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Electrophysiological study and catheter ablation procedure

Professor Fatih Duhan Bayran

The last two decades have witnessed significant developments in the diagnosis and management of arrhythmias, most people with an abnormal heart rhythm can lead a normal life if it is properly diagnosed. Diagnosing the type of the arrhythmias is the key to the treatment. Today, most of the advance heart centers use Electrophysiology studies (EPS) to test the electrical activity of your heart to find where an arrhythmia (abnormal heartbeat) is coming from. This can help doctors to decide whether patient needs medicine, a pacemaker, ICD, catheter ablation or surgery for arrhythmias. Cardiologist Professor Fatih Duhan Bayran M.D. explains heart’s electrical system and how to find and fix the problems of the rate or rhythm of the heartbeat with advanced methods.

What is the heart’s electrical system? 

Our heart has an electrical conduction system that is similar to power network of a city. In fact, the stimuli signaled from the main center (sinus node), which is located at right atrium, pass an intermediary station (atrioventricular node) between atria and ventricles following a short latent time and ultimately they spread to the ventricles again via specialized conduction means. Therefore, the electrical stimulation generated in the main center is conducted to all cardiac muscle (myocardial) cells and the heart is contracted.

Why do the disruptions occur in the heart’s electrical system? 

Normal conduction and stimulation system of heart may compromise due to various reasons. Sometimes, congenital accessory pathways lead to short circuits, resulting in accelerated heart rate, also known as tachycardia. Moreover, extra-nodal stimulations can be emitted, which implies any signal arising out of any region of heart, excluding above specified main stimulation center, and thus, heart rate increases.

What is electrophysiological diagnosis method? 

This diagnostic method, called electrophysiological study, investigates deviations by recording electrical signals directly on heart and by evaluating them after a catheter, also referred as electrode, is inserted through fine sheaths, which are inserted into the vessel located at inguinal and/or cervical region, to cardiac chamber(s). Thus, it is possible to understand whether main stimulation center of the heart and conduction systems function well.

Thus, if short circuit(s) is/are determined, punctuate energy is delivered with radio-waves and palpitation is completely eliminated. Or, if only one focus is responsible for palpitation, radio-waves are delivered and it is eliminated. This procedure is referred as catheter ablation. This method enabled elimination of most palpitations (tachycardia) permanently.

How does the electrophysiological diagnosis method affect the patient and how long does it take? 

You may feel palpitation when test stimulations are emitted to the intra-cardiac chambers during electrophysiological study. Or, you may have the same feeling when palpitation, the original complaint, is induced with electrical stimuli. Sometimes, external electrical shock can be required to correct palpitation, after tachycardia, rhythm is stimulated. You will not feel pain since you will be administered a sedative/anesthetic agent before the shock is applied. Diagnostic electrophysiological studies last 30-60 minutes. If it is a therapeutic study, the procedure will possibly last 1-4 hour(s).

Is there any risk of electrophysiological diagnosis method?

Those procedures are generally associated with low risk. However, it does not mean that it is totally free of problems. The risk of death is very low. Although rare, pericardial effusion (deposition of fluid between layers of pericardium) may develop secondary to the rupture of myocardium. Again, therapeutic procedure may rarely block normal conduction system of the heart, while radio-waves are delivered, since the short circuit, the underlying cause of the palpitation, is located close to the normal conduction system. In this case, permanent placement of pacemaker may be required. Bleeding, subcutaneous hematoma and resultant swelling and pain may develop at puncture site in 2-3% of all cases. However, those complications do not lead to significant problems and they spontaneously resolve.

Are there any alternatives of electrophysiological diagnosis method? 

Any other diagnostic method may not provide us with data which is obtained with electrophysiological study. It is usually preferred when other diagnostic methods are insufficient.

What is catheter ablation; when and how is it applied? 

Catheter ablation is a treatment for rhythm disorder performed by delivering radio-waves. This method is used for treatment of rhythm disorder, if rhythm disorder cannot be controlled with drugs or if the patient does not want to take drugs for lifetime. In some cases, rhythm disorder may be severe enough to threaten life. In such cases, catheter ablation method can be baseline option. The procedure can be carried out under local anesthesia, although some cases require general anesthesia. You will be administered sedative agents in order to feel comfortable during the procedure. You should rest without moving your legs for several hours in order to avoid bleeding.

What is the success rate of catheter ablation method? 

Success rate of treating rhythm disorders (in the form of accelerated heart rate) with catheter ablation may vary between 70 to 95 percent depending on type of palpitation and localization of short circuit. Success implies lack of recurrence. Rate of recurrence varies depending on the type of rhythm disorder, after palpitation is successfully treated. The rate is around 5-8% for palpitations which are secondary to short circuits in heart.

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