Initial procedure	Successful chronic total occlusion percutaneous coronary intervention performed but with septal haematoma formation, which was treated conservatively.
4 h post-procedure	Worsening haemodynamics prompting repeat angiography. Further expansion of septal haematoma, which was treated with coiling of the inflow and outflow of the culprit septal artery.
12 h post-procedure	Echocardiogram with near obliteration of the right ventricle. Impella RP placed with immediate normalization of haemodynamics.
Day 4 post-procedure	Impella RP weaned and removed.
Day 8 post-procedure	Discharged from the hospital.
2 weeks after discharge	Seen in follow-up clinic with no anginal symptoms or limitations.
3 months after procedure	Cardiac magnetic resonance imaging scan with complete resolution of septal haematoma.