Figure 6.

Change of restriction by the bottlenecks in the Fontan circuit: acute ventricular dysfunction. Acute changes of the ventricle such as severe bradycardia or tachycardia, ventricular dysfunction or acute excessive afterload may shift the critical bottleneck towards the ventricle. Such an episode will severely compromise the patient and may kill him if the ensuing rise of ventricular filling pressure reaches the level of systemic venous pressure. Treating the underlying ventricular problem may re‐shift the bottleneck and restore the prior output