What are the key diagnostic criteria for identifying cardiomegaly in a primary care setting?

Key diagnostic criteria for identifying cardiomegaly in a primary care setting include:

• Clinical assessment: Take a detailed history and perform a clinical examination to identify symptoms and signs suggestive of cardiac enlargement or heart failure, such as breathlessness, peripheral oedema, or abnormal heart sounds ¹.
• Chest X-ray: Use chest radiography to assess heart size; cardiomegaly is suggested by an increased cardiothoracic ratio (heart size greater than 50% of the thoracic diameter) on chest X-ray ¹.
• Electrocardiogram (ECG): Perform an ECG to detect abnormalities that may indicate cardiac enlargement or underlying cardiac pathology contributing to cardiomegaly ¹.
• Measurement of N-terminal pro-B-type natriuretic peptide (NT-proBNP): Elevated NT-proBNP levels support the presence of cardiac dysfunction, which may be associated with cardiomegaly ¹.
• Referral for echocardiography: If cardiomegaly is suspected clinically or on chest X-ray, refer for transthoracic echocardiography to confirm cardiac enlargement, assess ventricular size and function, and exclude valve disease or other structural abnormalities ¹,².

In summary, cardiomegaly in primary care is initially suspected based on clinical features and chest X-ray findings, supported by ECG and NT-proBNP testing, and confirmed by echocardiography performed by experienced operators ¹,².