413. What does oversensing look like on ECG? / What is runaway pacemaker and endless loop tachycardia? / What therapy may interrupt pacemaker-mediated tachycardia? July 11th, 2008 by reuben in pacemaker Back Top Tags: card 412. What is exit block and what are its causes? / Most common cause of undersensing / What does undersensing look like on ECG? 414. Pain in arm ipsilateral to pacemaker insertion suggests / Defibrillation with pacemaker in situ? / Why failure to capture post-defibrillation? Leave a Reply Cancel reply Please post any discussion to the emupdates Reddit page.