Long QT syndrome incidence is increasing in general population.A careful pre-,peri-and post-operative management is needed for patients with this syndrome because of the risk of Torsades de Pointes and malignant arrhy...Long QT syndrome incidence is increasing in general population.A careful pre-,peri-and post-operative management is needed for patients with this syndrome because of the risk of Torsades de Pointes and malignant arrhythmias.The available data regarding prevention of lethal Torsades de Pointes during anesthesia in patients with long QT syndrome is scant and conflicting:only case reports and small case series with different outcomes have been published.Actually,there are no definitive guidelines on pre-,peri-and post-operative anesthetic management of congenital long QT syndrome.Our review focuses on anesthetic recommendations for patients diagnosed with congenital long QT syndrome furnishing some key points for preoperative optimization,intraoperative anesthetic agents and postoperative care plan,which could be the best for patients with c-long QT syndrome who undergo surgery.展开更多
Acquired long QT syndromes and torsade de points often occur with underlying hypokalemia andbradycardia. With its fast inactivation property, the rapid activating component (Ikr) of the delayed rectifierpotassium curr...Acquired long QT syndromes and torsade de points often occur with underlying hypokalemia andbradycardia. With its fast inactivation property, the rapid activating component (Ikr) of the delayed rectifierpotassium current (IK) plays an important role in maintaining normal QT intervals. In this study, we evaluated the effects of different extracellular potassium ([K].) on the fast inactivation current of Ikr in guinea pigventricular myocytes. The results showed that [K]. had strong effects on the fast inactivation current ; thelower [K].(1, 3 mmol/L) significantly decreased the inactivation outward current (P＜0. 05); while higher[K]. (8, 10, 20 mmol/L) slightly increased the inactivation current (P>0. 05). These results may be of greatclinical significance. The lower [K]. decreased Ikr inactivation current, which may help to explain why acquired long QT syndromes and torsade de points often occur in the lower [K]. The correction of hypokalemia can increase the inactivation current, therefore, it is critical in the treatment of acquired long QTsyndromes and torsade de points.展开更多
BACKGROUND QT interval prolongation can induce torsades de pointes(TdP),a potentially fatal ventricular arrhythmia.Recently,an increasing number of non-cardiac drugs have been found to cause QT prolongation and/or TdP...BACKGROUND QT interval prolongation can induce torsades de pointes(TdP),a potentially fatal ventricular arrhythmia.Recently,an increasing number of non-cardiac drugs have been found to cause QT prolongation and/or TdP onset.Moreover,recent findings have demonstrated the key roles of systemic inflammatory activation and fever in promoting long-QT syndrome(LQTS)and TdP development.CASE SUMMARY A 30-year-old woman was admitted with a moderate to high-grade episodic fever for two weeks.The patient was administered with multiple antibiotics after hospitalization but still had repeating fever and markedly elevated C-reactive protein.Once after a high fever,the patient suddenly lost consciousness,and electrocardiogram(ECG)showed transient TdP onset after frequent premature ventricular contraction.The patient recovered sinus rhythm and consciousness spontaneously,and post-TdP ECG revealed a prolonged QTc interval of 560 ms.The patient’s clinical manifestations and unresponsiveness to the antibiotics led to the final diagnosis of adult-onset Still’s disease(AOSD).There was no evidence of cardiac involvement.After the AOSD diagnosis,discontinuation of antibiotics and immediate initiation of intravenous dexamethasone administration resulted in the normal temperature and QTc interval.The genetic analysis identified that the patient and her father had heterozygous mutations in KCNH2(c.1370C>T)and AKAP9(c.7725A>C).During the 2-year follow-up period,the patient had no recurrence of any arrhythmia and maintained normal QTc interval.CONCLUSION This case study highlights the risk of systemic inflammatory activation and antibiotic-induced TdP/LQTS onset.Genetic analysis should be considered to identify individuals at high risk of developing TdP.展开更多
