PLEASANTON, Calif., March 4, 2014 /PRNewswire/ -- On March 4, 2014, Thoratec Corporation initiated a voluntary worldwide Medical Device Correction in order to update its labeling and training materials for the HeartMate II ® LVAS Pocket System Controller (the "Pocket Controller"). This safety advisory is being issued because some patients and caregivers have experienced difficulties with the process of changing from a primary system controller to their backup system controller. These difficulties have resulted in four deaths and five reports of loss of consciousness or other symptoms of hypoperfusion. Of these nine events, eight occurred in patients who were converted to the Pocket Controller after being originally trained on an older model, the EPC System Controller. Two of the deaths occurred in patients who attempted to exchange system controllers while alone and, contrary to the labeling, without contacting the hospital first. The Urgent Medical Device Correction Letter sent to hospitals on March 4, 2014 communicated the reported incident rate over the past year and a half since the introduction of the Pocket System Controller in August 2012. Thoratec's investigations of these reports have not revealed any failures of the devices to meet specifications or deficiencies in quality control procedures. No product needs to be returned to Thoratec. Consumers who have the HeartMate II LVAS Pocket Controller should immediately contact their doctor for retraining on use of the device and to receive updated Patient Handbook information. Physicians who prescribe the HeartMate II LVAS Pocket Controller should immediately review the updated labeling and training materials provided in the Urgent Medical Device Correction Letter with all clinical personnel responsible for training patients and caregivers on the use of the Pocket System Controller. All patients using the Pocket Controller and their caregivers should be retrained on the use of the device and be provided with updated Patient Handbook information.