Abstract 3068: Intra-left Ventricular Contractile Dyssynchrony As An Independent Determinant Of Left Atrial Remodeling In Patients With Atrial Fibrillation Managed by Catheter-based Circumferential Pulmonary Venous Isolation
BACKGROUND. Enlarged left atrial volume (LAV), resulting from multifactorial pathogenesis, carries a poorer prognosis to patients with atrial fibrillation (AF) even under well rhythm control. We hypothesized that the preexistence of intra-left ventricular (LV) contractile dyssynchrony impaired diastolic filling, which contribute to atrial remodeling in AF patients.
METHODS. We investigated 40 patients (34 men and 6 women, mean age 60 ± 10 years) with paroxysmal or persistent AF who were converted mainly by catheter ablation-based circumferential pulmonary venous isolation and then pharmacologically maintained in sinus rhythm. Exclusion criteria included significant (>moderate) valvular heart disease, LV ejection fraction <55 %, or ischemic heart disease confirmed by positive stress tests or coronary angiography. The LAV was measured by 2D echocardiography [π×D1×D2×D3/6 from parasternal long-axis view (D1) and apical four-chamber view (D2 & D3)]. The peak myocardial systolic velocity (SM) and the time to peak SM (TS) of the 6-basal and 6-mid LV segments were measured by tissue Doppler imaging (TDI).
RESULTS. With similar AF duration before conversion, patients with LAV >40ml (n = 16) had similar baseline characteristics, cardiovascular medications, QRS width, and LV chamber sizes as those with LAV <40ml (n = 24). However, TDI showed the mean SM was borderline lower (6.3 ± 1.2 vs. 7.1 ± 1.2 cm/s, p < 0.05), and the maximal intersegmental difference in TS (77 ± 43 vs. 40 ± 22 ms, p < 0.003) was greater in patients with larger LAV. The intersegmental difference in TS correlated positively with LAV (r = 0.41, p < 0.009), and LV filling pressure estimated by early transmitral flow velocity/annular diastolic velocity was significantly higher (12.3 ± 7.8 vs. 8.7 ± 2.2, p < 0.045) in patients with intersegmental difference in TS >65 ms. After adjusting for age, gender, and the diastolic parameters, intersegmental difference in TS >65ms emerged as an independent determinant of larger LAV in multivariate logistic analysis (OR=17; 95% CI=2–166, p < 0.016).
CONCLUSIONS. Intraventricular dyssynchrony, which accompanied with elevated LV filling pressure, contributed independently to LA remodeling in AF patients converted into sinus rhythm by catheter ablation.