As a strategy for minimizing risk of device damage, it is recommended to place the pads at least 12 cm away from the pulse generator and to use the anteroposterior positioning of electrodes. All ICDs and permanent pacemakers should be interrogated after cardioversion is performed to ensure the proper functioning of these devices. An initial study from revealed a significant increase in the incidence of serious postcardioversion ventricular ectopy in patients that had ECG evidence of digitalis toxicity precardioversion.
Subsequent studies have confirmed that sustained ventricular ectopy post cardioversion is exceedingly rare and tends to occur with higher energy cardioversion along with other concomitant factors such as hypokalemia.
As with all tachyarrhythmias it is important to identify and treat the underlying cause. If cardioversion is deemed necessary it should be carried out starting with a lower energy level and ensuring the correction of any electrolyte abnormalities. Complications of cardioversion include skin burns, transient hypotension commonly from sedation , and EKG changes such as nonspecific ST-T wave changes or transient ST segment elevation.
High-energy shocks may also result in myocardial necrosis, which may present as a small rise in cardiac enzymes. Myocardial dysfunction may also occur due to myocardial stunning and is usually related to ischemia during cardiac arrest.
This complication usually improves in 24 to 48 hours post resuscitation. Rarely, pulmonary edema may occur as a result of left atrial standstill or LV dysfunction after cardioversion in patients with longstanding AF.
The two most common potentially life-threatening complications associated with cardioversion and defibrillation are arrhythmia and thromboembolism. Arrhythmias include sinus tachycardia, non-sustained VT, bradycardia and occasionally complete heart block that may require temporary cardiac pacing. Clinically significant VT or VF may also occur infrequently. Previous studies in patients with atrial fibrillation have reported a post cardioversion stroke risk of 1. Much of these studies are retrospective analyses of data from emergency room visits and their results have not been reproduced in the ICU setting.
The benefits of cardioversion in unstable AF outweighs the risk of clot embolization and therefore, urgent synchronized cardioversion should not be delayed in these patients. This div only appears when the trigger link is hovered over. Otherwise it is hidden from view. Forgot Username? About MyAccess If your institution subscribes to this resource, and you don't have a MyAccess Profile, please contact your library's reference desk for information on how to gain access to this resource from off-campus.
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Cardioversion and Defibrillation. Oropello J. John M. Oropello, et al. Critical Care. McGraw Hill;. Accessed November 14, Cardioversion and defibrillation.
McGraw Hill. Download citation file: RIS Zotero. Reference Manager. Autosuggest Results. The reason a shock must be synchronized is that the cardiac cycle has both a vulnerable and a refractory period. The refractory period occurs during the QRS complex see the image below. The T wave is considered the vulnerable period, especially the middle and second half of the T wave. By timing the shock to be delivered during the QRS complex, electrical stimulation is avoided during the vulnerable period, which reduces the risk of inducing ventricular fibrillation.
Defibrillation involves the delivery of a high-energy shock without the need to time the shock to the unstable rhythm see the image below. In this example, the delivered shock is not synchronized with the ECG because the rhythm is unstable and there is no apparent QRS complex or T wave to avoid. The rhythm was converted to NSR after the shock was delivered. Both defibrillation and synchronized cardioversion impose a therapeutic dose of electrical energy on the myocardium.
Defibrillation is used to treat certain types of arrhythmias ventricular fibrillation and pulseless ventricular tachycardia. Synchronized cardioversion is used to treat other arrhythmias, including atrial fibrillation AF , atrial flutter, and stable ventricular tachycardia when medications have failed to convert the rhythm, or when the patient is becoming unstable and the rhythm must be immediately terminated. AF is well recognized to be the most common dysrhythmia worldwide, and its prevalence is estimated to increase in the coming years, resulting in an increase of admission to the emergency department for symptoms related to this cardiac rhythm abnormality.
Even if no clots were found in your heart before your procedure, you'll take blood-thinning medications for at least several weeks after your procedure to prevent new clots from forming. For most people, cardioversion can quickly restore a regular heartbeat. It's possible you'll need additional procedures to keep a normal heart rhythm. Your doctor may suggest lifestyle changes to improve your heart health and prevent or treat conditions that can cause arrhythmias, such as high blood pressure.
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This content does not have an English version. This content does not have an Arabic version. Overview Cardioversion Open pop-up dialog box Close. Cardioversion During cardioversion, shocks are delivered to your chest by the cardioversion machine while your heart rhythm is monitored. Request an Appointment at Mayo Clinic. Share on: Facebook Twitter. Show references Cardioversion.
National Heart, Lung, and Blood Institute. Accessed March 26, American Heart Association. Epub Nov Resuscitation Council UK Guidelines. Ann Thorac Surg. Supraventricular arrhythmias. Am Fam Physician. Am J Cardiol. Epub Feb McNamara RL, Tamariz LJ, Segal JB, et al ; Management of atrial fibrillation: review of the evidence for the role of pharmacologic therapy, electrical cardioversion, and echocardiography.
Ann Intern Med. Reiffel JA ; Cardioversion for atrial fibrillation: treatment options and advances. Pacing Clin Electrophysiol. I have just seen the result of my 24 holter monitor which shows 13, PACs in 24 hours. Throughout that time I was in sinus rhythm.
I feel dreadful most of the time.
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