What are the key clinical features that suggest a diagnosis of hypertrophic cardiomyopathy in a young athlete?

Key clinical features suggesting hypertrophic cardiomyopathy (HCM) in a young athlete include:

• Exertional symptoms: Dyspnoea, chest pain, palpitations, or syncope during or immediately after exercise are important red flags indicating possible HCM rather than physiological athlete’s heart NICE CKS Malhotra & Sharma 2017.
• Family history: A family history of HCM or sudden cardiac death in first-degree relatives strongly supports the diagnosis NICE CKS Maron et al. 2020.
• Physical examination findings: A harsh systolic murmur that increases with Valsalva manoeuvre or standing suggests left ventricular outflow tract obstruction typical of HCM NICE CKS Malhotra & Sharma 2017.
• Electrocardiogram (ECG) abnormalities: Marked left ventricular hypertrophy, deep Q waves, T wave inversions, or arrhythmias on ECG are common in HCM and help differentiate it from athlete’s heart NICE CKS Bahlmann et al. 2015.
• Absence of typical athlete’s heart features: Disproportionate hypertrophy (wall thickness ≥15 mm), especially if asymmetric, and lack of regression with detraining favour HCM NICE CKS Bahlmann et al. 2015.
• Sudden cardiac arrest or unexplained syncope: These are critical clinical features that raise suspicion for HCM and warrant urgent evaluation NICE CKS Maron et al. 2020.

In summary, a young athlete presenting with exertional symptoms, a positive family history, characteristic murmur, abnormal ECG, and disproportionate hypertrophy should be evaluated for HCM to prevent adverse outcomes including sudden cardiac death NICE CKS Malhotra & Sharma 2017Maron et al. 2020Bahlmann et al. 2015.