tailieunhanh - 100 Questions in Cardiology - Part 9

Nhịp tâm thất phải được duy trì và điện tâm đồ theo dõi trong khi các yếu tố predisposing cho sự phát triển của xoắn đỉnh được xem xét và sửa chữa. Không có vai trò đối với các thuốc chống loạn nhịp thông thường trong việc quản lý của xoắn đỉnh de pointes: các thuốc chống loạn nhịp nhiều trái có thể làm trầm trọng thêm tình hình. | 174 100 Questions in Cardiology necessary. Ventricular pacing should be maintained and the ECG monitored while the factors predisposing to the development of torsade are considered and corrected. There is no role for conventional antiarrhythmic drugs in the management of torsade de pointes on the contrary many antiarrhythmics may aggravate the situation. Further reading Haverkamp W Shenasa M Borggrefe M et al. Torsade de pointes. In Zipes DP Jalife J eds. Cardiac electrophysiology from cell to bedside. WB Saunders 1995 Chapter 79. Tzivoni D Banai S Schuger C et al. Treatment of torsade de pointes with magnesium sulfate. Circulation 1988 77 392-7. 100 Questions in Cardiology 175 83 How do I assess the patient with long QT Should I screen relatives and how How do I treat them J Benhorin Patients affected by the congenital long QT syndrome LQT are often first assessed when syncope documented ventricular arrhythmia or aborted cardiac arrest affects them or a family member. The diagnostic cut-offs 100 sensitive for a congenitally-prolonged heart rate-corrected QT interval QTc on standard 12-lead ECG measured in lead II or V5 are sec children 16 years sec adult males and sec adult females after drug induced QT prolongation has been excluded. T wave morphology should also be carefully examined in particular for high takeoff late onset broad base bifid morphology with humps and beat-by-beat alternating polarity T wave alternans . In several LQT variants sinus bradycardia is an additional common feature. Holter monitoring should be performed to exclude repetitive ventricular arrhythmias of the torsade de pointes type. Family screening by 12-lead ECG of all first-degree relatives is mandatory in order to have a definite diagnosis of hereditary LQT. In Romano-Ward syndrome 1 20 000 births autosomal dominant transmission with 90 penetrance 50 of offspring of one affected parent are predicted to be similarly affected. Six associated genetic loci on chromosomes 3