The 24-hour heart monitoring method, also known as Holter, is a test that allows the patient to carry a small box the size of a cell phone with him or her and to move around without restricting normal activities, just to maintain a normal life. It is recommended not to sit or lie down all the time, but to do appropriate stair climbing or brisk walking, which can help induce the appearance of tachycardia or arrhythmia. It is only then that the presence of ECG abnormalities can be evaluated in case of panic, palpitations, chest tightness or discomfort in the precordial region. It is recommended not to play with the cell phone while having this ECG because it may interfere with the ECG waveform, and it is also recommended not to perform cardiac ultrasound or C T or MRI tests.