Regional quantification of left atrial early diastolic strain in two groups of patients with mitral stenosis: normal sinus rhythm vs atrial fibrillation.

BACKGROUND: Strain rate imaging (SRI) is proposed for assessing atrial function. There are limited studies on the role of SRI in assessing the left atrial (LA) function in patients with mitral stenosis (MS). We decided to assess LA early diastolic strain to evaluate LA conduit function in two groups of patients with MS.

METHODS: A total of 49 patients with moderate to severe MS, scheduled for percutaneous transluminal mitral commissurotomy, were categorized into two groups: normal sinus rhythm (NSR, n=24) and persistent atrial fibrillation (AF, n=25). Early diastolic strain was measured via SRI in four mid-left atrial walls by transthoracic echocardiography.

RESULTS: Left atrial volume was significantly higher in AF group. LA early diastolic strain was significantly reduced in AF patients in three walls: interatrial septum (-6.78±6.22% vs -11.44±6.35%, P=.016), anterior wall (-4.47±4.30% vs -12.52±10.62%, P=.002), and inferior wall (-2.87±3.23% vs -9.73±9.67%, P=.003). After adjustment for age, heart rate, LA volume, LA thrombus, and LAA emptying velocity, there was a significant correlation between the presence of AF and left atrial average early diastolic strain. This correlation was also remarkable between existence of AF and two LA walls (i.e., anterior and inferior walls of the LA).

CONCLUSION: There was reduced average early diastolic strain in the presence of AF compared to NSR in MS patients regardless of LA volume and age. In AF patients, there is not only a loss of atrial late diastolic contraction, but also there is a reduction in early diastolic shortening of LA myocardium.