In a study of patients with persistent atrial fibrillation, a shorter time from diagnosis to first catheter ablation was associated with reduced risk for atrial fibrillation recurrence at 2 years.
The researchers analyzed 1,241 patients (mean age, 61 years; 78.5% men) who underwent ablation for persistent AF for the first time between 2005 and 2012.
Oussama M. Wazni, MD, MBA,
professor of medicine and co-director of the Centers for Atrial Fibrillation and Ventricular Tachycardia at Cleveland Clinic, and colleagues stratified patients into quartiles based on time from first diagnosis of persistent AF
to first ablation: 1 year or less, 1.1 to 3 years; 3.1 to 6.5 years; and more than 6.5 years. Median time from diagnosis to ablation
was 3 years (interquartile range, 1-6.5).
Oussama M. Wazni
“Most of the studies have shown that with a longer duration of AF, the outcome of the ablation is not as good as with a shorter duration of AF, but no one looked at the exact timing of the diagnosis relating to when an ablation is done,” Wazni said in an interview with Cardiology Today. “From our own clinical experience … the longer they have been on medication, once [patients with persistent AF] show up for ablation, there is already a lot of scar tissue formation in the atrium, and that results in worse outcomes” even if their AF had been controlled by antiarrhythmic drugs at one time.
The primary outcome was recurrence of AF at 2 years.
Longer gap, worse outcomes
Wazni and colleagues found that the longer the diagnosis-to-ablation time, the higher the B-type natriuretic peptide (BNP) levels (P = .01), C-reactive protein levels (P < .0001) and left atrial size (P = .03).
They also found that longer diagnosis-to-ablation time was associated with a higher rate of recurrent AF at 2 years. Recurrence rates at 2 years were 33.6% for diagnosis-to-ablation time of 1 year or less, 52.6% for 1.1 to 3 years, 57.1% for 3.1 to 6.5 years and 54.6% for more than 6.5 years (categorical P < .0001).
“The inflammation and the remodeling in the atrium are still going on” in patients with persistent AF, Wazni said. “Even though the patient is not having AF because of the antiarrhythmic drugs, that process is probably still happening.”
In univariable analyses, Wazni and colleagues found the following factors to be significantly associated with arrhythmia recurrence at 2 years:
- female sex (HR = 1.28; 95% CI, 1.06-1.53);
- larger left atrium (HR per 1 cm2 increase = 1.02; 95% CI, 1.01-1.04);
- higher levels of BNP (HR per log increase = 1.16; 95% CI, 1.06-1.28);
- higher levels of CRP (HR per log increase = 1.1; 95% CI, 1.03-1.19);
- overall duration of AF history (HR per log increase = 1.22; 95% CI, 1.12-1.34);
- diagnosis-to-ablation time as a continuous variable (HR per log increase = 1.23; 95% CI, 1.14-1.31); and
- diagnosis-to-ablation time as a categorical variable (HR for longest quintile vs. shortest quintile = 1.94; 95% CI, 1.54-2.44).
“In addition to the recurrence rate, there was also an increase in the BNP level, which tells you about stretch in the left atrium, and CRP levels, which is a marker of inflammation, and also left atrial size,” Wazni said. “All these things taken together reinforce the idea that even though the patients may have been controlled on antiarrhythmic drugs, there were other histologic changes that were happening in the atrium that promote fibrosis and the persistence of AF.”
In multivariable analyses, diagnosis-to-ablation time as a continuous variable (HR per log increase = 1.27; 95% CI, 1.14-1.43), diagnosis-to-ablation time as a categorical variable (HR for longest quintile vs. shortest quintile = 2.44; 95% CI, 1.68-3.65) and larger left atrium (HR per 1 cm2 increase = 1.02; 95% CI, 1-1.04) were independently associated with arrhythmia recurrence at 2 years, according to the researchers.
Consider early ablation
Although U.S. guidelines recommend that patients with AF fail at least one antiarrhythmic drug before catheter ablation is attempted, they say that “it is not unreasonable to do an ablation without trying medicines first,” Wazni said. “These findings reinforce the fact that we should be careful and not just have patients linger for a long time before we offer them an ablation. It seems like if an ablation is offered earlier in the course, the better the outcome ultimately will be.”
Because this is a retrospective study, follow-up randomized controlled trials are needed, he said, noting that, in the meantime, for patients with persistent AF, clinicians “should start contemplating an ablation early on, and not wait until the patient has failed multiple medications before they send them to ablation.” – by Erik Swain
For more information:
Oussama M. Wazni, MD, can be reached at Cardiac Pacing and Electrophysiology, Department of Cardiovascular Medicine/J2-2, Cleveland Clinic, 9500 Euclid Ave., Cleveland, OH 44195; email: email@example.com.
Disclosure: The researchers report no relevant financial disclosures.