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Encyclopedia of Health and Medicine

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18 The Cardiovascular System<br />

they remain benign. Antiarrhythmia medications<br />

successfully treat the majority <strong>of</strong> symptomatic<br />

arrhythmias. These medications work by blocking<br />

certain aspects <strong>of</strong> the biochemical functions<br />

responsible for myocardial contractions. The cardiologist<br />

may prescribe two or more antiarrhythmia<br />

medications in combination to treat some kinds <strong>of</strong><br />

arrhythmias. People who have heart failure, CAD,<br />

valvular disease, <strong>and</strong> other heart disorders may<br />

take antiarrhythmia medications along with other<br />

medications to treat these conditions.<br />

Cardiologists select antiarrhythmia medications<br />

based on the characteristics <strong>of</strong> the arrhythmia,<br />

which may be simple or complex, as well as the<br />

presence <strong>of</strong> other cardiovascular conditions, any<br />

other medications the person may be taking, <strong>and</strong><br />

factors such as age <strong>and</strong> lifestyle. After starting<br />

antiarrhythmia therapy, it is important to continue<br />

until the cardiologist makes changes in the<br />

therapeutic approach. Suddenly stopping an<br />

antiarrhythmia medication can have significant<br />

consequences including serious arrhythmias.<br />

Antiarrhythmia medications can have serious<br />

side effects such as worsening the existing<br />

arrhythmia or causing new arrhythmias. Some<br />

medications work by causing heart block, for<br />

example, to interrupt the conduction <strong>of</strong> aberrant<br />

electrical impulses. Finding the right medication<br />

or combination <strong>of</strong> medications sometimes takes a<br />

period <strong>of</strong> trial regimens <strong>and</strong> dosages. As the condition<br />

responsible for the arrhythmia changes over<br />

time, sometimes it becomes necessary to change<br />

the medication regimen as well.<br />

Other interventions may become necessary if<br />

medications are ineffective or generate intolerable<br />

side effects. Such interventions may include<br />

• CARDIOVERSION, in which the cardiologist delivers<br />

(under sedation) a mild electrical shock<br />

through the chest wall to reorganize <strong>and</strong><br />

restore to normal the heart’s electrical activity<br />

• RADIOFREQUENCY ABLATION, a cardiac catheterization<br />

procedure in which the cardiologist uses<br />

radi<strong>of</strong>requency impulses to kill a small <strong>and</strong><br />

carefully targeted segment <strong>of</strong> myocardial cells<br />

to prevent them from initiating or conveying<br />

electrical impulses<br />

• implantable PACEMAKER, a small battery-operated<br />

device that emits an electrical impulse to<br />

trigger the heart’s contractions<br />

COMMONLY PRESCRIBED ANTIARRHYTHMIA MEDICATIONS<br />

Beta Blockers<br />

acebutolol (Sectral) atenolol (Tenormin) betaxolol (Kerlone)<br />

carteolol (Cartrol) esmolol (Brevibloc) labetalol (Normodyne)<br />

metoprolol (Lopressor) nadolol (Corgard) penbutolol (Levatol)<br />

pindolol (Visken) propranolol (Inderal) sotalol (Betapace)<br />

timolol (Blocadren)<br />

Calcium Channel Blockers<br />

amlodipine (Norvasc) bepridil (Vascor) diltiazem (Cardizem)<br />

felodipine (Plendil) isradipine (DynaCirc) nicardipine (Cardene)<br />

nifedipine (Procardia) nimodipine (Nimotop) nisoldipine (Sular)<br />

verapamil (Isoptin)<br />

Miscellaneous Actions<br />

adenosine<br />

digoxin<br />

Potassium Channel Blockers<br />

amiodarone (Cordarone) d<strong>of</strong>etilide (Tikosyn) ibutilide (Corvert)<br />

Sodium Channel Blockers<br />

disopyramide (Norpace) flecainide (Tambocor) lidocaine (Xylocaine)<br />

mexiletine (Mexitil) moricizine (Ethmozine) procainamide (Procan)<br />

propafenone (Rythmol) quinidine (Cardioquin) tocainide (Tonocard)

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