Cardiac electrophysiology study

Cardiac electrophysiology study is an invasive examination conducted in patients in whom a superficial 12-lead ECG and other non-invasive (painless) examination do not provide sufficient information to diagnose and treat heart rhythm disorders.

Electrophysiology study is performed at a specially equipped and specialized laboratory (electrophysiology laboratory – EP lab). The procedure can last 1-4 hours. After local anaesthesia is given in the groin area, 2 to 5 thin introducers (plastic tubes) are inserted and through the introducers electrophysiology catheters are placed in the femoral vein. Catheters can be introduced through the left and/or right femoral vein, and rarely through subclavian and/or jugular vein to the right heart (the choice is up to the cardiologist). The catheters are further introduced to the heart and placed in the heart under X-ray control. At the tip of each catheter an electrical signal coming from the heart is recorded.

Electrophysiology study is performed to clarify the nature of the arrhythmic disturbances and to determine where arrhythmia occurs. During the EP study the doctors want to cause the arrhythmia experienced by the patient in his life. The arrhythmia may be caused by the electrical impulses produced over the catheter tip and managed by doctors.

In most cases, the arrhythmias caused during the EP study are interrupted by the same impulses that caused them. However, there are times when one electroshock is needed to cease the arrhythmia. In accordance with the determined arrhythmia and its mechanism, the doctor will decide on antiarrhytmic therapy, ablation and/or prevention. In some cases, it is possible to completely cure clinical arrhythmia with radiofrequency ablation by ablating in the area where arrhythmia occurs. (see: Radiofrequency cardiac ablation).

Complications of electrophysiology study. With electrophysiological study, as with all invasive procedures, there is a possibility for complications. Local complications are most common, such as: a small haematoma at the groin (catheter introducing area) [occurs in 10%] or the possibility of prolonged bleeding at the groin (after catheter withdrawal), for a maximum of ten minutes [occurs in 1-3%]. Less frequent [occurring in total of <0.5%] are lesions from blood vessel pressure, their obstruction, infection, or nerve damage that are in close proximity of blood vessels. Lesions of blood vessels pressure near the heart or in the heart can occur in 1-2 cases in 500. The possibility of thromboembolic complications is even smaller [1-2 cases in 1000]. In most cases, the complications are passable or can be repaired during the electrophysiology study. In rare cases, immediate surgical intervention may be required in case of a major complication that may be hazardous to the patient. This happens in 1 in 1000 cases.

In conclusion, during electrophysiology study the risk is very low and the benefit that the patient gains is very high.