Micra AV Tracking During Exercise Testing

Tracking of Mechanically Sensed Atrial Activity During Exercise Using a Leadless Transcatheter Pacing System

The purpose of this study is to determine the effectiveness of the Micra AV 2.0 device during exercise or elevated heart rates. Participation in research studies is voluntary. In this study, participants will already be planned to have a Micra AV 2.0 device implanted. Participants will then undergo treadmill exercise testing and wear a Holter monitor. For each participant, the tracking performance of the Micra AV 2.0 will be evaluated at rest and during exercise. Follow up visits will occur as part of standard of care and each participant will be enrolled in the study for up to 6 months.

Study Overview

• Status: Withdrawn
• Conditions: Heart Block AV
• Intervention / Treatment: Device: Medtronic Micra AV Device

Detailed Description

Participants will be screened and eligible participants who express informed consent will complete exercise testing and holter monitoring. For each participant, the tracking performance of the atrial mechanically sensed, ventricular pacing device will be assessed at rest and during exercise using exercise testing. For each test, the sinus rate trend will be recorded alongside the presence or absence of a mechanically sensed ventricular paced event (AM-VP) for each sinus beat. The average tracking index in each phase of exercise testing - rest, exercise, and recovery - and across the spectrum of achieved heart rates across the cohort will be calculated and reported. Holter monitoring will also be used to assess tracking index across the spectrum of heart rates achieved during routine daily activities across a 24 hour period.

After enrollment, the following baseline information will be assimilated from the medical record and will be collected if not already done based on routine clinical care: date of pacemaker implant, pacemaker implant location (high septum, mid septum, apex), cardiac disease history, and programmed pacemaker parameters.

Exercise testing will be performed between one week and six months after Micra AV implant. Participants will complete preparation for exercise testing according to institutional standards. Participants will be given instructions to take all prescribed medications, including antiarrhythmic drugs and AV nodal blocking agents, according to their usual schedule, including on the day of the test.

Participants will be provided with a holter monitor. Participants will begin wearing the monitor during the rest period at the start of the exercise testing protocol. Exercise testing will be completed using standardized Micra AV device programming settings: VDD mode with nominal maximal tracking rate. Auto programming will be used to initialize device parameter selection. Following completion of auto programming, a MAM test will be performed to assess atrial signal discrimination. A fixed A3 discrimination threshold will then be selected which is approximately 1.0 m/s2 greater than the isolated accelerometer A3 signal.10 Other sensing parameters will be adjusted as clinically indicated to optimize atrial signal discrimination. Each participant will undergo device monitoring accompanied by external telemetry for 20 minutes at rest, followed by a fitness level-appropriate standardized stress protocol (e.g., Bruce protocol, Naughton protocol, Eckland protocol) on the treadmill or recumbent bicycle. They will perform graded exercise until achieving a heart rate of 130 bpm, or until physical fatigue, limiting chest pain (or discomfort), marked ischemia, or a drop in blood pressure occur (if such symptoms develop prior to reaching the target heart rate), supervised by a clinician experienced in performing cardiac stress testing. Once reaching 130 bpm, participants will remain at the current stage on their exercise protocol until physical fatigue, limiting chest pain (or discomfort), marked ischemia, or a drop in blood pressure occurs, or up to a maximum of twenty total minutes of exercise. Participants will be asked to report level of perceived exertion and fatigue level at pre-determined intervals. Cardiac rhythm will be recorded using 12-lead telemetry throughout the rest, exercise, and recovery periods. If the tracking index during exercise is lower than 70%, atrial sensing will be optimized using a MAM test.

The following data will be collected during exercise testing: exercise protocol utilized, protocol stage achieved, baseline cardiac rhythm, characterization of atrial and/or ventricular tachyarrhythmias, resting heart rate, peak heart rate, peak blood pressure, perceived level of exertion and fatigue, total exercise time, total metabolic equivalents (METs) achieved, and reason for termination.

The following data will be abstracted from device interrogation and 12-lead telemetry following the test: total number of sinus atrial beats, total number of premature atrial complexes (PAC), total number of premature ventricular complexes (PVC), number of tracked events, number of non-tracked ventricular paced events, and number of ventricular beats resulting from native AV conduction. Participants will continue to wear the provided holter monitor for the remainder of the 24 hour period. The following data will be collected during holter monitoring: average heart rate, peak heart rate, minimum heart rate, characterization of atrial and/or ventricular tachyarrhythmias, total number of sinus atrial beats, total number of premature atrial complexes (PAC), total number of premature ventricular complexes (PVC), number of tracked events, number of non-tracked ventricular paced events, and number of ventricular beats resulting from native AV conduction. Patient charts will be reviewed at the time of study completion to report clinical outcomes including death, device extraction, and/or transition to a transvenous pacing system.

