Classic ECG triad points to an unexpected cause of dyspnoea

There's more than meets the eye for this patient with laboured breathing

Freda is a 55-year-old retail worker who has been seeing her GP for many years for management of COPD.

She presents on this occasion with increasing dyspnoea on exertion and a worsening cough over the past two months.

She admits she has been intermittently adherent with her long-acting muscarinic receptor antagonist and inhaled corticosteroids/LABA combination therapy.

She also notices little relief with a short-acting beta agonist.

Freda denies any associated fevers, weight loss, night