Torsade (Torsade De Pointes)


General Information

History

Definitions


Risk Factors for Torsade


Etiology

Congenital Long QT Syndrome (see Congenital Long QT Syndrome, [[Congenital Long QT Syndrome]])

Autoimmune Disease with Anti-Ro/SSA Antibodies

Endocrine/Metabolic

Bradyarrhythmia

Intracranial Disease

Organic Heart Disease

QT Prolonging Drugs and Toxins (@ = definite association with torsade)

Anorexigens

Anti-Arrhythmics

Antihistamines (see H1-Histamine Receptor Antagonists, [[H1-Histamine Receptor Antagonists]])

Antimicrobials

Anti-Muscarinics

Anti-Neoplastic Agents

β2 Agonists (see β2-Adrenergic Receptor Agonists, [[β2-Adrenergic Receptor Agonists]])

Calcium Channel Blockers (see Calcium Channel Blockers, [[Calcium Channel Blockers]])

Gonadotropin-Releasing Hormone Agonists/Antagonists

Neurologic Medications

Opiates (see Opiates, [[Opiates]])

Psychiatric Drugs

Serotonin 5-HT3 Receptor Antagonists (see Serotonin 5-HT3 Receptor Antagonists, [[Serotonin 5-HT3 Receptor Antagonists]])

Sympathomimetics

Vasoactive Drugs

Other Medications

Toxins

Other QT Prolonging Conditions


Physiology

Drug-Induced Blockade of Outward IKr Potassium Current (Mediated by the Potassium Channel Encoded by the KCNH2 Gene)

Clinical Precipitants of Torsade in Acquired Long QT States

Clinical Precipitants of Torsade in Some Congenital Long QT Syndromes (Long QT Syndrome Types 1 and 2)


Diagnosis

Electrocardiogram (EKG) (see Electrocardiogram, [[Electrocardiogram]])

Relationship of QT Interval to Risk of Torsade


Clinical Manifestations

Cardiovascular Manifestations


Treatment

Congenital Long QT Syndrome

Beta Blockers (see xxxx, [[xxxx]])

Mexiletine (Mexitil) (see Mexiletine, [[Mexiletine]])

Permanent Dual Chamber Pacemaker

Left Chamber Sympathetic Denervation (Cardiothoracic Sympathectomy)

Automatic Implantable Cardioverter-Defibrillator (AICD) (see Automatic Implantable Cardioverter-Defibrillator, [[Automatic Implantable Cardioverter-Defibrillator]])

Acquired Long QT State

Defibrillation

Magnesium (see Magnesium Sulfate, [[Magnesium Sulfate]])

Two observational studies showed that IV magnesium sulfate can facilitate termination of torsades de pointes (irregular/polymorphic VT associated with prolonged QT interval)
– Magnesium sulfate is not likely to be effective in terminating irregular/polymorphic VT in patients with a normal QT interval
– A number of doses of magnesium sulfate have been used clinically, and an optimal dosing regimen has not been established
– When VF/pulseless VT cardiac arrest is associated with torsades de pointes, providers may administer an IV/IO bolus of magnesium sulfate at a dose of 1 to 2 g diluted in 10 mL D5W (Class IIb, LOE C).

Temporary Transvenous Overdrive Pacing (Atrial/Ventricular)

Isoproterenol (see Isoproterenol, [[Isoproterenol]])

Lidocaine (see Lidocaine, [[Lidocaine]])

Phenytoin (Dilantin) (see Phenytoin, [[Phenytoin]])

Sodium Bicarbonate (see Sodium Bicarbonate, [[Sodium Bicarbonate]])

Potassium Chloride (see Potassium Chloride, [[Potassium Chloride]])


References