Sunday, July 16, 2017
AF Ablation Partly a Placebo? Doctor-Patient Disagreement on AF Symptom Suggests Yes
July 12, 2017
ÖREBRO, SWEDEN — 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. 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 theheart.org | 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?"
The report from Björkenheim and colleagues, who have not replied to requests for comment, does not include the word "placebo." They do say patients' symptoms declined continuously when self-assessed, even though the reduced AF burden after ablation tended not to increase and symptoms improved by physician assessment only in the first 6 months.
"Since the continued improvement was not caused by a further reduction of the AF burden, an adaptation seems to have occurred, possibly partly because patients needed time to get used to fewer symptoms and less worry and anxiety due to a lower risk of recurrent AF episodes," they write.
"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.
Medscape Medical News © 2017
Cite this article: AF Ablation Partly a Placebo? Doctor-Patient Disagreement on AF Symptom Suggests Yes - Medscape - Jul 12, 2017.
I wonder whether the "placebo" effect might be due in part to partial denervation of the heart during the procedure. Some ablation techniques target the ganglionic plexi; often as we ablate we see profound "vagal" effects (including prolonged asystole). So far we have focussed on the effects on efferent vagal activity - but could we sometimes be affecting the afferent nerves and diminishing the patient's perception of AF, and perhaps be improving symptoms by masking the arrhythmia? If so, that's not a true "placebo" effect (since a sham ablation procedure would not have that "benefit").
Dr. J. Rod Gimbel10 hours ago
@Dr. DEREK CONNELLY That's why it would be great if there was courage to do a "sham" procedure trial.