The company is providing information to assist patients and clinicians in monitoring battery performance, recognizing abnormal behaviors and reinforcing proper power management.

However, premature or unrecognized deterioration of battery capacity or lapses in recommended power management pose a risk to the patient and, although rare, may result in serious injury or death.

In the notice, the company also instructed the patients to stop using the battery, if it shows abnormal behavior and contact their VAD Coordinator for a replacement.

The company said HeartWare batteries will begin to lose charge over time just like the battery in a mobile cell phone.

The company also requested the patients to replace the affected battery, if a fully-charged battery lasts less than two hours or if the controller switches back-and-forth between batteries.

According to the company a total of four deaths reported to HeartWare, which it says were not directly related to a faulty battery.

However, between January 1, 2011 and March 31, 2014, three deaths were reported that were potentially related to power source management.

A fourth death was originally reported as possibly related to power management, but was later determined to be more likely related to an accidental disconnection of the driveline.