World Heart (WHRT) SC 13D/A WORLD HEART / New Leaf Ventures II ownership change

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 1)*

World Heart Corporation

(Name of Issuer)

Common Stock, $0.001 par value per share

(Title of Class of Securities)

980905301

(CUSIP Number)

Craig L. Slutzkin

New Leaf Venture Management II, L.L.C.,

Times Square Tower

7 Times Square, Suite 3502

New York, NY 10036

(646) 871-6420

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

January 26, 2010

(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.  ¨

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See §240.13d-7 for other parties to whom copies are to be sent.

* The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

Persons who respond to the collection of information contained in this form are not

required to respond unless the form displays a currently valid OMB control number.

CUSIP No. 980905301 13D Page 2 of 23 Pages

1	NAMES OF REPORTING PERSONS. I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). New Leaf Ventures II, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a)  ¨        (b)  ¨
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)     WC
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)  ¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION     Delaware Limited Partnership
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER     0 shares
		8	SHARED VOTING POWER     4,498,383 shares
		9	SOLE DISPOSITIVE POWER     0 shares
		10	SHARED DISPOSITIVE POWER     4,498,383 shares
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     4,498,383 shares
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)  ¨
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)     30.54%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)     PN

CUSIP No. 980905301 13D Page 3 of 23 Pages

1	NAMES OF REPORTING PERSONS. I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). New Leaf Venture Associates II, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a)  ¨        (b)  ¨
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)     AF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)  ¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION     Delaware Limited Partnership
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER     0 shares
		8	SHARED VOTING POWER     4,498,383 shares
		9	SOLE DISPOSITIVE POWER     0 shares
		10	SHARED DISPOSITIVE POWER     4,498,383 shares
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     4,498,383 shares
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)  ¨
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)     30.54%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)     PN

CUSIP No. 980905301 13D Page 4 of 23 Pages

1	NAMES OF REPORTING PERSONS. I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). New Leaf Venture Management II, L.L.C.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a)  ¨        (b)  ¨
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)     AF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)  ¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION     Delaware Limited Liability Company
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER     0 shares
		8	SHARED VOTING POWER     4,498,383 shares
		9	SOLE DISPOSITIVE POWER     0 shares
		10	SHARED DISPOSITIVE POWER     4,498,383 shares
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     4,498,383 shares
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)  ¨
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)     30.54%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)     PN

CUSIP No. 980905301 13D Page 5 of 23 Pages

1	NAMES OF REPORTING PERSONS. I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Philippe O. Chambon
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a)  ¨        (b)  ¨
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)     AF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)  ¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION     French citizen
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER     0 shares
		8	SHARED VOTING POWER     4,498,383 shares
		9	SOLE DISPOSITIVE POWER     0 shares
		10	SHARED DISPOSITIVE POWER     4,498,383 shares
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     4,498,383 shares
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)  ¨
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)     30.54%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)     IN

CUSIP No. 980905301 13D Page 6 of 23 Pages

1	NAMES OF REPORTING PERSONS. I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). James Niedel
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a)  ¨        (b)  ¨
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)     AF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)  ¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION     United States citizen
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER     0 shares
		8	SHARED VOTING POWER     4,498,383 shares
		9	SOLE DISPOSITIVE POWER     0 shares
		10	SHARED DISPOSITIVE POWER     4,498,383 shares
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     4,498,383 shares
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)  ¨
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)     30.54%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)     IN

CUSIP No. 980905301 13D Page 7 of 23 Pages

1	NAMES OF REPORTING PERSONS. I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Vijay Lathi
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a)  ¨        (b)  ¨
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)     AF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)  ¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION     United States citizen
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER     0 shares
		8	SHARED VOTING POWER     4,498,383 shares
		9	SOLE DISPOSITIVE POWER     0 shares
		10	SHARED DISPOSITIVE POWER     4,498,383 shares
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     4,498,383 shares
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)  ¨
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)     30.54%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)     IN

CUSIP No. 980905301 13D Page 8 of 23 Pages

1	NAMES OF REPORTING PERSONS. I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Kathleen LaPorte
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a)  ¨        (b)  ¨
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)     AF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)  ¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION     United States citizen
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER     0 shares
		8	SHARED VOTING POWER     0 shares
		9	SOLE DISPOSITIVE POWER     0 shares
		10	SHARED DISPOSITIVE POWER     0 shares
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     0 shares
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)  ¨
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)     0%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)     IN

CUSIP No. 980905301 13D Page 9 of 23 Pages

1	NAMES OF REPORTING PERSONS. I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Ronald Hunt
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a)  ¨        (b)  ¨
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)     AF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)  ¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION     United States citizen
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER     0 shares
		8	SHARED VOTING POWER     4,498,383 shares
		9	SOLE DISPOSITIVE POWER     0 shares
		10	SHARED DISPOSITIVE POWER     4,498,383 shares
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     4,498,383 shares
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)  ¨
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)     30.54%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)     IN

