Journal of Interventional Cardiac Electrophysiology 4, 559±560(2000)

#2000 Kluwer Academic Publishers. Manufactured in The Netherlands.

The Editor's Forum

Don't You Agree, or What Part of the Problem Don't YouUnderstand?

A. John CammSam LevySanjeev SaksenaD. George Wyse

Understanding is hampered as often by poorcommunication as it is by lack of knowledge. Inthe area of atrial ®brillation (AF) management,both poor communication and lack of knowledgeretard our current understanding. The greatestbarrier to communication in the management ofAF is the lack of a widely accepted and widelyapplied clinical classi®cation scheme upon whichto base our dialogue and our research. There area plethora of terms in continuous daily use whenAF is discussed and no agreement about whatany of these mean. Such terms include, paroxys-mal, chronic, persistent, new onset, permanent,reversible or situational and many, many others.Furthermore, one can often ®nd two, or eventhree, of these adjectives describing the sameepisode of AF. It is often not clear whether theterms used are being applied to the patient or toan episode of AF. Is it any wonder we areconfused? A consequence of this problem is thatreading the literature on the pathogenesis andmanagement of AF, the commonest sustainedarrhythmia, is often like a visit to the legendaryTower of Babel.

Fortunately, an attack on this problem hasbeen launched. A study group composed ofexperts in the ®eld has recently met at EuropeanHeart House under the auspices of the WorkingGroups on Cardiac Arrhythmias and CardiacPacing of the European Society of Cardiology,and the North American Society of Pacing andElectrophysiology to discuss this problem anddevise potential solutions. A number of factorsneeded to be considered in any potential solutionto the problem and these were fully discussed inthe study group and consensus was reached onhow to address most of them in the scheme.Paramount in the minds of the study group wasthe need to keep the scheme simple so that it canbe easily remembered and therefore widely used.It is important to make a distinction betweenclassi®cation of an episode of AF and classi®ca-tion of a patient with AF. It also must be recog-nized that a patient with AF may move from onecategory to another over time. The study group

also wanted to use currently recognized terminol-ogy as much as possible and make the scheme ®tas best we can with our current knowledge aboutpathogenesis and therapy. Time will determinethe degree to which the study group succeeded inthis effort. At the same time, an overlappinggroup has been working on Clinical PracticeGuidelines for management of AF on behalf orthe American College of Cardiology, the AmericanHeart Association and the European Society ofCardiology. It is hoped that these activities will®nally produce an understandable, rational andreadily applicable clinical classi®cation schemefor AF. Such a scheme will allow us to communicatebetter at the bedside and elsewhere when we arediscussing AF. In addition, if such a scheme iswidely adopted by those investigating AF patho-genesis and management, it will be much easier tocompare and contrast the various studies andthereby our understanding will be improved. Itseems like such a simple thing, and yet.

The second problem is one that includes bothpoor communication and lack of knowledge.Speci®cally, the question is, `what are appropri-ate end points or outcome parameters for trials oftherapy in AF?' A frequently used end point is the®rst documented recurrence of AF or the ®rstsymptomatic, documented recurrence of AF.There are many others, including measures ofAF `burden' and, for the heart rate control strat-egy, the heart rate itself during rest and activity.The relationship of these measurements to clin-ical endpoints, such as, death, stroke, functionalcapacity and quality of life remains unknown.This de®cit is one of the greatest gaps in ourcurrent knowledge of AF. Furthermore, there hasbeen advancement in the technology of ourmeasuring tools. Current implantable pace-makers allow an accurate tabulation of episodeof AF and on the basis of such data, it seems thatAF is much more prevalent and ubiquitous thanwe have ever suspected. It is important to empha-size that many of these end points are reallysurrogates. More important to the patient aresymptoms, quality of life and their risks of

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death, stroke and worsening ventricular function.The pharmaco-economics of the management ofatrial ®brillation are also increasingly important.Unfortunately, such measurements have rarelybeen included in reports of trials of varioustherapies for AF. A similar study group of expertshas recently met at the European Heart House todiscuss the issues involved, to highlight theproblem and to make recommendations. It ishoped that the recommendations of the studygroup will de®ne the minimum basic require-ments for reporting of results of all studies of

therapies for AF. In addition, the recommenda-tions will point out the need for more research onthe outcome measures and endpoints themselvesand their relationship (if any) to clinical events.There is a spectrum of end points that can bechosen and it is important for investigators tochoose end points that are clinically relevant andaddress the objectives of the study.

For now we can only await the publication ofthe deliberations from these groups but we hopethey will come soon. Don't you agree? .

560 Camm et al.