Against the background of these remarkable developments, the guidelines needed to undergo many changes and revisions. ...the format has been revised again to include cardiac implantable electronic devices and catheter ablation therapies. ...prevention of systemic embolism using a left atrial appendage closure (LAAC) device is being established as a breakthrough treatment for AF patients who have difficulty in continuing anticoagulation therapy. Because early implantable cardioverter-defibrillators (ICDs) were highly invasive owing to the requirement for a thoracotomy, the indications for this treatment were highly limited. In 2004, cardiac resynchronization therapy (CRT) became available for patients with impaired cardiac function, and the usefulness of this treatment has been verified. especially in heart failure patients with complete left bundle branch block in Japan. Because patients with heart failure have a high risk of sudden death, an ICD with a biventricular pacing function (CRT defibrillator CRT-D) was also developed and approved in 2006.