Apple's (AAPL - Get Report)  released an extensive "Heart Study" recently showing that using the Apple Watch was successful in identifying participants who had irregular heart rhythms. But the study also showed that a large percentage of those receiving these notifications from their smartwatch were not confirmed by subsequent testing to have the condition, which is known as atrial fibrillation.

The health-related usage of wearables such as the Watch are seen as an increasingly important business for Apple as smartphone sales growth declines.

Apple paid for Stanford University to conduct the virtual survey starting in Nov. 2017 and lasting for eight months. The study enrolled more than 400,000 participants from the country who had both an Apple Watch and an iPhone (the study used people who had one of the first three versions of the Watch but not the latest Apple Watch 4, which also has an electrocardiogram feature, since it was only released in 2018).

Of that number, Apple said only about 0.5% were found by the Watch's optical pulse feature to have an irregular rhythm, and notified those users. Those without serious symptoms requiring immediate attention were mailed special EKG patches to wear on their chests for a week to confirm that they had atrial fibrillation.

But 66% of participants who were notified they had an irregular pulse were not confirmed to have atrial fibrillation by the EKG patch, indicating a false positive that could lead to concerns that wearables like the Watch could over-diagnose medical conditions. According to the study's authors, the low confirmation rate was not surprising since atrial fibrillation is an intermittent condition that might not be always be detected by the patch.

Gene Munster, the managing partner at Loup Ventures, said that despite the potential issues with the results, the Apple Watch's heart monitoring ability is still "light years ahead of anything else that's out there" and notes that he's optimistic about Apple's efforts to move into health care. 

"We do caution investors that while Apple will be a player in health care, it still remains to be seen what kind of business they can build around it," Munster said. 

Zev Fima, an analyst for Jim Cramer's Action Alerts Plus portfolio, which owns Apple, agreed that the survey results were encouraging for Apple's push into health care.

"While it's not very material at the moment, we think the study serves to further legitimize the company's push into healthcare," said "Health care is an area we think can provide significant growth for Apple as the Watch becomes more advanced and the massive baby boomer generation rapidly hits retirement age and enters those years where the need for continuous medical monitoring increases."

Will I Have Enough Money to Retire?

Want to learn about retirement planning from some of the nation's top experts? Join TheStreet's Robert "Mr. Retirement" Powell live in New York on April 6 for our Retirement Strategies Symposium. For a limited time, tickets are available for $99 for this full-day event. Check out the agenda, learn about the speakers and sign up here.