This issue of Cardiac Electrophysiology Clinics, guest edited by Mohammad Shenasa and Amin Al-Ahmad, is the second part of our?Advances in Cardiac Mapping and Catheter Ablation issue. Article topics will include, but are not limited to,?New Findings in Atrial Fibrillation Mechanisms; Mapping and Ablation of Neuraxial in Patients with Ventricular Arrhythmias; How to Map and Ablate Rotors in Atrial Fibrillation; Post-ablation Atrial Arrhythmias; Substrate Mapping in Atrial Arrhythmias; Substrate Mapping in Ventricular Arrhythmias; Challenges in Ablation of Complex Congenital Heart Disease; Mapping and Ablation of Ventricular Arrhythmias from the RV and LV Outflow Tract; Novel Insights on Idiopathic VF and Early Repolarization; Novel Observations in Mapping and Ablation in Brugada Syndrome; Ablations of Ventricular Arrhythmias; Mapping and Ablation of Arrhythmias from uncommon sites; Mapping and Ablation of VT in Patients with HF and Cardiomyopathies; Mapping and Ablation of Unmappable VT, VT Storm, and Those in Acute Myocardial Infarction; Mapping and Ablation of Ventricle Arrhythmia in patients of LVAD; Fluoroless Catheter Ablation of Cardiac Arrhythmias; Toward a Uniform Ablation Protocol for Paroxysmal; Persistent and Permanent AF; and The Ideal Mapping System.