Focusing on the most common left ventricular high voltage in the ECG, high voltage in the thoracic leads is a normal phenomenon if you are an athlete or a relatively thin young person. If for normal people, staying up late, drinking heavily, or having insomnia or exertion, the phenomenon of high ECG voltage may also occur, and the high voltage may disappear after a few days of rest. It is also important to note that left ventricular hypertrophy, which is mainly related to hypertension, is more common in middle-aged and elderly people, and usually occurs when the blood pressure is high for several years, or even high for more than a decade, and poorly controlled, and even some people show conduction block, especially left bundle branch conduction block. Therefore, in the diagnosis of left ventricular hypertrophy, the heart ultrasound mainly prevails, and the electrocardiogram only provides certain clues. There is no absolute standard value of voltage for diagnosing left ventricular hypertrophy in chest and limb leads, so the sensitivity and specificity of ECG examination for diagnosing left ventricular hypertrophy has certain defects.