ECG stress test is a standard method of non-invasive diagnosis of ischemic heart disease. Its results also allow to estimate the overall performance of the patient's circulatory system. The stress test consists of recording the ECG when the patient performs a physical exercise of increasing intensity. For this purpose, a treadmill or a cycle ergometer is used in our hospital. The entire examination usually lasts several minutes and ends when the test protocol is fulfilled, or earlier if the patient expresses such a wish to the physician conducting the examination.