Summary： Abnormal enhanced transmural dispersion of repolarization （TDR） plays an important role in the maintaining of the severe ventricular arrhythmias such as torsades de pointes （TDP） which can be induced in ...Summary： Abnormal enhanced transmural dispersion of repolarization （TDR） plays an important role in the maintaining of the severe ventricular arrhythmias such as torsades de pointes （TDP） which can be induced in long-QT （LQT） syndrome. Taking advantage of an in vitro rabbit model of LQT2, we de- tected the effects of KN-93, a CaM-dependent kinase （CaMK） II inhibitor on repolarization heteroge- neity of ventricular myocardium. Using the monophasic action potential recording technique, the action potentials of epicardium and endocardium were recorded in rabbit cardiac wedge infused with hypo- kalemic, hypomagnesaemic Tyrode＇s solution. At a basic length （BCL） of 2000 ms, LQT2 model was successfully mimicked with the perfusion of 0.5 μmol/L E-4031, QT intervals and the interval from the peak of T wave to the end of T wave （Tp-e） were prolonged, and Tp-e/QT increased. Besides, TDR was increased and the occurrence rate of arrhythmias like EAD, R-on-T extrasystole, and TDP increased under the above condition. Pretreatment with KN-93 （0.5μmol/L） could inhibit EAD, R-on-T extrasys- tole, and TDP induced by E-4031 without affecting QT interval, Tp-e, and Tp-e/QT. This study demon- strated KN-93, a CaMK II inhibitor, can inhibit EADs which are the triggers of TDP, resulting in the suppression of TDP induced by LQT2 without affecting TDR.展开更多
Prolongation of the QT interval is associated with adverse cardiac events specifically Torsades de pointes(TdP).There are multiple mediations that have a known,possible,or conditional risk for prolonged QT interval,bu...Prolongation of the QT interval is associated with adverse cardiac events specifically Torsades de pointes(TdP).There are multiple mediations that have a known,possible,or conditional risk for prolonged QT interval,but general practitioners’knowledge of these medications is unknown.We conducted a survey to assess internal medicine(IM)providers’knowledge of risk factors and medications associated with prolonged QT as well as provider experience and comfort when treating patients with prolonged QT.A 17-question,anonymous survey was constructed in 2019 and distributed to IM providers and residents at a tertiary care center.Questions included demographic information,6 Likert-scale questions gauging provider experience with prolonged QT,and 10 multiple choice clinical vignettes to assess clinical knowledge.Data was analyzed descriptively.Knowledge was assessed via clinical vignettes and compared by level of training.Forty-one responses were received out of a total of 87 possible respondents(47.1%response rate).About 70%of respondents see patients with acquired prolonged QT once monthly or more.95%rarely see congenital prolonged QT.When presented with QTc drug issues,73%of providers seldom or sometimes consulted pharmacy,but about half used online resources.The average correct score on the clinical vignettes was 5.59/10,with the highest scores seen in attending physicians in their first five years of practice(6.96/10).Our survey suggests that IM providers commonly encounter QT prolonging drugs.Educational efforts to improve knowledge of drug and patient risk factors for TdP may be needed.展开更多
Intravenous or oral administrations of erythromycin in humans have been reported to induce excessive prolongation of QT interval and even cause polymorphic ventricular tachycardia and torsade de points. Inthis study, ...Intravenous or oral administrations of erythromycin in humans have been reported to induce excessive prolongation of QT interval and even cause polymorphic ventricular tachycardia and torsade de points. Inthis study, we evaluated the effects of erythromycin on Ik, through direct measurement of the fast inactivationcurrent by using a two-pulses protocol. The results showed that erythrornycin 100 μmol/L restrained the fastinactivation current (P<0. 05), and its effects were both dose--dependent and voltage-dependent. As a result. the time course of erythromycin on the inactivation current was slow and washout was difficult. Our results expectedly may explain the reason why erythromycin slows the repolarization of action potential,lengthens QT interval, and causes torsade de points in humans.展开更多
