Objective: Ventricular filling takes place during the conduit and pump functio ns of the atrium. While studying whether relief of mitral valve obstruction impr oves atrial filling, the effect of age on atrial contribution to ventricular fil ling was studied before and after balloon mitral valvuloplasty (BMV) and on foll ow-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 betwe en 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 n oted. 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 simi lar. After BMV, there was increase in A-VTI and A-%in all the groups with a t rend 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 goo d. At follow-up of 11.3±1.2 months, changes achieved in total VTI, A-VTI, EVT I and A-%were maintained. Total VTI, A-VTI, E-VTI and A-%were similar at t he time of follow-up on comparing the three groups. But younger patients had si gnificantly 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 rela ted reduction in atrial contribution to ventricular filling that improves with r elief of MS. Advancing age reduces the immediate and late recovery of atrial con tribution after BMV. This may be due to increasing left atrial fibrosis with age that prevents an improvement in atrial pump function. The differential improvem ent in atrial function in younger patients warrants earlier intervention in MS to achieve better recovery of atr ial function. Objective: Ventricular filling takes place during the conduit and pump functio ns of the atrium. While studying whether relief of mitral valve obstruction impr oves atrial filling, the effect of age on atrial contribution to ventricular fil ling was studied before and after balloon mitral valvuloplasty ( Methods: Patients with mitral stenosis (MS) and sinus rhythm (n = 59) were divided into group I (<18 years, n = 13), group II (MV in in cm2), transmitral mean gradient (MG in mm Hg), velocity time integral (VTI in cm) of mitral Vti contributed by atrial systole (A-VTI), difference betwe en total VTI and A-VTI (E-VTI), percentage contribution of A-VTI to the total VTI 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 simi lar. After BMV, there was increase in A-VTI and A-% in all the groups with at rend 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 goo d. At follow-up of 11.3 ± 1.2 months, changes achieved in total VTI, A-VTI, EVT I and A-% were maintained. Total VTI, A-VTI, E- VTI and A -% were similar at t he time of follow-up on comparing the thre e groupsThere was a significant difference in the number of patients who underwent upper gastrointestinal endothelium compared with those who did not (P <0.01). Concurrent: Prior to BMV, there is an age rela ted reduction in atrial contribution to ventricular filling that improves with r elief of MS. Advancing age reduces the immediate and late recovery of atrial con tribution after BMV. This may be due to increasing left atrial fibrosis with age that prevents an improvement in atrial pump function. The differential improve ent ent in atrial function in younger patients warrants earlier intervention in MS to achieve better recovery of atr ial function.