IEC 60601-2-31:2020 applies to the BASIC SAFETY and ESSENTIAL PERFORMANCE of EXTERNAL PACEMAKERS powered by an INTERNAL ELECTRICAL POWER SOURCE, hereafter referred to as ME EQUIPMENT. This document applies to PATIENT CABLES as defined in 201.3.209, but does not apply to LEADS as defined in 201.3.206. HAZARDS inherent in the intended physiological function of ME EQUIPMENT within the scope of this document are not covered by specific requirements in this document except in 7.2.13 and 8.4.1 of the general standard. This document does not apply to the implantable parts of ACTIVE IMPLANTABLE MEDICAL DEVICES covered by ISO 14708-1. This document does not apply to EXTERNAL PACEMAKERS which can be connected directly or indirectly to a SUPPLY MAINS. This document does not apply to transthoracic and oesophageal pacing ME EQUIPMENT and antitachycardia ME EQUIPMENT. IEC 60601-2-31:2020 cancels and replaces the second edition published in 2008 and Amendment 1:2011. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) The requirement for testing for energy reduction has been removed; b) The test for exposure to external defibrillation has been completely revised; c) The exclusion for testing ESD immunity only with respect to air discharges has been removed; d) Alignment with the latest edition of ISO 14708-2 for pacemakers, as well as the associated EMC standard ISO 14117; e) Additional rationale for all changes.