Atrial fibrillation (AF) is the most common cardiac arrhythmia, affecting over 59 million people globally. It significantly increases the risk of stroke, heart failure, and mortality. Catheter ablation is now the first-line treatment for symptomatic AF, offering rhythm control and symptom relief. However, outcomes remain variable, with success rates of up to 70% after the first procedure and frequent need for repeat ablations. Ventricular arrhythmia (VA), on the other hand, is a life-threatening arrhythmia associated with sudden cardiac death, often requiring deeper and more precise ablation to treat scar-related circuits. Unfortunately, VA treatment outcomes with traditional radiofrequency ablation (RFA) remain suboptimal, with high recurrence rates, inadequate lesion depth, and procedural risks due to proximity to critical structures.
Pulsed Field Ablation (PFA) is a novel non-thermal ablation technology that has rapidly gained traction for AF due to faster procedures and a favourable safety profile compared to thermal methods like RFA. However, early real-world experience has uncovered critical limitations. At our centre, a patient developed severe haemolysis post-PFA, resulting in acute renal failure and dialysis, a complication now echoed in international reports but not observed in early trials. We implemented routine haemolysis screening, yet the procedural thresholds that cause red blood cell damage remain unknown, making prevention difficult.
Moreover, current PFA systems are optimised for thinner atrial tissue and may be inadequate for the deeper lesions required in VA ablation, an identical issue to RFA. Finally, no system presently offers real-time lesion visualisation, limiting intra-procedural feedback on lesion formation and durability.
This research project addresses these safety and efficacy gaps through three studies. First, we will define the haemolysis threshold during PFA using a blood-flow model to guide safer energy application. Second, we will test a novel duty-cycled approach that combines thermal (RFA) and non-thermal (PFA) energies to achieve deeper, more durable lesions suitable for VT. Third, we will validate LesioLogic, an impedance and thermal-based imaging system for real-time lesion visualisation, particularly within infarcted tissue.
Together, these studies aim to make PFA safer, more effective, and broadly applicable. By improving our understanding of haemolysis thresholds, enhancing lesion depth, and guiding real-time delivery, this research has the potential to significantly improve outcomes in patients with AF and life-threatening VT.
Last updated28 May 2026