{"id":11936,"date":"2025-06-17T00:51:08","date_gmt":"2025-06-16T22:51:08","guid":{"rendered":"https:\/\/valintermed.com\/?p=11936"},"modified":"2025-06-17T00:51:08","modified_gmt":"2025-06-16T22:51:08","slug":"sindrom-udlinennogo-intervala-qt-1","status":"publish","type":"post","link":"https:\/\/valintermed.com\/en\/medlibrary\/long-qt-interval-syndrome-1\/","title":{"rendered":"Long QT syndrome 1"},"content":{"rendered":"<div class=\"fpm_start\"><\/div>\n<p>Long QT syndrome is a hereditary or acquired cardiovascular disease characterized by impaired ventricular repolarization. The pathology manifests itself as an extension of the QT interval on the electrocardiogram (ECG), which creates the preconditions for the development of potentially life-threatening arrhythmias, such as polymorphic ventricular tachycardia of the &quot;pirouette&quot; type and sudden cardiac death. According to the study by Schwartz et al. (2009), cases where the QT interval exceeds 500 ms are especially dangerous, increasing the risk of developing malignant arrhythmias by 10 times compared to normal values.<\/p>\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_86 counter-flat ez-toc-counter ez-toc-light-blue ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Content<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 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href=\"https:\/\/valintermed.com\/en\/medlibrary\/long-qt-interval-syndrome-1\/#%D0%98%D1%81%D1%82%D0%BE%D1%80%D0%B8%D1%8F_%D0%B7%D0%B0%D0%B1%D0%BE%D0%BB%D0%B5%D0%B2%D0%B0%D0%BD%D0%B8%D1%8F_%D0%B8_%D0%B8%D0%BD%D1%82%D0%B5%D1%80%D0%B5%D1%81%D0%BD%D1%8B%D0%B5_%D0%B8%D1%81%D1%82%D0%BE%D1%80%D0%B8%D1%87%D0%B5%D1%81%D0%BA%D0%B8%D0%B5_%D1%84%D0%B0%D0%BA%D1%82%D1%8B\" >History of the disease and interesting historical facts<\/a><\/li><li class='ez-toc-page-1'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/valintermed.com\/en\/medlibrary\/long-qt-interval-syndrome-1\/#%D0%AD%D0%BF%D0%B8%D0%B4%D0%B5%D0%BC%D0%B8%D0%BE%D0%BB%D0%BE%D0%B3%D0%B8%D1%8F_%D1%81%D1%82%D0%B0%D1%82%D0%B8%D1%81%D1%82%D0%B8%D0%BA%D0%B0_%D0%B2%D0%BE%D0%B7%D0%BD%D0%B8%D0%BA%D0%BD%D0%BE%D0%B2%D0%B5%D0%BD%D0%B8%D1%8F_%D0%B7%D0%B0%D0%B1%D0%BE%D0%BB%D0%B5%D0%B2%D0%B0%D0%BD%D0%B8%D1%8F\" >Epidemiology (statistics of disease occurrence)<\/a><\/li><li class='ez-toc-page-1'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/valintermed.com\/en\/medlibrary\/long-qt-interval-syndrome-1\/#%D0%93%D0%B5%D0%BD%D0%B5%D1%82%D0%B8%D1%87%D0%B5%D1%81%D0%BA%D0%B0%D1%8F_%D0%BF%D1%80%D0%B5%D0%B4%D1%80%D0%B0%D1%81%D0%BF%D0%BE%D0%BB%D0%BE%D0%B6%D0%B5%D0%BD%D0%BD%D0%BE%D1%81%D1%82%D1%8C_%D0%BA_%D0%B4%D0%B0%D0%BD%D0%BD%D0%BE%D0%BC%D1%83_%D0%B7%D0%B0%D0%B1%D0%BE%D0%BB%D0%B5%D0%B2%D0%B0%D0%BD%D0%B8%D1%8E_%D0%B2%D0%BE%D0%B2%D0%BB%D0%B5%D1%87%D1%91%D0%BD%D0%BD%D1%8B%D0%B5_%D0%B3%D0%B5%D0%BD%D1%8B_%D0%B8_%D0%BC%D1%83%D1%82%D0%B0%D1%86%D0%B8%D0%B8\" >Genetic