{"id":10283,"date":"2026-04-04T14:23:22","date_gmt":"2026-04-04T14:23:22","guid":{"rendered":"https:\/\/cardiocases.com\/?post_type=ecg_case&p=10283"},"modified":"2026-04-04T14:23:23","modified_gmt":"2026-04-04T14:23:23","slug":"trace-8-15-tachycardie-polymorphe-et-allongement-majeur-de-lintervalle-qt","status":"publish","type":"ecg_case","link":"https:\/\/cardiocases.com\/fr\/ecg_case\/trace-8-15-tachycardie-polymorphe-et-allongement-majeur-de-lintervalle-qt\/","title":{"rendered":"Trac\u00e9 8.15: Tachycardie polymorphe et allongement majeur de l\u2019intervalle qt"},"content":{"rendered":"","protected":false},"featured_media":10511,"template":"","ecg_case_type":[257],"language_ecgcase":[259],"class_list":["post-10283","ecg_case","type-ecg_case","status-publish","has-post-thumbnail","hentry","ecg_case_type-ventricular-tachycardia","language_ecgcase-french"],"acf":{"ecg_case_title":"Trac\u00e9 8.15: Tachycardie polymorphe et allongement majeur de l\u2019intervalle qt","patient_description":"Femme de 73 ans avec myocardiopathie isch\u00e9mique, trait\u00e9e par erythromycine et antihista\u00ad minique dans le cadre d\u2019une pneumopathie communautaire avec diarrh\u00e9es; hospitalisation pour 3 \u00e9pisodes de syncopes s\u00e9v\u00e8res","quiz_question":"Sur cet ECG, on retrouve:","quiz_answer_1":"un rythme de base sinusal","quiz_answer_2":"une pause sur bloc auriculo-ventriculaire","quiz_answer_3":"une pause post-extrasystolique","quiz_answer_4":"une tachycardie ventriculaire polymorphe type torsade de pointes","quiz_answer_5":"une fibrillation atriale sur voie accessoire (syndrome de Wolff Parkinson White)","correct_answer":["A","C","D"],"ecg_image":10511,"ecg_description":"Rythme de base sinusal; aspect de QT \u201cmonstrueux\u201d pouvant d\u00e9passer une seconde; extrasystoles ventriculaires isol\u00e9es ou induisant une salve de tachycardie polymorphe, irr\u00e9guli\u00e8re \u00e0 QRS large avec variations importantes dans l\u2019amplitude et dans la polarit\u00e9 des complexes QRS; r\u00e9duction spontan\u00e9e","ecg_info_box":"Diff\u00e9rentes classes m\u00e9dicamenteuses \u00e0 vis\u00e9e cardiologique (antiarythmiques) ou pas (psychotropes, antibiotiques, antihistaminiques ...) peuvent induire un allongement de l\u2019intervalle QT pouvant favoriser la survenue d\u2019une torsade de pointes.","commentary_ecg":"Cette patiente pr\u00e9sentait des syncopes survenant dans le cadre d\u2019un intervalle QT extr\u00eamement long induit par la coexistence entre une cardiopathie isch\u00e9mique, des chiffres de kali\u00e9mie limites (3.5 \u00e0 l\u2019entr\u00e9e) \u00e0 la suite des diarrh\u00e9es et par une double prise m\u00e9dicamenteuse favorisant l\u2019allongement de l\u2019intervalle QT: un macrolide et un antihistaminique. L\u2019arr\u00eat de ces traitements et une recharge potassique ont permis de corriger cet aspect de QT long et d\u2019\u00e9viter la r\u00e9cidive des torsades de pointes et des syncopes. La liste des m\u00e9dicaments \u00e0 \u00e9viter dans l\u2019avenir car allongeant l\u2019intervalle QT a \u00e9t\u00e9 transmise \u00e0 la patiente et \u00e0 son m\u00e9decin traitant.