**3.6 Echo-doppler studies**

Echocardiogram is the most useful test in the diagnosis of this condition. It demonstrates LV hypertrophy (**Figure 1**), asymmetric septal hypertrophy (**Figures 1** and **2**),

### **Figure 1.**

*A. Parasternal long (A) and short (B) axis views of the left ventricle (LV) illustrating LV hypertrophy and strikingly thickened inter-ventricular septum (IVS). Ao, aorta; LVPW, LV posterior wall; RV, right ventricle. (reproduced from reference [10]).*

#### **Figure 2.**

*Parasternal short (left) and long (right) axis views of the left ventricle (LV) illustrating distinctly thickened interventricular septum (arrows in both images). Ao, aorta; LA, left atrium.*

and SAM of the mitral valve (**Figure 3**). The LV cavity is completely obliterated in systole (**Figure 4**). Doppler studies will detect abnormal mitral inflow Doppler patterns and mitral insufficiency and help to quantify LV outflow tract obstruction (**Figures 5** and **6**).

#### **Figure 3.**

*Parasternal echocardiographic long axis views of the left ventricle (LV) and mitral valve illustrating systolic anterior motion (SAM) of the mitral valve (thick arrows in both 'A' and 'B'). Note thickened inter-ventricular septum (thin arrows), particularly noticeable in 'B'. Ao, aorta; LA, left atrium; RV, right ventricle.*

#### **Figure 4.**

*Parasternal long-axis views of the left ventricle (LV) of a child with hypertrophic cardiomyopathy demonstrating total obliteration of the cavity of the LV (right image) in systole (arrows).*

#### **Figure 5.**

*A. Parasternal long axis 2D and color doppler recording showing turbulent flow (TF) in the left ventricular (LV) outflow tract. B. Continuous-wave doppler indicates a gradient of 39 mmHg (the insert in B). The triangular pattern of the doppler recording is suggestive of subaortic narrowing. Ao, aorta. (reproduced from reference [10]).*

Localized, atypical hypertrophy patterns as demonstrated in **Figures 7**–**9** may also be detected.

### **3.7 Differentiation from athlete's heart**

Some athletes develop LV hypertrophy and differentiation of this LV hypertrophy from that seen with HCM maybe not easy. Criteria that help differentiate these conditions [7] are listed in **Table 1**.
