Left atrial filling index predicts resting and saline-inducible elevation of left atrial pressure in atrial fibrillation with preserved left ventricular ejection fraction
T Nishikawa, S Tamaki, K Inoue, H Kawakami, R Horie, R Miyabe, Y Nakao, T Fujisawa, Y Akazawa, T Miyoshi, A Higaki, H Higashi, K Nishimura, S Ikeda, O YamaguchiAbstract
Introduction
The left atrial (LA) filling index, defined as the ratio of mitral early-diastolic inflow peak velocity (E) over LA reservoir strain (LARS), has emerged as a potential non-invasive marker of left ventricular (LV) filling pressure. However, whether it can identify elevated LV filling pressure unmasked by a saline challenge in patients with atrial fibrillation (AF) and preserved LV ejection fraction (LVEF) is unknown.
Purpose
We sought to evaluate the diagnostic utility of the LA filling index for resting and saline-inducible elevation of LA pressure (LAP) in patients with AF and preserved LVEF.
Methods
We prospectively enrolled consecutive patients undergoing catheter ablation for AF with LVEF ≥50% in whom mean LAP was directly measured. Patients with baseline LAP <15 mmHg received 500 mL of normal saline over 5 min. Filling-pressure status was defined as: no elevation (baseline LAP <15 mmHg and post-challenge LAP <18 mmHg), inducible elevation (baseline LAP <15 mmHg and post-challenge LAP ≥18 mmHg), and resting elevation (baseline LAP ≥15 mmHg). Transthoracic echocardiography was performed just before admission. LARS was measured in the apical four-chamber view, and the LA filling index was calculated as E/LARS as previously reported.
Results
A total of 134 patients were included (median age 69 [interquartile range 63–74] years, 34% female, 43% persistent AF). At baseline, LA filling index was significantly correlated with LAP (Figure A). Among them, 46 patients had no elevation, 33 patients had inducible elevation, and 55 patients had resting elevation, with stepwise higher LA filling index across groups (Figure B). In multivariable logistic regression adjusted for age, sex, body mass index, and rhythm during echocardiography, the LA filling index was independently associated with resting elevation and with combined inducible/resting elevation; areas under the receiver operating characteristic curve were 0.74 and 0.77, respectively. Furthermore, even after excluding patients in AF during echocardiography, diagnostic performance remained similar (0.72 and 0.74, respectively).
Conclusions
Our results suggest that the LA filling index could be a valuable predictor of elevated LV filling pressure at rest and after saline challenge in patients with AF and preserved LVEF, regardless of whether patients were in AF at the time of echocardiography.Figure AFigure B