Cardioversion is synchronized delivery of direct current energy (typically to the chest), but potentially directly to the myocardium by internal catheters. Unlike its asynchronous counterpart, defibrillation, cardioversion delivers direct current energy synchronously to the R-wave of the electrogram (or electrocardiogram) in order to prevent inadvertent discharge during the vulnerable cycle and resultant ventricular fibrillation.
It is important to know how to perform an external cardioversion for the treatment of hemodynamically stable tachycardias. The most frequent cardioversion indication is for conversion of atrial fibrillation or atrial flutter. During these arrhythmias, the rapid atrial rhythm must be disrupted and reset into a more normalized sinus rhythm.
In order to perform an electrical cardioversion, the patient must be connected to an external monitor and cardioverter-defibrillator device. An ECG is monitored or recorded either through such a device or separately. It is also optimal for the cardioverter-defibrillator to have external pacing capabilities should the patient become profoundly bradycardiac. If this procedure is performed electively, the patient should be administered oxygen via nasal cannula and should have an intravenous line inserted. The intravenous line could be used for fluids, conscious or deep sedation, antiarrhythmic drugs, and if necessary, resuscitation medications. Occasionally, during a cardioversion the patient may become bradycardiac, making it necessary to give epinephrine and/or atropine.