Using a novel method of late gadolinium enhancement (LGE) quantification, researchers found that patients with atrial fibrillation (AF) who had LGE ≤35% had a more favorable outcome, regardless of AF persistence at baseline.
The purpose of the study, recently published in JACC: Cardiovascular Imaging, was to examine the association of baseline LGE extent and AF recurrence using multivariable Cox proportional hazard models. AF recurrence after catheter ablation has been previously linked with baseline extent of left atrial (LA) LGE on cardiac magnetic resonance (CMR).
Of the 165 patients, 38.2% (63) experienced AF recurrence during 10.2 ± 5.7 months of follow-up. The primary procedural end point was the entrance block into pulmonary veins. Researchers defined recurrent AF as “symptomatic or asymptomatic AF, atrial tachycardia, or atrial flutter for > 30 seconds after a 3-month blanking period.”
After adjusting for confounders, baseline LGE extent was independently associated with recurrence (hazard ratio [HR]: 1.5 per 10% increased LGE; P<.001). For those patients with persistent AF, the intensity of association between LGE >35% was greater (HR: 6.5; P=.001 vs HR: 3.6; P=.001).
The mean age of patients was 60.0 ± 10.2 years, 46.1% had a history of hypertension, and 11.5% had a history of congestive heart failure. Those who had persistent AF were more likely to be male (87.3% vs 69.2%; P=.006), have a higher body mass index (30.5 ± 6.4 vs 27.7± 5.1 kg/m2; P=.003), have a lower left ventricular ejection fraction (56.1 ± 7.3% vs 58.2 ± 6.2%; P=.044), have a higher LA volume (164.2 ± 54.8 vs 145.8 ± 45.4; P=.021), and have greater LA LGE extent compared with those who had paroxysmal AF (41.1 ± 15.3% vs 31.9 ± 13.1%; P<.001).
Of those patients with persistent AF, 40.9% had AF recurrence compared with only 36.2% of patients with paroxysmal AF. Each 10% increase in extent of baseline LA LGE represented a 1.5 fold-increased hazard of AF recurrence (HR: 1.5; 95% confidence interval [CI]: 1.3-1.8; P<.001) in an unadjusted analysis.
While researchers did not find a statistical interaction or effect modification between AF type and LGE extent, they did observe a stronger association between LGE extent and AF recurrence in patients with persistent AF.
“As a result, patients with persistent AF that had ≤35% LGE had equivalent outcomes as those with paroxysmal AF and limited LGE,” they wrote. “Similarly patients with >35% LGE had poor outcomes regardless of AF type. This important result is contrary to current beliefs regarding uniformly lower AF ablation efficacy in persistent AF that result in discouragement of many such patients from undergoing ablation.”
Their findings suggest that patients with LGE ≤35% of LA myocardium may be considered for simple pulmonary vein isolation, regardless of AF persistence.
“Future studies are warranted to examine a) the utility of CMR-based patient selection for AF ablation and b) modification of current ablation methodologies in patients with LGE extent exceeding 35% of LA myocardium,” researchers concluded.
Khurram IM, Habibi M, Ipek EG, et al. Association of left atrial late gadolinium enhancement with arrhythmia recurrence following pulmonary vein isolation for paroxysmal and persistent atrial fibrillation. JACC Cardiovasc Imag. 2016. doi:10.1016/j.jcmg.2015.10.015.