PLEASANTON, Calif. -- The maker of a mechanical heart pump is recalling some versions of the device after the deaths of five people.

The California-based Thoratec Corp. is urging patients to have their implants checked. The warning follows 27 confirmed reports of cases in which wear and fatigue of an electrical wire required the devices to be replaced.

The company said the reports came over five years and involved nearly 2,000 implants. In five cases, the device could not be replaced and the patients died.

The affected devices were distributed directly to 87 hospitals throughout the United States and other countries, the company said on its Web site.

Customers and patients with questions may contact the company at 1-800-528-2577.

The FDA said the implantable ventricular assist devices are mechanical pumps that help a person’s heart that is too weak to pump blood through the body. They're designed to provide sufficient blood flow to a damaged or diseased heart, and are often used as a patient waits for a heart transplant. It is sometimes referred to as a “bridge to transplant” since it can help a patient survive until a heart transplant can be performed.

The FDA said the device was recalled because the air-driven may develop leaks when used externally, and that could result in not enough blood flow to and from the heart.