13. Immediate Effect of percutaneous transvenous mitral commissurotomy on atrial electromechanical delay and left atrial mechanical functions in patients with rheumatic mitral stenosis

Abstract

Rheumatic mitral stenosis (MS) is associated with prolonged inter and intra-atrial electromechanical delays and impaired left atrial (LA) mechanical functions, which are considered to be markers of atrial fibrillation (AF) risk. This study was conducted to assess the immediate effect of successful percutaneous transvenous mitral commissurotomy (PTMC) on these parameters. Methods: This observational study included 25 patients with symptomatic, severe MS (aged 34.1 ± 7.1 years, with mean mitral valve area (MVA) of 0.74 ± 0.13 cm2), in normal sinus rhythm, who underwent successful PTMC at our hospital. Inter-atrial (AEMD), left intra-atrial (L-IAEMD) and right intra-atrial (R-IAEMD) electromechanical delays were measured on tissue Doppler imaging. Phasic LA volumes (Vmax: maximal LA volume, Vmin: minimal LA volume and Vp: LA volume at P-wave onset) were measured by modified Simpson’s 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 the phasic LA volumes. PTMC was performed using the standard Inoue Balloon technique. All these parameters were evaluated and compared before and 24–48 h after PTMC. Results: Successful PTMC led to significant reduction in AEMD (p < 0.001), L-IAEMD (p < 0.001), R-IAEMD (p < 0.001), Vmax (p < 0.001), Vmin (p < 0.001) and Vp (p < 0.001). There were significant increments in LATEF (p = 0.001), LAEI (p = 0.002) and LAPEF (p = 0.05), while there was no significant change in LAAEF (p = 0.127) after PTMC. Conclusions: Successful PTMC has a favorable early impact on left atrial mechanical functions and other novel parameters of atrial electromechanical remodeling in MS patients. Large scale prospective studies are required to confirm whether improvement in these markers translates into reduced long term AF risk in these patients.