Prognostic significance of preoperative left ventricular ejection fraction and valve lesion in patients with aortic valve replacement

After aortic valve replacement, depressed left ventricular function, as assessed from the preoperative left ventricular ejection fraction, has been reported to improve significantly in patients with aortic stenosis, but to improve little or to a lesser degree In patients with aortic regurgitation. Accordingly, the effect of preoperative left ventricular ejection fraction and other variables on postoperative survival was examined in 229 patients after aortic valve replacement. The preoperative left ventricular ejection fraction, cardiac index and left ventricular end-diastolic pressure were found not to affect the 3 year postoperative survival rate in patients with aortic stenosis and mixed aortic valve disease. However, patients with aortic regurgitation and a left ventricular ejection fraction of less than 0.50 had a significantly poorer 3 year survival rate (64 ± 10 percent) than patients with aortic regurgitation and an ejection fraction of 0.50 or more (91 ± 8 percent) (p <0.02). The 3 year postoperative survival rate in patients with a reduced cardiac index (less than 2.5 liters/min per m²) and aortic regurgitation was also significantly lower (63 ± 10 percent) than the rate in patients with aortic regurgitation and a normal cardiac index (p <0.02). There was less significance in the difference between the 3 year postoperative survival rate of patients with aortic regurgitation whose left ventricular end-diastolic pressure was 15 mm Hg or less and those whose pressure was greater than 15 mm Hg (p <0.05). Thus, it may be advisable to monitor left ventricular ejection fraction noninvasively in patients with aortic regurgitation and to advise aortic valve replacement before the ejection fraction becomes severely depressed.     

Effects of intravenously administered propranolol on wall motion abnormalities

Although propranolol is frequently utilized as therapy for angina pectoris in patients with previous myocardial infarction, its effects on wall motion abnormalities in such patients have not been adequately defined. Accordingly, using external wall motion video tracking, we studied 18 patients with previous myocardial infarction and wall motion disorders and 5 normal subjects before and after administration of propranolol, 5 mg intravenously. Systolic time intervals, heart rate and left heart size (measured by the distance between the mid-line and left heart border in an X-ray film triggered at end-diastole after a standard inspiration) were also measured before and after administration of propranolol. In each instance propranolol produced a reduction in the amplitude and velocity of wall motion in areas of normal movement, hypokinesis and paradox, resulting in decreased outward bulging. In the normal subjects, the amplitude and velocity of wall motion also decreased. In the patients with previous myocardial infarction, propranolol increased the ratio of the preejection period to the left ventricular ejection time from a mean of 0.377 ± 0.03 (standard error of the mean) to 0.409 ± 0.03 (P <0.001); decreased heart rate by an average of 7.5 beats/min (P <0.001); and increased the distance from the mid-line to the left heart border from 94.3 ± 2.6 to 97.3 ± 2.6 mm (P <0.001). Similar changes occurred in the 5 normal subjects. We conclude that doses of propranolol sufficient to increase the ratio of the preejection period to left ventricular ejection time, decrease heart rate and increase heart size do not exaggerate preexisting paradoxical wall motion or accentuate latent areas of paradox in patients with previous myocardial infarction.     

A Preliminary Study of Hepatitis B Virus Replication during Short-Term (7-Day) Social Drinking

The purpose of this study is to determine the effect of short-term social drinking on hepatitis B virus (HBV) replication as measured by serum levels of hepatitis B virus DNA (HBV-DNA). We studied five male carriers of hepatitis B e antigen who were social drinkers. Levels of HBV-DNA, blood alcohol, and aspartate aminotransferase (AST) were measured during abstinence from alcohol, before and during a test dose (29.8 g) of alcohol which followed one week of abstinence, and before and during the same test dose which followed social drinking for one week. We observed no significant changes in HBV-DNA or AST levels. These data suggest that a single one-week period of social drinking in patients with chronic HBV infection does not cause enhanced viral replication. The risks of repeated ingestion of moderate amounts of alcohol by such patients have not been established. Interpretation of our data is limited by the small number of subjects, and further studies are needed. Nevertheless, our results are consistent with published recommendations that social drinking by nonalcoholic HBV carriers should be restricted but need not be totally forbidden.     

Behavioral change in preventive medicine

We designed and evaluated a program to teach internal medicine residents behavioral counseling skills for multiple risk factor modification. Integrating physician-patient communication, negotiation skills, and the transtheoretical model of behavior change, we used small group discussion and standardized patients. The 18 participating residents increased their ability to modify patient behavior during videotaped interviews, mean pretest/posttest score: 33.1/40.1 (Student’s pairedt test, p<.0001). Physician self-efficacy in screening for risk factors and effecting behavioral change in patients was increased (p<.0001), as were positive attitudes toward psychosocial factors (p<.003). Our teaching effectively increased the residents’ self-efficacy and performance of behavioral counseling.