The authors report on the behaviour of systolic time intervals, studied with a noninvasive poligraphic technique, under normal conditions, after adrenergic beta stimuls (orciprenaline) and successive beta blocker (pindolole) in 38 patients with obstructive cardiomyopathy. Under normal conditions, the authors observed a marked dispersion of PEP and TEVS data, which have, however, average normal values. The IPEP was reduced in 29% of cases, was normal in 47.3% and raised in 23.7%; the ITEVS was reduced in 55.2% of cases, was normal in 21.1%, raised in 23.7%; the PEP/TEVS was reduced in 23.7%, normal in 31.6% and raised in 44.7%. The beta stimulation demonstrated a number of behaviour patterns: the most frequent cause was a reduction of PEP in the cases where it had been raised or where it had remained within normal limits, an increase of TEVS in the cases where it had been diminished or normal, a reduction of the PEP/TEVS correlation where these values were increased or normal. The beta blocker, followed by beta stimulus, brought on variations opposite from those of the beta stimulation. Thus, one can consider the hypothesis that the possible behaviour patterns and combination of PEP and TEVS result from different anatomical and functional expressions that can become obstructive cardiomyopathy, according to the seriousness of the obstruction, the ventricular compliance and the contractility.