Abbreviations A-ATP atrial anti-tachycardia pacing ACC American College of Cardiology ACP advance care planning ACT activated clotting time AF atrial fibrillation AHA American Heart Association AHRE atrial high-rate episodes AVNRT atrioventricular nodal reentrant tachycardia BARC Bleeding Academic Research Consortium CBA cryoballoon ablation CIED cardiac implantable electronic device COR class of recommendation CRT cardiac resynchronization therapy CRT-D cardiac resynchronization therapy defibrillator CRT-P cardiac resynchronization therapy pacemaker CT computed tomography DAP dose–area product DAPT dual antiplatelet therapy DNAR Do Not Attempt Resuscitation DOAC direct oral anticoagulant EBM evidence-based medicine ESC European Society of Cardiology FDA Food and Drug Administration GOR grade of recommendation HF heart failure HFrEF heart failure with reduced ejection fraction HPSD high-power short-duration HRS Heart Rhythm Society ICD implantable cardioverter-defibrillator JCS Japanese Circulation Society JHRS Japanese Heart Rhythm Society LOE level of evidence LVEF left ventricular ejection fraction MRI magnetic resonance imaging MVP minimal ventricular pacing NASPE North American Society of Pacing and Electrophysiology NYHA New York Heart Association QOL quality of life RCT randomized controlled trial RFCA radio-frequency catheter ablation SCAF subclinical atrial fibrillation vHPSD very high-power short-duration Abbreviations of Research Names AATAC Ablation vs Amiodarone for Treatment of Atrial Fibrillation in Patients with Congestive Heart Failure and an Implanted ICD/CRTD ABRIDGE-J Ablation Perioperative Dabigatran in Use Envisioning in Japan ARISTESiA Apixaban for the Reduction of Thrombo-Embolism in Patients with Device-Detected Sub-Clinical Atrial Fibrillation ASSERT Asymptomatic Atrial Fibrillation and Stroke Evaluation in Pacemaker Patients and the Atrial Fibrillation Reduction Atrial Pacing Trial ASAP ASA Plavix Feasibility Study with Watchman Left Atrial Appendage Closure Technology ATTEST Atrial Therapy Efficacy and Safety Trial AXAFA AFNET 5 Anticoagulation Using the Direct Factor Xa Inhibitor Apixaban during Atrial Fibrillation Catheter Ablation: Comparison to VKA Therapy CABANA Catheter Ablation vs Antiarrhythmic Drug Therapy on Mortality, Stroke, Bleeding, and Cardiac Arrest Among Patients with Atrial Fibrillation CASTLE-AF Catheter Ablation for Atrial Fibrillation with Heart Failure CIRCA-DOSE Study Cryoballoon vs. Novel Anticoagulation Agents in Atrial Fibrillation PREVAIL Prospective Randomized Evaluation of the Watchman Left Atrial Appendage Closure Device in Patients with Atrial Fibrillation versus Long-term Warfarin Therapy PROTECT-AF Percutaneous Closure of the Left Atrial Appendage versus Warfarin Therapy for Prevention of Stroke in Patients with Atrial Fibrillation RATE Registry of Atrial Tachycardia and Atrial Fibrillation Episodes RE-CIRCUIT Randomized Evaluation of Dabigatran Etexilate Compared to Warfarin in Pulmonary Vein Ablation: Assessment of an Uninterrupted Periprocedural Anticoagulation Strategy SALUTE A Study to Evaluate the Safety and Effectiveness of the Left Atrial Appendage Closure Therapy Using WATCHMAN for Patients with NVAF at Increased Risk of Thromboembolism in Japanese Medical Environment SAVE PACe Search AV Extension and Managed Ventricular Pacing for Promoting Atrio-Ventricular Conduction SOS AF Stroke Prevention Strategies Based on Atrial Fibrillation Information from Implanted Devices STOP AF First Cryoballoon Ablation as Initial Therapy for Atrial Fibrillation STOP PERSISTENT AF Stop Persistent AF TACTIC-AF Tailored anticoagulation for non-continuous atrial fibrillation TRENDS A Prospective Study of the Clinical Significance of Atrial Arrhythmias Detected by Implanted Device Diagnostics VENTURE-AF Study Exploring Two Treatment Strategies in Patients with Atrial Fibrillation who Undergo Catheter Ablation Therapy WASP Watchman Occlusion in Long-standing Persistent Atrial Fibrillation Table of Contents I. Introduction 2 II. ...the main features of these focused updated guidelines are as follows. When the previous guidelines were announced, there were no guidelines or expert consensus that clarified the recommended therapeutic level; however, the new ACC/AHA/HRS guidelines in 2019 stated a recommended level, 3 and the initial concept of His bundle pacing was extended to conduction system pacing including both His bundle and left bundle pacing. ...based on the present consideration, we describe recommended levels of conduction system pacing.