人类心肌电生理过程存在着性别差异。长QT综合征时,女性发生尖端扭转性室性心动过速(torsade de pointes,TdP)的风险明显大于男性。越来越多的证据提示性激素可能影响重要的心肌复极电流,从而影响心肌复极的性别差异。该文综述长QT综合...人类心肌电生理过程存在着性别差异。长QT综合征时,女性发生尖端扭转性室性心动过速(torsade de pointes,TdP)的风险明显大于男性。越来越多的证据提示性激素可能影响重要的心肌复极电流,从而影响心肌复极的性别差异。该文综述长QT综合征TdP发生率的性别差异以及人类和动物心肌电生理的性别差异及其与性激素的相关研究,以阐明性激素在药物诱发心律失常性别差异中的作用及其机制。展开更多
文摘Long QT syndrome incidence is increasing in general population.A careful pre-,peri-and post-operative management is needed for patients with this syndrome because of the risk of Torsades de Pointes and malignant arrhythmias.The available data regarding prevention of lethal Torsades de Pointes during anesthesia in patients with long QT syndrome is scant and conflicting:only case reports and small case series with different outcomes have been published.Actually,there are no definitive guidelines on pre-,peri-and post-operative anesthetic management of congenital long QT syndrome.Our review focuses on anesthetic recommendations for patients diagnosed with congenital long QT syndrome furnishing some key points for preoperative optimization,intraoperative anesthetic agents and postoperative care plan,which could be the best for patients with c-long QT syndrome who undergo surgery.
文摘Acquired long QT syndromes and torsade de points often occur with underlying hypokalemia andbradycardia. With its fast inactivation property, the rapid activating component (Ikr) of the delayed rectifierpotassium current (IK) plays an important role in maintaining normal QT intervals. In this study, we evaluated the effects of different extracellular potassium ([K].) on the fast inactivation current of Ikr in guinea pigventricular myocytes. The results showed that [K]. had strong effects on the fast inactivation current ; thelower [K].(1, 3 mmol/L) significantly decreased the inactivation outward current (P＜0. 05); while higher[K]. (8, 10, 20 mmol/L) slightly increased the inactivation current (P>0. 05). These results may be of greatclinical significance. The lower [K]. decreased Ikr inactivation current, which may help to explain why acquired long QT syndromes and torsade de points often occur in the lower [K]. The correction of hypokalemia can increase the inactivation current, therefore, it is critical in the treatment of acquired long QTsyndromes and torsade de points.
基金the Beijing Key Clinical Subject Program and Beijing Municipal Administration of Hospitals Incubating Program,No.PX2018002.
文摘BACKGROUND QT interval prolongation can induce torsades de pointes(TdP),a potentially fatal ventricular arrhythmia.Recently,an increasing number of non-cardiac drugs have been found to cause QT prolongation and/or TdP onset.Moreover,recent findings have demonstrated the key roles of systemic inflammatory activation and fever in promoting long-QT syndrome(LQTS)and TdP development.CASE SUMMARY A 30-year-old woman was admitted with a moderate to high-grade episodic fever for two weeks.The patient was administered with multiple antibiotics after hospitalization but still had repeating fever and markedly elevated C-reactive protein.Once after a high fever,the patient suddenly lost consciousness,and electrocardiogram(ECG)showed transient TdP onset after frequent premature ventricular contraction.The patient recovered sinus rhythm and consciousness spontaneously,and post-TdP ECG revealed a prolonged QTc interval of 560 ms.The patient’s clinical manifestations and unresponsiveness to the antibiotics led to the final diagnosis of adult-onset Still’s disease(AOSD).There was no evidence of cardiac involvement.After the AOSD diagnosis,discontinuation of antibiotics and immediate initiation of intravenous dexamethasone administration resulted in the normal temperature and QTc interval.The genetic analysis identified that the patient and her father had heterozygous mutations in KCNH2(c.1370C>T)and AKAP9(c.7725A>C).During the 2-year follow-up period,the patient had no recurrence of any arrhythmia and maintained normal QTc interval.CONCLUSION This case study highlights the risk of systemic inflammatory activation and antibiotic-induced TdP/LQTS onset.Genetic analysis should be considered to identify individuals at high risk of developing TdP.
