Professor of the medical school of New York University, cardiologist Joseph Wiesel has filed a complaint against Apple to a federal court in Brooklyn, reports Bloomberg. The doctor claims that the company used its patented irregular heartbeat detection technology in its “smart” Apple Watch and is demanding compensation.

Some Apple Watch models are able to track users’ heart rate around the clock. The watch can also send notifications if the heart rate is lower or above average, as well as in the case of other heart rhythm disorders.

According to Wiesel, Apple used its innovative method of detecting atrial fibrillation in the watch by monitoring the pulse at certain time intervals. The doctor said that he first contacted the company in this regard in September 2017, passing his patent documentation. However, Apple “refused to negotiate in good faith,” so the cardiologist decided to go to court. He wants the company to stop using the technology without his permission and pay him a fee.

An Apple spokesman did not respond to Bloomberg’s request.