Effects of positive inotropic stimulation (post-extrasystolic potentiation) on non-uniformity of left ventricular contraction in patients with coronary artery disease.

In patients with chronic coronary artery disease, post-extrasystolic potentiation (PESP) slightly worsens relaxation, increasing the constant tau of ventricular pressure decay. However, it does not negatively influence left ventricular (LV) diastolic filling. To our knowledge, no data are available on the effects of PESP on segmental relaxation in chronic coronary artery disease. The effects of PESP on the LV pressure-volume (P/V) relationship and on segmental pressure-length loops (P/L) were studied in eight patients with coronary artery disease submitted to LV angiography. P/V loops were constructed by means of frame-to-frame analysis of ventriculograms and simultaneous high-fidelity LV pressure tracings; P/L loops were calculated by the endocardial movement of 45 chords intersecting the LV outline (centreline method). PESP was produced by programmed stimulation during ventriculography. P/V and P/L loops were studied in basal conditions and after PESP.(ABSTRACT TRUNCATED AT 250 WORDS)