4.3 Correlation between the AWT and fibrosis
A recent study showed that a thicker LA wall was associated with a stronger atrial maintenance substrate in patients with LA enlargement assessed by echocardiography.15 An enlarged LA and a thickened LA wall might seem to be contradicted. A thickened LA wall may implicate the stage of inflammation, edema. With the progression of AF to end-stage disease, remodeling may advance to atrial fibrosis, leading to a thinner AWT. Moreover, the observation of fractionated electrical activity with a low voltage on the electroanatomic map may be predictive of a high risk of AF initiation and persistence. The loss of an adaptive atrial thickening may be the tipping point at which fibrosis and scar become irreversible.16 In our study, the LA wall thickness was negatively correlated with the LGE-volume ratio and the correlation was significant at only the NPAs but not the PAs, which was consistent with these previous results.