Trial Outcomes & Findings for Micra Atrial TRacking Using A Ventricular AccELerometer 2 (NCT NCT03752151)

Last Updated: 2020-06-04

Results Overview

A subject will meet the primary endpoint if a paced or sensed ventricular beat is within 300 ms following an ECG confirmed P-wave for at least 70% of the ECG confirmed P-waves. The primary endpoint will be evaluated during the MARVEL 2 setup phase during MARVEL 2 Algorithm monitor mode (VDI pacing which is effectively VVI pacing) and during the 20-minute resting period in which the MARVEL 2 Algorithm is programmed to Adaptive mode (VDD pacing)

Recruitment status

COMPLETED

Study phase

Target enrollment

77 participants

Primary outcome timeframe

40 Minutes

Results posted on

2020-06-04

Participant Flow

Subjects were considered enrolled when they signed informed consent Subjects were enrolled between 22 January 2019 and 14 June 2019 at 12 study centers in 8 countries

Following enrollment, the MARVEL 2 algorithm was downloaded into the subject's implanted Micra pacemaker. Following download subjects were programmed to MARVEL 2 Algorithm monitor mode followed by MARVEL 2 adaptive mode. Two subjects exited prior to MARVEL 2 download; one did not meet the study inclusion/exclusion and one withdrew consent.

Participant milestones

Participant milestones
Measure	MARVEL 2 Monitor Mode Then MARVEL 2 Adaptive Mode Participants were programmed to MARVEL 2 algorithm monitor mode which provides standard VVI pacing for approximately 20 minutes. Then the MARVEL 2 algorithm was programmed to adaptive mode which provides VDD pacing for approximately 2 hours.
Overall Study STARTED	77
Overall Study COMPLETED	75
Overall Study NOT COMPLETED	2

Reasons for withdrawal

Reasons for withdrawal
Measure	MARVEL 2 Monitor Mode Then MARVEL 2 Adaptive Mode Participants were programmed to MARVEL 2 algorithm monitor mode which provides standard VVI pacing for approximately 20 minutes. Then the MARVEL 2 algorithm was programmed to adaptive mode which provides VDD pacing for approximately 2 hours.
Overall Study Withdrawal by Subject	1
Overall Study Protocol Violation	1

Baseline Characteristics

One patient who withdrew prior to download of the MARVEL 2 algorithm did not complete the baseline procedures.

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	MARVEL 2 Monitor Mode Then MARVEL 2 Adaptive n=77 Participants Participants were programmed to MARVEL 2 algorithm monitor mode which provides standard VVI pacing for approximately 20 minutes. Then the MARVEL 2 algorithm was programmed to adaptive mode which provides VDD pacing for approximately 2 hours.
Age, Continuous	77.6 years STANDARD_DEVIATION 11.8 • n=76 Participants • One patient who withdrew prior to download of the MARVEL 2 algorithm did not complete the baseline procedures.
Sex: Female, Male Female	31 Participants n=76 Participants • One patient who withdrew prior to download of the MARVEL 2 algorithm did not complete the baseline procedures.
Sex: Female, Male Male	45 Participants n=76 Participants • One patient who withdrew prior to download of the MARVEL 2 algorithm did not complete the baseline procedures.
Region of Enrollment Austria	6 participants n=77 Participants
Region of Enrollment Belgium	20 participants n=77 Participants
Region of Enrollment Hong Kong	11 participants n=77 Participants
Region of Enrollment United States	14 participants n=77 Participants
Region of Enrollment Denmark	4 participants n=77 Participants
Region of Enrollment Malaysia	15 participants n=77 Participants
Region of Enrollment France	6 participants n=77 Participants
Region of Enrollment Spain	1 participants n=77 Participants
Predominant heart rhythm Persistent 3rd degree AV block with normal sinus	40 Participants n=77 Participants
Predominant heart rhythm Intact atrioventricular conduction	18 Participants n=77 Participants
Predominant heart rhythm Other rhythm	15 Participants n=77 Participants
Predominant heart rhythm Rhythm indeterminate	2 Participants n=77 Participants
Predominant heart rhythm Participant exited prior to software download	2 Participants n=77 Participants

PRIMARY outcome

Timeframe: 40 Minutes

Population: Participants with a predominant heart rhythm of 3rd degree atrioventricular block and normal sinus function during the study period.

