Although uncommon, cardioversion does have risks. The procedure can sometimes worsen arrhythmias. Rarely, it can cause life-threatening arrhythmias. These irregular heartbeats are treated with electrical shocks or medicines.
Cardioversion can dislodge blood clots in the heart. These clots can travel to organs and tissues in the body and cause a stroke or other problems. Taking anticlotting medicines before and after cardioversion can reduce this risk.