Hemodynamic correlates of vectorcardiographic QRS loops in pure mitral stenosis.

The hemodynamic correlates of the vectorcardiographic types of right ventricular hypertrophy (RVH) according to Chou and Helm and those with normal QRS loop in the horizontal plane of Frank system were analyzed in 100 patients with pure mitral stenosis. All underwent right and left heart catheterization. Additionally, coronary arteriography was done on 16 whose ages were above 40. Type A RVH was associated with the most severe hemodynamic alterations with markedly elevated total pulmonary vascular resistance (TPVR), mean pulmonary artery pressure (MPAP), peak right ventricular pressure (RRVP) and the smallest mitral valve area (MVA). The severity of these parameters were to a lesser degree obtainable in type C but with no significant difference from type A (p greater than 0.05). However, types A and C were clearly separated from type B and normal QRS loop (p less than 0.05). Type B RVH and normal QRS loop showed milder hemodynamic changes and were not significantly different (p greater than 0.05). Our results indicate that in pure mitral stenosis the development of RVH is from a normal loop into type B, C and A reflecting an increasing severity of hemodynamic changes which affect the right ventricle. This order of development is different from the traditional view.