'Superimposed miracles': an extremely rare case of a septuagenarian with an unrepaired tetralogy of Fallot: a case report.

Specific anatomical, functional, and haemodynamic characteristics may be required for the long-term survival of patients with TOF. Pulmonary stenosis should be initially mild to guarantee pulmonary flow during childhood and adolescence, and gradual PS exacerbation should be paralleled with systemic-to-pulmonary collateral development or an extracardiac shunt. Moreover, reduced left ventricular compliance may act as a balancing factor against a right-to-left shunt. The presence of all of these special requirements may have contributed to the unusual survival for this patient.