Existing Pharmacological Treatments for Arrhythmia

Pharmacological treatment includes administering antiarrhythmic medications like the ones listed on this page in addition to hundreds of others. A complete list of antiarrhyhmic medications can be seen on http://rateadrug.com/Arrhythmia-Irregular-Heartbeat-symptoms-feedback.aspx . Normally because antiarrhythmic agents have a narrow toxic-therapeutic relationship, important compications of therapy can results from amounts of drug that only slightly exceed the amount necessary to produce beneficial effects. It is obvious that careful dosage is essential to maintain adequate but nontoxic amounts of drug in the body. There are many factors to consider when prescribing an antirarrhythmic medication: tissue type, the degree of acute or chronic damage, heart rate, membrane potential, heart rate, intrinsic tissue properties, orientation of myocardial fibers and other associated conditions. It therefore may take multiple attempts for a doctor to find the medication that is right for the patient. Tachycardias (beating too fast) and premature beats may be administered intravenously in an emergency situation or orally for long term treatment. Antiarrhythmic drugs can either suppress the quick-firing pacemaker tissue or depress the transmission of impulses that conduct too rapidly. In patients with atril fibrillation, a blood thinner is usually added to reduce the risk of blood clots and stroke. The effectiveness of antiarrhythmic drugs can be gauged by an electrocardiogram.

Most of the available antiarrhythmic drugs are grouped into four main classes according to Vaughan Williams classification: (I) Sodium Channel Blockers, (II) Beta-Blockers, (III) Potassium Channel Blockers and (IV) Calcium Channel Blockers. In most cases, the drugs have to be taken for the rest of the patient's life.

Class I: Sodium Channel Blockers
Sodium (Na) channel blockers slow conduction in fast-channel tissues by blocking fast sodium channels. These drugs are used for patients with ventricular arrhythmias or recurrent atrial fibrillation. These drugs are typically only used in patients who do not have a structural heart disorder because they may depress ventricular contractility. Some commonly prescribed sodium channel blockers are (generic, brand):
Disopyramide (Norpace)
Flecainide (Tambocor)
Lidocaine (Xylocaine)
Quinidine
Phenytoin (Dilantin)

Class II: Beta-Blockers
Beta-blockers decrease the heart rate and cardiac output, which lowers blood pressure by blocking the effects of adrenaline (what mediates the "fight or flight" response). They affect predominantly slow-channel tissues (SA and AV nodes), where they decrease rate of automaticity, slow conduction velocity and prolong refractoriness. These are used to treat sinus tachycardia, atrial flutter and atrial fibrillation. They are also used to treat chest pain. These are not to be used in patients with asthma. Some commonly prescribed beta-blockers are (generic, brand):
Acebutolol (Sectral)
Atenolol (Tenormin)
Metoprolol (Lopressor)
Nadolol (Corgard)
Propranolol (Inderal)

Class III: Potassium Channel Blockers
Potassium channel blockers prolong action potential duration and refractoriness in slow and fast channel tissues. The conduction velocity is not significantly affected but the capacity for the cardiac tissue to transmit impulses at high frequencies is reduced. These are helpful in patients with atrial flutter, atrial fibrillation and ventricular tachycardias. Some commonly prescribed potassium channel blockers are (generic, brand):
Amiodarone (Pacerone)
Dofetilide (Tikosyn)
Ibutilide (Corvert)
Sotalol (Betapace)

Class IV: Calcium Channel Blockers
Calcium channel blockers slow the heart rate by interrupting the movement of calcium into the heart. These are used to treat high blood pressure, chest pain and arrhythmias. These depress calcium dependent action potentials in slow channel tissues and thus decrease the rate of automaticity, slow conduction velocity and prolong refractoriness. These are especially helpful for patients with atrial fibrillation and supraventricular tachycardia. Some commonly prescribed calcium channel blockers (generic, brand):
Amlodipine (Norvasc)
Diltiazem (Cardizem)
Felodipine (Plendil)
Nifedipine (Procardia)
Verapamil (Covera)

As mentioned above, you can visit www.RateADrug.com to learn about others' experiences with most of the medications listed above. If you would like to let others know about your experience with a particular drug, fill out an anonymous 5 minute survey by clicking on Evaluate This Treatment! I hope you can find something to assist you in your journey with arrhythmia. If you have any questions or comments, please let me know!