Echophonocardiography in patients undergoing percutaneous mitral balloon valvotomy (PMV): the learning curve of PMV

Percutaneous mitral balloon valvotomy (PMV) was performed in 10 female patients with mitral stenosis; their mean age was 31 +/- 1 years. All patients underwent echophonocardiography (Echophono) before and less than 24 hours after PMV1. Cardiac catheterization and Echophono were repeated 10 and 22 months after PMV1. Eight patients with suboptimal results (defined as a post-PMV mitral valve area [MVA]/less than 1.0 cm2 and mean gradient greater than/10 mm Hg) underwent repeat PMV (PMV2) 10 months after PMV1. The Echophono data are correlated with clinical and hemodynamic changes produced by PMV1 and PMV2. MVA increased from 0.6 +/- 0.1 to 1.1 +/- 0.01 cm2 (p = 0.0009) when PMV1 was performed with a mean effective balloon dilating area (EBDA) of 5 +/- 0.19 cm2. MVA increased from 1.0 +/- 0.1 to 1.7 +/- 0.2 cm2 (p = 0.0002) when PMV2 was performed with larger EBDA (6.4 +/- 0.34 cm2). Two factors related to the learning curve account for the superior result of PMV2: (1) use of larger EBDA and (2) optimal position of the balloons parallel to the long axis of the left ventricle. PMV1 resulted in Echophono changes consistent with decreased severity of mitral stenosis: shortening of Q-S1 from 93 +/- 4 to 82 +/- 4 msec (p less than 0.05) and (Q-S1)-(S2-OS) from 1.8 +/- 0.8 to -0.9 +/- 0.6 (p less than 0.01); prolongation of S2-OS from 75 +/- 5 to 91 +/- 5 msec (p less than 0.05) and increase of EF slope from 7 +/- 1 to 17 +/- 4 mm/sec (p less than 0.05). Compared with PMV1, post PMV2 Echophono showed a further decrease in the severity of mitral stenosis: Q-S1 decreased to 78 +/- 3 msec and (Q-S1)-(S2-OS) decreased to -0.5 +/- 0.3 msec. S2-OS increased to 86 +/- 5 msec and EF slope increased to 22 +/- 4 mm/sec. The hemodynamic and Echophono changes produced by PMV1 and PMV2 persisted at the corresponding follow-up studies. There was no evidence of restenosis. Thus Echophono is a simple, low cost method helpful in the evaluation and follow-up of patients undergoing PMV.