MPAACS: Magnesium for the Prevention of Atrial Arrhythmias After Cardiac Surgery

Magnesium for the Prevention of Atrial Arrhythmias After Cardiac Surgery

The objective of our research is to determine whether treatment with magnesium will reduce the incidence of atrial fibrillation in patients undergoing cardiac surgery. Several small studies of magnesium have already been conducted, but these studies were small and the results conflicting. A large, well-conducted study of magnesium treatment is required to definitively determine whether magnesium is effective in preventing this common complication after surgery. In addition, our study will include patients undergoing valvular surgery, a group previously excluded from research despite the fact that they are at increased risk of atrial fibrillation.

Study Overview

• Status: Terminated
• Conditions: Coronary Artery Disease; Valvular Heart Disease
• Intervention / Treatment: Drug: intravenous magnesium

Detailed Description

All patients referred for non-emergent cardiac surgery for isolated CABG, isolated valvular heart surgery, or combined valvular and CABG surgery are eligible for the study. Subjects will be randomized prior to surgery (1:1) to receive 5 g magnesium or placebo (saline) bolus by the anaesthesiologist upon removal of the crossclamp. On postoperative days 1 through 4, subjects will receive either IV MgSO4 (5g in 250 ml normal saline) or IV placebo (250 ml normal saline) infusion over 4 hours daily. Atrial fibrillation (and other arrhythmias) will be detected by placing all subjects on continuous 24-hour ECG telemetry monitoring for postoperative days 0 through 4.

The study is powered to detect at least a 30% relative reduction in postoperative atrial fibrillation in the CABG group; n=756. Because of the higher incidence of atrial fibrillation in the Valve +/- CABG group a total of 500 patients will be required to detect at least a 30% difference between treatment groups. These sample sizes are based on an alpha of 0.05 and 80% power.

• Study Type: Interventional
• Enrollment (Actual): 927
• Phase: Phase 3

Contacts and Locations

Study Locations

• Canada
  • British Columbia
    • Vancouver, British Columbia, Canada, V6Z 1Y6
      • St. Paul's Hospital
    • Vancouver, British Columbia, Canada, V5Z 1L7
      • Vancouver General Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 20 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• patient undergoing coronary artery bypass surgery with or without valve procedure
• scheduled for on-pump or cardiopulmonary bypass protocol

Exclusion Criteria:

• existing atrial fibrillation/flutter in the past year or on antiarrhythmic medications
• ventricular fibrillation
• sustained ventricular tachycardia
• 2nd or 3rd degree heart block
• paroxysmal supraventricular tachycardia
• major aortic repair planned during open-heart procedure
• permanent atrial/ventricular pacemaker implanted
• dialysis dependent or creatinine clearance < 35 umoles/min or oliguric/anuric renal failure
• patient intolerant of beta blockers
• patient has reactive airways disease dependent on regular beta-adrenergic agents
• patient is scheduled to undergo off-pump surgical protocol

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
atrial fibrillation	0-4 days after surgery

Secondary Outcome Measures

Outcome Measure	Time Frame
stroke	0-4 days after surgery
death	0-4 days after surgery
myocardial infarction	4 days after surgery

Collaborators and Investigators

• Sponsor: University of British Columbia
• Collaborators: Heart and Stroke Foundation of Canada
• Investigators: Principal Investigator: Karin H Humphries, DSc, University of British Columbia/St. Paul's Hospital; Study Chair: Hubert Wong, PhD, University of British Columbia, Department of Health Care & Epidemiology

Study record dates

Study Major Dates

• Study Start: July 1, 2004
• Primary Completion (Actual): September 1, 2008
• Study Completion (Actual): February 1, 2009

Study Registration Dates

• First Submitted: November 7, 2005
• First Submitted That Met QC Criteria: November 7, 2005
• First Posted (Estimate): November 9, 2005

Study Record Updates

• Last Update Posted (Estimate): November 4, 2010
• Last Update Submitted That Met QC Criteria: November 3, 2010
• Last Verified: March 1, 2009

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Myocardial Ischemia; Cardiovascular Diseases; Vascular Diseases; Arteriosclerosis; Arterial Occlusive Diseases; Coronary Disease; Heart Diseases; Coronary Artery Disease; Heart Valve Diseases
• Other Study ID Numbers: 20R20015