\r\n\r\nL\u2019allongement iatrog\u00e8ne de l\u2019intervalle QT est connu depuis plusieurs d\u00e9cennies avec la mise en \u00e9vidence de torsades de pointes apr\u00e8s l\u2019introduction d\u2019un traitement par quinidine, un traitement antiarythmique de classe 1 allongeant le potentiel d\u2019action et l\u2019intervalle QT en interf\u00e9rant avec le fonctionnement des canaux potassiques. L\u2019allongement de l\u2019intervalle QT n\u2019est pas uniquement l\u2019apanage des m\u00e9dicaments prescrits \u00e0 vis\u00e9e cardiologique mais peut \u00e9galement \u00eatre observ\u00e9 avec certains psychotropes, antibiotiques, antihistaminiques ... Le risque potentiellement l\u00e9tal des troubles du rythme associ\u00e9s repr\u00e9sente un v\u00e9ritable cauchemar pour l\u2019industrie pharmaceutique et pour les \u00e9quipes m\u00e9dicales, car la survenue d\u2019arythmies est le plus souvent rare voire exceptionnelle mais aux cons\u00e9quences catastrophiques. Un certain nombre de m\u00e9dicaments a \u00e9t\u00e9 retir\u00e9 du march\u00e9 dans ce cadre. La question de la surveillance minimale n\u00e9cessaire est \u00e9galement pos\u00e9e. L\u2019augmentation possible de l\u2019intervalle QT apr\u00e8s introduction d\u2019un traitement par macrolide est connue et associ\u00e9e avec une augmentation modeste mais significative de la survenue d\u2019un trouble du rythme s\u00e9v\u00e8re (1 cas pour 8000 patients) ou d\u2019une mort subite (1 cas tous les 30000 patients). La question de retirer ce traitement du march\u00e9 s\u2019est pos\u00e9e m\u00eame si il faut int\u00e9grer le fait qu\u2019un macrolide est le traitement de premi\u00e8re ligne dans le cadre de certaines pathologies (pneumopathie communautaire, traitement de l\u2019Helicobacter Pylori, l\u00e9gionnelose) et que les alternatives ne sont pas nombreuses et sont \u00e9galement associ\u00e9es \u00e0 certaines limites (effets ind\u00e9sirables, risque de r\u00e9sistance).\r\n\r\nLa question de la surveillance \u00e0 proposer apr\u00e8s l\u2019introduction de ce traitement est pos\u00e9e. La r\u00e9alisation d\u2019un \u00e9lectrocardiogramme syst\u00e9matique chez les patients hospitalis\u00e9s est probablement possible mais non applicable quand l\u2019introduction du traitement est r\u00e9alis\u00e9e au domicile. De plus, l\u2019interpr\u00e9tation du trac\u00e9 et la mise en \u00e9vidence d\u2019un intervalle QT allong\u00e9 peut s\u2019av\u00e9rer difficile (pas chez cette patiente o\u00f9 l\u2019augmentation du QT est \u201cmonstrueuse\u201d). Il est probablement d\u00e9conseill\u00e9 de prescrire en m\u00eame temps 2 m\u00e9dicaments allongeant l\u2019espace QT et il est recommand\u00e9 de v\u00e9rifier l\u2019aspect \u00e9lectrocardiographique chez les patients pr\u00e9sentant 1 ou plusieurs facteurs de risque associ\u00e9s: hypokali\u00e9mie, hypomagn\u00e9s\u00e9mie ...","ecg_info_post_answer":"\"\""},"yoast_head":"\nTrac\u00e9 8.15: Tachycardie polymorphe et allongement majeur de l\u2019intervalle qt - 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-8-15-tachycardie-polymorphe-et-allongement-majeur-de-lintervalle-qt\/\" \/>\n<meta property=\"og:locale\" content=\"fr_FR\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Trac\u00e9 8.15: Tachycardie polymorphe et allongement majeur de l\u2019intervalle qt - Cardiocases\" \/>\n<meta property=\"og:url\" content=\"https:\/\/cardiocases.com\/fr\/ecg_case\/trace-8-15-tachycardie-polymorphe-et-allongement-majeur-de-lintervalle-qt\/\" \/>\n<meta property=\"og:site_name\" content=\"Cardiocases\" \/>\n<meta property=\"article:modified_time\" content=\"2026-04-04T14:23:23+00:00\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/cardiocases.com\/ecg_case\/trace-8-15-tachycardie-polymorphe-et-allongement-majeur-de-lintervalle-qt\/\",\"url\":\"https:\/\/cardiocases.com\/ecg_case\/trace-8-15-tachycardie-polymorphe-et-allongement-majeur-de-lintervalle-qt\/\",\"name\":\"Trac\u00e9 8.15: Tachycardie polymorphe et allongement majeur de l\u2019intervalle qt - 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