X0306 4 2013-05-20 0 0000350907 THORATEC CORP THOR 0001248380 DIMICK NEIL F 6035 STONERIDGE DRIVE PLEASANTON CA 94588 1 0 0 0 Common Stock 2013-05-20 4 S 0 1250 31.6068 D 35853 D Common Stock 2013-05-22 4 A 0 5651 0 A 41504 D Shares of Common Stock sold pursuant to a Sales Plan established by the Reporting Person on March 2, 2012, which Sales Plan is intended to comply with the requirements of Rule 10b5-1(c)(1) under the Securities Exchange Act 1934, as amended. This transaction was executed in multiple trades in prices ranging from $31.44 to $32.13. The price reported above reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request to the SEC staff, the Issuer, or a stockholder of the Issuer, information regarding the number of shares and prices at which the transaction was effected. Represents restricted stock units. Each restricted stock unit represents a right to receive one share of Thoratec Corporation common stock upon vesting. The restricted stock units fully vest on the one year anniversary of the grant. Annual stock grant according to the Company's Amended and Restated 2006 Incentive Stock Plan. Restricted stock units were granted pursuant to the Company's Amended and Restated 2006 Incentive Stock Plan with no payment received for the restricted stock units. /s/ David A. Lehman, Attorney-In-Fact 2013-05-22