Background/Objectives: Heart disease is common in COPD, yet it is underdiagnosed and undertreated. Heart failure (HF) is undiagnosed in up to 20% of hospital inpatients. Hospitalised exacerbations of COPD (ECOPD) confer high mortality and readmission rates, with an elevated temporal cardiac risk. We performed a pilot randomised controlled trial examining the feasibility and effect of inpatient structured cardiac assessment (SCA) to diagnose and prompt guideline-recommended treatment of heart disease. Methods: A total of 115 inpatients with ECOPD were randomised 1:1 to receive usual care (UC) or SCA, comprising transthoracic echocardiography, CT coronary artery calcium scoring, 24 h ECG, blood pressure, and diabetes assessment. Follow-up was for 12 months. The prevalence of underdiagnosis and undertreatment of heart disease were captured, and potential outcome measures for future trials assessed. Results: Among patients undergoing SCA, 42/57 (73.7%) received a new cardiac diagnosis and 32/57 (56.1%) received new cardiac treatment, compared with 11/58 (19.0%; p < 0.001) and 5/58 (8.6%; p < 0.001) in the UC group. More patients in the SCA group were newly diagnosed with HF (36.8% vs. 12.1%; p = 0.002). When heart disease was diagnosed, the proportion receiving optimal treatment at discharge was substantially higher in SCA (35/47 (74%) vs. 4/11 (34%); p = 0.029). The occurrence of a major adverse cardiovascular event (MACE) showed promise as an appropriate clinical outcome for a future definitive trial. MACEs occurred in 17.2% in usual care vs. 10.5% in SCA in one year, with a continued separation of survival curves during follow up, although statistical significance was not shown. Conclusions: A structured cardiac assessment during ECOPD substantially improved diagnosis and treatment of heart disease. HF and coronary artery disease were the most common new diagnoses. Future interventional trials in this population should consider MACEs as the primary outcome.