Zoll’s μCor Stick-On Sensor Studied as a Monitor of Heart Failure Complications

March 6, 2023—The American College of Cardiology (ACC) announced the presentation of a study demonstrating that patients with heart failure were 38% less likely to be readmitted to the hospital for heart failure complications within 90 days if they wore a stick-on sensor, the μCor (“Microcor”) system (Zoll Medical Corporation) that alerted their clinicians about fluid buildup in the lungs. The study was funded by Zoll Medical.

The μCor system, which is attached to the left side of the patient’s chest with an adhesive patch, uses radiofrequency signals to assess the wearer’s thoracic fluid index and send data to the patient’s clinician. The study sought to reduce hospital readmissions by helping patients and clinicians monitor for early signs of fluid buildup in the lungs and intervene before hospitalization is needed.

The presentation, “Impact of Heart Failure Management Using Thoracic Fluid Monitoring From a Novel Wearable Sensor: Results of the Benefits Of Microcor (μCor) in Ambulatory Decompensated Heart Failure (BMAD) Trial,” was delivered by John P. Boehmer, MD, at ACC.23/WCC, the ACC’s annual scientific session together with the World Congress of Cardiology held March 4-6, 2023, in New Orleans, Louisiana.

As noted in the ACC press release, the μCor device provides clinicians with actionable information about a patient’s condition remotely, which encourages clinicians to adjust medications earlier and prevent complications from escalating. Because it can be easily applied and removed, the experimental device could offer a less invasive and more cost-effective alternative to implantable sensors.

Dr. Boehmer, who is Professor of Medicine and Surgery at The Pennsylvania State University in State College, Pennsylvania, commented in the ACC press release, “It’s very exciting to have a positive result within the remote monitoring field. Having a wearable technology is particularly encouraging because it gives you the opportunity to monitor a patient during a high-risk interval and then stop monitoring when they exit that high-risk interval.”

The ACC press release, which summarized the study and its findings, reported that investigators enrolled 522 patients within 10 days of hospitalization for heart failure. All patients were fitted with a μCor monitor, which they wore continuously for 90 days.

Half the patients were enrolled to a control group; these patients wore the μCor monitor but information from the monitor was not sent to their clinician. This arm began first, and investigators used the data from this group to establish a threshold distinguishing between normal and elevated thoracic fluid levels.

The patients enrolled in the intervention arm wore the monitor and the data were sent to their treating clinician along with action alerts if their thoracic fluid level crossed the established threshold.

In the study’s primary endpoint, the investigators found that patients whose clinicians monitored thoracic fluid using the μCor system were 38% less likely to be hospitalized for heart failure within 90 days compared with patients whose clinicians did not receive this information. They were also 38% less likely to experience a combined endpoint that included heart failure–related emergency department visits, hospitalizations, or deaths.

“The challenge in remote monitoring studies is to get clinicians to react to the data,” advised Dr. Boehmer in the ACC press release. ”Our temptation is to look at the data but then manage patients as we always have managed patients. There was a clear threshold set up in this trial, and the clinicians did react to it. As a result, we saw treatment interventions that seem to have been effective.”

The study investigators noted that because the μCor system provides information about changes in the lungs before symptoms such as swelling become apparent, the device can encourage clinicians to intervene earlier and prevent complications from worsening. Common interventions in response to evidence of fluid buildup include prescribing diuretics to reduce fluid retention and increasing the dosage for a patient’s other heart failure medications.

Dr. Boehmer stated that μCor offers a convenient, less invasive alternative to existing monitoring devices. It can also be used intermittently to monitor patients only during high-risk periods, such as after a hospitalization, avoiding overburdening clinical staff with unnecessary data and focusing resources on the patients who can benefit most from close monitoring.

In the ACC press release, Dr. Boehmer noted that the study was moderately sized and not randomized; a larger, randomized trial would help to confirm the findings. In addition to its measurements of thoracic fluid, investigators plan to study how additional data collected by the μCor device, such as heart rate and breathing rate, could be incorporated into the data provided to clinicians to offer a more comprehensive picture of a patient’s condition.

It is also possible that the device could be useful for monitoring patients with lung diseases in addition to heart failure, advised the investigators.