CUSIP No. 980905301 13D Page 10 of 23 Pages

1	NAMES OF REPORTING PERSONS. I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Srinivas Akkaraju
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a)  ¨        (b)  ¨
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)     AF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)  ¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION     United States citizen
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER     0 shares
		8	SHARED VOTING POWER     4,498,383 shares
		9	SOLE DISPOSITIVE POWER     0 shares
		10	SHARED DISPOSITIVE POWER     4,498,383 shares
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     4,498,383 shares
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)  ¨
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)     30.54%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)     IN

CUSIP No. 980905301 13D Page 11 of 23 Pages

1	NAMES OF REPORTING PERSONS. I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY). Jeani Delagardelle
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a)  ¨        (b)  ¨
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS)     AF
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)  ¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION     United States citizen
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER     0 shares
		8	SHARED VOTING POWER     4,498,383 shares
		9	SOLE DISPOSITIVE POWER     0 shares
		10	SHARED DISPOSITIVE POWER     4,498,383 shares
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     4,498,383 shares
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS)  ¨
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)     30.54%
14	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)     IN

CUSIP No. 980905301 13D Page 12 of 23 Pages

Schedule 13D

Item 1. Security and Issuer.

This Amendment No. 1 to the statement on Schedule 13D (this “Amendment No. 1”) amends and supplements the statement on Schedule 13D filed on August 8, 2008 (the “Original 13D” and relates to the common stock, $.001 par value (the “Common Stock”) of World Heart Corp. (the “Issuer”) having its principal executive office at 4750 Wiley Post Way, Suite 120, Salt Lake City, UT 84116.

The purpose of this Amendment is to reflect the acquisition by the Reporting Persons of 388,350 shares of Common Stock and warrants to purchase up to an additional 776,700 shares of Common Stock in the aggregate. Except as specifically provided herein, this Amendment No. 1 does not modify any of the information previously reported on the Original 13D. Capitalized terms used but not otherwise defined in this Amendment No. 1 shall have the meanings ascribed to them in the Original 13D.

Item 2. Identity and Background.

This statement is being filed by New Leaf Ventures II, L.P. (“NLV II”), New Leaf Venture Associates II, L.P. (“NLV Associates”) and New Leaf Venture Management II, L.L.C. (“NLV Management” and together with NLV II and NLV Associates, the “Reporting Entities”) and Philippe O. Chambon (“Chambon”), James Niedel (“Niedel”), Vijay Lathi (“Lathi”), Ronald Hunt (“Hunt”), Srinivas Akkaraju (“Akkaraju”) and Jeani Delagardelle (“Delagardelle” and together with Chambon, Niedel, Lathi, Hunt and Akkaraju, the “Managing Directors”). The Reporting Entities and the Managing Directors collectively are referred to as the “Reporting Persons”.

Kathleen LaPorte resigned as a manager and member of NLV Management on October 1, 2008.

The address of the principal business office of NLV II, NLV Associates, NLV Management, Chambon, Niedel and Hunt is New Leaf Venture Partners, Times Square Tower, 7 Times Square, Suite 3502, New York, NY 10036. The address of the principal business office of Lathi, Akkaraju and Delagardelle is New Leaf Venture Partners, 2500 Sand Hill Road, Suite 203, Menlo Park, CA 94025.

The principal business of NLV II is to make, hold and dispose of equity and equity-related investments, principally in healthcare, medical device and life sciences companies. The principal business of NLV Associates is to act as the sole general partner of NLV II. The principal business of NLV Management is to act as the sole general partner of NLV Associates. The principal business of each of the Managing Directors is to manage the Reporting Entities and a number of affiliated partnerships with similar businesses.

During the five years prior to the date hereof, none of the Reporting Persons has been convicted in a criminal proceeding or has been a party to a civil proceeding ending in a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

Each of NLV II and NLV Associates is a limited partnership organized under the laws of the State of Delaware. NLV Management is a limited liability company organized under the laws of the State of Delaware. Each Managing Director other than Philippe O. Chambon is a citizen of the United States. Philippe O. Chambon is a citizen of France.

Item 3. Source and Amount of Funds or Other Consideration.

NLV II acquired 388,350 shares of Common Stock, a 15-month warrant exercisable at an exercise price of $4.90 per share for up to 388,350 shares of Common Stock (the “15-Month Warrant”) and a five-year warrant exercisable at an exercise price of $4.90 per share for up to 388,350 shares of Common Stock (the “Five-Year Warrant” and together with the 15-Month Warrant, the “Warrants”) from the Issuer for an aggregate purchase price of $2,000,002.50 on January 26,

CUSIP No. 980905301 13D Page 13 of 23 Pages

2010 (the purchase of the shares of Common Stock and the Warrants being collectively referred to hereinafter as the “Transaction”). No part of the purchase price in the Transaction was represented by funds or other consideration borrowed or otherwise obtained for the purpose of acquiring, holding, trading or voting the shares.

