Cases description
The first patient was a four years old girl with hypoplastic left heart
syndrome. She previously had undergone neonatal Norwood-Sano palliation
and bidirectional cavo-pulmonary connection at the age of three months.
Due to progressive cyanosis the patient was scheduled for tricuspid
valve repair and TCPC. Preoperatively the patient had a well-tolerated
junctional rhythm with constant retroconduction with preserved heart
rate excursions.
Weaning from bypass was uneventful and the patient was successfully
extubated after 12 hours.
During the first postoperative week abdominal congestion, right pleural
effusion (Fig 1A) and progressive desaturation were observed. Blood
chemistry disclosed increased liver enzymes and low albumin.
Transthoracic echocardiogram showed normal ventricular function and mild
AV valve regurgitation. Color-Doppler interrogation of the Fontan
conduit and sovrahepatic veins, disclosed phasic hepatopetal signal
consistent with a reversal flow through the fenestration on time with
atrial retroconduction (Fig 2). This observation was consistent with the
evidence of giant ‘atrial’ wave one the jugular venous pressure tracing.
Upon atrial pacing the reverse component of flow disappeared with a
slight increase in aortic velocity time integral (VTI).
Clinically, these echocardiographic changes were accompanied by
resolution of pleural effusion and progressive increase of oxygen
saturation and albumin normalization during the following days (Fig 1B).
Based on this findings she was scheduled for permanent atrial pacing
owing to persisting junctional rhythm.
The second patient was a five years old child who had undergone neonatal
systemic to pulmonary shunt and cavo-pulmonary connection at the age of
9 months, due to severe symptomatic Ebstein anomaly. TCPC was planned
because of progressive desaturation and effort intolerance. Few hours
after cardiopulmonary bypass weaning he developed hypotension and low
cardiac output syndrome requiring inotropic and vasopressor support. ECG
disclosed competitive retroconduted junctional rhythm. Function of
systemic ventricle and atrioventricular valve were normal. Similarly to
the first case there was phasic reversal flow through the fenestration
that was no longer detected during atrial pacing . Theses flow pattern
changes translated into VTI increase and resolution of lactacidemia, in
the following 24 hours, consistently with stroke volume and peripheral
perfusion improvement. Permanent pacemaker implantation was not needed
as sinus rhythm recovered after 72 hours.