Objective To investigate the association of mitral regurgitation (MR) on thromboembolic risk of patients with non-valvular atrial fibrillation (NVAF) undergoing transoesophageal echocardiography (TEE)-guided cardioversion.

Methods Data for consecutive patients who underwent TEE-guided cardioversion for NVAF between 2000 and 2012 were analysed. MR severity was assessed by Doppler echocardiography and classified as ≤mild, moderate or severe. Left atrial appendage emptying velocities were averaged for five consecutive cycles. Multivariable regression models were used to identify independent predictors of left atrial appendage thrombus (LAAT) and stroke.

Results 2950 patients (age, 69.3±12.2 years, 67% men) were analysed. 2173 (73.7%) had ≤mild MR; 631 (21.4%), moderate MR; and 146 (4.9%), severe MR. Patients with moderate (age, 72.4±10.7 years) and severe (age, 72.8±12.1 years) MR were older than those with ≤mild MR (age, 68.2±12.5 years). The prevalence of LAAT was 1.5% (n=43). CHA₂DS₂-VASc scores (≤mild MR, 3.0±1.6; moderate MR, 3.5±1.5; severe MR, 3.9±1.5; p<0.001) and heart failure frequency (≤mild MR, 38.4%; moderate MR, 48.0%; severe MR, 69.2%; p<0.001) were increasingly higher with greater MR severity. Multivariable logistic regression analysis showed no association of moderate MR (OR 0.77, 95% CI 0.38 to 1.56) or severe MR (OR 0.55, 95% CI 0.21 to 1.49) with LAAT. During a mean follow-up of 7.3±5.1 years (median 7.5, IQR, 2.7–10.9), 216 patients had an ischaemic stroke. Adjusted Cox regression analysis showed no significant association of moderate MR (HR 1.22, 95% CI 0.88 to 1.68) or severe MR (HR 0.73, 95% CI 0.31 to 1.46) with stroke.

Conclusions Among patients with NVAF, the presence or severity of MR was not associated with a decreased risk of LAAT or stroke.