Table 3.

ECG features of HCM.

ECG abnormalities in HCM
•Presence of deep S waves in V1 and V2 and large R waves in V5 and V6 strain repolarization changes are common findings (Fig. 2A).
•Pathological Q waves in the inferior and lateral leads with ≥ 40 ms duration and ≥ 3 mm depth suggest LV asymmetric septal hypertrophy. Lateral Q waves are more common than inferior Q waves in HCM. Occur in 20 to 50% of patients and are attributed to septal hypertrophy.
•P-wave abnormalities related to left atrial overload (duration > 120 ms, notch P-wave mitrale, Morris index) can be observed.
•Pre-excitation syndrome is observed in a glycogen-storage disease produced by LAMP2 or PRKAG2 mutations or Anderson-Fabry disease.
•Atrial fibrillation and supraventricular tachycardias are common. Ventricular dysrhythmias (e.g. VT) also occur and may be a cause of sudden death.
Apical HCM
•Giant negative T waves in precordial leads suggest HCM of the LV apex, initially described in Japan and called Yamagushi (Fig. 2B).