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Published on: May 28, 2019
Implantable Cardiac Alert System for Early Recognition of ST-Segment Elevation Myocardial Infarction
C Michael Gibson1, David Holmes2, Ghiath Mikdadi3
1Division of Cardiovascular Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
Insights
An implantable cardiac monitor alerted patients to potential ST-segment elevation myocardial infarction (STEMI) events. While not meeting primary efficacy goals, the device showed promise in detecting asymptomatic occlusive events in high-risk individuals.
Area of Science:
- Cardiology
- Biomedical Engineering
- Medical Devices
Background:
- Symptoms are unreliable indicators for acute coronary syndromes (ACS).
- Early perfusion restoration in ST-segment elevation myocardial infarction (STEMI) improves outcomes.
- High-risk ACS patients require advanced detection methods.
Purpose of the Study:
- To evaluate the safety and efficacy of an implantable cardiac monitor for early STEMI detection.
- To assess the AngelMed for Early Recognition and Treatment of STEMI (ALERTS) system's performance.
- To determine if the device reduces time to treatment for occlusive cardiac events.
Main Methods:
- A multicenter, randomized trial involving 907 high-risk ACS subjects.
- Subjects were randomized to a control group (alarms deactivated) or treatment group for 6 months.
- Primary endpoints included system-related complications, cardiac death, myocardial infarction, and detection-to-presentation time.
Main Results:
- The system met its safety endpoint with 96.7% freedom from complications.
- The primary efficacy endpoint was not significantly reduced in the treatment group versus control.
- Alarms significantly decreased detection-to-arrival time (51 min vs. 30.6 h) within a 90-day window.
- Positive predictive value increased and false positive rate decreased when alarms were active.
Conclusions:
- The implantable cardiac system effectively detects early ST-segment deviation and alerts patients.
- The ALERTS trial did not meet its primary efficacy endpoint.
- The device may benefit high-risk subjects by identifying potentially asymptomatic occlusive events.
Background:
Symptoms remain a poor prompt for acute coronary syndromes (ACS). Timely restoration of perfusion in ST-segment elevation myocardial infarction is associated with improved left ventricular function and survival.
Objectives:
This report details the results of ALERTS (AngelMed for Early Recognition and Treatment of STEMI), a multicenter, randomized trial of an implantable cardiac monitor that alerts patients with rapidly progressive ST-segment deviation.
Methods:
High-risk ACS subjects (N = 907) were randomized to a control (alarms deactivated) or treatment group for 6 months, after which alarms were activated in all subjects. The primary safety endpoint was absence of system-related complications (>90%). The composite primary efficacy endpoint was cardiac/unexplained death, new Q-wave myocardial infarction, or detection to presentation time >2 h.
Results:
Safety was met with 96.7% freedom from system-related complications (n = 30). The efficacy endpoint for a confirmed occlusive event within 7 days was not significantly reduced in the treatment compared with control group (16 of 423 [3.8%] vs. 21 of 428 [4.9%], posterior probability = 0.786). Within a 90-day window, alarms significantly decreased detection to arrival time at a medical facility (51 min vs. 30.6 h; Pr [pt < pc] >0.999). In an expanded analysis using data after the randomized period, positive predictive value was higher (25.8% vs. 18.2%) and false positive rate significantly lower in the ALARMS ON group (0.164 vs. 0.678 false positives per patient-year; p < 0.001).
Conclusions:
The implantable cardiac system detects early ST-segment deviation and alerts patients of a potential occlusive event. Although the trial did not meet its pre-specified primary efficacy endpoint, results suggest that the device may be beneficial among high-risk subjects in potentially identifying asymptomatic events. (AngelMed for Early Recognition and Treatment of STEMI [ALERTS]; NCT00781118).
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