• Study Type: Interventional
• Phase: Phase 4

Contacts and Locations

Study Locations

• United States
  • North Carolina
    • Durham, North Carolina, United States, 27710
      • Duke University Health System

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Age ≥18
• Written informed consent
• Presence of a Micra AV leadless pacemaker with the Micra AV 2.0 algorithm and at least 50% RV pacing
• High grade atrioventricular heart block as the primary indication for permanent pacing
• Sinus rhythm
• Physical ability to walk on a treadmill or ride a recumbent bicycle for exercise testing

Exclusion Criteria:

• Earlier version of the Micra leadless pacemaker
• Intact atrioventricular conduction
• Persistent atrial fibrillation
• Those with absolute contraindications to exercise testing:
• Acute myocardial infarction (MI) within 2 days
• Ongoing unstable angina
• Uncontrolled cardiac arrhythmia with hemodynamic compromise
• Active endocarditis
• Symptomatic severe aortic stenosis
• Decompensated heart failure
• Acute pulmonary embolism, pulmonary infarction, or deep vein thrombosis
• Acute myocarditis or pericarditis
• Acute aortic dissection
• Physical disability that precludes safe and adequate testing
• Inability to consent
• Patient refusal to participate
• Pregnant patients

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Micra AV Exercise Testing; All participants will have Micra AV 2.0 implanted then undergo exercise testing while wearing Holter Monitor	Device: Medtronic Micra AV Device; Participants will already be planned to have a Micra AV 2.0 device implanted. Participants will then undergo treadmill exercise testing and wear a Holter monitor to determine the effectiveness of the Micra AV 2.0 device during exercise or elevated heart rates.; Other Names: Micra AV Tracking During Exercise

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Average tracking index at rest	Calculated as the percentage of atrial mechanically sensed, ventricular paced event (AM-VP) divided by total VP percentage.	6 months
Average tracking index during exercise	Calculated as the percentage of atrial mechanically sensed, ventricular paced event (AM-VP) divided by total VP percentage.	6 months
Average tracking index during recovery	Calculated as the percentage of atrial mechanically sensed, ventricular paced event (AM-VP) divided by total VP percentage.	6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Average total AV synchrony at rest	Calculated as AM-VP percentage plus AM-VS percentage.	6 months
Average total AV synchrony during exercise	Calculated as AM-VP percentage plus AM-VS percentage.	6 months
Average total AV synchrony during recovery	Calculated as AM-VP percentage plus AM-VS percentage.	6 months
Average tracking index	The average tracking index across the spectrum of achieved heart rates across the cohort, categorized in 10-bpm ranges, from 55 bpm to 135 bpm.	6 months
Average total AV synchrony	The average total AV synchrony across the spectrum of achieved heart rates across the cohort, categorized in 10-bpm ranges, from 55 bpm to 135 bpm.	6 months
Device programming features among those with tracking index >70%	Percent of patients using auto threshold and window modes, and average A3 window, A3 threshold, A4 window, and A4 threshold values.	6 months
Clinical and device features which differentiate those with low tracking index	Clinical and device features which differentiate those with low tracking index (<70% tracking with ≥20% ventricular pacing) during the initial exercise test from those with high tracking index (if such a subset of patients exists).	6 months
Average tracking index during holter monitoring	• Average tracking index during holter monitoring across the spectrum of achieved heart rates across the cohort, categorized in 10-bpm ranges, from 55 bpm to 135 bpm.	6 months
Timeframe of optimal programing	Time (minutes) required to optimize programming prior to exercise testing.	6 months

Collaborators and Investigators

• Sponsor: Duke University
• Investigators: Principal Investigator: Camille Frazier-Mills, Duke Medicine - Cardiology

Study record dates

Study Major Dates

• Study Start (Estimated): May 1, 2024
• Primary Completion (Estimated): November 1, 2025
• Study Completion (Estimated): November 1, 2025

Study Registration Dates

• First Submitted: July 21, 2023
• First Submitted That Met QC Criteria: July 21, 2023
• First Posted (Actual): July 28, 2023

Study Record Updates

• Last Update Posted (Actual): April 17, 2024
• Last Update Submitted That Met QC Criteria: April 16, 2024
• Last Verified: April 1, 2024

More Information

Terms related to this study

• Keywords: Medtronic; AV Heart Block; High-grade Heart Block; MICRA AV
• Additional Relevant MeSH Terms: Pathologic Processes; Heart Diseases; Cardiovascular Diseases; Arrhythmias, Cardiac; Cardiac Conduction System Disease; Heart Block
• Other Study ID Numbers: Pro00112840

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