predisposition to the disease (involved genes and mutations)<\/a><\/li><li class='ez-toc-page-1'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/valintermed.com\/en\/medlibrary\/long-qt-interval-syndrome-1\/#%D0%A4%D0%B0%D0%BA%D1%82%D0%BE%D1%80%D1%8B_%D1%80%D0%B8%D1%81%D0%BA%D0%B0_%D0%B2%D0%BE%D0%B7%D0%BD%D0%B8%D0%BA%D0%BD%D0%BE%D0%B2%D0%B5%D0%BD%D0%B8%D1%8F_%D0%B4%D0%B0%D0%BD%D0%BD%D0%BE%D0%B3%D0%BE_%D0%B7%D0%B0%D0%B1%D0%BE%D0%BB%D0%B5%D0%B2%D0%B0%D0%BD%D0%B8%D1%8F_%D1%84%D0%B8%D0%B7%D0%B8%D1%87%D0%B5%D1%81%D0%BA%D0%B8%D0%B5_%D0%B8_%D1%85%D0%B8%D0%BC%D0%B8%D1%87%D0%B5%D1%81%D0%BA%D0%B8%D0%B5_%D1%84%D0%B0%D0%BA%D1%82%D0%BE%D1%80%D1%8B_%D1%80%D0%B8%D1%81%D0%BA%D0%B0_%D0%B4%D1%80%D1%83%D0%B3%D0%B8%D0%B5_%D0%B2%D0%BE%D0%B7%D0%BC%D0%BE%D0%B6%D0%BD%D1%8B%D0%B5_%D1%81%D0%B2%D1%8F%D0%B7%D0%B0%D0%BD%D0%BD%D1%8B%D0%B5_%D1%81_%D0%B4%D0%B0%D0%BD%D0%BD%D1%8B%D0%BC_%D0%B7%D0%B0%D0%B1%D0%BE%D0%BB%D0%B5%D0%B2%D0%B0%D0%BD%D0%B8%D0%B5%D0%BC\" >Risk factors for the development of this disease (physical and chemical risk factors, other possible ones associated with this disease)<\/a><\/li><li class='ez-toc-page-1'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/valintermed.com\/en\/medlibrary\/long-qt-interval-syndrome-1\/#%D0%94%D0%B8%D0%B0%D0%B3%D0%BD%D0%BE%D1%81%D1%82%D0%B8%D0%BA%D0%B0_%D0%B4%D0%B0%D0%BD%D0%BD%D0%BE%D0%B3%D0%BE_%D0%B7%D0%B0%D0%B1%D0%BE%D0%BB%D0%B5%D0%B2%D0%B0%D0%BD%D0%B8%D1%8F_%D0%9E%D1%81%D0%BD%D0%BE%D0%B2%D0%BD%D1%8B%D0%B5_%D1%81%D0%B8%D0%BC%D0%BF%D1%82%D0%BE%D0%BC%D1%8B_%D0%9B%D0%B0%D0%B1%D0%BE%D1%80%D0%B0%D1%82%D0%BE%D1%80%D0%BD%D1%8B%D0%B5_%D0%B8%D1%81%D1%81%D0%BB%D0%B5%D0%B4%D0%BE%D0%B2%D0%B0%D0%BD%D0%B8%D1%8F_%D0%A0%D0%B0%D0%B4%D0%B8%D0%BE%D0%BB%D0%BE%D0%B3%D0%B8%D1%87%D0%B5%D1%81%D0%BA%D0%B8%D0%B5_%D0%BE%D0%B1%D1%81%D0%BB%D0%B5%D0%B4%D0%BE%D0%B2%D0%B0%D0%BD%D0%B8%D1%8F_%D0%94%D1%80%D1%83%D0%B3%D0%B8%D0%B5_%D0%B2%D0%B8%D0%B4%D1%8B_%D0%B4%D0%B8%D0%B0%D0%B3%D0%BD%D0%BE%D1%81%D1%82%D0%B8%D0%BA%D0%B8_%D0%B7%D0%B0%D0%B1%D0%BE%D0%BB%D0%B5%D0%B2%D0%B0%D0%BD%D0%B8%D1%8F_%D0%94%D0%B8%D1%84%D1%84%D0%B5%D1%80%D0%B5%D0%BD%D1%86%D0%B8%D0%B0%D0%BB%D1%8C%D0%BD%D1%8B%D0%B9_%D0%B4%D0%B8%D0%B0%D0%B3%D0%BD%D0%BE%D0%B7\" >Diagnosis of this disease (Main symptoms, Laboratory tests, Radiological examinations, Other types of diagnosis of the disease, Differential diagnosis)<\/a><\/li><\/ul><\/nav><\/div>\n<h2><span class=\"ez-toc-section\" id=\"%D0%98%D1%81%D1%82%D0%BE%D1%80%D0%B8%D1%8F_%D0%B7%D0%B0%D0%B1%D0%BE%D0%BB%D0%B5%D0%B2%D0%B0%D0%BD%D0%B8%D1%8F_%D0%B8_%D0%B8%D0%BD%D1%82%D0%B5%D1%80%D0%B5%D1%81%D0%BD%D1%8B%D0%B5_%D0%B8%D1%81%D1%82%D0%BE%D1%80%D0%B8%D1%87%D0%B5%D1%81%D0%BA%D0%B8%D0%B5_%D1%84%D0%B0%D0%BA%D1%82%D1%8B\"><\/span>History