{"id":11150,"date":"2026-07-02T09:19:02","date_gmt":"2026-07-02T09:19:02","guid":{"rendered":"https:\/\/cardiocases.com\/?post_type=ecg_case&#038;p=11150"},"modified":"2026-07-02T11:32:11","modified_gmt":"2026-07-02T11:32:11","slug":"trace-4-9-pacemaker-mediated-tachycardia","status":"publish","type":"ecg_case","link":"https:\/\/cardiocases.com\/fr\/ecg_case\/trace-4-9-pacemaker-mediated-tachycardia\/","title":{"rendered":"Trace 4.9: Pacemaker mediated tachycardia"},"content":{"rendered":"","protected":false},"featured_media":9674,"template":"","ecg_case_type":[253],"language_ecgcase":[258],"class_list":["post-11150","ecg_case","type-ecg_case","status-publish","has-post-thumbnail","hentry","ecg_case_type-cardiac-pacing","language_ecgcase-english"],"acf":{"ecg_case_title":"Trace 4.9: Pacemaker mediated tachycardia","patient_description":"A 79-year-old man with a Medtronic dual-chamber pacemaker implanted for complete atrioventricular block; 3 days after discharge, he presented to the emergency department with palpitations; this ECG was recorded; programmed in DDD mode","quiz_question":"Regarding this ECG, which of the following is\/are the correct answer(s)?","quiz_answer_1":"The QRS complexes are spontaneous","quiz_answer_2":"The QRS complexes are paced","quiz_answer_3":"This is a ventricular tachycardia","quiz_answer_4":"This is a atrial 2:1 flutter","quiz_answer_5":"This could be a pacemaker mediated tachycardia","correct_answer":["B","E"],"ecg_image":11123,"ecg_description":"Wide-QRS tachycardia; a careful analysis of the ECG trace reveals a low-amplitude pacing artifact in leads V3 through V5; this is therefore an electrically driven tachycardia (ventricular pacing); several possibilities can be considered: supraventricular arrhythmia monitored at its maximum rate, reentrant tachycardia, or sinus tachycardia; Atrial activity is difficult to identify, making it hard to refine the diagnosis;","ecg_info_box":"The electrocardiographic diagnosis of electrical reentry tachycardia is based on the detection of tachycardia with ventricular pacing (wide QRS complex with a pacing artifact) and retrograde atrial conduction (negative P\u2019 waves in the inferior leads). This diagnosis can sometimes be difficult (due to artifacts and P\u2019 waves that are hard to identify), but it must always be considered in the presence of a regular, wide-QRS tachycardia in a patient with an implanted device. ","commentary_ecg":"Pacemaker mediated tachycardia (PMT) is the term used to describe an electrically driven tachycardia that most often occurs at the maximum pacing rate, with repeated sequences of ventricular pacing followed by retrograde atrial conduction. The initiation of a PMT results from the detection, outside refractory periods, of a retrograde P\u2019 wave, which triggers an AV delay\u2014often prolonged\u2014that in turn promotes retrograde conduction following ventricular pacing. A PMT is therefore a repetitive sequence in which the pacemaker responds to each retrograde P\u2019 wave by pacing the ventricle at a high rate, which in turn generates a retrograde P\u2019 wave. The cycle thus repeats indefinitely unless a retrograde block occurs or a specific pacemaker algorithm intervenes. \r\n\r\nThe presence of retrograde conduction is therefore an essential prerequisite for initiating and maintaining a PMT. Retrograde conduction is present in an average of 40% of patients receiving pacing at rest, across all indications. It is much more common in patients implanted for sinus node dysfunction than for atrioventricular block. These figures are high enough to warrant the systematic programming of effective protection. In addition to the presence of retrograde conduction, initiating a PMT requires programming an atrial pacing mode (DDD or VDD) and results in a temporary or permanent loss of atrioventricular synchronization. Indeed, if ventricular activity is properly synchronized with that of the atrium, retrograde conduction is blocked. The following events can promote temporary atrioventricular dissociation, retrograde conduction, and the triggering of a PMT: a ventricular extrasystole (the most common cause), an atrial premature beat with prolongation of the AV delay to maintain the programmed maximum heart rate, a programmed AV delay that is too long (the atrioventricular bundle has emerged from its refractory period at the time of ventricular pacing), external interference or myopotentials detected by the atrial lead, a failure in atrial detection or pacing...