What Is the Difference Between the Classes of Antiarrhythmics?

Antiarrhythmics are drugs used to treat disorders of the heart's rhythm. Heart arrhythmias can be present at birth or develop later from damage or irritation to the heart muscle which create irregularities in the heart's electrical system.

Types

• There are four classes of antiarrhythmics; class I are sodium channel blockers, class II are beta blockers, class III are potassium channel blockers and class IV are calcium channel blockers.

Function

• Sodium channel blockers slow the conduction of the heart's electrical impulses, while beta blockers reduce blood pressure and heart rate and block impulses that may cause irregular beats. Calcium channel blockers work much the same way as beta blockers, while potassium channel blockers slow cardiac electrical impulses.

Considerations

• Every patient will have an individual response to the medications used to treat arrhythmias, and sometimes a medication may change but not improve the condition or may possibly worsen the patient's condition. Sometimes a number of medications must be tried before finding the right one.

Significance

• Since a patient's response to antiarrhythmics cannot be accurately anticipated, it's important when trying a new medication regimen that the patient be closely monitored with a Holter monitor or electrophysiology studies over a 24 hour period.

Warning

• It is critical that the patient let the physician know about all other medications, even those taken over the counter or herbal remedies, as many things can affect the antiarrhythmic medication and some interactions can be dangerous. Also, many of these medications can cause sensitivity to sunlight.