11th May 2025

A 52-year-old man presents to general practice with worsening breathlessness and fatigue on exertion.

A 52-year-old man presents to general practice with worsening breathlessness and fatigue on exertion. He described an insidious onset over many months and more recently some increased swelling in his ankles. His past medical history includes hypercholesterolaemia and pre-diabetes. He takes atorvastatin 40 mg once daily. On further questioning, he reports a long history of daytime somnolence and is a heavy snorer at night. Further investigations go on to reveal a diagnosis of pulmonary hypertension. Which of the following investigations will most likely identify the underlying aetiology of his pulmonary hypertension? 

Select the SINGLE most appropriate option from the list below. Select ONE option only.