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II. ХИРУРГИЯ
SECONDARY PREVENTION OF SUDDEN CARDIAC DEATH IN PATIENT WITH LONG QT SYNDROME
Baimbetov A.K., Bizhanov K.A., Bairamov B.A., Sagatov I.Y.
Interventional Cardiology and Arrhythmology Department,
A.N. Syzganov's National Scientific Center of Surgery, Almaty, Kazakhstan
Abstract
Congenital long QT syndrome (LQTS) is an abnormally prolonged repolarization of the stomach due to hereditary defects in the sodium and potassium channels of the heart, which predispose patients with syncope, gastrointestinal arrhythmias, and sudden cardiac death. Early diagnosis and prophylactic treatment play an important role in preventing sudden cardiac death in patients with congenital LQTS. The diagnostic criteria for congenital LQTS are based on specific electrocardiographic data, clinical data, and adrenaline test results. Recently, a genotype-specific electrocardiographic pattern of congenital LQTS has also been described. Recent studies suggest the feasibility of genotype-specific treatment for LQTS, and soon, mutation-specific treatment is likely to become a new approach to this potentially deadly syndrome.
We present a case report that is verified by electrocardiographic and clinical diagnostic criteria, indicating LQTS. In this case, the cardioverter-defibrillator is implanted to the patient for the secondary prevention of sudden cardiac death. The patient experiences attacks of sudden palpitations with fainting, and the implanted defibrillator leads therapy from life-threatening ventricular tachycardia.
УДК 616.12-008.313.315
ABOUT THE AUTHORS
Bizhanov Kenzhebek Alibekovich -
JSC National Scientific Center of Surgery named after A.N.Syzganov, Department of Interventional Cardiology, Arrhythmology and Endovascular Surgery, interventional cardidiogist
Baimbetov Adil Kudaibergenovich -
JSC National Scientific Center of Surgery named after A.N. Syzganov, Department of Interventional Cardiology, Arrhythmology and Endovascular Surgery, Head of department, interventional cardiologist
Bairamov Binali Amrulaevich - JSC
National Scientific Center of Surgery named after A.N.Syzganov, Department of Interventional Cardiology, Arrhythmology and Endovascular Surgery, interventional cardiologist
Sagatov Inkar Yergalievich - JSC
National Scientific Center of Surgery named after A.N. Syzganov, Head of Research Management
Keywords
sudden cardiac death, secondary prevention
¥зартылган QT синдромы бар пациентте кенеттен болатын xYpeK eлiмiн eK^i регпк алдын алу
Баимбетов Э.К-, Бижанов К.Э., Байрамов Б.А., Саратов I.E.
Интервенциялык кардиология жэне аритмология бeлiмi,
А. Н. Сьстанов атында?ы Улттык ?ылыми хирургия орталы^ы, Алматы, Казакстан
Ацдатпа
Туа бткен узартыман QT интервалы синдромы (YИСQT) пациенттердi синкопальды куй, карыншалык аритмия жэне кенеттен болатын журек eлiмiне экеп соктыратын щрект'щ калий жэне натрий каналдарындагы тукым куалайтын акауларга байланысты карыншалардыц аномалды созылма-лы реполяризациясы деп сипатталады. Туа бгткен YИСQT бар пациенттерде кенеттен болатын журек елмн алдын алуда ерте диагностика жэне профилактикалык емдеу мацызды рел аткарады. Туа бгткен УИСQT-тiц диагностикалык критерийлерi электрокардиографиялык деректерге, клиникалык дерек-терге жэне адреналиннщ тест нэтижелерне непзделед'1. Жакында генотипке тэн туа бгткен YИСQT электрокардиографиялык паттерн сипатталды. Таяуда журпзшген зерттеулер бойынша, УИСQT-тыц генотип-спецификалык ем/ жузеге асырылады. Сондай-ак болашакта мутацияга беШм емдеу осы потенциалды кауШ синдромды емдеуд'щ жаца эдсне айналады. Б'з узартыляан QT синдромы бар, электрокардиографиялык жэне клиникалык диагностикалыккритерийлер аркылырасталран клиникалык жардайды усынамыз. Бул жащайда пациетке кенеттен болатын журек ел'ш'т екiншi ретпк алдын алу ушн кардиовертер-дефибриллятор имплантталган. Пациентте кенеттен болатын журек устамасы, та-лып калу байкалеан. Имплантталган дефибриллятор ем'рге кауШ карыншалык тахикардиядан куткару терапиясын щрпзед'!.