of the disease and interesting historical facts<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The first description of long QT syndrome was made in 1957 by Danish cardiologists Antoon Jervell and Fred Lange-Nielsen, who discovered a link between deafness and a tendency to sudden death in children. It is interesting to note that in 1963, American physician Bernard Lown introduced the term &quot;tachyarrhythmic shock&quot;, describing the mechanisms of development of fatal arrhythmias in this syndrome. An important step in the study of the pathology was the discovery in 1995 of the first genes responsible for the development of the syndrome - KCNQ1 and HERG. According to the historical analysis conducted by Gussak et al. (2000), more than 40% of the first clinical observations were associated with cases of sudden death of young athletes.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"%D0%AD%D0%BF%D0%B8%D0%B4%D0%B5%D0%BC%D0%B8%D0%BE%D0%BB%D0%BE%D0%B3%D0%B8%D1%8F_%D1%81%D1%82%D0%B0%D1%82%D0%B8%D1%81%D1%82%D0%B8%D0%BA%D0%B0_%D0%B2%D0%BE%D0%B7%D0%BD%D0%B8%D0%BA%D0%BD%D0%BE%D0%B2%D0%B5%D0%BD%D0%B8%D1%8F_%D0%B7%D0%B0%D0%B1%D0%BE%D0%BB%D0%B5%D0%B2%D0%B0%D0%BD%D0%B8%D1%8F\"><\/span>Epidemiology (statistics of disease occurrence)<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>According to modern epidemiological studies, the prevalence of congenital long QT syndrome is approximately 1:2000 newborns. However, it is worth noting a significant proportion of undiagnosed cases, especially among patients with a latent form of the disease. Statistics indicate that about 0.4% of the population have borderline QT interval values, which requires constant monitoring. In the age group of 15-40 years, the incidence of sudden cardiac death associated with this pathology is about 1.3 cases per 100,000 people\/year.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"%D0%93%D0%B5%D0%BD%D0%B5%D1%82%D0%B8%D1%87%D0%B5%D1%81%D0%BA%D0%B0%D1%8F_%D0%BF%D1%80%D0%B5%D0%B4%D1%80%D0%B0%D1%81%D0%BF%D0%BE%D0%BB%D0%BE%D0%B6%D0%B5%D0%BD%D0%BD%D0%BE%D1%81%D1%82%D1%8C_%D0%BA_%D0%B4%D0%B0%D0%BD%D0%BD%D0%BE%D0%BC%D1%83_%D0%B7%D0%B0%D0%B1%D0%BE%D0%BB%D0%B5%D0%B2%D0%B0%D0%BD%D0%B8%D1%8E_%D0%B2%D0%BE%D0%B2%D0%BB%D0%B5%D1%87%D1%91%D0%BD%D0%BD%D1%8B%D0%B5_%D0%B3%D0%B5%D0%BD%D1%8B_%D0%B8_%D0%BC%D1%83%D1%82%D0%B0%D1%86%D0%B8%D0%B8\"><\/span>Genetic predisposition to the disease (involved genes and mutations)<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>To date, more than 17 genes have been identified, mutations in which can lead to the development of long QT syndrome. The main genes and their characteristics are presented in the table:<\/p>\n<ul>\n<li><strong>KCNQ1<\/strong> \u2014 encodes the \u03b1-subunit of the potassium