**3.5 Chest X-ray and electrocardiogram (ECG)**

Chest X-ray is of limited value; the size of the heart may be normal or cardiomegaly may be present. The size of the heart may be normal even with marked LV hypertrophy. ECG is abnormal in 90% of patients; bizarre patterns are seen, but none are characteristic of HCM. Most commonly, increased LV voltages (deep S waves in V1 and V2 and tall R wave in V5 and V6) are detected. T wave inversion, deep q waves, and enlargement of the left atrium may be identified on the ECG in some patients. Unfortunately, the ECG pattern does not discriminate between obstructive and non-obstructive types or those at risk for sudden death. However, Holter monitoring is likely to detect arrhythmia [8, 9] and may help prognosticate [9].