Outcome measures

Outcome measures
Measure	MARVEL 2 Monitor Mode Then MARVEL 2 Adaptive n=40 Participants Participants were programmed to MARVEL 2 algorithm monitor mode which provides standard VVI pacing for approximately 20 minutes. Then the MARVEL 2 algorithm was programmed to adaptive mode which provides VDD pacing for approximately 2 hours.
Atrial Ventricular Pacing Synchrony Success During Rest Monitor Mode Success and Adaptive Mode Success	0 Participants
Atrial Ventricular Pacing Synchrony Success During Rest Monitor Mode Failed and Adaptive Mode Success	38 Participants
Atrial Ventricular Pacing Synchrony Success During Rest Monitor Mode Success and Adaptive Mode Fail	0 Participants
Atrial Ventricular Pacing Synchrony Success During Rest Monitor Mode Fail and Adaptive Mode Fail	2 Participants

PRIMARY outcome

Timeframe: Through study completion an average of one day

Population: Number of participants with the MARVEL 2 software downloaded onto their Micra implanted pacemaker

A participant will meet the primary endpoint if they are free from the following MARVEL 2 software related events during the entire Holter monitoring period where the MARVEL 2 features are enabled. Inappropriate pacemaker function events are defined as: 1. Cardiac pauses lasting longer than 2 cardiac cycles (where cardiac cycle length is defined by the programmed lower rate interval of the pacemaker), OR 2. Pacemaker oversensing induced tachycardia exceeding 3-minutes, defined as oversensing of the pacemaker's accelerometer signal leading to a heart rate exceeding 100 beats per minute.

Outcome measures

Outcome measures
Measure	MARVEL 2 Monitor Mode Then MARVEL 2 Adaptive n=75 Participants Participants were programmed to MARVEL 2 algorithm monitor mode which provides standard VVI pacing for approximately 20 minutes. Then the MARVEL 2 algorithm was programmed to adaptive mode which provides VDD pacing for approximately 2 hours.
Number of Participants Free From Inappropriate Pacemaker Function Events	75 Participants

SECONDARY outcome

Timeframe: 12 cardiac cycles

Population: Participants with paired LVOT VTI measurements during MARVEL 2 Adaptive mode (VDD pacing mode) and MARVEL 2 Monitor mode (VDI pacing which is effectively VVI pacing) with a predominant heart rhythm of persistent 3rd degree atrioventricular block and normal sinus rhythm

The secondary endpoint is left ventricular outflow tract (LVOT) velocity time integral (VTI) as obtained from echocardiogram while the MARVEL 2 features are in adaptive mode (VDD pacing) and while the MARVEL 2 features are in monitor mode (VDI pacing which is effectively VVI pacing). This was measured by the echo core laboratory that was blinded to the study participant and MARVEL 2 algorithm mode.

Outcome measures

Outcome measures
Measure	MARVEL 2 Monitor Mode Then MARVEL 2 Adaptive n=39 Participants Participants were programmed to MARVEL 2 algorithm monitor mode which provides standard VVI pacing for approximately 20 minutes. Then the MARVEL 2 algorithm was programmed to adaptive mode which provides VDD pacing for approximately 2 hours.
Left Ventricular Outflow Tract Velocity Time Integral	1.7 cm Interval 0.7 to 2.7

Adverse Events

MARVEL 2 Monitor Mode Then MARVEL 2 Adaptive Mode

Serious events: 3 serious events

Other events: 3 other events

Deaths: 0 deaths

Serious adverse events

Serious adverse events
Measure	MARVEL 2 Monitor Mode Then MARVEL 2 Adaptive Mode n=75 participants at risk Participants were programmed to MARVEL 2 algorithm monitor mode which provides standard VVI pacing for approximately 20 minutes. Then the MARVEL 2 algorithm was programmed to adaptive mode which provides VDD pacing for approximately 2 hours.
Vascular disorders Hypotension	1.3% 1/75 • Number of events 1 • 1 day
Cardiac disorders Ventricular tachycardia	1.3% 1/75 • Number of events 1 • 1 day
Cardiac disorders Myocardial haemorrhage	1.3% 1/75 • Number of events 1 • 1 day

Other adverse events

Other adverse events
Measure	MARVEL 2 Monitor Mode Then MARVEL 2 Adaptive Mode n=75 participants at risk Participants were programmed to MARVEL 2 algorithm monitor mode which provides standard VVI pacing for approximately 20 minutes. Then the MARVEL 2 algorithm was programmed to adaptive mode which provides VDD pacing for approximately 2 hours.
Gastrointestinal disorders Abdominal pain	1.3% 1/75 • Number of events 1 • 1 day
Ear and labyrinth disorders Vertigo	1.3% 1/75 • Number of events 1 • 1 day
Cardiac disorders Tricuspid valve incompetence	1.3% 1/75 • Number of events 1 • 1 day

Additional Information

Dana Wigert, Sr Prin Clinical Research Specialist

Medtronic, Plc

Phone: +17635262802

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee In most cases, the contract allows the principal investigator to publish their data after release of a multi-center publication per the publication strategy following Medtronic's review for disclosure of confidential information ("CI"), technical correctness, disclosure of patentable or copyrightable material, and selection and order of publications by the publications committee. Any such CI and/or item identified as not technically correct is deleted prior to publication/presentation.
Publication restrictions are in place

Restriction type: OTHER