Are class V antiarrhythmics beneficial?
In people with heart disease, the class V antiarrhythmics are used to treat certain heart rhythm disturbances affecting the upper chambers of the heart (the atria).3 They are not used to prevent arrhythmia. These antiarrhyhmics should be used with caution since men and women taking digoxin (Lanoxin) after having a heart attack have an increased risk of dying early.41-43 Digoxin may be used to relieve symptoms of atrial fibrillation (see below) in people with heart failure or severe damage to the left side of the heart.29
Prescribed Class V antiarrhythmics
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Miscellaneous Antiarrhythmics |
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Generic: |
Adenosine |
Digoxin |
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Brand: |
Adenocard IV |
Lanoxin |
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Administration: |
Oral, intravenous |
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Indications: |
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You should not be treated with these medications: |
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Common side effects: |
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Pregnancy/nursing: |
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What are the risks of heart rhythm drugs?
With the exception of beta blockers, the benefits of antiarrhythmic medications must be carefully balanced against the risk of triggering a fatal heart rhythm disturbance. These medications are generally reserved for people with life-threatening arrhythmias. Therapy is usually initiated in the hospital where you can be monitored.
Women taking antiarrhythmic medications have a higher risk than men of developing the life-threatening rapid heartbeat torsade de pointes (TdP), particularly with class IA medications and sotalol (Betapace), a class III antiarrhythmic.44-46 Women have a higher risk of TdP to begin with because the time between electrical activation and deactivation of the lower chambers of the heart is longer for women than men (called the QT interval in reference to the pattern produced on the ECG). Two-thirds of heart medication-induced TdP cases occur in women,45 and it is estimated that TdP accounts for 5% of the 300,000 sudden cardiac deaths each year.47
Magnesium
Low blood levels of magnesium increase the risk of heart rhythm disturbances. Older studies suggested that heart attack patients benefited from intravenous injections of magnesium.48, 49 Contemporary studies where most heart attack patients are treated with balloon angioplasty or clot busting drugs do not show a benefit for IV magnesium in men or women.50, 51 IV magnesium may help treat some life-threatening ventricular arrhythmias, including torsade de pointes (see Risks).3 It is not known whether dietary magnesium or supplements lower the risk of developing heart rhythm problems.
