What is done during a cardiac ablation?

What is Done During a Cardiac Ablation

Cardiac ablation is a minimally invasive catheter-based procedure where specialized catheters are advanced through blood vessels into the heart to deliver energy (typically radiofrequency) that destroys small areas of abnormal heart tissue causing arrhythmias, creating curative lesions through precise contact between the catheter tip and myocardium. 1

Core Procedural Steps

Vascular Access and Catheter Placement

• Catheters are inserted through peripheral blood vessels (typically femoral veins/arteries) and advanced into the heart chambers under fluoroscopic guidance 1
• Multiple catheters are positioned in various cardiac locations to record electrical signals from different areas simultaneously 1
• The operator must achieve adequate contact between the catheter and myocardium to create effective lesions 1

Mapping the Arrhythmia

• Complex intracardiac electrograms are recorded and interpreted to identify the precise location of abnormal electrical pathways or tissue causing the arrhythmia 1
• For left-sided arrhythmias (such as left atrial foci or left lateral accessory pathways), access requires either:
  • Transseptal puncture through the atrial septum to reach the left atrium 1
  • Retrograde aortic approach through the aorta to reach the left ventricle 2
• 3D electroanatomic mapping systems are frequently used to create real-time images of cardiac chambers and electrical activity 1

Energy Delivery and Tissue Ablation

• Radiofrequency energy is the primary ablation method, delivered through the catheter tip to heat and destroy targeted tissue 3, 4
• The energy creates small, controlled lesions that eliminate the arrhythmia substrate 1
• Success depends on creating adequate contact and delivering sufficient energy to form transmural or near-transmural lesions 1

Procedure-Specific Variations

Atrial Fibrillation Ablation (More Complex)

• Requires transseptal puncture for left atrial access 1
• Wide area circumferential ablation around pulmonary veins is the current standard approach, representing substrate modification rather than focal ablation 1
• Intracardiac echocardiography is often used to improve safety and monitor therapy during energy delivery 1
• 3D imaging integration from cardiac MRI or CT scans is frequently imported and merged with real-time electroanatomic mapping 1
• Procedure times average 4.5 hours 1

Supraventricular Tachycardia Ablation (Simpler)

• Targets specific pathways such as AV nodal reentry or accessory pathways (Wolff-Parkinson-White syndrome) 1
• Success rates exceed 95% for most supraventricular arrhythmias 2, 4
• Generally shorter procedure times and lower complication rates than AF ablation 1

Ventricular Tachycardia Ablation (Variable Complexity)

• For scar-related VT, mapping identifies the reentry circuit within scar tissue 5
• Techniques include: point-by-point ablation at circuit exit sites, linear lesion sets, or scar homogenization by ablating abnormal ventricular activity 5
• Epicardial mapping and ablation may be required, particularly in dilated cardiomyopathy or ARVC, accessed via pericardial puncture 5

Monitoring and Safety Measures

Real-Time Monitoring

• Continuous hemodynamic monitoring throughout the procedure 6
• Fluoroscopy provides real-time catheter visualization 1
• Transthoracic echocardiography should be readily available, particularly for AF ablation 1

Anesthesia Management

• Procedures can be performed under conscious sedation, deep sedation, or general anesthesia 6
• Anesthesia method significantly influences complication rates and success rates, as patient movement or pain can interfere with precise catheter positioning 6

Critical Pitfalls and Complications

Common Risks

• Overall major complication rate: 1.82-4.4% including vascular access complications, cardiac tamponade, and complete AV heart block 2
• AF ablation carries higher risks (2-11% complication rate) including perforation, tamponade, stroke, pulmonary vein stenosis, and atrioesophageal fistula (often fatal) 1
• Procedure-related mortality: 0-0.2%, with reported deaths from coronary artery dissection during left free-wall pathway ablation 2

Operator Requirements

• Physicians must be capable of managing bradyarrhythmia and AV heart block, as complete heart block can occur either as an intended endpoint or inadvertent complication 1
• Proficiency in pericardiocentesis is essential for managing cardiac tamponade 1
• For transseptal procedures, at least 20 supervised transseptal punctures are needed to demonstrate reasonable competence 1