scope:

This standard establishes minimum safety and performance requirements for electrocardiographic (ECG) systems with direct writing devices which are intended for use, under the operating conditions specified in this standard, in the analysis of rhythm and of detailed morphology of complex cardiac complexes. Subject to this standard are all parts of the electrocardiographic system necessary to obtain the signal from the surface of the patient's body, to amplify this signal, and to display it in a form suitable for diagnosing the heart's electrical activity. This standard defines requirements for the electrocardiographic recording system, from the input electrodes¹⁾ to the output display.

NOTE-The safety and performance criteria defined in this standard are intended principally for use in design qualification or evaluation by the manufacturer.

The referee test methods of section 4 are intended to provide means by which conformance with the standard can be established unambiguously. These tests are not intended for use in verifying the performance of individual devices, either for purposes of quality assurance inspections by the manufacturer or for purposes of routine inhospital inspections. Also, referee tests, by definition, allow for the use of alternative methods for design qualification, provided that the equivalence of the methods can be established in terms of comparability of test results with those of the referee methods.

Inclusions

Included within the scope of this standard are the following devices:

a) direct-writing electrocardiographs;

b) electrocardiographs used in other medical devices (e.g., patient monitors, defibrillators, stress testing devices), when such devices are intended for use in obtaining diagnostic ECG signatures;

c) electrocardiographs having a display that is remote from the patient (via cable, telephone, telemetry, or storage media), when such devices are intended for use in obtaining ECG signatures. These devices are subject to the functional performance requirements at the system output-input levels²⁾.

Exclusions

Not included within the scope of this standard are:

a) devices that collect ECG data from locations other than the external surface of the body;

b) devices for interpretation and pattern recognition (e.g., QRS detectors, alarm circuits, rate meters, diagnostic algorithms);

c) fetal ECG monitors;

d) ambulatory monitoring electrocardiographic devices, including ECG recorders and associated scanning and read-out devices;

e) diagnostic electrocardiographic devices utilizing nonpermanent displays;

f) vectorcardiographs, that is, the display of loops;

g) electrocardiographic devices intended for use under extreme or uncontrolled environmental conditions outside of a hospital environment or physician's office;

h) cardiac monitors, with or without heart rate meters and alarms, that are intended primarily for detecting cardiac rhythm. (These devices are covered by the ANSI/AAMI standard Cardiac monitors, heart rate meters and alarms.)

NOTE-Devices that provide selection between diagnostic and monitoring functions must meet the requirements of the appropriate standard-the standard for diagnostic electrocardiographic devices or the standard for cardiac monitors, heart rate meters and alarms-when selected for that function.

¹⁾Electrodes and associated cables are subject to the provisions of this standard in as much as they are required for conducting most of the performance and safety tests. Manufacturer-specified cables must be used for such tests, since defibrillator protection, diathermy protection, diatherymy protection, risk current, common mode rejection, and input impedance test results may depend on the cable characteristics; also, some devices may use buffer amplifiers as part of the electrode. Not covered by this standard are requirements for electrode size and for electrode performance independent of the system; not are connectors for electrodes and cables covered. The standard provides for up to 300-m V polarization voltage differences between electrodes. This will generally mean that dissimilar electode materials may not be used. Also, there is some question as to the polarization potentials attained with some types of electrodes; e.g., stainless steel, particularly after overload. Recovery from defibrillation overload may be especially compromised because of the characteristics of these electrodes. Section 3.1.2.1(d) requires a cautionary statement to be included in the operator's manual. Manufacturers are required by the standard to specify what type of electrode is acceptable for use with their equipment. (See also the AAMI standard for disposable ECG electrodes, applicable document 2.2.2.)

²⁾It is recognized that the quality of telephone line or other means of transmission cannot be controlled by the electrocardiograph manufacturer. If the ECG equipment is intended for use with telephone transmission, however, the standard requires that the manufacturer disclose the minimum performance characteristics of the remote transmission system (e.g., allowable error, noise level, frequency response) necessary to ensure that the total system meets the requirements of the standard.