Functional status in rate- versus rhythm-control strategies for atrial fibrillation: results of the Atrial Fibrillation Follow-Up Investigation of Rhythm Management (AFFIRM) Functional Status Substudy.
OBJECTIVE
The Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) functional status substudy aimed to test the hypothesis that functional status is similar in rate-control and rhythm-control strategies.


BACKGROUND
Randomized studies, including the AFFIRM study, have failed to demonstrate survival benefits between rate-control and rhythm-control strategies for atrial fibrillation (AF). However, AF may cause functional capacity or cognitive impairment that might justify maintenance of sinus rhythm.


METHODS
Investigators of the AFFIRM study enrolled 4,060 patients with AF who required long-term therapy and who were 65 years of age or older or who had another risk factor for stroke or death. New York Heart Association functional class (NYHA-FC) and Canadian Cardiovascular Society Angina Classification were assessed at initial and each follow-up visit. From 22 randomly chosen functional status substudy sites, 245 participants underwent 6-min walk tests and Mini-Mental State Examination (MMSE) at initial, two-month, and yearly visits. Patients were assigned randomly to rate-controlling drugs, allowing AF to persist, or rhythm-controlling antiarrhythmic drugs, to maintain sinus rhythm.


RESULTS
The NYHA-FC worsened with time in both rate-control and rhythm-control groups, with no differences between groups. Presence of AF was associated with worse NYHA-FC (p < 0.0001). No differences were observed in Canadian Cardiovascular Society Angina Classification or MMSE scores. Six-minute walk distance improved over time in both study arms. On average, walk distance was 94 feet greater in the rhythm-control group (adjusted p = 0.049).


CONCLUSIONS
Modest improvement in 6-min walk distance was noted in the rhythm-control arm. Presence of AF was associated with worse NYHA-FC. No difference in cognitive function was detected.
Chung
Mina K
MK
Department of Cardiovascular Medicine, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA. chungm@ccf.org
Shemanski
Lynn
L
Sherman
David G
DG
Greene
H Leon
HL
Hogan
David B
DB
Kellen
Joyce C
JC
Kim
Soo G
SG
Martin
Lisa Warsinger
LW
Rosenberg
Yves
Y
Wyse
D George
DG
D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000188:drug therapy* / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate; D006801:Humans; D008297:Male
D000889:Anti-Arrhythmia Agents