BIO Guard-MI

Biomonitoring in Patients with Preserved Left Ventricular Function after Diagnosed Myocardial Infarction

Jøns C et al, ACC 2022

First Outcome Trial on the Benefits of ICMs in Post-MI Patients


The BIO|GUARD-MI study is the first trial to investigate the impact of continuous arrhythmia monitoring with an implantable cardiac monitor (ICM) on clinical outcomes in post-myocardial infarction (MI) patients. Implantable cardiac monitors are also referred to as implantable loop recorders.

The study demonstrated that early treatment of high-risk, non-ST-segment elevation myocardial infarction (NSTEMI) patients guided by continuous arrhythmia monitoring with implantable loop recorders reduces major adverse cardiac events (MACE) by 31%. 

67% of patients with an implantable loop recorder had a first arrhythmia detected after two years, leading to guideline-recommended change in treatment in 39.4%. Only 6.7% of post-MI patients without an implantable loop recorder received a change in treatment. 

Read more about the study design, key results, and clinical relevance below. 

As presented at a Late-Breaking Clinical Trial session at the American College of Cardiology’s 71st Annual Scientific Session in Washington D.C. on April 4, 2022

Study Design

  • Randomized, controlled, parallel-group, open, prospective, multi-center, international study
  • To investigate whether the early diagnosis of cardiac arrhythmias, provided by the BIOMONITOR with Home Monitoring, and the consequent treatment of the patient will decrease the risk to experience a major adverse cardiovascular event (MACE) in patients after MI, with LVEF >35% and CHA2DS2-VASc score ≥4 (men) or ≥5 (women)
  • 790 patients 

Key Result 1

In the primary endpoint analysis of the total patient population, a trend towards MACE reduction in the implantable cardiac monitor (ICM) group was observed but did not reach statistical significance (HR=0.84, p=0.21).
A sub-group analysis shows a 31% reduction of MACE in patients with non-ST segment elevation myocardial infarction (NSTEMI).


Primary endpoint: Time to first MACE in NSTEMI and STEMI

BIOGUARD-MI key results

↓ 31%

MACE reduction with ICM in NSTEMI patients

BIOGUARD-MI key results

Key Result 2

The benefit of ICM-guided treatment in NSTEMI patients appears to be connected to their higher risk for primary endpoint events.


Risk for primary endpoint in NSTEMI and STEMI

BIOGUARD-MI key results

↑ 75%

increased risk of MACE in NSTEMI patients

Key Result 3

Continuous arrhythmia monitoring in post-MI patients identifies a large arrhythmia burden, and many of the arrhythmias require guideline recommended therapies.


Detection of arrhythmias and treatment

BIOGUARD-MI key results

Clinical Relevance

  • Arrhythmias are connected to poor outcomes after myocardial infarction.
  • BIO|GUARD-MI is the first trial to investigate the impact of continuous arrhythmia monitoring with ICMs on clinical outcomes in post-MI patients. 
  • Early treatment of high-risk NSTEMI patients guided by continuous arrhythmia monitoring with BIOMONITOR and Home Monitoring may reduce major adverse cardiac events (MACE).

Study Objective 
  • To investigate whether early treatment after ICM-documented arrhythmias in high-risk post-MI patients improves outcome 
Primary Endpoints
  • Time to first major cardiac adverse event (MACE)
  • MACE is defined as death for cardiovascular reasons or unplanned hospitalization for cardiovascular reasons
Sample Size
  • 790 patients
Clinical Sites
  • 60 investigational sites in Europe, Australia, and USA
Main inclusion Criteria
  • History of MI according to guidelines
  • CHA2DS2-VASc-Score ≥ 4 in men / ≥ 5 in women
  • LVEF > 35 % 
Main Exclusion Criteria
  • Permanent oral anticoagulation treatment for atrial fibrillation
  • Pacemaker or ICD implanted or indication for implantation
  • Biomonitor 2 or BIOMONITOR III + Home Monitoring
  • Patients were followed for a median duration of 2.5 years after randomization
Study Duration
  • August 2015 - April 2020
Reference no.
  • NCT02341534
Steering Committee
  • Dr. Christian Jons (Rigshospitalet, Denmark)
  • Prof. Steffen Behrens (Vivantes Humboldt-Klinikum & Klinikum Spandau, Germany)
  • Professor Peter Sogaard (Aalborg University Hospital, Denmark)
  • Prof. Poul Erik Bloch Thomsen (Denmark)


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