1. Arrhythmia 2. Ventricular and atrial hypertrophy 3. Myocardial ischemia, myocardial infarction

Arrhythmia refers to the rhythm, frequency, origin, conduction velocity and activation sequence of cardiac impulses There are many types of abnormalities.

If the shape, duration, and amplitude of each waveform of the electrocardiogram exceed the normal range, it is an abnormality of the electrocardiogram.