Introduction
Fontan circulation critically depend on pulmonary resistances and atrial pressure. [1] It has been observed that during sinus rhythm blood predominantly flow during atrial relaxation. Furthermore loss of atrioventricular synchrony may lead to phasic increase of atrial pressure which is transmitted to the Fontana circuit. [2] Heart rhythm optimization is recognized as a pivotal component of the follow up in this group of patients, while the impact of even self limited period of junctional rhythm is less defined, particularly wether the heart rate trend is acceptable.
We describe two cases of acute heart failure, after fenestrated total cavo-pulmonary connection (TCPC) which resolved after 48 h of atrial pacing. We demonstrated acute changes of Fontan flow pattern during the two modality of pacing that strictly correlated with the clinical status.