Which investigations are recommended for confirming a diagnosis of arrhythmogenic cardiomyopathy in primary care?

In primary care, confirming a diagnosis of arrhythmogenic cardiomyopathy (ACM) begins with a thorough clinical assessment including history and examination, focusing on symptoms such as palpitations, syncope, or family history of sudden cardiac death under 40 years. Initial investigations should include a resting 12-lead electrocardiogram (ECG) to detect abnormalities suggestive of ACM, such as ventricular arrhythmias or conduction disturbances. If ACM is suspected based on clinical features or ECG findings, urgent referral to cardiology is recommended for further evaluation ¹.

Primary care should arrange blood tests to exclude other causes of palpitations or cardiac symptoms, including full blood count, urea and electrolytes, thyroid function tests, liver function tests, and HbA1c ¹.

An echocardiogram should be requested if structural heart disease is suspected clinically or on ECG, as it can identify right ventricular morphological abnormalities consistent with ACM ¹. However, echocardiography in primary care may have limited sensitivity for early ACM changes, so specialist imaging such as cardiac MRI is usually required after referral ¹.

Ambulatory ECG monitoring (e.g., Holter monitor) may be used in primary care to document arrhythmias if symptoms are frequent, but the diagnosis of ACM requires specialist assessment including advanced imaging and genetic testing ¹.

Recent literature emphasizes the genetic basis of ACM and the importance of identifying pathogenic mutations, which is beyond the scope of primary care but critical for confirming diagnosis and family screening (Karmouch et al., 2018). Morphological disarrangement of the right ventricle, a hallmark of ACM, is best characterized by cardiac MRI, which is not routinely available in primary care but is essential in specialist cardiology evaluation (Avagimyan et al., 2022).

In summary, primary care investigations to support suspicion of arrhythmogenic cardiomyopathy include:

• Detailed clinical history and examination focusing on arrhythmic symptoms and family history ¹
• Resting 12-lead ECG to detect arrhythmias or conduction abnormalities ¹
• Blood tests to exclude other causes of symptoms ¹
• Echocardiogram if structural heart disease is suspected ¹
• Ambulatory ECG monitoring if arrhythmias are frequent ¹
• Urgent referral to cardiology for advanced imaging (cardiac MRI) and genetic testing to confirm diagnosis (Karmouch et al., 2018; Avagimyan et al., 2022)