Implantable STEMI monitor

Implantable STEMI monitor

AngelMed Guardian system (Angel Medical Systems, Eatontown, New Jersey) is an implantable device which detects ischemic events using a pacemaker lead positioned at right ventricular apex [1]. The device detects ischemic events by analyzing shifts in ST segment. It compares ST deviation of a 10 second electrogram with baseline data. If the shift in ST segment is greater than the heart rate dependent programmable threshold, an emergency alert signal is generated. The implantable device gives a vibratory alert and an external associated device gives auditory and visual alert.

ALERTS (AngelMed for Early Recognition and Treatment of STEMI) trial was a multicenter, randomized trial of the device [2]. Nine hundred and seven high risk acute coronary syndrome patients were randomized to a control group in which alarms are deactivated and a treatment group in which alarms were active, for a period of 6 months. Absence of system related complications was the primary safety endpoint. Composite primary efficacy endpoint was cardiac/unexplained death, new Q wave myocardial infarction or detection to presentation time of more than 2 hours. Safety was achieved with 96.7% freedom from system-related complications.

Detection-to-door delay among the treatment group patients was 51 minutes. Detection-to-door time was more than 30 hours in the control group. Aggressive follow up with device interrogation was needed to capture all silent myocardial infarctions in the control group.

An important limitation of the study was an unanticipated low event rate. This could be the reason for no significant difference in the hard clinical outcome of cardiovascular or unexplained death.

A substudy of the same trial reported on treatment delay in patients with acute coronary syndrome events [3]. The Alarms ON group showed reduced delays with 55% of the emergency department visits for acute coronary syndrome in less than 2 hours compared to 10% in the Alarms OFF group (p < 0.0001).

AngelMed Guardian system has been approved for use in the United States for patients with previous acute coronary syndrome who continue to be at high risk for recurrent acute coronary syndrome, according to 2021 ISHNE/HRS/EHRA/APHRS Expert Collaborative Statement [4].

References

1. Hopenfeld B, John MS, Fischell DR, Medeiros P, Guimarães HP, Piegas LS. The Guardian: an implantable system for chronic ambulatory monitoring of acute myocardial infarction. J Electrocardiol. 2009 Nov-Dec;42(6):481-6.
2. Gibson CM, Holmes D, Mikdadi G, Presser D, Wohns D, Yee MK, Kaplan A, Ciuffo A, Eberly AL III, Iteld B, Krucoff MW. Implantable Cardiac Alert System for Early Recognition of ST-Segment Elevation Myocardial Infarction. J Am Coll Cardiol. 2019;73(15):1919-27.
3. Holmes DR Jr, Krucoff MW, Mullin C, Mikdadi G, Presser D, Wohns D, Kaplan A, Ciuffo A, Eberly AL 3rd, Iteld B, Fischell DR, Fischell T, Keenan D, John MS, Gibson CM. Implanted Monitor Alerting to Reduce Treatment Delay in Patients With Acute Coronary Syndrome Events. J Am Coll Cardiol. 2019 Oct 22;74(16):2047-2055.
4. Varma N, Cygankiewicz I, Turakhia MP, Heidbuchel H, Hu YF, Chen LY, Couderc JP, Cronin EM, Estep JD, Grieten L, Lane DA, Mehra R, Page A, Passman R, Piccini JP, Piotrowicz E, Piotrowicz R, Platonov PG, Ribeiro AL, Rich RE, Russo AM, Slotwiner D, Steinberg JS, Svennberg E. 2021 ISHNE/HRS/EHRA/APHRS Expert Collaborative Statement on mHealth in Arrhythmia Management: Digital Medical Tools for Heart Rhythm Professionals: From the International Society for Holter and Noninvasive Electrocardiology/Heart Rhythm Society/European Heart Rhythm Association/Asia-Pacific Heart Rhythm Society. Circ Arrhythm Electrophysiol. 2021 Feb;14(2):e009204.