Electrophysiology study (EPS)
An electrophysiology study (EPS) is a detailed study of the heart's electrical system and is done to investigate an abnormal heart rhythm (arrhythmia).
The heart's electrical system
Parts of the heart that make a heartbeat.
The heart has four chambers. Two upper chambers (atria) pump blood to the two lower chambers (ventricles). In order for the heart to pump, it requires an electrical impulse to start a heartbeat.
Each heartbeat originates from the sinoatrial (SA) node — the heart's natural pacemaker — which is located in the upper right atrium.
This impulse travels through the atria, signaling them to contract. The impulse is received by the atrioventricle (AV) node. The AV node acts as a relay center to delay the impulse before sending it from the atria to the ventricles.
The impulse then spreads throughout the muscle of the ventricles, stimulating them to contract.
Normally, impulses are generated from the sinus node at a rate of 60 to 100 beats per minute (bpm). That is called a normal sinus rhythm. Sometimes the heart will beat slower than 60 bpm (called bradycardia) or faster than 100 bpm (called tachycardia).
Tachycardias that start in the upper chambers of the heart are called supraventricular tachycardia. Heartbeats that are too slow or too fast may cause fainting, fatigue, palpitations (fluttering in the chest), shortness of breath, chest pain or pressure.
Before the study
During the study
After the study
When to call your doctor
Call your doctor if you develop:
Experts at these hospitals perform electrophysiology studies:
Abnormal heart rhythm
Arrhythmia or dysrhythmia is an irregular heartbeat or rhythm. This can happen when your heart has extra beats, when it beats too fast or too slow.
Source: Allina Patient Education, Helping Your Heart, fourth edition, cvs-ahc-90648; Allina Patient Education, Electrophysiology Study (EPS), cvs-ahc-11798
Reviewed by: Allina Patient Education experts
First Published: 10/04/2002
Last Reviewed: 09/21/2011