Insertable Cardiac Monitor for Primary Atrial Fibrillation Detection in High-Risk Heart Failure Patients (ASSERT-AF)

March 19, 2026 updated by: Ilan Goldenberg, University of Rochester

Insertable Cardiac Monitor for Primary Atrial Fibrillation Detection in High-Risk Heart Failure Patients (ASSERT-AF)

Patients with heart failure (HF) represent a large population of patients who are at high risk for complications related to undiagnosed atrial fibrillation (AF). However, currently there are limited modalities for early AF detection and subsequent stroke prevention in this high-risk population. An implantable cardiac monitor (ICM) is inserted subcutaneously and can provide long term arrhythmia information via remote monitoring.

The ASSERT-AF study seeks to accurately define the burden of AF and other arrhythmias in high-risk HF patients using an ASSERT ICM.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Detailed Description

Over 6 million people in the United States suffer from heart failure (HF). By the year 2030 the prevalence of HF is expected to exceed 8 million people. Heart failure accounts for 1 million hospital admissions each year, costing our economy in excess of $30 billion dollars per year. Mortality in patients with HF remains high, and nearly half of all patients diagnosed with HF will die within 5 years. More than half of all patients admitted with HF decompensation have preserved left ventricular systolic function. Patients with HF and mildly reduced or preserved left ventricular systolic function are at high risk for developing atrial fibrillation (AF), the occurrence of which often contributes to HF decompensation and increases morbidity and all-cause mortality. Similarly, patients with AF are at high risk for developing HF due to loss of atrio-ventricular synchrony and rapid uncontrolled ventricular rates. Detection of AF can be challenging and may go undiagnosed in asymptomatic or minimally symptomatic patients through conventional monitoring methods. Patients with HF represent a large population who are at risk for complications related to undiagnosed AF. AF increases the risk of stroke five-fold and the risk of death nearly two-fold. Moreover, strokes related to AF are twice as likely to be fatal or severely disabling compared to strokes due to other causes, such as ischemic small vessel disease or atheromatous large vessel disease. Cardiac implantable electronic devices (CIEDs), can be used for the early detection of AF in asymptomatic or mildly symptomatic patients with HF. However, current guidelines provide an indication for prophylactic implantable cardioverter defibrillator (ICD) only in HF patients with left ventricular ejection fraction (LVEF) ≤ 35%, whereas there are limited data for device-based detection of AF in HF patients with more preserved LVEF.

Implantable cardiac monitors (ICM) are devices that can be injected into the subcutaneous tissue and can provide automatic electrocardiographic recordings of asymptomatic arrhythmias as well as patient triggered electrocardiographic recordings of symptomatic episodes during long term follow-up. Implantable cardiac monitors are be paired with remote monitoring systems, capable of rapid remote review of electrograms. Accordingly, we hypothesize that a management strategy that incorporates ICM implantation in patients with HF and LVEF >35% will result in a significantly higher rate of AF detection leading to arrhythmia related interventions compared to conventional monitoring and follow-up in patients with HF.

Study Type

Interventional

Enrollment (Estimated)

477

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • New York
      • Rochester, New York, United States, 14642
        • University of Rochester Medical Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Male and female patients more than 18 years of age (no upper age limit)
  • HF exacerbation requiring initiation or augmentation of decongestive therapy in a hospital setting (hospitalization or emergency department visit) during the past 24 calendar months prior to consent date OR current treatment with loop-diuretics (furosemide, bumetanide, or torsemide).
  • LVEF > 35% on a cardiac imaging study (echocardiogram, nuclear imaging, cardiac magnetic resonance imaging) performed during the past 24 calendar months prior to consent date
  • One or more FDA-approved indications for an Abbott ICM (unexplained symptoms such as: dizziness, palpitations, chest pain, syncope, and shortness of breath, as well as patients who are at risk for cardiac arrhythmias).
  • Willing to undergo an Abbott ICM implant and agree to remote ICM monitoring.

