Electrocardiogram (ECG) is a record of electrical activity of the heart. PQRST waves represent
the electrical activities of atria and ventricles. A complete three-dimensional electrical activity is
possible to be recorded using a 12-lead ECG. The normal and different routinely-met clinical ECG
are elaborated and discussed. This routine, normal and abnormal ECG, like arrhythmias and heart
block records as well as their clinical notes shall be educational information for the medical students.