Heart Attack and Antiarrhythmic Medicines

During a heart attack, damage to the heart muscle can increase the risk of abnormal heart rhythms, called arrhythmias. Arrhythmias can prevent the heart from effectively pumping blood, and if serious, lead to sudden death. Antiarrhythmic drugs help the heart beat more normally, usually by suppressing abnormal beats or by regularizing the heart rate.

There are a wide variety of drugs available to treat the various causes of abnormal rhythms. In emergencies, some of these drugs are given via an IV. Oral forms of medicine are used to treat more chronic arrhythmias.

Antiarrhythmic medications include:

• Class I drugs: Sodium channel blockers
• Class II drugs: Beta-blockers
• Class III drugs: Action potential-prolonging agents
• Class IV drugs: Calcium channel blockers

Antiarrhythmic drugs help treat heart-attack related arrhythmias by slowing the electrical activity in the heart. Drugs in the various classes have the same overall effect but work through different mechanisms.

Some antiarrhythmics also have other effects.

• Beta-blockers decrease demands on the heart and lower blood pressure. They may limit the amount of heart damage and help to prevent future heart attacks.
• Calcium channel blockers lower blood pressure and may be given to patients who cannot take beta-blockers. Recent research indicates they are not helpful in the early treatment of heart attack, nor do they prevent future heart attacks.

Read more details about Antiarrhythmic Medicines.

The main issue with antiarrhythmic drugs is that unless the underlying rhythm problem can be corrected, they must be taken indefinitely. Also, one of the more unpredictable side effects of some of these medicines is the risk of making the arrhythmia worse. Talk to your doctor about the specific side effects or warning signs to watch for based on the drug you are taking:

• Sodium channel blockers
• Beta-blockers
• Action potential-prolonging agents
• Calcium channel blockers