Author + information
- Published online September 13, 2017.
- aDepartment of Medicine, University of Toronto, Toronto, Ontario, Canada
- bDivision of Cardiology, St. Michael’s Hospital, Toronto, Ontario, Canada
- ↵∗Address for correspondence:
Dr. Paul Dorian, Department of Medicine, St. Michael's Hospital, 30 Bond Street, 6-050Q, Toronto, Ontario, M5B 1W8, Canada.
Assessing outcomes in patients with atrial fibrillation (AF), and particularly after an AF ablation, is not straightforward. As with any treatment, both physicians and patients desire an improvement in symptoms and quality of life and a reduction in morbidity and, if possible, mortality.
In the case of ablation for AF, there is no convincing evidence that catheter ablation reduces major morbidity or mortality. In selected patients, ablation can be very effective at reducing symptom burden, and thus it is advocated in many patients with AF and recommended in guidelines for patients who have symptomatic AF refractory or are intolerant to antiarrhythmic medication (1).
Assessing improvement in symptoms and quality of life is not as simple as it may seem. Patients with AF, and particularly those undergoing AF ablation procedures, are likely to be highly symptomatic from 1 or more of the cardinal symptoms associated with AF, which include an unpleasant awareness of cardiac action; breathlessness, particularly on exercise; fatigue; chest discomfort, dizziness, or lightheadedness, and occasionally syncope.
However, quality of life is a more comprehensive and complex concept than symptoms alone. Quality of life in patients with AF can also be adversely affected by the side effects from medications, worry about the condition of AF and perceptions about current and future risks of adverse outcomes, fear of bleeding among those on anticoagulants, financial and insurance-related concerns from being labelled with a cardiac disorder, and the potential for “anticipatory anxiety” regarding the risk of recurrence and future morbid events. These concerns can lead to major limitations in social and physical activities, even in the absence of symptoms from AF itself. For these reasons, symptoms in AF correlate with but do not account for all of the health-related quality of life impairments that may be present with AF.
In addition, there are patient factors associated with quality of life beside the subjective consequences of the arrhythmia itself (2). These include patient age (younger patients have more quality of life impairment than older patients do), sex (women have poorer quality of life overall than men do), underlying psychosocial factors and cognitive impairment (higher burden correlated with poorer quality of life) (3), as well as the influence of common comorbidities that may be present in AF, including coronary disease, sleep apnea, pulmonary disease, and a family history of AF (2).
The assessment of quality of life after radiofrequency ablation is made even more complex by the possibility of procedural complications, and the patient expectations from a procedure that offers a potential prospect of complete symptom relief, but also the risk of procedural failure, arrhythmia recurrences, and the need to repeat procedures.
In this context, the study by Björkenheim et al. (4) in this issue of JACC: Clinical Electrophysiology helps place into much clearer context patient-reported outcomes, as well as caregiver-reported outcomes, after radiofrequency ablation for AF. They administered an AF-specific questionnaire (the AF6) to 57 patients, before and 6, 12, and 24 months after radiofrequency ablation for AF. Physicians were asked to rate the patients’ symptoms using the European Heart Rhythm Association (EHRA) classification. The vast majority of patients had at least moderate symptoms at baseline, although it should be noted that 6 patients had an AF score <10 at baseline (with a maximum total score of 60), one-quarter had a score of 16 or less, and 35% were in EHRA class 1 (corresponding to “no symptoms”). Post-procedural AF events were very accurately documented using an implanted loop recorder, and patient-recorded and physician assessment of symptoms were evaluated as a function of AF recurrences. Overall, the AF6 score improved from a median of 30 to a median of 17 at 6 months, and there was further improvement to a median of 7 at 12 months. The proportion in EHRA classes 2 to 4 decreased from 65% to 25% and 30%, respectively, at 6 and 12 months.
Björkenheim et al. (4) confirm what seems intuitive, that a reduction in or absence of documented AF following ablation is associated with fewer symptoms than the continued presence of arrhythmias. Patients and physicians alike seem to agree that in the absence of AF, symptoms improve, often markedly.
A strength of this study is the use of an AF-specific questionnaire, the AF6, which specifically asks about symptoms that are directly related to AF (an additional important item is “worry or anxiety due to atrial fibrillation,” which may be only indirectly related to the AF burden), as well as a complete and accurate measure of “true” AF burden afforded by the use of implantable recorders.
