Rapid, disordered contraction of the heart muscles whereby the heart flutters in an uncontrolled manner (fibrillation) is the most serious type of arrhythmia. Ventricular fibrillation (VF) is thought to be responsible for many of the 335,000 sudden cardiac deaths reported each year.1 Because reduced blood flow to the heart often causes or contributes to this heart rhythm disturbance, VF is a concern for heart attack patients.52
>Most cases of VF occur in the first four hours after a heart attack. The risk of dying from this heart rhythm disturbance has declined with improved heart attack treatments, but VF can cause death in the first day after a heart attack.53 Heart attack patients used to be given the class I antiarrhythmic lidocaine to prevent VF, but this is no longer done because there is no clear evidence that it reduces the risk of dying and some evidence suggets that it may be harmful.54, 55 Intravenous beta blockers help prevent ventricular fibrillation early after a heart attack and are given to patients who can tolerate beta blockers. When VF occurs, it is treated with cardioversion; an electric shock is delivered to the heart using paddles placed on the chest (as commonly seen on television medical dramas). VF that is not corrected by shock may be treated with amiodarone, a class III antiarrhythmic. If VF occurs more than 2 days after a heart attack, you may need to have an ICD implanted.56
Ventricular tachycardia (VT) is a rapid heartbeat affecting the lower chambers of the heart. Most cases of VT occur within the first 48 hours after a heart attack. Often, this rhythm disturbance will correct itself without needing treatment. VT that does not impair blood flow to the heart may be treated with medication, preferably amiodarone.57 VT that impairs blood flow to the heart requires electric shock treatment (cardioversion). People who experience VT that impairs blood flow to the heart more than 2 days after a heart attack have a poor prognosis and may need to have an ICD implanted.56, 58
The most common cardiac arrhythmia is atrial fibrillation (AF), a rapid, disordered contraction of the heart muscles whereby the heart flutters in an uncontrolled manner. Atrial fibrillation affects 2.2 million people in the US, and approximately 55% of people discharged with a diagnosis of AF are women.1 Heart attack patients who experience AF have a higher risk of dying or experiencing other heart problems both in the hospital and in the long-term than heart attack patients who do not suffer this heart rhythm disturbance.59-61 When medical therapy is required, intravenous beta blockers slow the heart rate. The calcium channel blockers verapamil (Covera or Verelan) and diltiazem (Cardizem or Tiazac) may be used for controlling the rapid heart rate in the short-term in patients who cannot take beta blockers; however, calcium channel blockers increase the risk of dying after a heart attack when used for longer periods of time.40 Digoxin (Lanoxin) is no longer the first-choice medication for the management of AF, but it may be used in patients with heart failure or severe damage to the left side to the heart. 3, 62 Sotalol (Betapace) or amiodarone (Cordarone or Pacerone) may be used for intermediate or long-term treatment of AF after a heart attack.63 Sotalol is generally the first choice because it has fewer serious side effects than amiodarone.29
Heart attack patients who develop a dangerously slow heartbeat (bradycardia or bradyarrhythmia) are best treated with a pacemaker. When medication is needed, amiodarone (Cordarone or Pacerone) or sotalol (Betapace) may be used.
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