Implanted Monitor Alerting to Reduce Treatment Delay in Patients With Acute Coronary Syndrome Events

David R. Holmes, Mitchell W. Krucoff, Chris Mullin, Ghiath Mikdadi, Dale Presser, David Wohns, Andrew Kaplan, Allen Ciuffo, Arthur L. Eberly, Bruce Iteld, David R. Fischell, Tim Fischell, David Keenan, M. Sasha John, C. Michael Gibson

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Background: Increased pre-hospital delay during acute coronary syndrome (ACS) events contributes to worse outcome. Objectives: The purpose of this study was to assess the effectiveness of an implanted cardiac monitor with real-time alarms for abnormal ST-segment shifts to reduce pre-hospital delay during ACS events. Methods: In the ALERTS (AngeLmed Early Recognition and Treatment of STEMI) pivotal study, subjects at high risk for recurrent ACS events (n = 907) were randomized to control (Alarms OFF) or treatment groups for 6 months, after which alarms were activated in all subjects (Alarms ON). Emergency department (ED) visits with standard-of-care cardiac test results were independently adjudicated as true- or false-positive ACS events. Alarm-to-door (A2D) and symptom-to-door (S2D) times were calculated for true-positive ACS ED visits triggered by 3 possible prompts: alarm only, alarms + symptoms, or symptoms only. Results: The Alarms ON group showed reduced delays, with 55% (95% confidence interval [CI]: 46% to 63%) of ED visits for ACS events <2 h compared with 10% (95% CI: 2% to 27%) in the Alarms OFF group (p < 0.0001). Results were similar when restricted to myocardial infarction (MI) events. Median pre-hospital delay for MI was 12.7 h for Alarms OFF and 1.6 h in Alarms ON subjects (p < 0.0089). Median A2D delay was 1.4 h for asymptomatic MI. Median S2D delay for symptoms-only MI (no alarm) in Alarms ON was 4.3 h. Conclusions: Intracardiac monitoring with real-time alarms for ST-segment shift that exceeds a subject's self-normative ischemia threshold level significantly reduced the proportion of pre-hospital delays >2 h for ACS events, including asymptomatic MI, compared with symptoms-only ED visits in Alarms OFF. (AngeLmed for Early Recognition and Treatment of STEMI [ALERTS]; NCT00781118)

Original languageEnglish (US)
Pages (from-to)2047-2055
Number of pages9
JournalJournal of the American College of Cardiology
Issue number16
StatePublished - Oct 22 2019


  • implantable cardiac monitor
  • ischemia monitoring
  • pre-hospital delay
  • silent myocardial infarction
  • supply-side ischemia
  • symptom-to-door time

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine


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