From the Guidelines
Hypertrophic cardiomyopathy (HCM) is characterized by unexplained left ventricular (LV) hypertrophy associated with nondilated ventricular chambers, and its diagnosis is often recognized by a maximal LV wall thickness of 15 mm or more, as stated in the 2011 ACCF/AHA guideline 1. The signs and symptoms of HCM can vary widely among patients, but common presentations include:
- Shortness of breath, especially during physical activity
- Chest pain
- Fatigue
- Palpitations
- Lightheadedness
- Fainting episodes (syncope), particularly during or immediately after exercise Physical examination may reveal a harsh systolic murmur that intensifies with Valsalva maneuver or when standing from a squatting position, an abnormal S4 heart sound, or a displaced point of maximal impulse. Diagnostic findings include left ventricular hypertrophy on electrocardiogram (ECG), often with ST-segment and T-wave abnormalities, and asymmetric septal hypertrophy on echocardiogram with a septal thickness exceeding 15mm, as noted in the 2011 ACCF/AHA guideline 1. Some patients develop left ventricular outflow tract obstruction, causing symptoms to worsen, and family history is important as HCM is often genetic with an autosomal dominant inheritance pattern, as discussed in the American College of Cardiology/European Society of Cardiology clinical expert consensus document on hypertrophic cardiomyopathy 1. Sudden cardiac death may be the first manifestation in some cases, especially in young athletes, making early detection crucial, and regular cardiac screening is recommended for first-degree relatives of affected individuals, as emphasized in the 2011 ACCF/AHA guideline 1.
From the Research
Signs of Hypertrophic Cardiomyopathy
The signs of hypertrophic cardiomyopathy (HCM) can be identified through various diagnostic methods, including electrocardiogram (ECG) and echocardiogram. Some key signs and features of HCM include:
- Abnormal ECG results, which may be the only manifestation of the disease at an early stage 2
- Pathological Q-waves, deep S-waves in V1-V3, or high R-waves in V4-V6 due to left ventricular hypertrophy with T-wave (TW) depression or negative TWs 3
- Negative giant TWs, often found in apical HCM 3
- Non-specific ST-T changes with diphasic or flat TWs 3
- Isolated inverted TW in lateral leads (usually aVL) 3
- Left ventricular outflow tract (LVOT) gradient, which can be significant in some cases 4
- Left atrial enlargement, which carries a significant risk of thromboembolism 4
- Atrial fibrillation (AF), which can also increase the risk of thromboembolism 4
Diagnostic Methods
Diagnostic methods for HCM include:
- ECG, which is an essential tool for evaluating patients with HCM 2, 5, 3
- Echocardiogram, which plays a crucial role in the assessment of patients with HCM, including diagnosis, screening, management formulation, prognosis, and follow-up 6
- Genetic testing, which should be considered in high-risk mutations where there are diagnostic uncertainties 4
- Cardiac magnetic resonance imaging (CMR), which can be used to confirm HCM diagnosis 5
Risk Factors
Risk factors for sudden death in patients with HCM include: