Johnson & Johnson said it has temporarily paused the rollout of its Varipulse heart device in the U.S., citing an abundance of caution as the company investigates four reported stroke events.

Varipulse, a pulsed field ablation system, received FDA approval in November for treating a type of abnormal heart rhythm condition.

Shares of the drug and device maker fell 3% in afternoon trade, while rivals Boston Scientific and Medtronic gained 5% and 4%, respectively.

"We are working diligently to complete the investigation according to our medical safety processes and resume the U.S. External Evaluation," J&J said in a statement.

An external evaluation is a limited roll out intended to collect doctors' feedback on a new technology before a broader full release.

J&J said it initiated the pause on January 5. The company added that commercial activity and cases outside the U.S. would not be affected by the pause.