Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM)

March 24, 2016 updated by: National Heart, Lung, and Blood Institute (NHLBI)
To compare two standard treatment strategies for atrial fibrillation: ventricular rate control and anticoagulation vs. rhythm control and anticoagulation.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

BACKGROUND:

Atrial fibrillation is an extremely common and increasingly prevalent cardiac arrhythmia, particularly in the elderly, and is an important risk factor for stroke. Management of atrial fibrillation remains controversial, and although antiarrhythmic drugs are widely used for this condition, clinical studies to support their use are meager. Management of atrial fibrillation has at least three components: restoration and maintenance of sinus rhythm; heart rate control when maintenance of sinus rhythm or when cardioversion is not attempted or impossible; and anticoagulation. The first component of management uses antiarrhythmic drugs and the second uses a different group of antiarrhythmic drugs and catheter ablation. The third is anticoagulant therapy for patients in whom normal sinus rhythm cannot be maintained or in whom cardioversion is not attempted.

The initiative was developed by staff of the Clinical Trials Branch and the NHLBI Working Group on Atrial Fibrillation which met in Bethesda in April, 1993. The initiative was given concept clearance by the February 1994 National Heart, Lung, and Blood Advisory Council. The Request for Proposals was released in May 1994.

DESIGN NARRATIVE:

A randomized multicenter trial. The trial enrolled only patients with atrial fibrillation who were at high risk for stroke, that is, over 65 years of age or less than 65 and with one or more other risk factors for stroke such as systemic hypertension, diabetes mellitus, congestive heart failure, transient ischemic attack, prior cerebral vascular accident. High risk patients were treated with the anticoagulant warfarin. Cardioversion (electrical or pharmacologic) might have been attempted before randomization, but if it was unsuccessful, the patient was excluded from further consideration for randomization. Normal sinus rhythm must have persisted for one hour or greater after cardioversion to qualify as successful cardioversion. Patients were randomly assigned to treatment groups which included maintenance of sinus rhythm or heart rate control. Both treatment groups had two steps.

In the maintenance of sinus rhythm group, the choice of drugs was left to the primary treating physician, to be chosen from amiodarone, sotalol, propafenone, flecainide, quinidine, moricizine, disopyramide, procainamide, and combinations of these drugs. Atrioventricular nodal blocking drugs were also administered unless contraindicated. The major substudy for AFFIRM randomized initial drug choice among amiodarone, sotalol, and class I drugs. Prior drugs which were ineffective or poorly tolerated were not repeated. There were various drug exclusions depending on the patient's condition. Patients in the maintenance of sinus rhythm group had multiple cardioversions as needed. If there was treatment failure or intolerance after two or more pharmacologic trials, patients were considered for innovative therapy in Step II. In Step II, two maintenance doses of amiodarone were included, a low dose of 100 to 200 mg/day and a normal dose of 300 to 400 mg/day. Each dose of amiodarone was considered to be a single drug trial, so that patients who received treatment with amiodarone at both dosage levels were considered to have had two drug trials. It was not mandatory that Step II therapies be applied in any individual patient. The following innovative Step II therapies were approved for use in the study: (1) ablation of an atrial focus in patients with type I atrial flutter, if it was clinically documented that the atrial flutter led to atrial fibrillation; (2) atrial pacing alone, with or without documented bradycardia; (3) atrial pacing and antiarrhythmic drugs, with either single site or multiple site atrial pacing; and (4) surgical maze or atrial isolation procedures at selected centers. Catheter-based ablative procedures, such as those attempting to mimic the maze procedure were not approved in this study. Implanted atrial cardioverter defibrillators were also not approved. All therapy was periodically reviewed and subject to modification by the Steering Committee with concurrence by the DSMB and the NHLBI. In the event that sinus rhythm was not maintainable by any treatment, patients crossed over to rate control and anticoagulation.

The heart rate control arm used heart rate as the therapeutic target, rather than dose of medications. Drug dosage was adjusted to achieve target heart rates. During atrial fibrillation, heart rate was assessed both at rest and during activity at each clinic visit. The pharmacologic therapies approved for use in this arm included: beta blockers, verapamil, diltiazem, digoxin, or combinations of these drugs . When Step I pharmacologic therapies failed after two or more drug trials, the treating physician could select an approved Step II innovative therapy. The two innovative therapies approved for use with the heart rate control arm were: (1) atrioventricular node modification by catheter ablation, with or without placement of a pacemaker, with or without continued drugs to slow atrioventricular node conduction, and (2) total atrioventricular junctional ablation and placement of a pacemaker.

The primary endpoint by which the two strategies were compared was total mortality, analyzed by intention-to-treat. Secondary endpoints were composite end points (total mortality, disabling intracranial bleed, stroke, disabling anoxic encephalopathy, cardiac arrest, major noncentral nervous system bleed, cost of therapy, and quality of life. Follow-up was a minimum of two years and an average of 3.5 years. Recruitment and intervention extended from November 1995 through October 1999 with 4,060 patients enrolled by 213 sites.

Study Type

Interventional

Phase

  • Phase 3

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

65 years to 100 years (Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Elderly men and women with atrial fibrillation and other risk factors for stroke.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

National Heart, Lung, and Blood Institute (NHLBI)

Investigators

  • H. Greene, Statistics and Epidemiology Research Corporation (S.E.R.C.)

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

March 1, 1995

Study Completion

September 1, 2002

Study Registration Dates

First Submitted

October 27, 1999

First Submitted That Met QC Criteria

October 27, 1999

First Posted (Estimate)

October 28, 1999

Study Record Updates

Last Update Posted (Estimate)

March 25, 2016

Last Update Submitted That Met QC Criteria

March 24, 2016

Last Verified

November 1, 2005

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 100

Plan for Individual participant data (IPD)

Study Data/Documents

  1. Individual Participant Data Set
    Information identifier: AFFIRM
    Information comments: NHLBI provides controlled access to IPD through BioLINCC. Access requires registration, evidence of local IRB approval or certification of exemption from IRB review, and completion of a data use agreement.
  2. Study Protocol
  3. Study Forms

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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