Roughly two years after Apple brought an ECG monitor to its wrist-worn devices, connected ECG device-maker AliveCor has raised a patent lawsuit against the tech giant.

Filed yesterday in the U.S. District Court for the Western District of Texas, the suit argues that the tools included in the Apple Watch Series 4 and later devices infringe on three patents held by AliveCor, all of which focus on cardiac arrhythmia.

The company said in the suit that Apple was aware of these patents, and that the company has infringed and continues to infringe upon them. In addition to Apple halting the alleged infringement, AliveCor is seeking payment for damages to its company for its attorney fees and for other fees associated with the suit.

About a year prior to the unveiling of the Apple Watch's ECG, AliveCor had launched an Apple Watch strap with a built-in ECG sensor called the KardiaBand. And although the company's interim CEO told MobiHealthNews that AliveCor was "not convinced that Apple’s excellent, engaging product is a competitor yet," it ended sales of the KardiaBand later that same year. In the meantime, AliveCor has focused on its six-lead smartphone ECG device and software-based screening and analysis services for consumers and provider users.

Patently Apple reports that the Cupertino company has been granted a new patent for non-invasive measurement of blood pressure.

The methods described in the patent includes embodiments in which the technology can be used to measure mean arterial pressure or blood pressure changes via wrist-worn devices, "which are less bulky than current devices and may facilitate more frequent and accurate blood pressure monitoring." Images included in the patent also demonstrate the use of sensors housed in the band of a watch, along with other components designed to improve accuracy.

This follows previous patent applications from Apple that similarly suggested that a blood pressure monitoring feature could come to the smartwatch.

Apple has locked in a December 14 launch date for Fitness+, its premium exercise and wellness subscription offering teased back in September.

The service combines video workouts and the Watch's activity-tracking features to help users visualize their performance during and after their session. Per the company's announcement, Fitness+ will be launching with 10 types of workouts, including cycling, strength, rowing and yoga, as well as features that will provide users with personalized activity recommendations.

The service requires a Series 3 or later smartwatch and a recent version of iOS. The subscription comes in at $9.99 per month, or $79.99 per year.