Apple Watch Series 4 at the Steve Jobs Theater during an event to announce new Apple products Wednesday, Sept. 12, 2018, in Cupertino, Calif.

Marcio Jose Sanchez | AP

Apple and Johnson & Johnson, a pharma giant, announced plans to team up on Tuesday on a new study that aims to study whether Apple Watch can detect a heart rhythm irregularity called atrial fibrillation among seniors, and encourage them to seek medical help.

Atrial fibrillation is a condition that can result in an increased risk of strokes and other serious outcomes. Those over the age of 65 are at much higher risk that their younger counterparts.

Although it might seem like yet another partnership between Big Tech and pharma, there are at least three reasons why this study is a big deal and an unprecedented move for both companies.

Size and scope

According to Johnson & Johnson’s Paul Butron, vice president of medical affairs, who spoke to CNBC by phone, this study represents the largest randomized trial in the history of cardiovascular disease.

At a minimum, the goal is to recruit 150,000 people who will be randomly assigned into one of two buckets. Either they’ll be navigated iPhone app, called Heartline, which provides health education and tips. Or they’ll be given the Apple Watch, either as a loaner device or at a heavily subsidized price of $49 plus tax. That’s a heavy discount from the $399 Apple Watch Series 5, and both companies are contributing to offer the discount.

Participants can also receive cash rewards for meeting goals in the app. It also connects to Medicare’s Blue Button API, which gives patients access their claims data, including information on bills.

Because of the size of the study, it could take three years for the companies to publish the results. A start-up called Evidation Health is helping with the research, the companies said. It might not be successful. There are still some unknowns, which the study will need to explore. Burton confirmed that the companies will publish either way.

If the study is succeeds — both in using the app to encourage people to take their medications (oftentimes, blood thinners) and in detecting atrial fibrillation in a high-risk population — that could lead to private Medicare plans that help their members pay for the Apple Watch. Apple is already in active discussions with many of these plans.

Pharma, tech and retail

The study involves a collaboration between Johnson & Johnson, Apple and a large retailer. By phone, Burton said that seniors who are assigned a watch can pick it up in store or get it shipped from Best Buy.

There are customer service reps available to seniors who need help setting up the device, but they can also ask for assistance at Best Buy. From there, they’ll bring the device home to be monitored.

That is a step towards a much-discussed future of health care: Aging in place. The idea is to use devices to help alert seniors to medical conditions before they get serious, and to send alerts to emergency services if a serious event occurs, like a fall.

It may eventually help seniors live independently for longer and cut down on expensive health care outcomes, such as emergency room visits. Partnerships between tech, pharma and retail are required to move the industry closer to that holy grail.

Alleviating concerns from cardiologists

Apple has been critiqued by cardiologists for its regulated medical features, largely because it has built its device for a general audience.

Cardiologists are nervous that Apple Watch is collecting new health signals that aren’t particularly helpful. If a young person has atrial fibrillation once or twice, it doesn’t necessarily mean that a physician should prescribe blood thinners, for example. There are a list of risk factors that doctors have to consider, such as age, gender and medical history.

Apple is clearly hearing these concerns.

As Burton summed it up: “atrial fibrillation is a silent epidemic, and most of it is seen in over-65 population.”

Jeffrey Wessler, a cardiologist based in New York who has expressed concerns with Apple’s approach, praised this focus on seniors. “This study represents an important step forward for the clinical utility of consumer-grade wearables,” he said.

“Apple can move beyond the dubious effects of broad based screening and actually demonstrate the effectiveness of a watch-based intervention to improve clinical outcomes,” he continued.

Correction: This story was updated to clarify that CNBC spoke with Paul Burton.