{"id":2904,"date":"2009-09-07T16:03:25","date_gmt":"2009-09-07T16:03:25","guid":{"rendered":"http:\/\/cardiophile.org\/?p=2904"},"modified":"2023-12-10T07:21:08","modified_gmt":"2023-12-10T01:51:08","slug":"pacemaker-tips-2","status":"publish","type":"post","link":"https:\/\/johnsonfrancis.org\/professional\/pacemaker-tips-2\/","title":{"rendered":"Pacemaker terminology"},"content":{"rendered":"<p><iframe loading=\"lazy\" width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/d3_Hu9hpRtA?si=tSYCZE0KtrO7L3-F\" title=\"YouTube video player\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" allowfullscreen><\/iframe><\/p>\n<h2><span style=\"color: #008000;\">Pacemaker terminology<\/span><\/h2>\n<p><strong>Rheobase<\/strong>: Minimum voltage which will capture the myocardium at any pulse width.<br \/>\n<strong>Chronaxie<\/strong>: Pulse width needed for capture at twice the rheobase voltage<br \/>\n<strong>Electrogram<\/strong> (EGM; egram): Intracardiac signal picked up by the intracardiac electrode<br \/>\n<strong>Slew rate<\/strong>: Slope of the electrogram<br \/>\n<strong>Current of injury<\/strong>: ST elevation occurring in the ECG monitored from the electrode tip as the lead makes contact with the myocardium<\/p>\n<p><strong>Pacemaker blanking period<\/strong>: To prevent damage to the sensing circuit by the pacing spike, the sensing circuit is turned off for a short period immediately after the spike is delivered.<\/p>\n<p><strong>Refractory period<\/strong> is the period after the blanking period during which a sensed event does not reset the lower rate interval. But an event sensed in this period will extend the ventricular refractory period. A signal sensed during the refractory period is designated Vr and a signal sensed beyond the refractory period is designated Vs.<\/p>\n<p><strong>Noise mode response<\/strong>: Sensing multiple noise signals causes reversion to interference mode and pacing will occur in asynchronous mode. This prevents asystole due to oversensing.<br \/>\nT wave oversensing need not be associated with tall T wave on surface ECG. But the T wave of the EGM will be sufficient for resetting the lower rate interval \u2013 both QRS and T wave will be designated as Vs in the report.<\/p>\n<p>Sensed AV interval is always kept lower than the paced AV interval because the P wave is sensed only later due to the low slew rate of the P wave.<\/p>\n<p>Atrial based versus ventricular based DDD pacemakers: In atrial based pacemakers, AA interval is constant while VA interval is constant for ventricular based pacemakers.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Pacemaker tips 2<\/p>\n","protected":false},"author":1,"featured_media":38646,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"nf_dc_page":"","footnotes":""},"categories":[6],"tags":[758,2572,2744,3265,3331,3613],"class_list":["post-2904","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-ecg-electrophysiology","tag-chronaxie","tag-noise-mode-response","tag-pacemaker-blanking-period","tag-refractory-period","tag-rheobase","tag-slew-rate"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.9 - 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