\r\n\r\nEarly pacemakers were not protected against this type of runaway activity, and tachycardia could persist indefinitely, causing symptoms that were sometimes highly debilitating. Prolonged PMT can indeed be difficult to tolerate, with symptoms ranging from a simple feeling of discomfort or palpitations to cardiac decompensation in patients with underlying heart disease.","ecg_info_post_answer":"<img class=\"alignnone wp-image-10422 size-full\" src=\"https:\/\/cardiocases.com\/wp-content\/uploads\/2026\/04\/trace-4-9-ecg2.png\" alt=\"\" width=\"864\" height=\"766\" \/>\r\n\r\n<strong>Trace description\u00a0<\/strong>\r\n\r\nAnalysis of the EGM confirms the diagnosis of electrical reentry tachycardia: an uninterrupted sequence of VP-AS cycles (ventricular pacing, atrial sensing) with a prolonged AV delay to ensure that the maximum tracking rate is not exceeded;"},"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.0 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Trace 4.9: Pacemaker mediated tachycardia - Cardiocases<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/cardiocases.com\/fr\/ecg_case\/trace-4-9-pacemaker-mediated-tachycardia\/\" \/>\n<meta property=\"og:locale\" content=\"fr_FR\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Trace 4.9: Pacemaker mediated tachycardia - Cardiocases\" \/>\n<meta property=\"og:url\" content=\"https:\/\/cardiocases.com\/fr\/ecg_case\/trace-4-9-pacemaker-mediated-tachycardia\/\" \/>\n<meta property=\"og:site_name\" content=\"Cardiocases\" \/>\n<meta property=\"article:modified_time\" content=\"2026-07-02T11:32:11+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/cardiocases.com\/wp-content\/uploads\/2026\/03\/trace-4-9-ecg.png\" \/>\n\t<meta property=\"og:image:width\" content=\"1\" \/>\n\t<meta property=\"og:image:height\" content=\"1\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/png\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Dur\u00e9e de lecture estim\u00e9e\" \/>\n\t<meta name=\"twitter:data1\" content=\"1 minute\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/cardiocases.com\\\/ecg_case\\\/trace-4-9-pacemaker-mediated-tachycardia\\\/\",\"url\":\"https:\\\/\\\/cardiocases.com\\\/ecg_case\\\/trace-4-9-pacemaker-mediated-tachycardia\\\/\",\"name\":\"Trace 4.9: Pacemaker mediated tachycardia - Cardiocases\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/cardiocases.com\\\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\\\/\\\/cardiocases.com\\\/ecg_case\\\/trace-4-9-pacemaker-mediated-tachycardia\\\/#primaryimage\"},\"image\":{\"@id\":\"https:\\\/\\\/cardiocases.com\\\/ecg_case\\\/trace-4-9-pacemaker-mediated-tachycardia\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/cardiocases.com\\\/wp-content\\\/uploads\\\/2026\\\/03\\\/trace-4-9-ecg.png\",\"datePublished\":\"2026-07-02T09:19:02+00:00\",\"dateModified\":\"2026-07-02T11:32:11+00:00\",\"breadcrumb\":{\"@id\":\"https:\\\/\\\/cardiocases.com\\\/ecg_case\\\/trace-4-9-pacemaker-mediated-tachycardia\\\/#breadcrumb\"},\"inLanguage\":\"fr-FR\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/cardiocases.com\\\/ecg_case\\\/trace-4-9-pacemaker-mediated-tachycardia\\\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"fr-FR\",\"@id\":\"https:\\\/\\\/cardiocases.com\\\/ecg_case\\\/trace-4-9-pacemaker-mediated-tachycardia\\\/#primaryimage\",\"url\":\"https:\\\/\\\/cardiocases.com\\\/wp-content\\\/uploads\\\/2026\\\/03\\\/trace-4-9-ecg.png\",\"contentUrl\":\"https:\\\/\\\/cardiocases.com\\\/wp-content\\\/uploads\\\/2026\\\/03\\\/trace-4-9-ecg.png\"},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/cardiocases.com\\\/ecg_case\\\/trace-4-9-pacemaker-mediated-tachycardia\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/cardiocases.com\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Trace 4.9: Pacemaker mediated tachycardia\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/cardiocases.com\\\/#website\",\"url\":\"https:\\\/\\\/cardiocases.com\\\/\",\"name\":\"Cardiocases\",\"description\":\"Real cardiac device traces, pacemaker &amp; 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