Previous studies suggest that patients with mitral regurgitation (MR) have a reduced incidence of embolic cerebral vascular accident (CVA), assuming that the regurgitating jet “washes out” and prevents the formation of left atrial thrombus (LAT). However, the incidence of MR in patients with LAT is largely unknown. The purpose of the study was to evaluate the incidence of MR in atrial fibrillation (AF) patients with LAT and its impact on embolic events.
69 consecutive patients (male/female=36/33, age 70.2±11.7 years) with AF and documented LAT on transesophageal echocardiogram (TEE) prior to contemplated cardioversion were evaluated for MR. The thrombus was located in the left atrial appendage in 67 and the left atrial body in 2 patients. The severity of MR by color flow imaging was classified into four grades, trivial (1+), mild (2+), moderate (3+) and severe (4+).
All but 2 (67/69, 97%) patients demonstrated MR. MR severity was 1+ in 20 (29%), 2+ in 27 (39%), 3+ in 17 (26%), and 4+ in 3 (5%) patients. During the follow-up of 29.1±27.5 months after TEE, 3 patients (4.3%) with LAT in left atrial appendage had embolic CVA. Their INR at time of CVA was 2.9, 3.84 and 2.5. The CVA incidence had no significant difference between patients with MR ≥ 3+ (1/18, 5.6%) compared to <3+ (2/51, 3.9%) (p=NS). However, the incidence of spontaneous echo contrast in left atrium was higher in patients with MR < 3+ (47/51, 92.2%) than MR ≥ 3+ (14/18, 77.8%, p=0.034).
MR is very common in AF patients with LAT, suggesting that MR may not protect against the formation of left atrial clot. The occurrence of embolic CVA also was not decreased by the presence or severity of MR although the incidence of spontaneous echo contrast in left atrium was lower in patients with ≥ 3+ MR.
The embolic events are not related to the severity of MR. Further studies with larger number of patients and longer follow-up seems indicated.
Xuedong Shen, None.