Which investigations should be prioritized for a patient with suspected cardiomegaly and heart failure symptoms?

Prioritized investigations for a patient with suspected cardiomegaly and symptoms of heart failure include:

• Measurement of N-terminal pro-B-type natriuretic peptide (NT-proBNP) to support the diagnosis of heart failure. An NT-proBNP level above 2000 ng/litre requires urgent specialist assessment and transthoracic echocardiography within 2 weeks, while levels between 400 and 2000 ng/litre warrant specialist assessment and echocardiography within 6 weeks. Levels below 400 ng/litre make heart failure less likely but do not exclude it if clinical suspicion remains ¹.
• Transthoracic echocardiography to assess cardiac structure and function, including left ventricular systolic and diastolic function, valve disease, and to exclude intracardiac shunts. This is essential to confirm cardiomegaly and evaluate the cause of heart failure symptoms ¹.
• Electrocardiogram (ECG) to detect arrhythmias, ischemic changes, or other cardiac abnormalities that may contribute to heart failure ¹.
• Chest X-ray to evaluate heart size (confirm cardiomegaly), pulmonary congestion, and exclude other causes of symptoms such as pneumonia or pneumothorax ¹.
• Blood tests including renal function, thyroid function, liver function, lipid profile, glycosylated haemoglobin (HbA1c), full blood count, and urinalysis to identify contributing or alternative diagnoses and assess comorbidities ¹.
• Consider pulmonary function tests (peak flow or spirometry) if respiratory causes are suspected ¹.

Summary: Initial priority is NT-proBNP measurement followed by transthoracic echocardiography and ECG. Chest X-ray and relevant blood tests support diagnosis and management planning. Further imaging (e.g., cardiac MRI) may be considered if echocardiography images are suboptimal ¹.