European Heart Journal Advance Access originally published online on January 16, 2006
European Heart Journal 2006 27(5):621-622; doi:10.1093/eurheartj/ehi723
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Classification of atrial fibrillation: reply
The Libin Cardiovascular Institute of Alberta
University of Calgary
and Calgary Health Region
3330 Hospital Drive NW
Calgary
Alberta
Canada T2N 4N1
E-mail address: dgwyse{at}ucalgary.ca
Drs Tenczer and Tomcsanyi draw further attention to the classification of atrial fibrillation (AF). Clarity, simplicity, and precision compete with one another in any classification scheme. Clarity and simplicity are major determinants of whether or not a classification scheme will be used. Precision minimizes ambiguity, contributing to utility, but can make a classification scheme cumbersome. These problems were recognized in devising the scheme for the classification of an episode of AF promoted in the treatment guidelines.1,2 The scheme is designed for classification of a single episode of AF and classification of a patient with AF is dealt with elsewhere.3 The current scheme has strength in its simplicity, utility at the bedside, theoretic and therapeutic implications. A weakness of the scheme is the arbitrariness of the time-base.
Leaving aside new onset (first detected) and permanent (accepted) AF, there are essentially two forms of AF—paroxysmal and persistent. It is generally agreed that the distinction between these two is that paroxysmal AF is self-terminating within a short period of time, whereas persistent AF is long lasting, usually, but not always, terminated by cardioversion. An observation period must be specified for self-termination within a short period of time. In the current scheme the time limit is set at 7 days. Drs Tenczer and Tomcsyani, many others and even the Guidelines1 agree that what we mean by paroxysmal AF mostly terminates within a shorter period of time, usually 24–48 h. Of course, some AF terminates spontaneously after much longer periods of time. I have observed spontaneous termination of AF after more than 7 years. Is there practical value to further subdivide episodes of AF into that self-terminating in various time-based ‘bins’, as suggested by Drs Tenczer and Tomcsanyi? Such a proposal is more precise but has some drawbacks. It makes the scheme more complex. Terms like ‘acute’ and ‘chronic’ are inherently ambiguous. Its theoretic and/or practical importance is unknown.
In the current scheme there are two potential errors of classification: (i) calling long-lasting episodes of AF ‘paroxysmal’; and (ii) calling short and self-terminating episodes of AF ‘persistent’. The scheme of Drs Tenczer and Tomcsanyi would promote the former. My editorial highlighted the latter. Cardioversions are often done within 7 days or even 24 h from the onset of AF. Some of these episodes of AF will indeed be long-lasting (persistent AF) but some would be short-term and would self-terminate if allowed to do so (paroxysmal AF). The Guidelines committee recognized the problem and chose a pragmatic but arbitrary approach, calling for all of these to be classified as episodes of persistent AF.1 The AF Guidelines are currently being re-written but the classification scheme is unaltered. Any modifications to the current scheme should be simple, practical, and evidence-based, if possible. To modify the scheme a wide consensus should be sought and the imprimatur of professional organizations, such as the European Cardiac Society, American Heart Association, American College of Cardiology, Heart Rhythm Society, and others would be highly desirable.
References
- Fuster V, Ryden LE, Asinger RW, Cannom DS, Crijns HJ, Frye RL, Halperin JL, Kay GN, Klein WW, Levy S, McNamara RL, Prystowsky EN, Wann LS, Wyse DG. ACC/AHA/ESC Guidelines for the Management of Patients with Atrial Fibrillation. 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) developed in collaboration with North American Society of Pacing and Electrophysiology. Eur Heart J 2001;22:1852–1923.
[Free Full Text] - Levy S, Camm AJ, Saksena S, Aliot E, Breithardt G, Crijns H, Davies W, Kay N, Prystowsky E, Sutton R, Waldo A, Wyse DG. International consensus on nomenclature and classification of atrial fibrillation: a collaborative project of the Working Group on Arrhythmia and Working Group on Pacing of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. Europace 2003;5:119–122.
[Free Full Text] - McNamara RL, Brass LM, Drozda JP Jr, Halperin JL, Kerr CR, Levy S, Malenka DJ, Mittal S, Pelosi F Jr, Rosenberg Y, Stryer D, Wyse DG, Radfor MJ, Goff DC Jr, Grover FL, Heidenreich PA, Peterson ED, Redberg RF. ACC/AHA key data elements and definitions for measuring clinical management and outcomes of patients with atrial fibrillation: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Data Standards (Writing Committee to Develop Standards on Atrial Fibrillation). Circulation 2004;109:3223–3243.
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