Exclusion Criteria:

  • Existing implantable cardioverter defibrillator (ICD), biventricular ICD, implantable cardiac monitor or pacemaker.
  • Known or documented history AF or atrial flutter any time in past.
  • Has had a heart transplant
  • Participation in other clinical trials (observational registries are allowed with approval from the Coordination Center)
  • Unable or unwilling to cooperate with the protocol
  • Unable or unwilling to sign the consent for participation

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Conventional Management
The conventional management arm will use arrhythmia signs and symptoms to determine occurrence of arrhythmias.
Other: Conventional Management and monitoring
Subjects randomized to the conventional management arm of the trial will undergo arrhythmia monitoring based on clinical indications and per standard available modalities including periodic electrocardiograms (ECG), Holter and/or event monitoring.
Experimental: ASSERT insertable cardiac monitor
The ASSERT implantable cardiac monitor (ICM) is an FDA-approved device that can be injected into the subcutaneous tissue and can provide automatic as well as patient triggered electrocardiographic recordings of symptomatic episodes during long term follow-up. This Implantable cardiac monitor is paired with a remote monitoring smartphone application called My Merlin that capable of rapid remote review of electrograms to be utilized in this study for arrhythmia detection. The ASSERT ICM is indicated for the monitoring and diagnostic evaluation of patients who experience unexplained symptoms such as: dizziness, palpitations, chest pain, syncope, and shortness of breath, as well as patients who are at risk for cardiac arrhythmias. It is also indicated for patients who have been previously diagnosed with atrial fibrillation or who are susceptible to developing atrial fibrillation.
Device: ASSERT Insertable Cardiac Monitor
Subjects will be subcutaneously implanted with an Abbott ASSERT ICM with the device implant procedure per standard of care and current labelling. Data related to subjects' arrhythmias, via the Merlin.net Patient CareNetwork will be transmitted on a monthly basis to the treating physician and subsequently to the study coordination and database center (CCRC) at the University of Rochester. Data on the frequency/types of symptomatic (patient triggered) versus ICM detected (asymptomatic) arrhythmic events will be collected and adjudicated. Clinical data on medication, device interventions, cardiovascular events will be collected at follow-up visits.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Median Time to first detection of AF lasting > 5 minutes
Time Frame: 24 months
Defined as ICM detected AF in the intervention (implantable cardiac monitor) arm or captured by clinical symptoms and documented by ECG or Holter in the conventional arm.
24 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Time to initiation of guideline directed anti-arrhythmic and HF interventions
Time Frame: 24 months
Interventions such AF ablation, initiation of antiarrhythmic, anticoagulation, beta-blocker therapy and others.
24 months
Number cardiovascular hospitalizations or death
Time Frame: 24 months
Total number of cardiovascular hospitalizations or death in each arm.
24 months
Compare healthcare utilization using Abbott ICM vs. non-ICM monitoring.
Time Frame: 24 months
Including emergency department visits, unplanned office visits, cardiovascular hospitalization or death
24 months
Mean quality of life measured using the Kansas City Cardiomyopathy Questionnaire (KCCQ)
Time Frame: 24 months
All KCCQ scores are scaled from 0 to 100 and frequently summarized in 25-point ranges, where scores represent health status as follows: 0 to 24: very poor to poor; 25 to 49: poor to fair; 50 to 74: fair to good; and 75 to 100: good to excellent.
24 months
Mean percentage of time spent in atrial fibrillation (AF Burden)
Time Frame: 24 months
AF burden, defined as average percentage of time spent in AF (i.e. amount of time spent in AF divided by the total amount of time a patient was monitored). AF burden will be quantified only in the intervention arm.
24 months
Time to detection of composite of arrhythmic events endpoint
Time Frame: 24 months
Arrhythmic events consisting of AF, sustained ventricular tachycardia, and high-risk bradyarrhythmias (high degree AV block or sinus pause > 5 seconds), whichever occurs first.
24 months

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Compare the effect of patient-triggered transmissions on the time to Abbott ICM detection of arrhythmic events triggered by symptomatic recordings versus automatically detected arrhythmic event recordings.
Time Frame: 24 months
24 months
Evaluate the rate of actionable interventions following symptom triggered event versus the rate of actionable interventions associated with automatic detected arrhythmic events.
Time Frame: 24 months
Including initiation of oral anticoagulation, guideline directed medical therapy, device and procedural interventions.
24 months
Correlate ICM interrogation data relating to heart sounds, body posture, activity, sleep detection and heart rate variability, with the risk of new heart failure events.
Time Frame: 24 months
Such as hospitalizations, ED visits, unplanned office visits, out patients treatment with intravenous diuretic.
24 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Rochester

Collaborators

Abbott

Investigators

  • Principal Investigator: Ilan Goldenberg, MD, University of Rochester

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 31, 2023

Primary Completion (Estimated)

July 1, 2028

Study Completion (Estimated)

July 1, 2028

Study Registration Dates

First Submitted

March 24, 2021

First Submitted That Met QC Criteria

March 24, 2021

First Posted (Actual)

March 26, 2021

Study Record Updates

Last Update Posted (Actual)

March 23, 2026

Last Update Submitted That Met QC Criteria

March 19, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • STUDY00007311

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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