What is an ablation?

What is an Ablation?

Ablation is a medical procedure that uses energy sources to destroy or remove abnormal tissue, commonly used to treat cardiac arrhythmias by creating controlled lesions that interrupt abnormal electrical pathways in the heart. 1

Types of Ablation

Cardiac Ablation

• Radiofrequency (RF) ablation is the most common type, using high-frequency alternating current to generate frictional heat that produces coagulative necrosis of targeted tissue 1
• Cryoablation uses extreme cold (freezing of tissue at -20°C to -60°C) to destroy abnormal tissue 2
• Microwave ablation uses electromagnetic waves to heat tissue at 60°-100°C 2
• Electroporation is a newer, non-thermal technique that targets cell membrane permeability 2

Tumor Ablation

• Thermal ablation techniques are used for treating tumors in the liver, kidney, lung, and other organs by heating tissue to cytotoxic levels (above 60°C) or cooling it below -40°C 2, 1
• Technical success in tumor ablation refers to whether the tumor was treated according to protocol and completely covered by the ablation zone 1
• Technique efficacy refers to complete ablation of macroscopic tumor as evidenced by imaging follow-up or alternative techniques 1

Cardiac Ablation Applications

Arrhythmia Treatment

• Catheter ablation has revolutionized the field of electrophysiology and is now the treatment of choice for several arrhythmias 1
• For atrial fibrillation (AF), pulmonary vein isolation is the cornerstone technique, targeting the areas where abnormal electrical signals originate 3, 4
• AV junction ablation is well-established for controlling ventricular response in patients with poor rate control despite medical therapy 5
• Catheter ablation is indicated in patients with scar-related heart disease presenting with incessant ventricular tachycardia (VT) or electrical storm 1

Efficacy and Success Rates

• Complete AV block by radiofrequency ablation of the AV junction has an efficacy rate of 70-95% (usually 87% or more) 5
• For atrial fibrillation, long-term success rates including multiple procedures vary from 50-80% 3
• Technical success rates should be documented and reported for all ablation procedures 1

Procedural Considerations

Energy Sources

• Radiofrequency energy is most commonly used, creating well-demarcated lesions through heating 1, 2
• Direct current (DC) shocks were used in early ablation procedures but had limitations due to barotrauma and higher complication rates 1
• Different energy sources have specific advantages and limitations, with no single "perfect" ablation device for all situations 6

Technique

• Most procedures are performed using a percutaneous approach, though some may require laparoscopy 1
• Mapping and ablation may be performed during ongoing arrhythmia (activation mapping) or in sinus rhythm (substrate ablation) 1
• For tumor ablation, ablation confirmation refers to postprocedural imaging to verify complete coverage of the target 1

Risks and Complications

• Complication rates are generally less than 2% for cardiac ablation procedures, with procedure-related deaths estimated at 0.1% 1, 5
• Serious complications can include cardiac tamponade, stroke, valvular disruption, coronary occlusion, and death 1, 7
• For AV node modification, the most common complication is inadvertent heart block through ablation of both fast and slow AV nodal pathways 5
• For tumor ablation, complications should be documented and reported according to validated classification systems 1

Patient Selection

• Good candidates for AF ablation are relatively younger patients with symptomatic and frequent episodes of AF, with no significant structural heart disease and no significant left atrial enlargement 3
• Catheter ablation is recommended in patients with symptomatic atrial tachyarrhythmias when drugs are not tolerated or the patient does not wish to take them 5
• For ventricular tachycardia, catheter ablation is indicated in patients with recurrent ICD shocks due to sustained VT 1
• Thermal ablation with radiofrequency is the standard of care for patients with very early stage hepatocellular carcinoma (BCLC 0 and A) not suitable for surgery 1