Cardiac dysrhythmia Drugs Phenomena

Cardiac dysrhythmia (also known as arrhythmia or irregular heartbeat) is any of a large and heterogeneous group of conditions in which there is abnormal electrical activity in the heart.

The heartbeat may be too fast or too slow, and may be regular or irregular. A heart beat that is too fast is called tachycardia and a heart beat that is too slow is called bradycardia.

Some arrhythmias are life-threatening medical emergencies that can result in cardiac arrest. In fact, cardiac arrythmias are one of the most common causes of death when travelling to a hospital. Others cause symptoms such as an abnormal awareness of heart beat (palpitations), and may be merely uncomfortable.

These palpitations have also been known to be caused by atrial/ventricular fibrillation, wire faults, and other technical or mechanical issues in cardiac pacemakers/defibrillators. Still others may not be associated with any symptoms at all, but may predispose the patient to potentially life threatening stroke or embolism.

precipitated by antiarrhythmic therapy, which means it is a side effect associated with the administration of some existing antiarrhythmic drugs, as well as drugs for other indications. In other words, it is a tendency of antiarrhythmic drugs to facilitate emergence of new arrhythmias. Some arrhythmias are very minor and can be regarded as normal variants. In fact, most people will on occasion feel their heart skip a beat, or give an occasional extra strong beat; neither of these is usually a cause for alarm.

The term sinus arrhythmia refers to a normal phenomenon of mild acceleration and slowing of the heart rate that occurs with breathing in and out. It is usually quite pronounced in children, and steadily decreases with age. This can also be present during meditation breathing exercises that involve deep inhaling and breath holding patterns.

Proarrhythmia is a new or more frequent occurrence of pre-existing arrhythmias, paradoxically

Antiarrhythmic drugs

<sup>Symptomatic tachycardias and premature beats may be treated with a variety of antiarrhythmic drugs. These may be given intravenously in an emergency situation or orally for long-term treatment. These drugs either suppress the abnormal firing of pacemaker tissue or depress the transmission of impulses in tissues that either conduct too rapidly or participate in reentry.

In patients with atrial fibrillation, a blood thinner (anticoagulant or antiplatelet agent such as aspirin) is usually added to reduce the risk of blood clots and stroke.

When tachycardias or premature beats occur often, the effectiveness of antiarrhythmic drug therapy may be gauged by electrocardiographic monitoring in a hospital, by using a 24-hour Holter monitor or by serial drug evaluation with electrophysiologic testing.

The relative simplicity of antiarrhythmic drug therapy must be balanced against two disadvantages. One is that the drugs must be taken daily and indefinitely. The other is the risk of side effects. While side effects are a risk of all medication, those associated with antiarrhythmic drugs can be very hard to manage. They include proarrhythmia, the more-frequent occurrence of preexisting arrhythmias or the appearance of new arrhythmias as bad as or worse than those being treated.

Some commonly prescribed antiarrhythmic drugs include (generic name first; common brand names in parentheses – read drug brand name disclaimer above):</sup>

• ^{Amiodarone (Cordarone, Pacerone)}
• ^{Bepridil Hydrochloride (Vascor)}
• ^{Disopyramide (Norpace)}
• ^{Dofetilide (Tikosyn)}
• ^{Dronedarone (Multaq)}
• ^{Flecainide (Tambocor)}
• ^{Ibutilide (Corvert)}
• ^{Lidocaine (Xylocaine)}
• ^{Procainamide (Procan, Procanbid)}
• ^{Propafenone (Rythmol)}
• ^{Propranolol (Inderal)}
• ^{Quinidine (many trade names)}
• ^{Sotalol (Betapace)}
• ^{Tocainide (Tonocarid)}

http://en.wikipedia.org/wiki/Cardiac_dysrhythmia