基金supported by Natural Science Foundation of Hubei Province,China(No.2008CDB163)
文摘Summary： Abnormal enhanced transmural dispersion of repolarization （TDR） plays an important role in the maintaining of the severe ventricular arrhythmias such as torsades de pointes （TDP） which can be induced in long-QT （LQT） syndrome. Taking advantage of an in vitro rabbit model of LQT2, we de- tected the effects of KN-93, a CaM-dependent kinase （CaMK） II inhibitor on repolarization heteroge- neity of ventricular myocardium. Using the monophasic action potential recording technique, the action potentials of epicardium and endocardium were recorded in rabbit cardiac wedge infused with hypo- kalemic, hypomagnesaemic Tyrode＇s solution. At a basic length （BCL） of 2000 ms, LQT2 model was successfully mimicked with the perfusion of 0.5 μmol/L E-4031, QT intervals and the interval from the peak of T wave to the end of T wave （Tp-e） were prolonged, and Tp-e/QT increased. Besides, TDR was increased and the occurrence rate of arrhythmias like EAD, R-on-T extrasystole, and TDP increased under the above condition. Pretreatment with KN-93 （0.5μmol/L） could inhibit EAD, R-on-T extrasys- tole, and TDP induced by E-4031 without affecting QT interval, Tp-e, and Tp-e/QT. This study demon- strated KN-93, a CaMK II inhibitor, can inhibit EADs which are the triggers of TDP, resulting in the suppression of TDP induced by LQT2 without affecting TDR.
文摘Prolongation of the QT interval is associated with adverse cardiac events specifically Torsades de pointes(TdP).There are multiple mediations that have a known,possible,or conditional risk for prolonged QT interval,but general practitioners’knowledge of these medications is unknown.We conducted a survey to assess internal medicine(IM)providers’knowledge of risk factors and medications associated with prolonged QT as well as provider experience and comfort when treating patients with prolonged QT.A 17-question,anonymous survey was constructed in 2019 and distributed to IM providers and residents at a tertiary care center.Questions included demographic information,6 Likert-scale questions gauging provider experience with prolonged QT,and 10 multiple choice clinical vignettes to assess clinical knowledge.Data was analyzed descriptively.Knowledge was assessed via clinical vignettes and compared by level of training.Forty-one responses were received out of a total of 87 possible respondents(47.1%response rate).About 70%of respondents see patients with acquired prolonged QT once monthly or more.95%rarely see congenital prolonged QT.When presented with QTc drug issues,73%of providers seldom or sometimes consulted pharmacy,but about half used online resources.The average correct score on the clinical vignettes was 5.59/10,with the highest scores seen in attending physicians in their first five years of practice(6.96/10).Our survey suggests that IM providers commonly encounter QT prolonging drugs.Educational efforts to improve knowledge of drug and patient risk factors for TdP may be needed.
文摘Intravenous or oral administrations of erythromycin in humans have been reported to induce excessive prolongation of QT interval and even cause polymorphic ventricular tachycardia and torsade de points. Inthis study, we evaluated the effects of erythromycin on Ik, through direct measurement of the fast inactivationcurrent by using a two-pulses protocol. The results showed that erythrornycin 100 μmol/L restrained the fastinactivation current (P<0. 05), and its effects were both dose--dependent and voltage-dependent. As a result. the time course of erythromycin on the inactivation current was slow and washout was difficult. Our results expectedly may explain the reason why erythromycin slows the repolarization of action potential,lengthens QT interval, and causes torsade de points in humans.
文摘人类心肌电生理过程存在着性别差异。长QT综合征时,女性发生尖端扭转性室性心动过速(torsade de pointes,TdP)的风险明显大于男性。越来越多的证据提示性激素可能影响重要的心肌复极电流,从而影响心肌复极的性别差异。该文综述长QT综合征TdP发生率的性别差异以及人类和动物心肌电生理的性别差异及其与性激素的相关研究,以阐明性激素在药物诱发心律失常性别差异中的作用及其机制。
