Extent and magnitude of low-voltage areas assessed by ultra-high-density electroanatomical mapping correlate with left atrial function.

INTRODUCTION

The extent of left atrial (LA) adverse remodeling as a cardiac disease marker has become increasingly important. In patients with atrial fibrillation (AF), atrial remodeling (AR) is accompanied by increased mortality. The relation between LA function and the extent of low-voltage areas (LVAs) has not yet been systematically investigated.

METHODS

In patients with AF undergoing catheter-ablation, LA was studied using echocardiography and ultra-high-density mapping (Rhythmia®). Fibrosis (i.e. extent of LVAs) was estimated by quantifying areas with bipolar electrogram amplitudes of ≤0.5, ≤0.4, ≤0.3, ≤0.2 or ≤0.1 mV.

RESULTS

A total of 22 patients with a mean LVEF of 53 ± 2% was studied. Mean LA volume index (LAVI) was significantly increased at 39 ± 3 ml/m indicating AR. Size of LVAs was 57 ± 7 cm representing 47 ± 5% of the total LA area (low-voltage set to ≤0.5 mV). With low-voltage set to ≤0.4, ≤0.3, ≤0.2 and ≤0.1, total area decreased to 34 ± 6, 28 ± 6, 22 ± 5 and 12 ± 3 cm. LAVI positively correlated with the extent of LVAs at all cut-offs. Mean LA emptying fraction was 42 ± 3% and showed a negative correlation with LVAs with low-voltage set to ≤0.4 mV. Moreover, mean LA strain was 13 ± 2% and correlated with LVAs with low-voltage at all cut-offs further supporting the notion that the extent of LVAs impacts LA function. Notably, with low-voltage set to ≤0.2, ≤0.3 and ≤0.4 mV impaired LA strain was detected with an accuracy of >76% (p < 0.05).

CONCLUSION

Structural (i.e. LAVI) and functional (i.e. LA emptying fraction and LA strain) parameters of the LA correlate with the extent of LVAs.