Excerpt

While chest pain is a common symptom of patients presenting to clinics and emergency wards, only about six percent of patients presenting to the emergency room with acute chest pain are ultimately diagnosed with myocardial infarction. Identification of which patients with chest pain are experiencing myocardial ischemia or infarction is critical, since a delay in diagnosis can impede the application of effective therapies, such as thrombolytic agents or percutaneous coronary intervention (PCI). Tests that identify patients with significant coronary artery disease (CAD) serve as a means of facilitating aggressive implementation of secondary preventive strategies. Thus, accurate diagnostic tests and protocols are imperative in order to properly triage patients presenting with chest pain.

In patients where CAD is suspected – either because of the presence of risk factors for CAD or because of symptoms that may represent manifestations of CAD (e.g., chest pain) – the standard electrocardiogram (ECG) is one of the most commonly performed tests. The ECG is nearly universally available, noninvasive, easy to perform, relatively inexpensive, and can usually be completed in less than 10 minutes. However, a resting ECG has limited sensitivity for detecting CAD.

New devices that seek to improve ECG capabilities have been proposed – specifically, devices that are potentially capable of detecting significant CAD or myocardial ischemia. An enhanced ECG-based test might demonstrate greater positive or negative predictive values, thereby limiting the harms associated with delays in treatment, or providing the diagnostic information necessary to avoid invasive diagnostic or therapeutic interventions.

The Coverage and Analysis Group at the Centers for Medicare and Medicaid Services (CMS) requested this report from The Technology Assessment Program (TAP) at the Agency for Healthcare Research and Quality (AHRQ). AHRQ assigned this report to the Duke Evidence-based Practice Center (Contract No. HHSA 290-2007-10066I). The purpose of the technology assessment is to summarize the available clinical and scientific evidence on ECG-based signal analysis technologies for evaluating patients with suspected CAD. Some ECG-based technologies have been used for other purposes (e.g., detection of malignant arrhythmias), but these are not the focus of the current report. Rather, this report will concentrate on commercially available ECG-based signal analysis technologies to inform AHRQ and CMS about the utility of these emerging technologies for diagnosing CAD.

Contents

• Peer Reviewers
• Acknowledgements
• Executive Summary
• 1. Introduction
  • Epidemiology of Coronary Artery Disease (CAD)
  • CAD vs. Ischemia vs. Infarct
  • Diagnostic Testing and Risk Stratification for CAD
  • The Role and Limitations of the ECG in the Diagnostic Workup of CAD
  • Evaluating Emerging ECG-based Technologies
  • Objectives of this Report
• 2. Methods
  • Key Questions
  • Analytic Framework
  • Approach
• 3. Results
  • Key Question 1a Devices and Methods for ECG-based Signal Analysis
  • Key Question 1b Gold Standard Tests for Diagnosing CAD
  • Key Question 2 Evidence on the Use of ECG-based Signal Analysis Technologies for the Diagnosis of Suspected CAD
• 4. Discussion
  • Summary of Findings
  • Limitations of Current Studies
  • Strengths and Limitations of this Review
  • Future Research
  • Summary
• References
• Acronyms and Abbreviations
• Appendix A PubMed® Search Strategies
• Appendix B ECG-Based Signal Analysis Devices – Gray Literature Sources, Search Terms, and Results
• Appendix C Inclusion/Exclusion Criteria
• Appendix D Quality Criteria
• Appendix E Evidence Tables – Published Studies Evaluating Reviewed Devices
• Appendix F Quality Assessment Ratings

This report is based on research conducted by the Duke Evidence-based Practice Center under contract to the Agency for Healthcare Research and Quality (AHRQ), Rockville, MD (Contract No. HHSA 290-2007-10066I). The findings and conclusions in this document are those of the author(s) who are responsible for its contents; the findings and conclusions do not necessarily represent the views of AHRQ. No statement in this article should be construed as an official position of the Agency for Healthcare Research and Quality or of the U.S. Department of Health and Human Services.

The information in this report is intended to help health care decision-makers; patients and clinicians, health system leaders, and policymakers, make well-informed decisions and thereby improve the quality of health care services. This report is not intended to be a substitute for the application of clinical judgment. Decisions concerning the provision of clinical care should consider this report in the same way as any medical reference and in conjunction with all other pertinent information, i.e., in the context of available resources and circumstances presented by individual patients.

This report may be used, in whole or in part, as the basis for development of clinical practice guidelines and other quality enhancement tools, or as a basis for reimbursement and coverage policies. AHRQ or U.S. Department of Health and Human Services endorsement of such derivative products may not be stated or implied.

None of the investigators has any affiliations or financial involvement related to the material presented in this report.