Quality of Life in Atrial Fibrillation
Abstract & Commentary
By John P. DiMarco, MD, PhD, Professor of Medicine, Division of Cardiology, University of Virginia, Charlottesville. Dr. DiMarco does research for Medtronic, is a consultant for Medtronic, Novartis, and St. Jude, and is a speaker for Boston Scientific.
Source: Suman-Horduna I, et al. Quality of life and functional capacity in patients with atrial fibrillation and congestive heart failure. J Am Coll Cardiol 2013;61:455-460.
The Atrial Fibrillation and Congestive Heart Failure (AF-CHF) trial randomized 1376 patients with AF and CHF to rhythm- or rate-control treatment strategies. The primary outcome in AF-CHF was cardiovascular mortality, and no difference in that endpoint was seen between the groups. Secondary outcomes including all-cause mortality, worsening heart failure, and stroke also showed no difference. This study examined the effects of rhythm-control and rate-control strategies on quality of life and functional capacity in AF-CHF.
Patients in AF-CHF had advanced heart failure and had not been in persistent AF for longer than 12 months. The rhythm-control strategy largely consisted of amiodarone with electrical cardioversions as needed. The rate-control strategy used target heart rates < 80 beats per minute at rest and < 110 beats per minute during 6-minute walk tests. A quality-of-life questionnaire, the Medical Outcome Short Form 36 (SF-36), was administered at baseline and at 4 months. The SF-36 was then subdivided into a physical component summary (PCS) and a mental component summary (MCS) score. Functional status (New York Heart Association [NYHA] Class) was determined at baseline, 3 weeks, 4 months, and then at four monthly intervals. Six-minute walk tests were also performed at these specified time points.
There were 833 patients who completed the baseline quality-of-life assessment before randomization and 749 patients who completed the 4-month follow-up questionnaire. Quality-of-life scores and functional capacity at baseline were depressed. The composite scores for physical and mental health improved from baseline to 4 months in both rhythm- and rate-control groups. When the prevalence of sinus rhythm was included as a variable, patients with a low prevalence of sinus rhythm had a nonsignificant trend toward greater improvement in both the physical and mental component scores than those with a lower prevalence of sinus rhythm. Similarly, the 6-minute walk test assessment of exercise capacity improved in both the rhythm- and rate-control groups. There was no significant difference in the improvement in 6-minute walk test distance in those in the high prevalence sinus rhythm vs the low prevalence sinus rhythm group. NYHA functional class changes showed a similar pattern. There was no difference between the rhythm-control and the rate-control groups, but those patients with a high prevalence of sinus rhythm were more likely to manifest an improvement in their NYHA functional class.
The authors conclude that quality of life and functional capacity in patients with AF and CHF are markedly depressed in many patients and can improve with both rhythm and rate control strategies. Patients in whom sinus rhythm can be maintained may have greater improvement in NYHA functional class and quality of life.
AF-CHF and the AFFIRM trial are the two studies that provide the most convincing evidence that mortality in AF is not improved with a pharmacologic rhythm-control as opposed to a rate-control strategy. AFFIRM previously reported that quality of life and functional status changes were similar with both strategies. Now, that observation has also been confirmed in AF-CHF. Finally, both trials have now reported that in patients in whom sinus rhythm could be maintained, a trend toward better quality of life was observed. However, this type of “responder analysis” should not be misinterpreted as proving that rhythm control is superior to rate control for all patients since responders are likely to be healthier than nonresponders in ways not accounted for in the reported analyses. I, therefore, still make at least an initial attempt to restore and maintain sinus rhythm in patients with any symptoms I think are due to AF. What I most importantly try to avoid is overzealous treatment with multiple cardioversions and high drug doses unless the patient’s symptoms justify such attempts.
The observations from AF-CHF and AFFIRM apply strictly only to pharmacologic strategies for rhythm and rate control. Several reports have shown that responders to AF ablation procedures will have improved quality of life, and this is particularly true in patients with paroxysmal AF. We’re still awaiting data from trials like CABANA to see if the same benefits can be achieved in older patients with persistent AF.