is for medical professionals to read only
Evidence-based medical . The rational use of medicine
QT interval refers to the distance between the starting point of the QRS wave group and the end point of the T wave , representing the time required for the entire process of ventricular muscle depolarization and repolarization.
QT interval prolongation is the biggest harm of long QT syndrome (LQTS), that is, a group of syndromes that can easily lead to malignant ventricular arrhythmia (especially torsional ventricular tachycardia, namely TdP, ventricular fibrillation, etc.), fainting and sudden death due to QT interval prolongation and T wave abnormality [1].
LQTS can be divided into congenital and acquired, while acquired LQTS can be caused by metabolic abnormalities (such as acute hypokalemia, etc.), diseases (such as myocarditis , subarachnoid hemorrhage , etc.) and various drugs that cause prolonging the QT interval [2].
Common drugs that can cause QT interval prolongation
▌amidoodarone
amidoodarone can lead to QT interval prolongation, and its effect of QT interval prolongation is related to the dose. The larger the dose, the more obvious the QT interval prolongation is. The incidence of events in arrhythmia in is 2%, resulting in uniform prolongation of the QT interval and is not easy to form reentry. Moreover, amiodarone itself has a certain β receptor blocking effect and calcium channel blocking effect, which can reduce the early post-depole caused by it. Therefore, although amiodarone can lead to significant QT interval prolongation, the incidence of TdP is not that high [3-5].
▌ domperidone
domperidone has a potential risk of QT interval prolongation and TdP. Especially when combined with other drugs that cause QT interval prolongation, or combined with low potassium and other risk factors such as CYP3A4 inhibitors ( erythromycin , clarithromycin, azithromycin, ketoconazole , itraconazole, voriconazole) and other risk factors, the risk of TdP will be further increased [3-4].
▌ Macrolide antibacterial drugs
Macrolide antibacterial drugs such as erythromycin and clarithromycin have been clearly reported to have side effects of QT interval prolongation, leading to TdP and sudden cardiac death. Its arrhythmic effect is considered to be related to potassium channel blockade, leading to prolonging of the QT interval. At the same time, macrolide antibacterial drugs are metabolized by CYP3A4. If the combination of CYP3A4 inhibitors will lead to more obvious prolongation of the QT interval and the risk of TdP is further increased [3-4,6].
Prevention and treatment of drug-induced QT interval prolongation
Proficient in common clinical drugs that may lead to QT interval prolongation, pay attention to the correct usage and dosage, and dosage as much as possible without overuse and long-term use on the basis of ensuring efficacy.
Try to avoid the concurrent use of drugs that may lead to prolonging the QT interval.
Try to avoid using other drugs that may affect the metabolism of such drugs.
When patients have non-pharmacological factors that prone to QT interval prolongation (such as elderly people, bradycardia , congenital LQTS, electrolyte disorder , diabetes , hypertension , cerebrovascular disease, coronary heart disease , heart failure , hypothyroidism, etc.), avoid using drugs that may lead to QT interval prolongation under close observation.
The QT interval prolongation and TdP caused by drugs must be stopped. First, any drugs that are known to prolong the QT interval should be stopped, electrolyte disorders should be corrected, and heart rate of should be increased. In those with mild QT interval prolongation, the QT interval will generally gradually return to normal after stopping the drug; if the QT interval prolongs to TdP, ECG monitoring should be performed immediately, and isoproterenol should be used. Some patients will implant temporary or permanent pacemaker . The goal is to increase the heart rate, shorten the QT interval, prevent abnormal repolarization or early postpolarization, and prevent sudden cardiac death [3-4,7].
More popular medicines in the department, where to learn? What is the
QT interval? Is it dangerous to prolong the
QT interval?
What drugs can cause QT interval prolongation?
The dry medicine you want
Decision Assistant " Evidence-based medicine " module has 👇
Download Decision Assistant Appp, check it anytime, anywhere~
References: l1 [1] Zheng Meixia. Causes and clinical treatment of acquired QT interval prolongation with torsion of the tip and clinical treatment [J]. Chinese Medicine and Clinical, 2018, 18(11): 1936-1937. [2] He Yang. Potential dangers of QT interval prolongation caused by drugs [J]. Electronic Journal of Cardiovascular Diseases in Integrated Traditional Chinese and Western Medicine, 2018, 6(8): 178-179. [3] Huang Zhenhua. Drug-induced QT interval prolongation and tip Research progress on torsional ventricular tachycardia [J]. Chinese Journal of New Drugs and Clinical, 2016, 35(7): 473-477. [4] Lu Yue, Wang Lin, Yang Yanru, et al. Literature analysis of 129 cases of drug-derived Q-T interval prolongation with torsional ventricular tachycardia [J]. Tianjin Pharmacy, 2021, 33(2): 22-27. [5] Du Yipeng, Ouyang Hong, Bu Tong, et al. 1 case of torsional ventricular tachycardia caused by short-term oral administration of amiodarone [1] [1] J]. Electrocardiogram and Circulation, 2021, 40(1): 88-90. [6] Zhang Yanting, Chen Yuan, Zhao Wei. Research progress on cardiac safety of erythromycin [J]. Drug Biotechnology, 2018, 25(2): 166-170. [7] Ding Cai, Zhang Xinli, Wang Qiong, et al. Preliminary discussion and enlightenment on drug use risk management due to QT interval prolongation [J]. China Pharmacovigilance, 2018, 15(9): 545-549.
