Apple is working on expanding the heart monitoring capabilities of future Apple Watches, according to sources cited by Bloomberg. Following in the footsteps of AliveCor, maker of Kardia-branded accessories for iPhones and Apple Watches, Apple is said to be developing an integrated electrocardiogram (ECG/EKG) reader for the Apple Watch.

The feature would enable future Apple Watch users to go beyond the devices’ current heart rate tracking functionality, providing specific visualizations of healthy heart rhythms and potentially dangerous arrhythmias. Doctors and patients rely on EKGs for quantification of suspected skipped or irregular heartbeats, which can literally save lives of otherwise unsuspecting individuals. Affordable, portable EKG readers are a relatively recent phenomenon.

Adding EKG functionality to the Apple Watch is a logical next step for Apple, though not without challenges. EKG readings would assist Apple and medical institutions in collaborating on existing health-related research projects, which have notably but not exclusively focused on heart-related issues. Paired with certain apps, the light sensors inside current Apple Watches can be used to spot blood flow changes in the wrist, and alert users when their heart rates spike after periods of comparative rest. But they cannot directly or accurately measure the rhythms of the heart via imperceptible electrical signals, the key feature of an EKG.

According to the report, Apple’s implementation could substantially differ from Kardia’s solutions by integrating heart-monitoring leads directly into the frame of the Apple Watch rather than in a band or separate box, requiring only an extended pinch of the frame to monitor and record heartbeats. If true, the feature would likely subject the Apple Watch itself to U.S. Food and Drug Administration (FDA) regulation, like AliveCor’s KardiaBand for Apple Watch, a $199 single-lead EKG that reportedly required two years to receive agency clearance. Other countries’ health agencies might also require separate approvals.

While current-generation Apple Watches contain integrated heart rate monitors, the functionality was deemed basic enough by the FDA to escape advance approval. Apple, however, subsequently anticipated that the FDA might step in if additional health-related features were added to the Watch. Consequently, Apple’s Tim Cook said in an interview that the company might offload new health features into accessories or apps so as not to delay regular Watch hardware updates.

Bloomberg’s report includes the typical disclosure, noting that the development process remains ongoing, and the EKG technology may not be included in future products. Given the historically slow pace of FDA approvals, this particular innovation — no matter how worthwhile and needed it is — may not come to market in the near term.