QT prolongation

Revision as of 06:06, 5 February 2014 by Rossdonaldson1 (talk | contribs) (DDX)

Diagnosis

  • QTc >440 (male), >460 (female)
  • >500 = real concern (may result in torsades)

DDX

  1. Pause Dependent (Aquired)
    1. Drug induced
      1. Antidyrhythmics
      2. Phenothiazines
      3. TCAs
      4. Organophosphates
      5. Antihistamines
    2. Electrolyte Abnormalities (hypoKalemia, hypoMag, hypoCa)
    3. Diet related (starvation, low protein)
    4. Severe Bradycardia/AV Block
    5. Hypothyroid
    6. Contrast injection
    7. CVA (intraparenchymal)
    8. MI
  2. Adrenergic Dependent
    1. Congenital
      1. Jarvel/Lange-Nielsen
        1. (+deafness; AR)
      2. Romano-Ward synd
        1. (nl hearing; AD)
      3. Sporatic
      4. Mitral valve prolapse
    2. Acquired
      1. CVA (subarachnoid)
      2. Autonomic surg (catechol excess: neck dissection, carotid endarterect, truncal vagotomy)

Treatment

  1. Pause Dependent (precipitated by bradycard)
    1. Unstable/sustained torsades--> unsynch countershock
    2. Stable
      1. Treat underlying prob
      2. Increase HR (isoproterenol or overdrive pacing
      3. Magnesium sulfate IV
      4. Consider amiodarone
  2. Adrenergic Dependent (precipited by tachycardia)
    1. Unstable/sustained torsades--> unsynch countershock
    2. Stable
      1. slow HR (B-blockers)
      2. May consider magnesium

Drug List

  1. Antiarrhythmics
    1. Amiodarone, disopyramide, dofetilide, flecainide, ibutilide, mexiletine, procainamide, quinidine, sotalol
  2. Antibiotics
    1. Macrolide
      1. Azithromycin, erythromycin, clarithromycin
    2. Fluoroquinolone
      1. Ciprofloxacin, gatifloxacin, gemifloxacin, levofloxacin, moxifloxacin, ofloxacin
    3. Other
      1. Pentamidine, telithromycin, trimethoprim-sulfamethoxazole
  3. Antidepressants
    1. Amitriptyline, citalopram, doxepin, fluoxetine, nortriptyline, paroxetine, sertraline, venlafaxine
  4. Antiemetics
    1. Dolasetron, droperidol, granisetron, ondansetron
  5. Antifungals
    1. Fluconazole, itraconazole, ketoconazole, voriconazole
  6. Antihypertensives
    1. Nicardipine
  7. Antineoplastics
    1. Lapatinib, nilotinib, sunitinib, tamoxifen
  8. Antimalarials
    1. Chloroquine, halofantrine
  9. Antipsychotics
    1. Chlorpromazine, clozapine, galantamine, haloperidol, lithium, paliperidone, pimozide, quetiapine, risperidone, thioridazine, ziprasidone
  10. Antivirals
    1. Amantadine, atazanavir, foscarnet
  11. Diuretics
    1. Indapamide
  12. Immune suppressants
    1. Tacrolimus
  13. Opiates
    1. Methadone
  14. Phosphodiesterase inhibitors
    1. Sildenafil, vardenafil
  15. Skeletal muscle relaxants
    1. Tizanidine
  16. Urinary antispasmodics
    1. Solifenacin

See Also

Source

  • Rosen
  • Tintinalli