A Review of Novel and Emerging Non-Radiofrequency Ablation Modalities for Ventricular Arrhythmias: Towards an Individualized Substrate-guided Choice of Ablation Technology

Radiofrequency (RF) catheter ablation is the first-line modality for ventricular tachycardia (VT) ablation. Yet, recurrence rates of scar-related VTs are substantial, particularly in the complex and heterogenous nonischaemic cardiomyopathies. To address the still unmet need of delivering durable lesions to all functionally critical areas, including in conventionally inaccessible (e.g. deep mid-myocardial) or prohibitive areas (e.g. proximity to coronaries), a number of alternative interventional approaches have been proposed. Multiple reviews have summarized advanced RF strategies of how to target challenging VT substrates, but the spectrum for ablation modalities to treat ventricular arrhythmias is also rapidly growing beyond the well-established RF technology. Alternative energy sources and delivery modes to treat ventricular arrhythmias include ultra-low temperature cryoablation, pulsed field ablation, laser ablation, high-intensity focused ultrasound ablation and shock wave ablation. Stereotactic body radiation, chemical ablation with ethanol and autonomous nervous system modulation are further promising technologies to reduce arrhythmia burden. The wide variety of emerging approaches and techniques offers new opportunities to select tailored VT ablation strategies based on the individual substrate and VT characteristics. This review aims to present rational and evidence of emerging and cutting-edge non-RF VT ablation technologies to provide the reader with a compact update of this rapidly evolving field of cardiac electrophysiology. This will be complemented by a discussion about the specific VT substrates for which the individual technologies may prove to be most useful.