An asymptomatic 72-year-old man with cardiomegaly was referred to our centre for assessment. His medical history comprised metastatic colonic cancer and granulomatosis with polyangiitis.

Transthoracic echocardiography was performed. In the apical four-chamber view, a large cavity was identified adjacent to the apex, measuring 45 × 54 mm (Fig. 1A and Supplementary Video 1). All apical segments of the left ventricle were thin and akinetic. On colour Doppler, bidirectional blood flow due to swirling of blood was observed within the cavity (Fig. 1B and Supplementary Video 2). Contrast-enhanced echocardiography established the …