АВТОРЛАР ТУРАЛЫ
Бижанов Кенжебек Элiбекулы -
А.Н. Сызганов атындагы Улттыкгылыми хирургия орталыгыныц интервенциялык кардиология, аритмология жэне эндоваскулярлыкхирургия белiмшесiнiц дэрiгерi1 интервенциялык кардиолог
Баимбетов ддл Кудайбергенулы -
А.Н. Сызганов атындагы Улттыкгылыми хирургия орталыгыныц интервенциялык кардиология, аритмология жэне эндоваскулярлык хирургия белiмшесiнiц мецгерушс, интервенциялык кардиолог
Байрамов Бинали Амрулаулы -
А.Н. Сызганов атындагы Улттык гылыми хирургия орталыгыныц интервенциялык кардиология, аритмология жэне эндоваскулярлык хирургия белiмшесiнiц дэрiгерi1 интервенциялык кардиолог
Сагатов 1икэр Ерталиулы -
А.Н. Сызганов атындагы Улттык гылыми хирургия орталь^ыныц Fылыми-зерттеу менеджмент/ бел!мш1ц басшысы
Туйш сездер
кенеттен болатын журек ел1м1б екiншiлiк алдын алу
Вторичная профилактика внезапной сердечной смерти у пациента с синдромом удлиненного QT
ОБ АВТОРАХ
Бижанов Кенжебек Алибекович -
отделение интервенционной кардиологии, аритмологии и эндоваскулярной хирургии АО «Национальный научный центр хирургии имени А.Н. СызFанова», интервенционный кардиолог
Баимбетов Адиль Кудайбергенович -
отделение интервенционной кардиологии, аритмологии и эндоваскулярной хирургии АО «Национального научного центра хирургии имени А.Н. СызFанова», заведующий отделением, интервенционный кардиолог
Байрамов Бинали Амрулаевич -
отделение интервенционной кардиологии, аритмологии и эндоваскулярной хирургии АО «Национальный научный центр хирургии имени А.Н. СызFанова», интервенционный кардиолог
Сагатов Инкар Ергалиевич -
руководитель отдела менеджмента научно-исследовательских работ АО «Национальный научный центр хирургии имени А.Н. СызFанова»
Ключевые слова
внезапная сердечная смерть, вторичная профилактика
Баимбетов А.К., Бижанов К.А., Байрамов Б.А., Сагатов И.Е.
Отделение интервенционной кардиологии и аритмологии,
Национальный научный центр хирургии им. А. Н. Сызганова, Алматы, Казахстан
Аннотация
Врожденный синдром удлиненного интервала QT (СУИQT) характеризуется аномально продолжительной реполяризацией желудочков из-за наследственных дефектов в натриевых и калиевых каналах сердца, которые предрасполагают пациентов к синкопальным состояниям, желудочковым аритмиям и внезапной сердечной смерти. Ранняя диагностика и профилактическое лечение играют важную роль в предотвращении внезапной сердечной смерти у пациентов с врожденным СУИQT. Диагностические критерии врожденного СУИQT основаны на определенных электрокардиографических данных, клинических данных и результатах теста на адреналин. Недавно также был описан специфический для генотипа электрокардиографический паттерн врожденной СУИQT. Недавние исследования предполагают выполнимость генотип-специфического лечения СУИQT, и в ближайшем будущем специфичное для мутаций лечение, вероятно, станет новым подходом к этому потенциально смертельному синдрому. Мы представляем клинический случай, который подтверждается электрокардиографическими и клиническими диагностическими критериями, свидетельствующий о синдроме удлиненного QT. В данном случае, пациентке был имплантирован кардиовертер-дефибриллятор для вторичной профилактики внезапной сердечной смерти. У пациентки возникают приступы внезапного сердцебиения с обмороками, и имплантированный дефибриллятор проводит спасительную терапию от жизенугрожающей желудочковой тахикардии.
Case Report
A 25-year-old woman who was recently diagnosed with an attack was taken by an ambulance service to an emergency hospital. The patient notes sudden attacks of loss of consciousness with spontaneous resolution within a few minutes over the past 4-5 months. From the family history, it was found out that the mother suddenly died at a younger age, and then the older brother also died from sudden death at an early age. Patient's hemodynamic parameters were stable. A 12-lead ECG showed the QT interval duration - 570 msec (Figure 1) and a corrected QT interval was calculated - 700 msec. The presence of U waves correlating with its low potassium levels of 3.3. The clinical condition of the patient quickly improved, but already in
the intensive care unit, a new attack of a sudden heartbeat arose. A wide complex polymorphic ventricular tachycardia was recorded on the monitor, which recovered to the sinus rhythm within a few seconds. After the initial episode, the patient had two more episodes of ventricular tachycardia over the next few minutes, which resolved spontaneously after 5-7 seconds. A serial ECG performing in the intensive care unit revealed a prolonged QT interval, which gradually decreased to a standard duration of 2 days. Given the history of sudden cardiac deaths in the family and episodes similar to patient events, a congenital long QT syndrome was diagnosed, and implantation of a cardioverter-defibrillator was planned for the secondary prevention of sudden cardiac death. Prescribed therapy
Figure 1.
Patient's ECG shows a prolonged QT interval -570 msec.
Vl , . V4 \ ч -
\l 1 1 1 1
К—570 msec 1
V? А к V. I А
\ V -1 — i—
L_
J ч 1— —
with titration of doses of beta-blockers depending on blood pressure. Then the patient was transferred to the arrhythmology department of our centre for further observation, and a cardioverter-defibrillator was implanted. A few days later, the patient was discharged home after electrolyte correction, with an improvement in the general condition of the patient. Later, the patient had another attack, and during follow up of the ICD, she recorded cognitive therapy for polymorphic ventricular tachycardia. (Report fragments are shown in Figure 2.)
