Patient was educated that antiarrhythmic medications are basically grouped into four classes. Medications belonging to these four classes act differently to exert their antiarrhythmic effect. The four classes are as follows:
- Class I antiarrhythmic medications
- These medications block the sodium channels in the cardiac muscle to exert their antiarrhythmic effect and so, are called sodium channel blockers.
- These medications inhibit arrhythmias by inhibiting the depolarization of cardiac tissues and slowing down the conduction velocity of cardiac impulse.
- Class II antiarrhythmic medications:
- These medications block the action of noradrenaline on Beta-1 receptors in the pacemaker tissues. So, they are called Beta-blockers.
- These medications reduce the excitability of pacemaker cells, inhibit the rapid impulses initiated in the pacemaker cells, and thus, slow down the heart rate.
- Class III antiarrhythmic medications
- These medications block the potassium channels in the cardiac muscle to exert their antiarrhythmic effect and so, are called potassium channel blockers.
- These medications inhibit arrhythmias by inhibiting the repolarization of cardiac tissues and prolonging the refractory period.
- Class IV antiarrhythmic medications
- These medications block the calcium channels in the pacemaker cells and blood vessels, to exert their antiarrhythmic effect and so, are called calcium channel blockers.
- These medications reduce the excitability of pacemaker cells, inhibit the rapid impulses initiated in the pacemaker cells, and thus, slow down the heart rate.
