Anticoagulation in Patients With Atrial Fibrillation and Congestive Heart Failure

Anticoagulation in Patients With Atrial Fibrillation and Congestive Heart Failure

READER’S COMMENT Anticoagulation in Patients With Atrial Fibrillation and Congestive Heart Failure The recent study of Al-Khatib and colleagues1 pres...

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READER’S COMMENT Anticoagulation in Patients With Atrial Fibrillation and Congestive Heart Failure

The recent study of Al-Khatib and colleagues1 presented a nonrandomized comparison of 1,009 patients with atrial fibrillation associated with congestive heart failure divided into rhythm and ratecontrol groups. In this study, after a follow-up of 2 years and adjusting for differences in baseline characteristics and medications, no significant difference in mortality between rhythm and rate-control groups was found (29% vs 31%, respectively, p ⫽ 0.48). This result differs from the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) study that demonstrated a trend toward mortality reduction at 5 years in the rate-control group (21% vs 24% in the rhythm-control group, p ⫽ 0.08). The investigators speculated that probable reasons for the observed differences are the greater use of amiodarone (64% vs 38% in AFFIRM), and differences in patients treated with rhythmcontrol therapy who were younger, had less severe coronary artery disease, and were treated more often with warfarin, ␤ blockers, and angiotensin-converting enzyme inhibitors than cases with rate-control therapy. We note that the rate of anticoagulation of 55% in the rate-control group in this study is extremely low, considering that only patients

with congestive heart failure, a major risk factor for thromboembolic events,3 were included. Furthermore, in the rhythm-control group, the rate of 60% was surprisingly slightly higher than that observed in the rate-control group. Thus, we can speculate that the indication for anticoagulation in this series considered the presence of atrial fibrillation and congestive heart failure more essential than the option to use class I or III drugs for rhythm control, or ␤ blockers, calcium channel blockers, or digoxin for rate control. At each assessment during the AFFIRM study, ⬎85% of patients in the rate-control group were taking warfarin, and after the first 4 months of the trial, there was a decrease in the use of warfarin in the rhythm-control group; however, the overall proportion of patients receiving warfarin remained approximately 70% throughout the trial. In clinical practice, the underuse of anticoagulation in treating atrial fibrillation has frequently been been reported.4,5 A recent study, reviewing data from 23 series from North America and Europe with different patient risk profiles, reported a mean rate of anticoagulation ⬍50% (range 15% to 79%).4 Our experience, in a Brazilian tertiary outpatient clinic, also demonstrated a rate of dose-adjusted warfarin therapy of 55% in the overall group of patients with atrial fibrillation, and a rate of only 61% in patients with moderate to

©2005 by Excerpta Medica Inc. All rights reserved. The American Journal of Cardiology Vol. 95 June 15, 2005

high risk for thromboembolic events.5 The proportions of anticoagulation therapy in the series of AlKhatib and colleagues1 probably influenced their different results compared with a large randomized trial.2 Their study also demonstrates the necessity of improving anticoagulation rates in high-risk patients for thromboembolic events, particularly those considered for the rate-control strategy. Henrique H. Veloso,

MD

Rio de Janeiro, Brazil Angelo A.V. de Paola,

MD

Sao Paulo, Brazil

1. Al-Khatib SM, Shaw LK, Lee KL, O’Connor C,

Califf RM. Is rhythm-control superior to rate-control in patients with atrial fibrillation and congestive heart failure? Am J Cardiol 2004;94:797– 800. 2. The Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) Investigators. A comparison of rate-control and rhythm-control in patients with atrial fibrillation. N Engl J Med 2002; 347:1825–1833. 3. Fuster V, Rydén LE, Asinger RW, Cannom DS, Crijns HJ, Frye RL, Halperin JL, Kay GN, Klein WW, Levy S, et al. ACC/AHA/ESC guidelines for the management of patients with atrial fibrillation: executive summary. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines and Policy Conferences (Committee to Develop Guidelines for the Management of Patients with Atrial Fibrillation). J Am Coll Cardiol 2001;38: 1231–1266. 4. Buckingham TA, Hatala R. Anticoagulants for atrial fibrillation: why is the treatment rate so low? Clin Cardiol 2002;25:447– 454. 5. Mesas CE, Veloso HH, de Paola AA. Anticoagulation for atrial fibrillation: underutilization in a Brazilian tertiary outpatient clinic. Clin Cardiol 2004;27:592–593. doi:10.1016/j.amjcard.2005.01.035

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