[Electrocardiographic exercise test in assessment of hemodynamic patterns of mitral stenosis (author's transl)].

An ECG exercise test was performed in 36 patients with mitral stenosis, all in sinus rhythm and without digitalis therapy. In 21 subjects (group I = 58.6%) the test was negative, in the other 15 (group II = 41.7%) ischemic abnormalities of the ST segment were recorded during exercise; the mean value for the age is the same in both groups. All patients underwent cardiac catheterization; pulmonary pressure--and in 15 patients also cardiac output with thermodilution technique--were measured at rest and during the same exercise used for the ECG test. No relationship was found between ECG response and pulmonary capillary pressure (PCP), neither at rest nor during exercise, while exercise pressure values were well correlated with those at rest. The group I cardiac index (IC) and systolic index (IS) are significantly higher than in group II; the difference is remarkably more evident for the same indexes recorded during exercise, with splitting values, between the two groups, of 5000 ml/min/m2 for IC and 40 ml/beat/m2 for IS. Heart rate changes induced by exercise were similar in both groups, thus confirming the importance of the behaviour of output indexes. It is therefore possible to identify in mitral disease hemodynamic patterns due to different grouping of pathological features above (PCP) and below (IC) the valvular stenosis. Various hypothesis could be made in order to interpret the relationship between cardiac output and ischemic response to exercise. Anyway our results indicate that exercise ECG test is a non invasive technique useful to identify, among patients affected by mitral stenosis, those with a low IC and, mainly, those in whom this parameter fails to increase adequately with exercise.