study were as follows: 1) to establish baseline values for the maternal renal artery systolic-diastolic ratio (S/D) as a function of gestational age in normal pregnancies, and 2) to determine whether renal artery blood flow indices can accurately identify those pregnancies complicated by, or destined to develop, hypertensive disorders. Using a pulsed Doppler scanner, maternal renal artery duplex evaluation was performed in four groups of women: normotensive nonpregnant, normotensive pregnant, chronic hypertensive pregnant, and preeclamptic. In 30 normotensive pregnant women followed longitudinally, no change was noted in the renal artery S/D as gestational age advanced, with mean (+/- SD) values of 2.5 +/- 0.20 and 2.6 +/- 0.21 for the left and right sides, respectively. No clinically meaningful discriminations were detected when the four groups were compared. We conclude that maternal renal artery Doppler waveforms are not significantly altered by either pregnancy or hypertensive complications in pregnancy.

Female↗
PubMed1991

Reliability of pleural fluid lymphocyte counts in the antenatal diagnosis of congenital chylothorax.

Two cases are presented in which fetal thoracentesis was performed to evaluate pleural effusions. In the first, a fetus with nonimmune hydrops had pleural effusions with lymphocyte counts consistent with congenital chylothorax. However, amniotic fluid cultures grew cytomegalovirus and the diagnosis of congenital cytomegalovirus infection was confirmed at autopsy. In the second, the pleural fluid lymphocyte count was lower than that considered to be diagnostic of congenital chylothorax. Nevertheless, the clinical course in this case and the patient's history of two previous infants who were presumed to have that disease suggest that this was the most likely diagnosis. These cases emphasize that pleural fluid lymphocyte counts alone are not reliable in establishing the cause of hydrothorax before birth.

Adult↗