Electrocardiographic and hemodynamic effects of a multicomponent dietary supplement containing ephedra and caffeine: a randomized controlled trial.

Context: Metabolife 356, a multicomponent dietary supplement containing ephedra and caffeine (DSEC) in addition to several other components, is the top-selling dietary weight loss supplement. Given its common use, anecdotal reports of cardiovascular and cerebrovascular adverse events, and paucity of safety data, further research with this DSEC was warranted.

Objective: To determine the impact of the DSEC on corrected QT (QTc) interval duration and systolic blood pressure (SBP).

Impact of prophylactic i.v. magnesium on the efficacy of ibutilide for conversion of atrial fibrillation or flutter.

The impact of prophylactic i.v. magnesium on the efficacy of ibutilide for conversion of atrial fibrillation and flutter to normal sinus rhythm was studied.

Amiodarone prevents symptomatic atrial fibrillation and reduces the risk of cerebrovascular accidents and ventricular tachycardia after open heart surgery: results of the Atrial Fibrillation Suppression Trial (AFIST).

Background: Atrial fibrillation (AF) is a common complication after cardiothoracic surgery (CTS). The role of amiodarone added to beta blocker as a preventive strategy in elderly patients undergoing CTS is not known. The Atrial Fibrillation Suppression Trial (AFIST) was a double blind, placebo-controlled trial that evaluated the efficacy of oral amiodarone in patients 60 years or older undergoing CTS.

Intravenous plus oral amiodarone, atrial septal pacing, or both strategies to prevent post-cardiothoracic surgery atrial fibrillation: the Atrial Fibrillation Suppression Trial II (AFIST II).

Background: The effect of a hybrid intravenous and oral prophylactic amiodarone regimen on postcardiothoracic surgery (CTS) atrial fibrillation (AF) is unknown. The impact of active atrial septal pacing on post-CTS AF has not been well characterized. In addition, the effect of using both amiodarone and atrial septal pacing together to prevent atrial fibrillation is unknown.

Effects of ischemia on repolarization in patients with single and multivessel coronary disease.

To evaluate if QT dispersion (QTd) may be affected by the number of obstructed coronary arteries (CAs) in patients with acute myocardial infarction (MI) and undergoing angioplasty, and to evaluate if QTd may be affected by ejection function of the heart. The infarct related CA was identified by coronary angiography in 141 patients (97 men, mean age 61.6 +/- 12.

Hemodynamic and electrocardiographic effects of short-term Ginkgo biloba.

Objective: To evaluate the immediate and short-term hemodynamic and electrocardiographic effects of Ginkgo biloba (ginkgo).

Methods: Healthy volunteers were randomized to receive ginkgo 120 mg or placebo twice daily for 7 days in this prospective, double blind trial. After at least a 7-day washout period, subjects were crossed over to an additional 7 days of alternate therapy.

Effects of intravenous magnesium sulfate on the QT interval in patients receiving ibutilide.

Study Objective: To determine the effect of intravenous magnesium sulfate on the QT and QTc intervals in patients receiving ibutilide for immediate chemical cardioversion of atrial flutter or fibrillation.

Design: Prospective, randomized, double-blind, placebo-controlled trial.

Setting: Hospital cardiology unit.

The immediate and short-term effect of successful percutaneous coronary intervention on repolarization in acute myocardial infarction patients.

Objectives: The primary objective was to assess the immediate and short-term impact of successful percutaneous coronary intervention (PCI) on QT dispersion (QT disp) and corrected QT dispersion (QTc disp). Secondarily, the impact of PCI on QT and QTc disp within different infarct-related arteries and the impact of successful PCI in these different arteries were evaluated.

Methods: Patients (n = 140, age 61.

The effect of head-upright tilt table testing for vasovagal syncope on P-wave duration.

Fluid shifts in vasovagal syncope may be reflected in electrocardiographic P-wave duration. We examined the effect of head-upright tilt-table testing (HUT) on P-wave duration among patients with positive or negative HUT. P-wave duration was measured at baseline and several post-HUT time points.

Ineffective ICD therapy due to excessive alcohol and exercise.

A 49-year-old man with dilated cardiomyopathy and an ICD received eight unsuccessful shocks for a single episode of ventricular tachycardia after excessive alcohol intake and exercise. The patient had low defibrillation thresholds just 8 days prior to his event during a routine 6-week postimplant electrophysiological study. Defibrillation threshold testing after his incident confirmed the low energy requirement for ventricular tachycardia termination.

A comparison of two individual amiodarone regimens to placebo in open heart surgery patients.

Background: This study compares the ability of two oral amiodarone regimens to reduce the risk of atrial fibrillation (AF) as compared with the placebo among elderly open heart surgery (OHS) patients receiving beta blockade.

Methods: This is a randomized, double-blinded, placebo-controlled trial of 220 patients undergoing OHS. Patients (average age, 73 years) received 7 g of oral amiodarone more than 10 days starting 5 days before OHS (slow load; n = 56), a 6 g oral amiodarone regimen more than 6 days starting 1 day before OHS (fast load; n = 64), or matching placebo in one of the two previously mentioned regimens (n = 100).