Measuring outcomes after catheter ablations for AF

Study author Anna Björkenheim, University Hospital Örebro, Sweden

Published in the Journal of the American College of Cardiology (JACC): Clinical Electrophysiology, Björkenheim et al’s study of patient- and physician-reported outcomes of atrial fibrillation (AF) ablation has analysed the complex variables and subjectivity in assessing AF-related symptoms. The study, as Dorian and Angaran’s editorial comment in the same publication argues, demonstrates some limitations of physicians relying on the European Heart Rhythm Association (EHRA) classification to assess AF symptoms throughout treatment.

Assessing improvement in symptoms and quality of life is a complex task, with many potential pitfalls where subjectivity and bias can affect reported outcomes as perceived by AF patients as well as physicians.

Dorian and Angaran point out that the cardinal symptoms associated with AF are not the only factors affecting patients’ quality of life. From adverse effects of medications to worrying about future risks associated with AF, to financial and insurance-related concerns, patients can experience a wide range of quality of life impairments that do not necessarily correspond to the presence of AF itself after an ablation.

The Björkenheim et al study followed 57 patients in two Scandinavian hospitals, all scheduled for AF radiofrequency ablations. Symptoms and outcomes were assessed in three ways during a period of over 24 months. Firstly, AF burden was continuously recorded by an implantable loop recorded (ILR) inserted in the left parasternal area before ablation. Secondly, physicians were asked to rate the patients’ symptoms using the EHRA classification before ablation and then at 6, 12 and 23 months after. Finally, the patients themselves were given an AF-specific questionnaire, the AF6, to be filled out simultaneously with the EHRA-based physicians’ reports.

Different perception of outcomes: measuring the subjective

While patients and physicians in most cases agreed when symptoms improve in the absence of AF, the study concludes that the “perception of outcomes after AF ablation differs a great deal between patients and their physicians”. Björkenheim et al observe that 21 out of 57 patients reported an improved, worsened or unchanged state of their quality of life while the physician’s report indicated a contradicting trend.

Where discrepancies crop up, there is a multitude of possible explanations. A foundation for perception of outcome lies in the expectations of what treatment of AF—whether with ablation or medication—can bring. As involving surgical procedures makes it difficult to perform blinded studies, treatment expectations can come to influence outcome evaluations significantly in this case. Dorian and Angaran suggest that “a clear and detailed explanation of the risks and benefits of ablation procedures in the process of informed consent and shared decision-making” is needed in order to limit surprising results.

Speaking to Cardiac Rhythm News, study author Anna Björkenheim (Department of Cardiology, School of Medical Sciences, Örebro University, Örebro, Sweden) discusses the problematic nature of assessing symptoms of AF: “Patients are very different and many may have difficulties in describing how and what they feel, especially at a short visit at a health care facility.  Assessing symptoms in AF can be especially challenging as the arrhythmia is often paroxysmal and the AF episodes of various duration and frequency. After AF ablation, the perception of AF may change and asymptomatic AF episodes are common. Symptoms are naturally very different in sinus rhythm and in AF, and can be underestimated when questionnaires are administered in absence of AF.”

A question of questionnaires

Importantly, the study highlights the usefulness of an AF-specific questionnaire such as the AF6 in capturing a more comprehensive measurement of patient experienced symptoms.

Björkenheim explains that the questionnaire has now been in clinical practice for over ten years. “The AF6 was developed to evaluate the symptomatology of patients with AF before and after an intervention and the first investigated study population consisted of patients undergoing cardioversion. Advantages with the AF6 questionnaire include, in addition to being AF-specific, that it is short and can be included in a routine clinical visit, that it is easy to understand and that it has an excellent response rate.”

While Dorian and Angaran suggest that broader questionnaires may be similarly useful, Björkenheim cautions: “Generic questionnaires such as the Short Form 36 have a limited sensitivity. Patient-reported outcomes and clinician/physician-reported outcomes such as the EHRA classification and the Canadian Cardiovascular Society Severity of Atrial Fibrillation scale measure different components of perceived patient well-being. Both may be useful to assess a patient and to decide on treatment, although our study showed a poor correlation between physician and patient perception.”

“I think the important lesson from our study is that assessment of symptom severity should come directly from the patient as patients are the key stakeholders of their health. An AF-specific instrument such as the AF6 could be a useful tool for this assessment, and there are good reasons to believe that well designed and developed disease-specific instruments that capture the view of the patients contribute to arrive at the optimal treatment decision.”