channel IKs, mutations are detected in 30-35% cases<\/li>\n<li><strong>KCNH2(HERG)<\/strong> \u2014 is responsible for the formation of the fast component of the slow rectifying potassium conductivity IKr, occurs in 25-30% cases<\/li>\n<li><strong>SCN5A<\/strong> - encodes the \u03b1-subunit of the INa sodium channel, found in 5-10% cases<\/li>\n<li><strong>CACNA1C<\/strong> - participates in the regulation of calcium channels, associated with a severe variant of the disease (Timothy syndrome)<\/li>\n<\/ul>\n<p>It is important to note that most mutations are transmitted in an autosomal dominant manner, although recessive forms of the disease also exist.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"%D0%A4%D0%B0%D0%BA%D1%82%D0%BE%D1%80%D1%8B_%D1%80%D0%B8%D1%81%D0%BA%D0%B0_%D0%B2%D0%BE%D0%B7%D0%BD%D0%B8%D0%BA%D0%BD%D0%BE%D0%B2%D0%B5%D0%BD%D0%B8%D1%8F_%D0%B4%D0%B0%D0%BD%D0%BD%D0%BE%D0%B3%D0%BE_%D0%B7%D0%B0%D0%B1%D0%BE%D0%BB%D0%B5%D0%B2%D0%B0%D0%BD%D0%B8%D1%8F_%D1%84%D0%B8%D0%B7%D0%B8%D1%87%D0%B5%D1%81%D0%BA%D0%B8%D0%B5_%D0%B8_%D1%85%D0%B8%D0%BC%D0%B8%D1%87%D0%B5%D1%81%D0%BA%D0%B8%D0%B5_%D1%84%D0%B0%D0%BA%D1%82%D0%BE%D1%80%D1%8B_%D1%80%D0%B8%D1%81%D0%BA%D0%B0_%D0%B4%D1%80%D1%83%D0%B3%D0%B8%D0%B5_%D0%B2%D0%BE%D0%B7%D0%BC%D0%BE%D0%B6%D0%BD%D1%8B%D0%B5_%D1%81%D0%B2%D1%8F%D0%B7%D0%B0%D0%BD%D0%BD%D1%8B%D0%B5_%D1%81_%D0%B4%D0%B0%D0%BD%D0%BD%D1%8B%D0%BC_%D0%B7%D0%B0%D0%B1%D0%BE%D0%BB%D0%B5%D0%B2%D0%B0%D0%BD%D0%B8%D0%B5%D0%BC\"><\/span>Risk factors for the development of this disease (physical and chemical risk factors, other possible ones associated with this disease)<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The development of the syndrome can be triggered by various environmental factors. The main triggers include:<\/p>\n<ul>\n<li>Electrolyte disturbances, especially hypokalemia and hypomagnesemia<\/li>\n<li>Taking certain medications, including class IA and III antiarrhythmic drugs<\/li>\n<li>Extreme physical activity, especially in individuals with a genetic predisposition<\/li>\n<li>Stressful situations and emotional tension<\/li>\n<li>Certain infectious diseases and febrile conditions<\/li>\n<\/ul>\n<h2><span class=\"ez-toc-section\" id=\"%D0%94%D0%B8%D0%B0%D0%B3%D0%BD%D0%BE%D1%81%D1%82%D0%B8%D0%BA%D0%B0_%D0%B4%D0%B0%D0%BD%D0%BD%D0%BE%D0%B3%D0%BE_%D0%B7%D0%B0%D0%B1%D0%BE%D0%BB%D0%B5%D0%B2%D0%B0%D0%BD%D0%B8%D1%8F_%D0%9E%D1%81%D0%BD%D0%BE%D0%B2%D0%BD%D1%8B%D0%B5_%D1%81%D0%B8%D0%BC%D0%BF%D1%82%D0%BE%D0%BC%D1%8B_%D0%9B%D0%B0%D0%B1%D0%BE%D1%80%D0%B0%D1%82%D0%BE%D1%80%D0%BD%D1%8B%D0%B5_%D0%B8%D1%81%D1%81%D0%BB%D0%B5%D0%B4%D0%BE%D0%B2%D0%B0%D0%BD%D0%B8%D1%8F_%D0%A0%D0%B0%D0%B4%D0%B8%D0%BE%D0%BB%D0%BE%D0%B3%D0%B8%D1%87%D0%B5%D1%81%D0%BA%D0%B8%D0%B5_%D0%BE%D0%B1%D1%81%D0%BB%D0%B5%D0%B4%D0%BE%D0%B2%D0%B0%D0%BD%D0%B8%D1%8F_%D0%94%D1%80%D1%83%D0%B3%D0%B8%D0%B5_%D0%B2%D0%B8%D0%B4%D1%8B_%D0%B4%D0%B8%D0%B0%D0%B3%D0%BD%D0%BE%D1%81%D1%82%D0%B8%D0%BA%D0%B8_%D0%B7%D0%B0%D0%B1%D0%BE%D0%BB%D0%B5%D0%B2%D0%B0%D0%BD%D0%B8%D1%8F_%D0%94%D0%B8%D1%84%D1%84%D0%B5%D1%80%D0%B5%D0%BD%D1%86%D0%B8%D0%B0%D0%BB%D1%8C%D0%BD%D1%8B%D0%B9_%D0%B4%D0%B8%D0%B0%D0%B3%D0%BD%D0%BE%D0%B7\"><\/span>Diagnosis