Dear Colleagues,

Ventricular arrhythmias (VAs) including premature ventricular contractions (PVCs), ventricular tachycardias (VTs), and ventricular fibrillation are usually symptomatic and can be life-threatening. When VAs are drug-refractory, catheter ablation is considered to treat these VAs. As electrophysiology and technologies have been advancing, the indications for catheter ablation of VAs have expanded, and to date, even some types of polymorphic VTs and ventricular fibrillation can be treated by catheter ablation.

The mechanisms of VAs are focal or reentry. The focal type of VAs can be treated by catheter ablation targeting their origins. The re-entrant type of VAs can be treated by catheter ablation targeting their substrates. The targets of catheter ablation of polymorphic VTs and ventricular fibrillation are their triggering PVCs and substrates. The targets of catheter ablation of VAs are usually located at endocardial sites but sometimes at the intramural or epicardial sites. Catheter ablation of intramural and epicardial VAs is always challenging. Epicardial catheter ablation through the transvenous and transpericardial approaches can treat epicardial VAs but it can often be limited by anatomical barriers. Special techniques such as bipolar ablation, needle catheter ablation, and alcohol ablation may be required to treat epicardial and intramural VAs.

Imaging modalities such as computed tomography and magnetic resonance imaging can be utilized to identify substrates (scar burden) of VAs and understand the anatomy during preprocedural planning. These imaging data can be integrated into three-dimensional electro-anatomical maps to guide the catheter ablation.

As above mentioned, recent advancements in technologies, equipment, and techniques for catheter ablation of VAs have been remarkable. The Special Issue "Advancements in catheter ablation of VAs" will collect high-quality original research papers and comprehensive reviews on recent advancements in catheter ablation of VAs. The topics of interest include, but are not limited to:

• Epicardial mapping and ablation
• Intramural substrate and needle catheter ablation
• Pulse field ablation
• Imaging-guided ablation
• Catheter ablation of ventricular fibrillation
• High resolution mapping
• Catheter ablation of premature ventricular contractions
• Catheter ablation of electrical storms
• Alcohol ablation
• Bipolar ablation
• Large trials

Prof. Takumi Yamada
Guest Editor