Ventricular Fibrillation

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).

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

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

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.

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).