Reversible Acute Fontan Circulation Failure Secondary to Retroconducted Junctional Rhythm. Clinical Echocardiographic Correlation

Abstract Background: Sequential atrioventricular activation plays a critical role in the physiology of Fontan circulation. Although bradycardia is usually well tolerated, retroconducted junctional rhythm may acutely increase atrial pressure impairing cardiac output. Echocardiographic evaluation can reveal clues of this hemodynamic condition. The clinical impact of arrhythmic disturbance on the follow up of patients who had undergone total cavo-pulmonary connection is well recognized but the role of, transient periods of retroconducted junctional rhythm on the immediate post-operative course is less defined. Case presentation: We describe two cases of acute Fontan circulatory failure due to postoperative retroconducted escaping junctional rhythm despite an adequate heart rate and circadian variation. The patients rapidly improved after atrial pacing, allowing discharge with a minimal dose of diuretic.Conclusion: In the absence of any hemodynamic target, hearth rhythm should be systematically checked after TCPC irrespective of adequacy of heart rate. Likewise, efficiency of temporary atrial pacing should be granted and surgeons should have a low threshold for epicardial lead implantation.