Diagnosis

When to suspect HCM

HCM should be suspected in a patient who presents with nonspecific but limiting cardiac symptoms. It should also be considered in individuals with a history of a previous cardiac event or a family history of HCM. Additionally, the presence of a heart murmur or abnormalities on an ECG may raise suspicion of HCM and warrant further evaluation³³.

Symptoms & potential indicators

Suspicion of HCM can be raised based on clinical symptoms, family history, abnormalities detected on an electrocardiogram, or findings from a routine medical examination³⁴.

Symptoms

HCM is a heart condition with highly variable manifestations, including morphological, functional, and clinical characteristics. This means that patients may present with a wide range of symptoms, from mild discomfort to more severe manifestations.

Symptoms may appear as one or more of the following^35-36:

Parents with HCM or a history of sudden/unexpected death.
Reviewing the family history over three to four generations can help identify HCM and family members who may be at risk¹².

Abnormal ECG findings are observed in approximately 90–96% of patients with HCM, and no specific ECG pattern is pathognomonic^37-38.
Common abnormalities include³⁹:
- ST-T wave changes
- Wide R waves (V5 and V6)
- Pathological Q waves
- Repolarization changes (strain pattern)
- Deep S waves (V1 and V2)
- P wave abnormalities
- Increased QRS voltages
- Deep T-wave inversion

Patients with classic HCM may present with a systolic ejection murmur, a prominent apical impulse, an abnormal carotid pulse, and a fourth heart sound³⁴. The murmur is best heard over the lower left sternal border and becomes louder with manoeuvres that decrease preload (e.g., Valsalva or standing from the squatting position)⁴⁰.

First-line tests

HCM is characterized by left ventricular hypertrophy (LVH) that cannot be explained by another cardiac, systemic, or metabolic disease³⁴. Echocardiography is the fundamental imaging modality for most patients³⁴.

Journal of the American Collega of Cardiology, Vol 54, Issue 3, Bos JM et al, Diagnostic, Prognostic, and Therapeutic Implications of Genetic Testing for Hypertrophic Cardiomyopathy, pages 201-2011, Copyright 2009, with permission of Elsevier

2D echocardiography is used to characterize all walls of the left ventricle.

Wall thickness should be evaluated in all segments of the LV, from base to apex⁴¹.
2D echocardiography is particularly useful because LVH is often asymmetric or confined to the apex⁴².

Parasternal Short-Axis View (PSAX)

The PSAX view, with orthogonal beam alignment, provides the most accurate measurement as it avoids oblique orientation, which can lead to overestimation of wall thickness⁴³.

Parasternal Long-Axis View (PLAX)

The PLAX view is useful for examining the apex and, if needed, the right ventricle^44-12.

LVH can also be measured with M-mode echocardiography, although it is limited because it only assesses the basal segments of the interventricular septum and posterior wall⁴¹.
Features to look for on M-mode suggestive of HCM⁴⁵:
- Asymmetric septal hypertrophy
- Systolic anterior motion (SAM) of the mitral valve
- Small LV cavity
- Septal immobility
- Premature aortic valve closure

Advanced imaging

In some cases, HCM can cause left ventricular outflow tract (LVOT) obstruction due to narrowing of the LVOT³⁴. This may lead to elevated intracavitary pressures, mitral regurgitation, myocardial ischemia, and other abnormalities³⁴.

Imaging approaches to determine LVOT obstruction

2D echocardiography or Doppler echocardiography can help determine the cause and severity of left ventricular outflow tract (LVOT) obstruction¹².

Measurement of late systolic peak velocity⁴⁶.
Measurement of the maximal instantaneous gradient derived from peak velocity^44-47.

Special cases of LVOT obstruction

Mid-ventricular obstruction occurs in approximately 10% of patients with HCM⁴⁸.
Can occur in ventricles with hyperdynamic function and/or concentric hypertrophy⁴⁴.
Usually observed in older patients with a sigmoid septum⁴⁴.

Alternative imaging

When transthoracic echocardiography (TTE) is inadequate, consider transoesophageal echocardiography (TOE) or cardiac magnetic resonance imaging (CMR). In symptomatic patients with inconclusive noninvasive imaging, left and right heart catheterisation may be considered to assess LVOT gradient and filling pressures⁴⁹.

Doppler Mode Selection

The choice of Doppler mode depends on the imaging objective⁴⁴:

Site of obstruction: Pulsed-wave Doppler (PW)
Degree of obstruction: Continuous-wave Doppler (CW)

Provocative testing to detect LVOT obstruction

Detection and quantification of LVOT obstruction should be performed both at rest and with provocation, using manoeuvres such as the Valsalva manoeuvre or standing up from a squatting position^34-46.
This is particularly important for patients whose LVOT gradient at rest or under standard echocardiographic provocation is <50 mmHg³⁴.
Patients with low resting gradients (<30 mmHg) may demonstrate obstructive gradients with provocation; those with modest resting gradients (30–49 mmHg) can develop significant gradients (≥50 mmHg) during exercise^50-51-52-53.

Provocation based on Resting Gradient

Many patients with HCM do not demonstrate LVOT obstruction at rest; therefore, provocation is recommended when the resting gradient is <50 mmHg.

External resources

Consult the external clinical guidelines below for additional references¹².

Clinical diagnosis flowchart

This flowchart illustrates the key steps in evaluating and diagnosing cardiomyopathies, including symptom assessment, family history, physical examination, ECG, imaging, and further testing when needed¹².

Patient testimonials

HCM can affect daily life in many ways, both physically and emotionally. Patient stories offer a unique perspective on living with HCM, illustrating the challenges, adaptations, and strategies people use to manage their condition.

Next step: Treatment options

Learn more about the role of cardiac myosin inhibition
within today’s therapeutic landscape for HCM.

Discover page >

Imaging modules

Learn how to apply imaging techniques to identify
and assess HCM in clinical practice.