of this disease (Main symptoms, Laboratory tests, Radiological examinations, Other types of diagnosis of the disease, Differential diagnosis)<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The key diagnostic method is a standard ECG with calculation of the corrected QTc interval. The following approaches are used to verify the diagnosis:<\/p>\n<ul>\n<li>Holter ECG monitoring for 24-48 hours<\/li>\n<li>Genetic testing to detect mutations<\/li>\n<li>Echocardiography to rule out structural heart disease<\/li>\n<li>Treadmill test for assessing QT dynamics during exercise<\/li>\n<li>Laboratory tests for blood electrolytes<\/li>\n<\/ul>\n<p>In the differential diagnosis, it is necessary to exclude other causes of QT prolongation, such as hypertrophic cardiomyopathy and metabolic disorders.<\/p>\n<p>(To be continued in the next post due to text space limitations)<\/p><script data-noptimize=\"\" data-wpfc-render=\"false\">\nfpm_start( \"true\" );\n<\/script>\n\n<div class=\"fpm_end\"><\/div>","protected":false},"excerpt":{"rendered":"<p>Long QT syndrome is a hereditary or acquired cardiovascular disease characterized by impaired repolarization of the ventricles of the heart. The pathology manifests itself in<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[298],"tags":[],"class_list":["post-11936","post","type-post","status-publish","format-standard","hentry","category-medlibrary"],"_links":{"self":[{"href":"https:\/\/valintermed.com\/en\/wp-json\/wp\/v2\/posts\/11936","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/valintermed.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/valintermed.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/valintermed.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/valintermed.com\/en\/wp-json\/wp\/v2\/comments?post=11936"}],"version-history":[{"count":1,"href":"https:\/\/valintermed.com\/en\/wp-json\/wp\/v2\/posts\/11936\/revisions"}],"predecessor-version":[{"id":15261,"href":"https:\/\/valintermed.com\/en\/wp-json\/wp\/v2\/posts\/11936\/revisions\/15261"}],"wp:attachment":[{"href":"https:\/\/valintermed.com\/en\/wp-json\/wp\/v2\/media?parent=11936"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/valintermed.com\/en\/wp-json\/wp\/v2\/categories?post=11936"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/valintermed.com\/en\/wp-json\/wp\/v2\/tags?post=11936"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}