Classic ECG triad points to an unexpected cause of dyspnoea

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.