Acute effect of balloon mitral valvotomy on serial electrocardiographic changes and their haemodynamic correlation.

The effect of acute haemodynamic changes that occur following balloon mitral valvotomy on the electrocardiogram were studied in 25 patients with isolated rheumatic mitral stenosis. Statistically significant changes were observed in the characteristics of P-wave and QRS axis. Patients who showed changes in P-wave had significantly greater fall in left atrial mean pressure (p < 0.025), lesser residual transmitral gradient (p < 0.025) and greater percentage change in mitral valve area (p < 0.01) following balloon mitral valvotomy. Good correlation was seen between the decrease in right axis deviation of QRS axis and fall in mean pulmonary artery pressure (r = +0.56, p < 0.001) and pulmonary vascular resistance (r = +0.48, p < 0.05). Transient arrhythmias were seen in six patients. All these changes occurred within 72 hours, and in the majority of patients within 24 hours. These results demonstrate that the acute haemodynamic changes following balloon mitral valvotomy produce corresponding changes on electrocardiogram and these changes indicate a significantly greater degree of haemodynamic benefit from the procedure than when these changes are not seen.