BACKGROUND: Beta-blockers and amiodarone reduce the frequency of atrial fibrillation after open-heart surgery but the effectiveness of oral amiodarone in older patients already receiving beta-blockers is unknown. We have assessed the efficacy of oral amiodarone in preventing atrial fibrillation in patients aged 60 years or older undergoing open-heart surgery. METHODS: We did a randomised, double-blind placebo-controlled trial in which patients undergoing open-heart surgery (n=220, average age 73 years) received amiodarone (n=120) or placebo (n=100). Patients enrolled less than 5 days before surgery received 6 g of amiodarone or placebo over 6 days beginning on preoperative day 1. Patients enrolled at least 5 days before surgery received 7 g over 10 days beginning on preoperative day 5. FINDINGS: Patients on amiodarone had a lower frequency of any atrial fibrillation (22.5% vs 38.0%; p=0.01; absolute difference 15.5% [95% CI 3.4-27.6%]), and there were significant differences in favour of the active drug for symptomatic atrial fibrillation (4.2% vs 18.0%, p=0.001), cerebrovascular accident (1.7% vs 7.0%, p=0.04), and postoperative ventricular tachycardia (1.7% vs 7.0%, p=0.04). Beta-blocker use (87.5% amiodarone vs 91.0% placebo), nausea (26.7% vs 16.0%), 30-day mortality (3.3% vs 4.0%), symptomatic bradycardia (7.5% vs 7.0%), and hypotension (14.2% vs 10.0%) were similar. INTERPRETATION: Oral amiodarone prophylaxis in combination with beta-blockers prevents atrial fibrillation and symptomatic fibrillation and reduces the risk of cerebrovascular accidents and ventricular tachycardia.

Administration, Oral↗

PubMed2001

Obesity. Healthy genes could mean smaller jeans.

Explore the source record for details and available documents.

Anti-Obesity Agents↗

PubMed2001

Parkinson's disease. Lubricating gummed-up brains.

Explore the source record for details and available documents.

Drug Delivery Systems↗

PubMed2001

An evaluation of the change in electrocardiographic P-wave variables after acute caffeine ingestion in normal volunteers.

BACKGROUND: Caffeine's effect on supraventricular dysrhythmias is poorly understood, and establishing a marker to predict atrial fibrillation may help to explain supraventricular dysrhythmias caused by caffeine. OBJECTIVE: To evaluate the effects of caffeine (mean 6.1 mg/kg) on maximum P-wave duration and P-wave dispersion in normal volunteers. METHOD: A randomised, double-blind, placebo-controlled, crossover study in 10 healthy volunteers at least 17 years of age at the University of Connecticut. Participants abstained from caffeinated products for at least 2 days before study initiation and were randomly allocated on different days to receive placebo or caffeine 400 mg. For each of the study phases, a baseline 12-lead electrocardiogram (ECG) was performed and a subsequent 12-lead ECG was performed 3 h after ingesting the study drug. RESULTS: No significant changes were found within intra- or intergroup comparisons for any P-wave variables measured. CONCLUSION: Single dose caffeine (400 mg) does not affect average P-wave duration, maximum P-wave duration or P-wave dispersion in normal individuals.

Adult↗

PubMed2001

A placebo controlled evaluation of the antifibrillatory effects of carvedilol.

This article evaluates the antifibrillatory effects of carvedilol 5 mg/kg and vehicle (dimethyl-formamide) over time. Sprague-Dawley rats were anesthetized and intubated. They underwent baseline ventricular fibrillation threshold (VFT) determination and then received 1 of the 2 treatments (n = 10/group) over 8 minutes. VFT and determinations were performed at 2, 7, 15, 30, 45, and 60 minutes postinfusion. Carvedilol significantly increased the VFT at 2, 7, 15, 30 minutes versus baseline and the vehicle control group. Carvedilol significantly reduced the heart rate and the mean arterial pressure at every evaluable time point versus baseline and vehicle control. Carvedilol showed significant antifibrillatory effects versus baseline and vehicle for the first 30 minutes but not thereafter, even though the heart rate and mean arterial pressure remain significantly reduced.

Adrenergic beta-Antagonists↗

PubMed2001

An evaluation of the impact of gender and age on QT dispersion in healthy subjects.

OBJECTIVES: To determine if gender, age, and gender per age category, have an impact on QT and QTc dispersion in healthy volunteers. METHODS: This study was undertaken in 150 patients (50 per age group, 75 males, 75 females). The age groups included young (20-40 years), middle-aged (41-69 years) and elderly (> 70 years) subjects. The QT intervals on a 12 lead ECG were determined and Bazett's formula was used to derive the QTc intervals. The QT and QTc dispersion were determined by subtracting the shortest QTc interval from the longest on each 12-lead recording. RESULTS: Males had higher QT dispersion than females (50 +/- 22 vs 42 +/- 18 ms, P = 0.017) but QTc dispersion was not significantly changed. No significant differences were seen among the different age categories for QT or QTc dispersion. In elderly subjects, males had higher QT and QTc dispersion than females (54 +/- 23 vs 42 +/-15 ms, P = 0.039 and 63 +/- 23.7 vs 48 +/- 21 ms, P = 0.032, respectively). CONCLUSIONS: When evaluating the effect of gender in different age categories, elderly males have significantly greater QT and QTc dispersion than elderly female subjects. No other gender differences were noted for QT or QTc dispersion in the other two age categories. When evaluating a population of healthy volunteers, regardless of age, gender has an impact on QT dispersion but no significant interaction with QTc dispersion. Evaluating age without dividing the data by gender yields no significant differences in QT or QTc dispersion.

Adult↗