How is ventricular tachycardia (VT) evaluated in unstable patients?

Updated: Dec 05, 2017
  • Author: Steven J Compton, MD, FACC, FACP, FHRS; Chief Editor: Jeffrey N Rottman, MD  more...
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Answer

Advanced cardiac life support (ACLS) protocols should be quickly followed. Laboratory tests should be deferred until electrical cardioversion has restored sinus rhythm and the patient is stabilized. If the patient is hemodynamically stable at presentation, a 12-lead ECG and electrolyte levels may be obtained before attempted conversion with medications or direct current (DC) cardioversion. Note that if electrolyte levels are not obtained in an acute evaluation of VT post conversion, the hyperadrenergic state or hemodynamic compromise often associated with VT may affect the subsequently obtained electrolyte laboratory values.

The ECG should be repeated once sinus rhythm has been restored, or when prior VT is suspected, as in a patient who experienced syncope. The ECG may also provide clues for differentiating among potential arrhythmia mechanisms or causes of VT, such as the following:

  • Acute or chronic infarction
  • Ischemia
  • Myocardial scar
  • Ventricular preexcitation
  • Hypertrophy
  • Conduction disease
  • QT prolongation
  • Other precordial repolarization abnormalities (eg, Brugada syndrome, arrhythmogenic right ventricular dysplasia [ARVD])

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