[Post-extrasystolic potentiation in chronic Chagas' heart disease. A radiologic contrast ventriculography study].

OBJECTIVE To determine the existence and frequency of the phenomenon of post-extrasystolic potentiation in dyssynergic myocardial areas of patients with chronic Chagas' heart disease studied by use of radiologic contrast ventriculography. METHODS This study is a semiquantitative retrospective analysis of radiologic contrast ventriculography in patients with chronic Chagas' disease, who were consecutively studied to assess the mechanisms of ventricular tachycardia. RESULTS Of the 72 patients initially included, in only 20 patients was possible the ventriculographic analysis for the purposes of this study. The phenomenon of post-extrasystolic potentiation was observed in 11 (55%) of these patients, and a 15.31% improvement was observed in the contractility score from the baseline to the post-extrasystole condition (P=0.0001). That phenomenon occurred even in ventricular segments with an intense deficit in contractility. CONCLUSION The phenomenon of post-extrasystolic potentiation is observed in a significant proportion of patients with chronic Chagas' heart disease, in whom the phenomenon could be angiographically analyzed, indicating the existence of potentially recruitable contractile reserve in ventricular regions, showing marked dyssynergy. Additional studies for clarifying the underlying mechanisms are required.