伍伟锋2010.12.4

院内获得性尖端扭转型室速防治 --AHA/ACC 院内获得性 TdP 防治专家共识临床

要点

尖端扭转型室速（ torsade de pointes,TdP ）

TdP 定义• TdP 一词也能用描述少数 QT 间期不延长的多形性室

速，因为部分患者伴有隐匿性长 QT 综合征• 但最好用来描述 QT 间期显著延长（ >500ms ），

伴 T- U 波畸形的多形性室速，因为这类室速有着不同的发生机制和治疗方法

问题的提出• 药物引起的获得性长 QT 综合征 (LQTS) 伴

TdP 发作心脏骤停恶性事件极罕见• 与院外服用同一种药物患者相比，住院患者

药物 LQTS 伴 TdP 发生可能性明显增高• 住院患者还其它心律失常促发因素– 老年人：有心脏病基础、肝肾功能受损– 电解质紊乱– 心动过缓– 静脉用药

内容• The ECG characteristics of TdP

• Premonitory ECG Signs of TdP

• Drugs That Cause TdP

• TdP Risk Factors

• Management of Drug-Induced QT Prolongation

• Management of Drug-Induced TdP

一、 Characteristic Pattern of TdP

typical feature

• 1 、 twisting of the QRS complexes around the isoelectric line– not be evident in all ECG leads

• 2 、 short-long-short pattern of R-R cycles– R-on-T PVC

• 3 、 warm-up phenomenon– The rate ofTdP:160-240 beats/minute

• 4 、 frequently terminates spontaneously– Some cases degenerates into VF

• VF 与 TdP 的区别–R-on-T PVC ： short coupling interval

–The rate of VF:250~500 beats/minute

–does not terminate without defibrillation

二、 Premonitory ECG Signs of TdP

• QT-interval prolongation ：–male QTc>470ms ， female>480ms

–QTc >500 ms

• T-U deformity

• macroscopic T-wave alternans

Circulation.2010,121:1049

三、 Drugs That Cause TdP

• Antiarrhythmic ：– Procainamide 、 Quinidine 、 Sotalol 、 Disopyramide 、

Ibutilide 、• Antibiotic ：– Erythromycin （红霉

素）、 Clarithromycin 、 Sparfloxacin• pain control ：– Methadone （美沙酮）

• Antipsychotic ：– Chlorpromazine （氯丙嗪）、 Thioridazine( 硫利达嗪 )

• Gastrointestinal stimulant ：– Cisapride( 西沙比利 )

• Cancer/leukemia ：– Arsenic trioxide( 三氧化二砷 )

四、 TdP Risk Factors

• 1 、 QTc >500 ms

• 2 、 Use of QT-prolonging drugs

– Concurrent use of more than 1 QT-prolonging drug

– Rapid infusion by intravenous route

• 3 、 Heart disease– Congestive heart failure

– Myocardial infarction

• 4 、 Advanced age

• 5 、 Female sex

• 6 、 Hypokalemia

• 7 、 Hypomagnesemia

• 8 、 Hypocalcemia

• 9 、 Treatment with diuretics

• 10 、 Impaired hepatic drug metabolism (hepatic dysfunction or drug-drug interactions)

• 11 、 Bradycardia

– Sinus bradycardia, heart block, incomplete heart block with pauses

• 12 、 Premature complexes leading to short-long-short cycles

五、 Management of Drug-Induced QT Prolongation

• 1 、 Continuous QTc monitoring

–QTc>500 ms or increase>60ms

• accompanied by Premonitory ECG Signs of TdP

• 2 、 Appropriate actions include– discontinuation of the culprit drug

– Bradyarrhythmias 、 electrolyte abnormalities

– the ready availability of an external defibrillator

– highest possible ECG monitoring surveillance ：• Patients should not be transported from the unit for

diagnostic or therapeutic procedures

– Intravenous Magnesium sulfate 2 g

(Class IIa, Level of Evidence: B)

六、 Management of Drug-Induced TdP

• directcurrent cardioversion

–Sustained TdP• does not terminate spontaneously

• degenerates into ventricular fibrillation

• intravenous magnesium sulfate

–Magnesium sulfate 2 g

(Class IIa, Level of Evidence: B)

–repeat infusions of magnesium sulfate 2 g

•TdP persist

• temporary transvenous pacing–Atrial or ventricular

–at rates 70 beats/minute

• Repletionof potassium– levels of 4.5 to 5 mmol/L

–Class IIb, Level of Evidence: C