Introduction:
The management of patients with non-valvular atrial fibrillation (NVAF) and low CHA2DS2-VASc scores remains controversial. Left atrial appendage (LAA) function is a known risk factor for embolisms.
Hypothesis:
In this study, we aimed to investigate the value of the relationship between transthoracic echocardiography (TTE) parameters and LAA function in low-risk (CHA2DS2-VASc score, 0-1) patients with NVAF.
Methods:
This retrospective study included 370 consecutive patients with NVAF who underwent both TTE and transesophageal echocardiography (TEE). The LAA emptying flow velocity was assessed using TEE. We established that an LAA emptying flow velocity of <25 cm/s was associated with a high risk of thrombus formation.
Results:
Of the 370 patients, 146 (40%) had a CHA2DS2-VASc score of 0-1. These patients with low-risk NVAF were further stratified into the low-flow (LAA emptying flow velocity < 25 cm/s, n = 19) and normal-flow (LAA emptying flow velocity ≥ 25 cm/s, n = 127) groups according to LAA function (atrial fibrillation during TEE: n = 63). The age, gender, CHA2DS2-VASc score, and left ventricular ejection fraction did not differ between the two groups. The low-flow group had a significantly greater left atrial volume index (LAVI) than the normal-flow group (51.6 ± 19.8 vs. 32.3 ± 12.1 ml/m2, p < 0.01). A LAVI of 37.8 ml/m2 predicted a LAA emptying flow velocity of <25 cm/s with a sensitivity of 73% and specificity of 83% among patients with low-risk atrial fibrillation (area under the curve, 0.818, p < 0.001, Figure).
Conclusions:
Approximately 13% of patients with NVAF and CHA2DS2-VASc score of 0-1 had reduced LAA emptying flow velocity as well as left atrial enlargement. The use of LAVI may improve the current embolism risk stratification system among these patients.
Second-Generation Cryoballoon Ablation for Atrial Fibrillation ― A Detailed Analysis of the Impact of Left Atrial Volume Index on Clinical Outcome ―