Although there is a clear and significant correlation between the burden of AF post-ablation and the AF6 measure of symptoms and quality of life, Figure 3 in their paper (4) shows that there is a wide range of AF6 scores in patients with an extremely low AF burden after ablation, and although on the average, AF burden is related to quality of life, many patients with minimal AF burden have substantial symptoms or impairment of quality of life even after ablation. Conversely, some patients with a higher AF burden after ablation have a diminution of or few symptoms following ablation, as has been previously reported (5).
This observation, as well as the observation that there is an inconsistent relationship between the AF score before versus after ablation even among patients with virtually no AF (Figure 1A in Björkenheim et al. (4)), suggests that there are many important variables at play beyond the AF burden itself that determine what a patient’s quality of life is after an ablation procedure and the potential improvement in symptoms following ablation.
A second important observation that arises from the useful study by Björkenheim et al. (4) is the relatively poor correlation between physician perception, as defined by the EHRA class, and patient perception, as defined by a change in AF6 scores. In general, physicians and patients agree when quality of life or symptoms are improved after ablation. However, in many cases, patients perceive no benefit whereas physicians feel their patients have improved, or patients perceive a benefit and physicians feel there has been no change in symptoms (EHRA class), highlighting a disconnection between patients’ and physicians’ perceptions. This is perhaps not so surprising considering that treatment expectations are an important predictor of treatment outcomes (6), particularly after surgical procedures where “blinding” is difficult, and that these expectations may differ between patients and their caregivers. Figure 2A in the paper by Björkenheim et al. (4) highlights this difference in perception between patients and physicians; in 21 of 57 patients, either the patient or physician believes that the quality of life has either worsened or improved, but the other party records no change or a change in the opposite direction.
These discrepancies may be in part related to a limitation of the EHRA classification (7), which refers to symptoms in AF, but does not take into account other dimensions of quality of life that are important to patients, such as anxiety, treatment concerns, and ongoing or anticipated adverse effects of medication, some of which are captured in the AF6 scale used in this study. Measures of quality of life that are more generic, such as the patient-reported Short Form 36 scale, or the provider-reported Canadian Cardiovascular Society Severity of Atrial Fibrillation (SAF) Scale (which explicitly “makes the important distinction between symptoms attributable to AF itself and the effects of these symptoms on well-being”) (8) may allow a closer correspondence between patient perceptions and caregiver perceptions in the evaluation of the outcome of (or the need for) treatment.
The distinction between symptoms and overall quality of life is highlighted by randomized clinical trials of AF ablation versus antiarrhythmic therapy, in which symptoms are more substantially improved after ablation than after drug therapy, and yet quality of life as measured by generic scales such as the Short Form 36 improve similarly after these 2 treatment strategies (9,10).
The evaluation of treatment response in nonblinded studies can be importantly influenced by treatment expectations. As noted by Björkenheim et al. (4), “physicians were more likely to indicate improvements in terms of a better EHRA class. Complete freedom from AF did not preclude that patients felt some symptoms, while patients with AF burden up to 10% indicated symptomatic improvement after ablation.”
The potential for bias introduced by the awareness of the treatment being administered has been well documented in studies of pacing for vasovagal syncope. As noted by Sud et al. (6), “in the absence of any treatment effect in the double-blind trials, the observed effect among the pacemaker versus medical therapy trials could represent an ‘expectation’ response. That is, patients who have undergone surgical pacemaker implant might expect to have fewer syncopal recurrences. Moreover, physicians assessing outcome events are not immune to this phenomenon, and it is possible that outcome ascertainment could be influenced as well.”
Lastly, there are potential long-term adverse effects from AF ablation procedures that are poorly captured by the usual reports of immediate post-procedural complications, but that may affect patient quality of life late after ablation. These include persistent sinus tachycardia, intermittent atrial tachycardia, phrenic nerve damage causing breathlessness, gastroparesis-causing gastrointestinal symptoms, in addition to the long-term worries about their future that many patients with AF ablation experience.
The findings by Björkenheim et al. (4), as well as our understanding of the complexities in measuring symptoms and/or overall quality of life after AF ablation, highlight the need for close patient and caregiver communication and a clear and detailed explanation of the risks and benefits of ablation procedures in the process of informed consent and shared decision making, so that there are a minimum of “surprises” after this useful, but complex-to-evaluate procedure.
The authors are grateful for the assistance of Kim Dawdy in the preparation of this manuscript.
↵∗ Editorials published in JACC: Clinical Electrophysiology reflect the views of the authors and do not necessarily represent the views of JACC: Clinical Electrophysiology or the American College of Cardiology.
Dr. Dorian has reported receiving consulting fees and grant support from Bristol-Myers Squibb, Pfizer, Servier, and Bayer. Dr. Angaran has reported receiving consulting fees from Bristol-Myers Squibb and Servier.
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