Overview
This lecture covers the indications for an electrophysiology (EP) study, key arrhythmias, EP lab equipment, catheter placement, procedural steps, and potential risks.
Indications for EP Study
- EP studies are recommended when symptomatic arrhythmias are documented on ECG and further evaluation is needed.
- Indications include bradyarrhythmias (slow rhythms), tachyarrhythmias (fast rhythms), and for planning/performing ablation procedures.
- EP studies are typically performed in patients with unexplained syncope, suspected structural heart disease, or survivors of sudden cardiac death.
Bradyarrhythmias
- Bradyarrhythmias involve slow heart rates due to problems with impulse generation (SA node issues) or impulse propagation (AV block).
- SA node dysfunction may present as sinus bradycardia, sinus pauses, arrest, or sick sinus syndrome.
- AV block can be within the AV node (often reversible) or below it (usually requires a permanent pacemaker).
Tachyarrhythmias and Ablation
- Tachyarrhythmias such as supraventricular tachycardia (SVT), Wolff-Parkinson-White (WPW), and ventricular tachycardia (VT) are evaluated with EP studies.
- Ablation procedures aim to eliminate sources of arrhythmia, especially atrial fibrillation and atrial flutter.
EP Lab Equipment and Catheter Placement
- EP catheters are insulated wires with distal electrodes for recording or pacing, connected to an external junction box.
- Common catheters: High Right Atrium (HRA), His Bundle (H), Right Ventricular Apex (RVA), Coronary Sinus (CS), and Radio Frequency (RF) ablation catheter.
- Placement is typically via the femoral vein under fluoroscopic guidance in a sterile environment.
Recording and Mapping
- Catheters record intracardiac electrograms (EGMs) to analyze conduction pathways.
- Signals from different catheters correlate with ECG intervals (e.g., HRA with P wave, H with PR/QRS, RVA with QRS).
- 3D mapping systems assist in visualizing electrical activity and guiding ablation.
EP Lab Procedure
- Patient preparation includes consent, fasting, baseline state, discontinuing antiarrhythmic drugs, and possible sedation.
- Staff includes an electrophysiologist, cardiac nurses, and a technologist, all ACLS-trained.
- Risks include vascular complications, infection, arrhythmia induction, AV nodal damage, and cardiac tamponade.
Key Terms & Definitions
- Arrhythmia — abnormal heart rhythm.
- Bradyarrhythmia — slow heart rhythm.
- Tachyarrhythmia — fast heart rhythm.
- Electrogram (EGM) — intracardiac electrical recording.
- Fluoroscopy — real-time X-ray imaging.
- Ablation — procedure to destroy arrhythmogenic tissue.
- Sick Sinus Syndrome — SA node dysfunction causing bradyarrhythmia.
Action Items / Next Steps
- Review catheter locations and their corresponding ECG/EGM correlations.
- Read about procedural risks and patient preparation for EP studies.
- Prepare for upcoming session on catheter placement details.