Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, University of Calgary and Calgary Health Region, Room G009, Health Sciences Center, 3330 Hospital Drive NW, Calgary, Alberta, Canada T2N 4N1
* Corresponding author. Tel: +1 403 220 2052; fax: +1 403 284 5594. E-mail address: dgwyse{at}ucalgary.ca
This editorial refers to Atrial fibrillation management: a prospective survey in ESC member countries. The Euro Heart Survey on atrial fibrillation
by R. Nieuwlaat et al., on page 2422
The Euro Heart Survey on atrial fibrillation (AF) is a registry of patients in Europe who were seen by a cardiologist for AF over a 12-month period in 2003 and 2004. In the data presented,1 we see a snapshot of several aspects of AF at this particular moment in time in Europe. Registries are an important tool for description of any number of aspects of a particular medical condition, including its management. Their strength lies in the fact that data are provided on a large number of patients and the cross-sectional aspects of the data are advantageous; in this case, the number of countries is also large. Limitations include the degree of adherence to definitions, rigour, completeness and uniformity of data collection, and potential selectivity in patient enrolment (consecutiveness) among others. Nevertheless, they are useful for description of practice patterns among a group of physicians, for development of proposals to modify physician behaviour, and for identifying hypotheses to be tested in randomized, controlled clinical trials. Although subsequent follow-up data from the survey are expected, for now the authors have focused on describing the practices of European cardiologists and contrasting their findings with some of the recommendations of the AF treatment guidelines.2 It is often said that a picture is worth a thousand words. In this case, the metaphor of the registry as a picture supports this adage in the number of words needed to describe and discuss the picture we are being shown.
There is also a need for lots of words because of some blurriness in this picture, which leads to some uncertainties. One of the most evident uncertainties is whether the patients in the registry are representative of all European patients with AF or even of all European patients with AF who see a cardiologist. Although I have no idea of how many patients with AF actually get to see a cardiologist in Europe, I suspect that many are treated by primary care physicians and this may vary greatly from country to country. Thus, the registry should not be considered to be a representative of all European patients with AF. It is also not clear that the registry data are even representative of all European patients with AF who see a cardiologist. It can be seen, for example, that the contribution of patients by country is not proportional to population of the various countries from which patients were enrolled. However, this difference is blurred somewhat by the grouping of the registry countries into regions. In this respect, a registry is not a particularly robust epidemiological data source. Nevertheless, the registry is an impressive compilation of data from widely diverse geopolitical areas.
I was surprised a little by the large number of patients who were seeing a cardiologist because of their first detected episode of AF. I am not sure what to make of this observation. I doubt that it means that most patients see a cardiologist after their first detected episode of AF. This particular datum may be more of a reflection of the nature of the enrolling sites. As the authors note, there was probably some blurriness in the picture because of some uncertainties and unfamiliarity with the definitions of various categories of AF. In this article, I found the definition of persistent AF a little unclear, particularly with respect to what was being said about cardioversion. The troublesome area in these definitions is how to categorize an episode of AF that lasts <7 days because of cardioversion (either electrical or pharmacological) done before 7 days from the onset of AF has elapsed. My understanding of the definition in the Guidelines2 is that any cardioversion leads to labelling the episode as persistent and if that occurs before 7 days of AF, particularly within 24 h of the onset of AF, then some paroxysmal AF will be erroneously categorized as persistent. In contrast, calling episodes that are cardioverted within 7 days of onset of AF paroxysmal probably results in similar misclassification in the other direction. Nevertheless, the definition of permanent AF is quite clear and yet a small number of these patients were cardioverted or treated with a class-I or class-III anti-arrhythmic drug, which seems to dispute that definition and further bring into question the precision of measurement of proportions of patients with various classes of AF in the registry.
Other findings of the survey reinforce findings of other studies. The strong association between AF and hypertension is once again clearly evident. It is also indeed gratifying to see that symptoms appear to be an important determinant of selection of the rhythm control approach. Current evidence suggests that control of symptoms is probably the major indication for selecting the rhythm control approach, as no other benefit has been clearly established for this approach.3 Unfortunately, we are not told much more about the nature or severity of the symptoms. In this article, it is said that palpitation and/or syncope was the most common symptoms. The former is not surprising but I was surprised by the prominence of syncope, which in my experience is uncommon, whereas fatigue and dyspnea are very common.4 A method to easily quantify the severity of symptoms due to AF at the bedside is badly needed as long as the degree of symptoms is a major factor in making therapeutic decisions. However, a surprisingly high number of asymptomatic patients were treated with the rhythm control approach. The reasons for this observation are a little more uncertain. Certainly, patient preference often comes into play in the selection of the approach to rhythm management, but there probably remain a number of physicians who consider the rhythm control approach superior in spite of the evidence. One does wonder whether the risks of therapy have been adequately considered in selection of this approach in asymptomatic patients. It also seems noteworthy that the category of permanent AF is applied to the more elderly patients with more extensive coexisting disease. This would seem to be appropriate. It should be recognized that this categorization is really a judgement decision on the part of the physician.
It is also gratifying to see the high usage of anti-coagulation in those considered eligible for anti-coagulation. It is always difficult to say for certain from this type of data who are eligible and who are ineligible. Nevertheless, the observation that >60% of eligible patients were receiving an oral anti-coagulant suggests that European cardiologists are paying close attention to this very important aspect of management of AF, at least at first contact. It will be interesting to see whether this finding persists as the use of warfarin tends to fall off over time.5 Aside from the issue of whether the data are robust enough to determine who are eligible and who are ineligible for oral anti-coagulants, there is some emerging uncertainty in this area. There are at least five different risk stratification schemes in use for determination of the need for oral anti-coagulation in patients with AF. Although generally similar, these schemes are not in complete agreement, particularly with respect to the proper course of action in patients with moderate risk. Some experts consider hypertension in the absence of another risk factor to indicate low risk for stroke when the hypertension is well treated and would recommend aspirin as adequate therapy for stroke prevention in such patients. Some schemes allow for the use of either aspirin or oral anti-coagulants in moderate risk patients.2 Thus, it is not surprising that there is some confusion on this point among treating physicians. In the European survey, there is evidence for this confusion from the high proportion of patients considered ineligible who were in fact taking oral anti-coagulants. In contrast, this observation may be due to deficiencies in the database that misclassify eligible and ineligible patients or it may reflect patient preferences. It does appear that European cardiologists have taken the approach that if there is any doubt, patients should be treated with an oral anti-coagulant.
It is not possible to comment on all the findings of the survey in a small space and I have tried to highlight what I consider to be some of the more important and interesting aspects of the survey's findings. Others will take notice of other things. It has been a formidable task to construct the registry, collect, and analyse the data. In spite of the inherent weakness of registries in general, this one appears to have been well done. The data are interesting and will undoubtedly lead to a number of hypotheses that will subsequently be tested in more rigorous studies. We can also look forward with anticipation to follow-up data that are being collected as part of the survey.
Conflict of interest: none declared.
Footnotes
The opinions expressed in this article are not necessarily those of the Editors of the European Heart Journal or of the European Society of Cardiology.
References
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