Left atrial strain can predict right ventricular impairment and developement of atrial fibrilation in patients with severe mitral stenosis better than transmitral gradients
Authors: Vriz O , Blassy B , Almozel A , Almohammadi SM , Galzerano D , Alfehaid A , Veldtman G , Alamri M 
Published: February 2021

Funding Acknowledgements

Type of funding sources: None.

Introduction. Rheumatic heart disease is a major health problem in developing countries and remains the leading cause of mitral valve stenosis (MS) and valve replacement in adults. Left atrial (LA) inflammation due to rheumatic carditis, pressure overload because of mitral stenosis, lead to fibrosis and remodeling to progressive lost of LA reservoir/compliant capacity that might be responsible of the pressure backward load to the pulmonary circulation. The aims of the study were to determine if 1) there is any correlation between LA strain parameters with pulmonary systolic arterial pressure (PASP) and other parameters related with pulmonary pressure and right ventricular (RV) function and 2) if LA strain can better identify those patients who developed atrial fibrilation (AF). 

Methods. Strain of the LA was measured in 101 patients retrospectively enrolled with severe MS using two dimensional speckle tracking (2DSTE).  Sixty of them were in sinus rhythm (SR) and 40 in atrial fibrillation (AF). The LA 2DSTE was measured from the 4 chamber view of 2 consecutive cycles at expiration and offline evaluated. Based on the QRS onset, the positive peak strain curve was defined as LA end systolic strain. The end of the reservoir phase was defined as 1 frame before mitral valve opening (LA- RES). When the patient was in SR, immediately after the P wave, LA contractile function was identified (LA-booster). Strain of the free wall and global RV was measured in 4CH. A standard echocardiographic assessment was done in accordance with the recommendation of the American Society of Echocardiography. 

Results.  Patients mean age was 47.4 ± 11.9 years, 30 males and 71 females. Mean gradient across the mitral valve (MV) was 8.3 ± 5.1 mmHg and the MV area derived by pressure half time was 1.3 ± 0.3 cm2, LVEF was 51.79 ± 11.3%. Right ventricular (RV) function parameters were TAPSE 19.6 ± 5.2 mm, S` 10.5 ± 2.5 cm/s, RV fraction area change 35.6 ± 9.1% and RV free wall peak strain – 17.96 ± 6.5%. LVMi 51.79 ± 11.3 gr/m2, SVi 34.6 ± 10.3 ml/m2. LA-RES 11.18 ± 3.7%, LA volume in systole 128.3 ± 48.3 ml, LAEF 20.1 ± 12.5%.  The group was divided according to tertiles of LA-RES (group 1, 33 patients, strain was &lt; =7%, group 2, 32 patients with strain between 8 and 13%, group 3, 32 patients, strain &gt; =14%). There was a decrease in PASP (group 1, 42.3 ± 17.8 mmHg; group 2, 38.3 ± 17.9 mmHg; group 3, 31.6 ± 17.9 mmHg, p =0.028) and PVR (group 1, 2.5 ± 1; group 2, 2.0 ± 0.6; group 3, 1.6 ± 0.4, p&lt; 0.0001) as LA-RES increased. RV function represented by TAPSE, Sm, RVFAC and RV free wall strain significantly increased as LA-RES increased. The area under the ROC curve was calculated for LA-RES, MV mean gradient, MV area derived by PHT and LA systolic volume as a predictors of AF. LA-RES was the one that better predicted the presence of AF.

Conclusion. In severe MS, LA-RES was able to better identify those with higher PASP and worst RV function. Moreover LA-RES was also able to better predict those patients who developed AF.