Ventricular Fibrillation


Risk

  • VFIB/VTach: Most frequent rhythm in sudden cardiac arrest and the most frequent cause of death in pts with coronary disease.

  • Risk of VF complicating an acute MI: 4–7%; has remained unchanged for several years.

  • 1-y mortality in survivors of near sudden death: 20–30% if nonresponsive to antiarrhythmics (20–50% of survivors).

Perioperative Risks

  • Primary VFIB associated with acute infarction may not affect prognosis if treated promptly with defibrillation.

  • Secondary VFIB (preceded by pump failure or hypotension) associated with 75–80% mortality during hospitalization

Worry About

  • Hypoxemia, hypercarbia, hyperkalemia or hypokalemia, ischemia, hypomagnesemia, digitalis toxicity, acid–base abnormalities, and coronary graft failure

  • Antiarrhythmic drug levels

  • Availability of defibrillator, myocardial ischemia, and early revascularization

Overview

  • Asynchronous, chaotic contractions of ventricles with no organized ventricular depolarization and therefore no QRS complexes and no cardiac output.

  • Coarse VFIB indicates recent onset and is readily correctable with prompt defibrillation.

  • Fine VFIB (coarse asystole) indicates delay since collapse; successful resuscitation is more difficult.

Etiology

  • Usually ischemic; often associated with an LV aneurysm

  • Idiopathic cardiomyopathy

  • Coronary spasm or graft failure, especially in the immediate postop period

  • Hypothermia

  • Long-QT syndrome is associated with VTach, especially torsades de pointes (one type of polymorphic VTach; other types are not associated with long-QT).

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