Effect of age on atrial contribution to ventricular filling after balloon mitral valvuloplasty in mitral stenosis

Objective: Ventricular filling takes place during the conduit and pump functions of the atrium. While studying whether relief of mitral valve obstruction improves atrial filling, the effect of age on atrial contribution to ventricular filling was studied before and after balloon mitral valvuloplasty (BMV) and on follow-up at 1 year. Methods: Patients with mitral stenosis (MS) and sinus rhythm (n=59) were divided into group I (<18 years, n=13), group II (<30 years, n=29) and group III (>30 years, n=17). Two-dimensional mitral valve area (MVA in cm2), transmitral mean gradient (MG in mm Hg), velocity time integral (VTI in cm) of mitral valve flow, VTI contributed by atrial systole (A-VTI), difference between total VTI and A-VTI (E-VTI), percentage contribution of A-VTI to the total VTI (A-%) and difference between A-% before and after BMV (δ-A-%) were noted. Follow-up data was obtained at 1 year. The change in A-% at follow-up (A-%-FU) was calculated as the difference between A-% before BMV and A-% at follow-up. Results: There was a similar increase in MVA with a reduction in MG among the three groups. Among the three groups, total VTI and E-VTI before and after BMV were similar. Before BMV, in all the groups, A-VTI and A-% were similar. After BMV, there was increase in A-VTI and A-% in all the groups with a trend to be more in younger patients. A-VTI was significantly higher in group I only. But E-VTI had decreased significantly in all groups and tended to be less in younger patients. In younger patients, δ-A-% after BMV was significantly higher (13.2±7.6, 7.9±5.1 and 6.5±4.5, respectively, in groups I, II and III; p<0.01). Correlation coefficient of age against δ-A-% was −0.55 (p<0.01). Correlation coefficients of δ-A-% against post-BMV-MVA and MG were not good. At follow-up of 11.3±1.2 months, changes achieved in total VTI, A-VTI, E-VTI and A-% were maintained. Total VTI, A-VTI, E-VTI and A-% were similar at the time of follow-up on comparing the three groups. But younger patients had significantly higher A-%-FU (12.1±5.8, 9.4±4.6 and 7.3±3.1, respectively, in groups I, II and III; p<0.01). Conclusions: Prior to BMV, there is an age related reduction in atrial contribution to ventricular filling that improves with relief of MS. Advancing age reduces the immediate and late recovery of atrial contribution after BMV. This may be due to increasing left atrial fibrosis with age that prevents an improvement in atrial pump function. The differential improvement in atrial function in younger patients warrants earlier intervention in MS to achieve better recovery of atrial function.