AF Ablation Partly a Placebo? Doctor-Patient Disagreement on AF Symptom Suggests Yes

July 12, 2017

ÖREBRO, SWEDEN ( UPDATED WITH COMMENTARY ) — Although symptoms from atrial fibrillation (AF) usually diminished after catheter ablation in a recent small series, as did the burden of AF by continuous ECG, the perception of remaining symptoms by patients often did not match the assessment by physicians[1]. Many patients reported relief of symptoms even in cases where the arrhythmia persisted despite the ablation procedure.

"Patient-reported and physician-assessed outcomes both correlated with the AF burden after AF ablation, but there were frequent discrepancies between the patient and the physician, especially at higher AF burdens," state the authors, led by Dr Anna Björkenheim (Örebro University, Sweden).

Freedom from AF or low AF burden after ablation was usually associated with a reduction in symptoms, "but symptom relief also occurred despite little effect on the arrhythmia," they write in a report published June 28, 2017 in JACC: Clinical Electrophysiology.

The patients who underwent ablation of documented paroxysmal or persistent AF at two centers in Sweden sometimes had symptoms after the procedure despite showing no AF on a loop recorder or improved symptoms even though their AF burden was considerable, according to the group.

This study and other research, they write, "suggest a difference between what the patients might perceive and what the physician can detect." They add, "To our knowledge, our study is the only one to correlate these findings with complete knowledge of the underlying cardiac rhythm."

Ignorance Is Bliss?

The findings are plausible and seem to mesh with the literature and experience, Dr Brian Olshanksy (University of Iowa, Iowa City) told | Medscape Cardiology.

They speak to the limitations of documented AF as a surrogate for ablation success and support the known possibility that a substantial part of AF ablation's symptomatic benefit is due to a placebo effect, something that most practitioners are aware of, even though "nobody wants to talk about it," Olshanksy said.

"The economics being what it is, no one wants to know how much of the effect is placebo," he said. "How many of these procedures are being done inappropriately, at huge cost, without any real benefit more than placebo?"

"We believe that symptom relief after AF ablation is due to denervation during the procedure decreasing the patient's perception of AF rather than the placebo effect," Bjorkenheim said in emailed comments. 

"Interestingly, the symptom relief seems to last at least 2 years after AF ablation, which also speaks against the placebo effect," she said.

"Symptoms are the main reason for AF ablation, but the poor correlation between symptoms and AF burden also supports extended monitoring after AF ablation."

"Some of the Effect Is Not Real"

The procedure itself has become widespread even though "nobody has shown any mortality benefit, no one has shown a benefit in terms of stroke reduction" in randomized, placebo-controlled trials, Olshansky noted.

But "the real issue, and the reason the patient goes through this, is reduction in symptoms and improvement in quality of life and functionality," he said.

"The procedure needs to be tailored for symptom reduction, because that's what it's there for. And it's done with the idea that some of the effect is not real, and some of it is." AF ablation, he said, should be for "patients who have more symptoms."

The current report's authors seem to agree. "The perception of outcomes after AF ablation differs a great deal between patients and their physicians, which emphasizes that patient-reported outcomes should be one primary aim of AF ablation done to evaluate symptom relief and improve health-related quality of life."

The study included 57 patients, 54 of whom had available 24-month data; 43% underwent a repeat ablation during follow-up.

They reported their symptoms on the six-item AF6 questionnaire, and physicians noted their perception of patient symptoms according to European Heart Rhythm Association (EHRA) class, which ranges from no symptoms in class I to disabling symptoms in class IV. The patients received an implantable ECG loop recorder to document AF burden.

Patient (AF6) and Physician (EHRA class) Assessment of Symptom Status Over 2 Years

End points Baseline 6 mo 12 mo 24 mo
AF6 sum score, median (IQR) 30 (17–38) 17 (2–30) 7 (0–19) 9 (0–27)
AF6 sum score, mean difference vs baseline 9.3 16.6 13.6
EHRA class I (%) 35 76 70 82
EHRA class II (%) 41 19 26 13
EHRA class III (%) 22 6 4 6
EHRA class IV (%) 2 0 0 0
All changes over 24 months, P<0.001
AF6 scores are 0 (no symptoms) to 10 (severe symptoms) for the individual domains, which were "breathing difficulties at rest," "breathing difficulties upon exertion," "limitations in day-to-day life due to AF," "feeling of discomfort due to AF," "tiredness due to AF," and "worry/anxiety due to AF"
European Heart Rhythm Association (EHRA) class I (no symptoms), II (mild symptoms), III (severe symptoms), or IV (disabling symptoms)

AF6 composite scores for symptoms improved along with improving EHRA class, with the association becoming significant at 6 and 12 months (P<0.001 at both times) and at 24 months (P=0.049) after ablation, the group reports.

"There were 11 (20%), 12 (22%), and 16 (30%) patients, respectively, who reported no symptoms at all (AF6 score 0) at 6, 12, and 24 months after ablation. Five (9%) patients did not report any symptoms at any time after ablation."

There was improvement in EHRA class only during the first 6 months while AF6 scores continuously improved for at least 12 months, "indicating that AF6 is a more sensitive tool for measuring patients' symptoms," they write.

"In spite of a low correlation between the EHRA class and the AF6 sum score, the prediction ability was low and the change in EHRA class was not concordant with the change in the AF6 sum score in nearly half of the patients, demonstrating a discrepancy between physicians' and patients' assessment of AF-specific symptoms."

Symptoms vs AF Burden

The AF6 sum score was significantly associated with AF burden on the loop recorder at 6 months (P<0.01), 12 months (P<0.01), and 24 months (P<0.01).

When the AF burden was <0.5% at 24 months, the EHRA class was always improved, while the results were less consistent in patients with AF burden >0.5%. In the 19 patients with an AF burden >0.5%, 42% were reported to be improved by one EHRA class, the group writes.

"Thus, the physician-assessed EHRA class correlated well with the AF burden when the burden was very low but not when the AF burden was higher."

Björkenheim and colleagues had no relevant financial relationships. Olshanksy discloses having been a speaker and consultant for Lundbeck and On-X and holding clinical trial leadership positions for Amarin and Boehringer Ingelheim.

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