Reported here are 162 cases of atrial ectopic tachycardia, a specific type of the supraventricular arrhythmia, which is characterized by the distinct P waves on the ECG, which follow at the rate of 400 and more per minute. Although atrial ectopic tachycardia is similar to the supraventricular paroxysmal tachycardia and atrial flutter, it differs from them by the mechanism of the development. Atrial ectopic tachycardia is caused by the failure or weakening the sinus node and the appearance of the ectopic focus in the atria. Such arrhythmia occurs in the following 4 types: with atrial to ventricular excitation ratio 1:1; with incomplete atrio-ventricular block; with complete atrioventricular block; and in combination with atrial fibrillation. Atrial ectopic tachycardia often takes lingering course and is hardly responsive to the medical treatment. The cases of arrhythmia, characterized by the broad P waves on the ECG tend to the progressive course. 17 cases of atrial ectopic tachycardia treated by electrostimulation (ES) which had 100% positive effect are presented and ES advantages over the drug therapy are underlined. The frequent transition of this arrhythmia into the atrial fibrillation is outlined.