室性早搏落在前一个心动周期的T波上,称R onT现象。因为T波是心室肌的复极波,业已证明T波顶峰前30毫秒是心室肌易颤期。在急性心肌梗塞、洋地黄中毒、Q—T间延长等条件下,R on T易于促发室性心动过速或心室纤颤。动物试验与临床实际都证明了这一点,因此R on T已为临床医生所重视。然而R on P Premature ventricular contractions fall on the T wave of the previous cardiac cycle, said R onT phenomenon. Because T wave is a complex polar wave of ventricular muscle, it has been demonstrated that the first 30 ms of T wave peak is a ventricular myxoid. In acute myocardial infarction, digitalis poisoning, prolongation of Q-T and other conditions, R on T is prone to trigger ventricular tachycardia or ventricular fibrillation. This has been proven both in animal experiments and in clinical practice, so R on T has been given the attention of clinicians. However R on P