The leftward deviation of the electrocardiographic axis and the change of the low voltage T in the chest conduction may be caused by left ventricular hypertrophy, which can be treated by using drugs such as propranolol hydrochloride tablets under the guidance of the doctor, and surgery if necessary. 1. Drug treatment: once the patient has left ventricular hypertrophy, it may lead to chest wall hypertrophy, which may lead to left deviation of the electrocardiographic axis and change of low voltage T in chest conduction. Patients can use propranolol hydrochloride tablets, metoprolol succinate extended-release tablets and other drugs under the guidance of doctors for treatment. 2. Surgery: For patients with cardiac insufficiency, severe outflow tract obstruction and unsatisfactory drug treatment, septal septectomy and other surgical methods can be considered for treatment. Once the patients have leftward deviation of cardiac electrical axis and change of low voltage T in chest conduction, it is recommended to go to the hospital for further examination in time and choose the appropriate treatment according to the actual situation under the guidance of the doctor.