The challenge of optimising ablation lesions in catheter ablation of ventricular tachycardia

Abstract

Over the last decade, radiofrequency catheter ablation (RFCA) has become an established treatment for ventricular arrhythmias (VA). The recent international consensus report supports RFCA as a first-line therapy for VA in normal heart Ventricular Tachycardia (VT) and in structural heart VT after ineffective anti-arrhythmic drug (AAD) therapy. 1 Several groups have taken this further, proposing prophylactic VT ablation before implantable cardiac defibrillator (ICD) insertion; however this remains an area of debate. 2 Though

The value of functional substrate mapping in ventricular tachycardia ablation

“…4 Substrate ablation strategies that have been developed include scar homogenization, 5 scar dechanneling, targeting zones of isochronal crowding, and elimination of local abnormal ventricular activities (LAVAs) or late potentials (LPs), defined as isolated high-frequency local electrograms (EGMs) after the offset of the terminal portion of the QRS complex ( Table 1 ). 6 , 7 , 8 However, outcomes of all these methods are similar, with procedural success as low as 47% 3 , 9 , 10 , 11 and incidence of procedural complications of about 5% to 10%. 12 Techniques that target all abnormal potentials or regions of scar border zone (SBZ) include ablation of large areas of myocardium either endocardially or epicardially.…”

Surpoint algorithm for improved guidance of ablation for ventricular tachycardia (SURFIRE‐VT): A pilot study

“…Also for prolonged energy deliveries, the contribution of RF application duration is proportionally less important for lesion creation than CF. 29 To overcome some of these limitations, the AI was introduced.…”

Structure and function of the ventricular tachycardia isthmus

“…The benefit of catheter ablation in reentrant VT patients with structural heart disease is wellknown, with freedom from recurrence approaching 70% (188). However, the success rate with this procedure has plateaued, despite advances in both mapping catheter technology and electroanatomic mapping systems (188,189). High density multi-electrode catheters can enhance the possibility of detailed activation mapping of even poorly tolerated VTs because they can be produced in a reasonable time frame.…”

“…When no compete diastolic pathway is evident, substrate-guided ablation has become the method of choice to guide procedures. The ablation strategies that have been developed include scar homogenization, scar dechanneling, targeting zones of isochronal crowding, elimination of near-field activity, and elimination of late potentials at sites of conduction slowing during sinus rhythm (188,189), although efficacy is limited. Moreover, ablation success is in part dependent on the indicator used, such as contact force and impedance drop, which are imperfect measures to determine the irreversible loss of cellular J o u r n a l P r e -p r o o f excitability needed to interrupt the circuit by myocardial heating with temperatures exceeding 50°C (189).…”

“…Although not yet realized, there is the potential for a well-placed ablation lesion no more than several centimeters across to abolish all inducible VTs in patients (92), and this has also been shown in canine (31,98,119) and swine (118) postinfarction models. A recently developed technique termed core isolation, although it involves more extensive ablation, may prove useful for eliminating all possible VT morphologies that can occur (102,189). It is performed by defining the putative isthmus and early exit sites.…”