Discussion
The QT interval is an indicator of the electrical activity of the heart, in particular the repolarization of the cell membrane. It is well known that the absolute QT interval provides a superficial visualization of the duration of the main action of the cell. Despite the coincidence of QTc at rest between healthy people and patients with LQTS, a 12-lead ECG remains one of the available methods for detecting LQTS, and the base QTc interval is one of the main diagnostic criteria.
Figure 2.
Fragments from the patient's device report: a) Plot shows the sudden onset of ventricular tachycardia (more 200 bpm), the device has detection in time, and for 9 seconds applies therapy with 36 Joules, at the end sinus rhythm was accurately recovered. b) An electrogram episode of the onset of ventricular "torsade de point type" tachycardia is shown, then it passes into ventricular fibrillation. A cardioversion of 36 joules stops a life-threatening tachycardia. A-atrial channel, V-ventricular channel, the arrow indicates the time of the shock delivery.
Of most considerable diagnostic importance is the significant prolongation of the QT interval, paroxysms of tachycardia torsades de pointes, and syncope episodes. Congenital long QT syndrome is a genetically heterogeneous disease in which more than five different chromosome loci are involved. At least four genes have been identified that determine the development of congenital prolongation of the QT interval. The most common form of long QT syndrome in young people is the combination of this syndrome with mitral valve prolapse. The detection rate of QT interval prolongation in individuals with mitral and/or tricuspid valve prolapse reaches 33%. Congenital LQTS is a potentially life-threatening condition caused by mutations in the genes encoding the ion channels of the heart, which lead to an increase in the ventricular action potential. Genetic testing of symptomatic patients or their asymptomatic family members can identify patients at risk for life-threatening arrhythmias and a type of prolonged QT, as this has important management implications. Three forms (LQT1, LQT2 and LQT3) from congenital LQTS form, have been well characterized. These three forms have also been described better based on their specific ECG morphology. Recent studies show that even in patients with acquired LQTS (for example, as a result of taking drugs prolonging QT), there are clinically silent gene mutations that lead to explicit QT prolongation only when exposed to drugs prolonging QT [7]. This explains why some patients are more likely than others to QT interval prolongation at a given dose of prolonged medication, even after adjusting for other factors that can make longer the QT interval. The clinical course of congenital LQTS is highly dependent on the gene. Although cardiac events are more frequent and occur at a younger age in patients with LQT1 and LQT2, they are potentially more deadly in patients with the LQT3 genotype. Patients with LQT1 and LQT2 genotypes usually benefit from high-dose beta-blocker therapy. However, patients with LQT3 are at higher risk at a lower heart rate and could potentially benefit from pace stimulation. Besides, they shorten their QT interval longer with sodium channel blockers [8]. In order to prevent cardiac troubles, drugs such
References
1. Mullally J., Goldenberg I., Moss A. et al. Risk of life-threatening cardiac events among patients with long QT syndrome and multiple mutations. Heart Rhythm 2013; 10 (3): 378-382.
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as adrenaline, antihistamines, erythromycin, trimethoprim, quinidine, procainamide, disopyramide, sotalol and others, cisapride, ketoconazole, fluconazole, intraconazole, tricyclic antidepressants, phenothiidiadiuret derivatives, others are excluded [9]. According to international recommendations, p-blockers are the drug of choice [10,11]. In this series, the first drug is propranolol. Doses of drugs are selected individually, focusing on the response received. Antiadrenergic therapy is effective in most patient with LQTS, reducing the risk of arrhythmias and reducing the duration of the QT interval. It should be noted that a break in taking p-blockers is fraught with cardiac complications. The response to p-blockers and mexiletine depends on the type of mutation and trigger factors. In particular, mexiletine in people with LQT3 syndrome with a protein mutation of F1473 exacerbates further prolongation of QT interval [12]. In LQT1 syndrome, p-blockers are effective if physical exertion is a provoking factor, but not valid if rhythm disturbances occur in a dream [13]. Emergency therapy is aimed at stopping episodes of torsades de pointes and sudden death and includes the exclusion of provocative agents, intravenous administration of solutions of potassium, magnesium, less often isoproterenol. In patients with frequent life-threatening rhythm disturbances of the high-risk group for sudden death, the implantation of cardioverter-defibrillator is mandatory [14].
Conclusion
Timely diagnosis of QT interval prolongation and its dispersion, including during Holter monitoring, ECG and during exercise tests, will highlight a group of patients with an increased risk of developing ventricular arrhythmias, syncope and sudden death. Beta-blockers, in combination with magnesium, are effective agents for the prevention and treatment of ventricular cardiac arrhythmias in patients with congenital and acquired forms of long QT syndrome. The described clinical case report clearly demonstrates that the implantation of a cardioverter-defibrillator is an effective and safe method for the prevention of sudden cardiac death in patients with long QT syndrome.
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