Dublin-based Medtronic plc is highlighting results from the MARVEL 2 study showing that an investigational set of algorithms in the Micra Transcatheter Pacing System (TPS) helps those with normal sinus node function and atrioventricular (AV) block.

"Results from the MARVEL 2 study show that new investigational algorithms in the Micra TPS significantly improve AV synchrony and cardiac function in patients with complete AV block and normal heart rhythm," company spokesperson Ryan Mathre confirmed to BioWorld MedTech. To that end, the results back up the idea that the algorithms may allow more patients to benefit from a leadless pacemaker.

Armed with findings from MARVEL 2 and a previous study, the company has submitted a new leadless pacemaker, Micra AV, to the U.S. FDA to target those patients with AV block and normal sinus rhythm.

The MARVEL 2 study assessed 75 patients with a Micra TPS at 12 centers in Hong Kong, Malaysia, Europe and the U.S. Investigators evaluated the safety and effectiveness of accelerometer-based atrial sensing algorithms, which were downloaded to the Micra TPS device.

Patients' AV synchrony was assessed with continuous device telemetry and an electrocardiogram Holter monitor during 20 minutes of rest and single-chamber ventricular (VVI) pacing. The study's primary efficacy objective was met, with a significantly greater percentage of complete heart block patients with normal sinus rhythm having greater than 70% AV synchrony during algorithm-mediated AV synchronous pacing vs. VVI pacing (38 of 40 patients vs. 0 patients). The median percent AV synchrony was 94.3% during AV synchronous pacing vs. 26.9% during VVI pacing.

In addition, the study's primary safety objective was met, with no pauses or episodes of pacing-induced tachycardia reported during algorithm mediated AV synchronous pacing.

Going leadless

The FDA gave the green light in April 2016 to Micra for patients who need a single-chamber pacemaker. (See BioWorld MedTech, April 8, 2016.) The device, which is comparable to a large vitamin in terms of size, is the first and only leadless pacemaker approved for use in the U.S. It does not require leads or a surgical pocket under the skin, reducing the potential for complications.

Mathre noted that the company anticipates a possible Micra AV approval and availability as early as the first half of next year.

The approval could have a range of benefits for an expanded number of patients. Larry Chinitz, MARVEL 2 study co-principal investigator, cardiac electrophysiologist and director of NYU Langone's Heart Rhythm Center in New York, noted that leadless pacing results in fewer infection-related complications.

"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," Chinitz said. 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."

Mathre noted that estimates pegged the number of pacemaker patients with AV block at about 40%. "We anticipate that approximately half of pacemaker patients would be eligible for a leadless option if Micra AV is approved and commercially available," he added. The company also has plans to expand this indication to those markets offering Micra.

Generating excitement

During the company's August earnings call, Kristen Stewart with Barclays asked about Micra AV, and CEO Omar Ishrak called it "the one product that I'm certainly most excited about." He noted that the company was the pioneer in the pacemaker field and now had the opportunity to really shake up the market.

For his part, Mike Coyle, executive vice president and group president of the cardiac and vascular group, also saw great potential for the solution. "Now as we move into the Micra AV, we basically have been to date really confined to patients who needed ventricular pacing who also had atrial fibrillation. Now we – any patients with AV block, impact conduction in the – or normal rhythm in the atrium becomes a candidate for this device."

The results from the MARVEL 2 study are slated for presentation Nov. 16 during a Featured Science session at American Heart Association 2019 and were published in JACC: Clinical Electrophysiology. The article is titled "Atrioventricular synchronous pacing using a leadless ventricular pacemaker: Results from the MARVEL 2 study."

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