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L Levenson

Publications and source records attributed to L Levenson.

7 recordsLinked to original sources
PubMed1994

Decreased perceptual sensitivity to emotion-evoking stimuli in depression.

We measured two aspects of emotional response in depressed patients, as a preliminary study of the potential usefulness of such measures for elucidating pathophysiological mechanisms. First we used electromyography to measure the automatic mimicry on an individual's own face of facial displays of emotion observed on the faces of others. Next we used the fused dichotic listening paradigm to measure selective perception of both positive and negative emotion-related words as opposed to neutral words. Patients failed to show the normal facial mimicry of both positive and negative facial displays, despite normal cognitive processing of the stimuli. They also heard significantly fewer positive and negative words on the dichotic tests than did healthy controls. This suggests that depressed patients are hyposensitive to emotion-related stimuli in general.

Adult↗
PubMed1988

Intraoperative myocardial ischemia: localization by continuous 12-lead electrocardiography.

Based primarily on results obtained during exercise treadmill testing, electrocardiographic (ECG) leads II and V5 are the suggested optimal leads for detecting intraoperative myocardial ischemia. However, these recommendations have not been validated in this setting using all 12 ECG leads. Accordingly, the authors studied 105 patients with known or suspected coronary artery disease (CAD) undergoing noncardiac surgery with general anesthesia by continuously recording the 12-lead ECG intraoperatively in all patients. The average duration of monitoring was 8.2 +/- 2.7 h (mean +/- SD). Ischemic episodes (i.e., greater than or equal to 1-mm horizontal or downsloping ST depression, greater than or equal to 1.5-mm slowly upsloping ST depression or greater than or equal to 1.5-mm ST elevation in a non-Q wave lead) occurred in 25 patients (24%). Out of 51 ischemic episodes, 45 involved ST depression alone, and the remaining six involved both ST depression and elevation. ST segment changes occurred in a single lead only in 14 episodes, while multiple leads were involved in 37 episodes. Lead sensitivity was estimated assuming that all ST segment changes were true positive responses. Sensitivity using a single lead was greatest in V5 (75%) and V4 (61%), and intermediate in II, V3, and V6 (33%, 24%, and 37%, respectively). The remaining seven leads demonstrated very low sensitivity (2-14%) or exhibited no ischemic changes (I and a VL). Combining leads V4 and V5 increased sensitivity to 90%, while the standard clinical combination, II and V5, was only 80% sensitive. Sensitivity increased to 96% by combining II, V4, and V5. The further addition of V2 and V3 (five leads) increased sensitivity to 100%. This study confirms previous recommendations for the routine use of a V5 lead (either uni- or bipolar) in all patients at risk for ischemia. V4 is more sensitive than lead II, and should be considered as a second choice. However, lead II, superior for detection of atrial dysrhythmias, is more easily obtained with conventional monitors. The use of all three would appear to be the optimal arrangement for most clinical needs, and is recommended if the clinician has the capability.

Aged↗
PubMed1978

Effect of morphine on splanchnic blood flow.

Splanchnic blood flow was measured by the constant infusion of indocyanine green given before and after morphine 0.2 mg/kg (maximum 15 mg) intravenously in 13 patients. Splanchnic blood flow increased from 1012 +/- 98 ml/min to 1200 +/- 118 ml/min after the administration of morphine, a 19 per cent increase (P less than 0.025). Splanchnic vascular resistance decreased from 0.094 +/- 0.010 to 0.081 +/- 0.010 mmHg min/ml, a 16 per cent decrease (P less than 0.001). There was no significant change between baseline and post-morphine values in systemic arterial pressure (92.2 +/- 3.8 and 89.0 +/- 2.9 mmHg), hepatic vein wedge pressure (7.1 +/- 1.0 and 7.8 +/- 0.6 mmHg), or right atrial mean pressure (4.5 +/- 0.6 and 4.3 +/- 0.7 mmHg). This study shows that morphine induced significant splanchnic arteriolar dilatation.

Abdomen↗
PubMed1977

The changing status of ejection fraction as a predictor of early mortality following surgery for acquired heart disease.

Several reports in the literature and our experience prior to 1974 support the thesis that operative risk in patients with acquired heart disease and poor ventricular function (as assessed by a biplane ejection fraction [EF] less than or equal to 0.40) was very significantly increased over the risk in patients with normal ventricular function. These results led to disagreement in the literature regarding the advisability of surgery in patients with poor ventricular function. Various EFs from less than 0.31 to less than 0.50 were suggested as contradicting elective surgery, while more aggressive groups recommended surgery in all patients with angina. Precise comparison of the results reported by different groups was not always possible because of the common reliance on single-plane right anterior oblique ventriculograms, which tend to underestimate EF and overestimate operative risk. Using biplane ventribulograms for accurate estimation of EF, we have demonstrated a significant reduction in 30-day operative risk to a clinically acceptable 3 percent (1/32) for single valve replacement and aortocoronary surgery patients with poor ventricular function (EF less than or equal to 0.40) during 1974. Considering the high risk of medically treated patients with reduced ventricular function, these results support further evaluation of surgical palliation for patients with valvular or coronary heart disease and reduced ventricular function.

Cardiac Volume↗