Background: Rheumatic mitral stenosis (MS) is associated with progressive impairment of left atrial (LA) mechanical
functions. This study was conducted to assess the acute impact of Balloon Mitral Valvotomy (BMV) on these functions.
Methods: This single centre observational study included 25 patients with severe MS (aged 34.1 ± 7.1 years, with mean
mitral valve area of 0.74 ± 0.13 cm²), in sinus rhythm, who underwent successful BMV at our hospital. Phasic LA volumes
(Vmax: maximal LA volume, Vmin: minimal LA volume, and Vp: LA volume at the onset of P-wave) were measured by modified
Simpsons method. Parameters of LA reservoir function i.e. LA total emptying fraction (LATEF) and LA expansion
index (LAEI); conduit function i.e. LA passive emptying fraction (LAPEF); and pump function i.e. LA active emptying
fraction (LAAEF) were calculated from these volumes. All these parameters were evaluated before and 24-48 hours after
BMV. Results: Successful BMV led to significant reduction in Vmax (p < 0.001), Vmin (p < 0.001), and Vp (p < 0.001). There
was a significant increase in LATEF (p= 0.001) and LAEI (p= 0.002). LAPEF increased insignificantly (p= 0.057), while
there was no significant change in LAAEF (p =0.127) after BMV. Conclusion: Successful BMV leads to early improvement
in left atrial reservoir and conduit functions, without significantly affecting left atrial pump function. Whether these
acute changes translate into long term left atrial reverse remodelling and clinical benefits thereof needs to be established
by further studies.
Key words: Rheumatic Heart Disease, Mitral Stenosis, Left Atrial Volume, Left Atrial Functions, Balloon Mitral Valvotomy.