No abstract

Funding Acknowledgements Type of funding sources: None. Correlation of left atrial reservoir function with diastolic filling and stroke volume of the left ventricle in patients with rheumatic mitral stenosis Introduction It has been theoretically known that the left atrium (LA) plays a key role in compensating for the lack of diastolic left ventricular (LV) filling induced by mitral stenosis (MS). However, due to the lack of adequate tools to assess the LA function, proving this concept turned out to be difficult. With the recent introduction of two-dimensional (2D) Speckle Tracking Echocardiography (STE) for exploring LA mechanics, this concept can be demonstrated. Purpose To assess correlation between LA reservoir function determined by 2D STE derived global strain and LV filling and stroke volumes. Methods We prospectively performed comprehensive trans thoracic echocardiography (TTE) in patients with rheumatic MS. Basic echocardiographic parameters were recorded, including indexed LA volume, mitral valve area (MVA) using planimetry and pressure half time (PHT), trans mitral mean gradient, maximal trans tricuspid velocity (MTTV), mitral inflow using continuity equation and LV stroke volume. Studied parameters represent the mean of at least three consecutive cardiac cycles. LA global strain curve and peak reservoir strain data were obtained on a standard four-chamber view using STE technique. Results We enrolled a total of 186 patients with rheumatic MS between February 2018 and February 2021. The mean age of our cohort was 50.55 ± 12.07 yrs. A number of patients were thereafter excluded from the study due to impaired systolic LV function (n = 12), severe mitral or aortic regurgitation (n = 7, n = 1 respectively). A total of 69.4% of our cohort were female (n = 129), 56.2% (n = 104) had history of percutaneous transvenous mitral commissurotomy (PTMC), 59.9% had permanent atrial fibrillation (n = 109) and 15,2% had history of ischemic stroke (n = 28). The most prominent comorbidities were hypertension (16.3%, n = 30) and diabetes mellitus (15.8%, n= 29). The mean 2D MVA was 1.40 ± 0.47 cm², mean PHT derived MVA was 1.47 ± 0.52 cm², mean gradient was 10.72 ± 5.82 mmHg, mean indexed LA volume was 80.70 ± 45.34 ml/m² and mean MTTV was (3.09 ± 0.62m/s). The mean mitral inflow value was 85.80 ± 28.56 ml/beat and the mean stroke volume was 70.64 ± 25.51 ml/beat. First, we found a statistically significant correlation between LV stroke volume and 2D mitral valve area (r = 0.284, p < 0.001). Interestingly, LA peak reservoir phase correlated positively with mitral inflow (r = 0.377, p < 0.001) and LV stroke volume (r = 0.213, p = 0.008). It also correlated with MTTV (r= -0.234, p = 0.009). However, we did not find any correlation between indexed LA volume and mitral inflow (r=-0.068, p = 0.359) and a weaker correlation with LV stroke volume was demonstrated (r=-0.184, p = 0.014). Conclusion LA reservoir function assessed by 2D STE is well correlated with diastolic mitral inflow and LV stroke volume in patients with rheumatic MS.

Introduction Rheumatic mitral stenosis (MS) is still frequent in low income countries. Unlike the other left sided valvular heart diseases, symptoms' occurrence is still not well understood. Previous attempts to correlate mitral valve area (MVA), pulmonary hypertension and even mitral valve stenosis severity scores with symptoms' severity have failed to establish any strong relationship. Recent advances in the characterization of the left atrium (LA) function by echocardiographic strain technique, yielded a new understanding of symptoms genesis in MS. Purpose To assess the correlation between LA reservoir function determined by two-dimensional (2D) Speckle Tracking Echocardiography (STE) and New York Heart Association (NYHA) functional status in patients with MS. Methods We prospectively performed comprehensive 2D trans thoracic echocardiography (TTE) in patients with rheumatic MS. Echocardiographic parameters, such as indexed LA volume, trans mitral mean gradient, maximal trans tricuspid velocity (MTTV), valve area using planimetry and pressure half time (PHT) were recorded. All doppler parameters are expressed as a mean of at least three measurements. LA global strain curve and peak reservoir strain value were then obtained on a four-chamber view. NYHA functional status was assessed just before performing the echo procedure. Results We enrolled 186 patients with rheumatic MS, with a mean age of 50.55±12.07 years. 20 patients were excluded from the study because of the presence of impaired systolic LV function (n=12), severe mitral regurgitation (n=7) or severe aortic regurgitation (n=1). A total of 69.4% of our cohort were female (n=129), 56.2% (n=104) had a history of percutaneous transvenous mitral commissurotomy (PTMC), 59.9% had permanent atrial fibrillation (n=109). The mean MVA was 1.40±0.47 cm2, PHT derived Area was 1.47±0.52 cm2, mean gradient was 10.72±5.82 mmHg, mean indexed LA volume was 80.70±45.34 ml/m2 and mean MTTV was (3.09±0.62m/s). 75 patients (39.9%) were in NYHA III or IV functional class. Mean LA reservoir strain value was 11.08±7.76%. Comparing the group in NYHA III or IV functional class with the group NYHA I or II functional class, there was no statistically significant difference in mean MVA by planimetry or PHT, nor in mean gradient, MMTV or indexed LA volume. Interestingly, the NYHA III or IV functional status group had a significantly lower mean LA reservoir strain value compared to the NYHA I or II functional status group (8.94±5.57% vs 11.92±8.31%, p=0.011). Even in mild MS patients with a planimetry MVA ≥1.5cm2 (n=65), a significantly lower mean LA reservoir strain value was found in NYHA III or IV group compared to the NYHA I or II group (15.08±10.09% vs 9.76±4.35%, p=0.05). Conclusion LA reservoir function is highly correlated to the severity of symptoms in rheumatic MS. FUNDunding Acknowledgement Type of funding sources: None.