Cardiac electrophysiological study

What is an EPS and how is it performed

Electrophysiological study of the heart (EPS) is a cornerstone of modern interventional cardiology, used for a detailed study of electrical processes in the heart muscle. In clinical practice, specialists rely on two types of this study. The first is non-invasive transesophageal electrophysiological study (TEEPS). The second, more precise method is invasive intracardiac EPS.

The technique of the intracardiac study involves the insertion of special flexible catheters equipped with miniature electrodes. These catheters are advanced directly into the heart chambers, allowing the arrhythmologist to record electrical activity directly from the myocardial walls. The main clinical goal of this procedure is precise topographic diagnosis. The specialist must accurately determine the localization of accessory conduction pathways, which serve as the anatomical substrate for the development of rhythm disorders.

The role of EPS in the diagnosis of supraventricular tachycardias

Diagnosis of supraventricular tachycardias (SVT) is a multi-component process in which electrophysiological testing plays a decisive, though not isolated, role. A comprehensive assessment of the patient's condition includes a wide range of electrocardiographic methods and functional tests.

The basis for detecting SVT is a standard 12-lead ECG. It is not only essential for the initial diagnosis, but is also used to monitor the efficacy and safety of prescribed antiarrhythmic therapy (AAT) or previously performed catheter ablation.

Long-term monitoring is used to record transient rhythm disorders. This group includes classic 24-hour (or multi-day) Holter monitoring, as well as the use of wearable and implantable cardiac event recorders. If the patient already has antiarrhythmic devices, physicians analyze the memory of implanted pacemakers and cardioverter-defibrillators (ICDs). This helps detect silent episodes of rapid atrial rhythm.

In addition to assessing electrical activity, transthoracic echocardiography (TCHO) is a crucial imaging method. Its purpose is to detect any structural changes in the heart. Additionally, the clinician's arsenal includes functional tests: exercise stress testing, vagal maneuvers, and passive orthostatic testing (tilt table test).

From diagnosis to treatment: catheter ablation

The field of interventional diagnostics is inextricably linked with the radical treatment of arrhythmias. After an abnormal bundle of cells or an accessory conduction pathway has been successfully localized during an intracardiac EPS, the patient is scheduled for catheter ablation.

The principle of this procedure is the targeted destruction (physical interruption) of the identified pathological pathway. Technically, this is achieved through several methods, among which transvenous electrocoagulation and laser techniques predominate.

The result of a properly performed radical intervention is the prevention of future arrhythmia episodes. Eliminating the pathological focus helps restore normal sinus rhythm.

Bleeding risk assessment

When planning intracardiac procedures, the question of their safety naturally arises. In modern clinical practice, most cardiological and arrhythmological procedures are classified as interventions with a low risk of bleeding. Hemorrhagic complications are rare and of low clinical significance.

The low-risk group includes:

• Standard electrophysiological study (EPS).
• Catheter ablation (except for certain complex protocols).
• Pacemaker or implantable cardioverter-defibrillator (ICD) implantation.

Exceptions to this rule are technically complex procedures necessitated by severe comorbidities in the patient, such as congenital heart and vascular defects.

For comparison, interventions with a similarly low risk of bleeding include vascular angiography via a radial approach (performed via a. radialis), upper gastrointestinal endoscopy with biopsy, and urological prostate or bladder biopsy.

Class and exam questions

What else to study on this topic

• Mechanisms of transvenous electrocoagulation and laser ablation
• Indications and technique of the passive orthostatic test (tilt table test)
• Use of vagal maneuvers in supraventricular tachycardias
• Specifics of analyzing the memory of implantable devices (pacemakers and ICDs)
• Types of wearable cardiac event recorders

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.