November 10, 2019
MARVEL 2 Evaluates Algorithms for Use With Medtronic's Micra Transcatheter Pacemaker in Treatment of Atrioventricular Block
November 11, 2019—Medtronic announced results from the MARVEL 2 trial were published online by Clemens Steinwender, MD, et al in Journal of the American College of Cardiology (JACC): Clinical Electrophysiology.
The company advised that the MARVEL 2 study results will be presented during a featured science session at AHA 2019, the American Heart Association scientific sessions held November 16–18 in Philadelphia, Pennsylvania.
MARVEL 2 shows that an investigational set of algorithms in Medtronic’s Micra transcatheter pacing system (TPS) significantly improves synchrony and cardiac function in patients with atrioventricular (AV) block, a condition resulting in impaired electrical conduction between the chambers of the heart.
According to Medtronic, the MARVEL 2 study evaluated 75 patients with a Micra TPS at 12 centers in Hong Kong, Malaysia, Europe, and the United States. Investigators evaluated the safety and effectiveness of accelerometer-based atrial sensing algorithms, which were downloaded to the Micra TPS device.
In the study, 40 patients had complete heart block and normal sinus rhythm and were eligible for inclusion in the primary efficacy analysis. All 75 patients were included in the primary safety objective. Investigators evaluated the ability of the Micra accelerometer to monitor and detect atrial contractions and enable coordinated pacing between the atrium and ventricle, thereby providing AV synchrony.
Using continuous device telemetry and an electrocardiogram Holter monitor, patients’ AV synchrony was measured during 20 minutes of rest and during single-chamber ventricular (VVI) pacing.
The company reported that the study’s primary efficacy objective was met, with a significantly greater percentage of complete heart block patients with normal sinus rhythm having > 70% AV synchrony during algorithm-mediated AV synchronous pacing (38 of 40 patients, 95%) than VVI pacing (0 patients, P < .001 for proportion of patients with > 70% synchrony). The median percent AV synchrony was 94.3% during AV synchronous pacing compared with 26.9% during VVI pacing.
In addition, blood flow from the left ventricle (velocity time integral, a proxy for stroke volume), increased by 1.7 cm (on an absolute scale, 95% confidence interval, 0.7–2.7 cm; P = .002; or 8.8% on a relative scale) during AV synchronous pacing compared with single-chamber ventricular pacing mode in patients with normal sinus rhythm with complete heart block.
The study’s primary safety objective was met, with no pauses or episodes of pacing-induced tachycardia reported during algorithm-mediated AV synchronous pacing in any of the 75 patients.
Medtronic advised that it submitted the new Micra AV leadless pacemaker for approval by the FDA to expand the indicated population to AV block and normal sinus rhythm. The submission, which is now under review, is supported by positive results from both the MARVEL 2 study and the MARVEL study. The Micra AV is not approved for sale in the United States and is available for investigational use only, advised Medtronic.
Medtronic’s first leadless pacemaker, the Micra TPS, received FDA approval in April 2016 for patients who need a single-chamber pacemaker.
MARVEL 2 study coprincipal investigator, Larry Chinitz, MD, commented in Medtronic’s announcement, “While leadless pacing has many advantages compared to traditional pacemakers—including fewer infection-related complications—leadless pacemakers are currently only capable of single-chamber ventricular sensing and pacing.
“Our investigation shows that accelerometer-based atrial-sensing algorithms can sense signals from the atrium in the heart and make calculated adjustments to when ventricular pacing occurs, thus improving coordination between the atrium and ventricle. These results provide further evidence that these novel investigational algorithms added to the Micra TPS may allow more patients, including those with normal sinus rhythm and AV block, to benefit from a leadless pacemaker.” Dr. Chinitz is a cardiac electrophysiologist and Director of NYU Langone’s Heart Rhythm Center in New York, New York.