Adults with cyanotic congenital heart disease, including Eisenmenger syndrome, are a remarkable group of people. While there is an eagerness to cite the historic increase in survival of patients with congenital heart diseases, outside these successes are those for whom surgery either was not or could not be offered who, nevertheless, beat the odds and survived. These cyanotic individuals often relate stories of being told they would not live to reach the age of 4 or 12 or 20, yet, in an extraordinary show of resilience, are now in their fifth decade or beyond. For most, exertional tolerance is below normal, but they, otherwise, carry on with life, including careers and family. They tell anecdotes of healthcare providers who, upon noting their low oxygen saturation, erroneously raise an alarm for immediate resuscitation. They defy providers’ expectations by maintaining full-time employment, flying abroad, living at high altitude1 or surviving neurosurgery. They have important physiological adaptations that allow them to carry on, although with an ongoing risk that their fragile balance could be unfavourably tipped at any time.

Recognising both their remarkable survivorship and ongoing risks, cyanotic adults with congenital defects merit focused scientific consideration despite their low numbers. It is, therefore, gratifying to see researchers and editors give attention to these unique survivors. Investigators from Copenhagen have pooled data on over 100 cyanotic adults from Sweden and Denmark for several descriptive investigations.2 ,3 In their Heart paper, the Danes explore the prevalence of cerebral and pulmonary thromboembolic ‘events’ through comprehensive imaging.4 They studied 98 patients with brain MRI, CT pulmonary angiography and/or ventilation/perfusion (V/Q) scintigraphy or single-photon emission CT (SPECT). The majority had Eisenmenger physiology. Twenty per cent had a clinical history of thrombotic events (requiring hospitalisation) whereas imaging evidence of either cerebral or pulmonary phenomena was …