Item 4. Purpose of Transaction.

NLV II acquired the Common Stock and the Warrants for investment purposes. Depending on market conditions, its continuing evaluation of the business and prospects of the Issuer and other factors, NLV II and other Reporting Persons may dispose of or acquire additional shares of the Issuer. Pursuant to the terms of the Securities Purchase Agreement dated January 21, 2010 (the “Securities Purchase Agreement”), which was entered into by and among NLV II, the Issuer, and certain other shareholders (the “Other Shareholders”), NLV II purchased (i) 388,350 shares of the Common Stock of the Issuer, (ii) 15-Month Warrant and (iii) Five-Year Warrant. The 15-Month Warrant is immediately exercisable and is exercisable until 15-months from the date of issuance. The Five-Year Warrant is immediately exercisable and is exercisable until the fifth anniversary of the date of issuance. Except as set forth above, none of the Reporting Persons has any present plans which relate to or would result in:

(a) The acquisition by any person of additional securities of the Issuer, or the disposition of securities of the Issuer;

(b) An extraordinary corporate transaction, such as a merger, reorganization or liquidation, involving the Issuer or any of its subsidiaries;

(c) A sale or transfer of a material amount of assets of the Issuer or any of its subsidiaries;

(d) Any change in the present board of directors or management of the Issuer, including any plans or proposals to change the number or term of directors or to fill any existing vacancies on the board;

(e) Any material change in the present capitalization or dividend policy of the Issuer;

(f) Any other material change in the Issuer’s business or corporate structure;

(g) Changes in the Issuer’s charter, bylaws or instruments corresponding thereto or other actions which may impede the acquisition of control of the Issuer by any person;

(h) Causing a class of securities of the Issuer to be delisted from a national securities exchange or to cease to be authorized to be quoted in an inter-dealer quotation system of a registered national securities association;

(i) A class of equity securities of the Issuer becoming eligible for termination of registration pursuant to Section 12(g)(4) of the Securities Exchange Act of 1934; or

(j) Any action similar to any of those enumerated above.

Item 5. Interest in Securities of the Issuer.

(a) NLV II is the record owner of 3,721,683 shares of Common Stock, the 15-Month Warrant to purchase up to 388,350 shares of Common Stock and the Five-Year Warrant to purchase up to 388,350 shares of Common Stock (collectively, the “NLV II Shares”). The Warrants are currently exercisable. As the sole general partner of NLV II, NLV Associates may be deemed to own beneficially the NLV II Shares. As the sole general partner of NLV Associates, NLV Management may be deemed to own beneficially the NLV II Shares. As the individual managers of NLV Management, each of the Managing Directors also may be deemed to own beneficially the NLV II Shares.

CUSIP No. 980905301 13D Page 14 of 23 Pages

Each of the Reporting Persons may be deemed to own beneficially 30.54% of the Issuer’s Common Stock, which percentage is calculated based upon 14,731,023 shares reported to be outstanding. Each of the Reporting Persons, except NLV II, disclaims beneficial ownership of the NLV II Shares except to the extent of their pecuniary interest therein, if any.

(b) Regarding the number of shares as to which such person has:

(i) sole power to vote or to direct the vote: See line 7 of cover sheets.

(ii) shared power to vote or to direct the vote: See line 8 of cover sheets.

(iii) sole power to dispose or to direct the disposition: See line 9 of cover sheets.

(iv) shared power to dispose or to direct the disposition: See line 10 of cover sheets.

(c) Except as set forth in Item 3 above, none of the Reporting Persons has effected any transaction in the Common Stock during the last 60 days.

(d) No other person is known to have the right to receive or the power to direct the receipt of dividends from, or any proceeds from the sale of, shares beneficially owned by any of the Reporting Persons.

(e) Not Applicable.

Item 6. Contracts, Arrangements, Undertakings or Relationships with Respect to Securities of the Issuer.

The response to Item 4 is incorporated by reference.

In connection with the Securities Purchase Agreement, the Issuer, NLV II, and the Other Shareholders entered into a Registration Rights Agreement, dated January 21, 2010 (the “Registration Rights Agreement”), which grants NLV II certain rights with respect to registration under the Securities Act of 1933, as amended (the “Act”). Under the terms of the Registration Rights Agreement, within sixty days after January 26, 2010 (the “Closing Date”), the Issuer is obligated to file with the SEC a registration statement on Form S-3 (or, if the Issuer is not then eligible to use Form S-3 to register the resale of the Registrable Securities, on such form of registration statement as is then available to effect a registration for resale of the Registrable Securities) covering the resale of the Registrable Securities. Registrable Securities are defined as (i) the shares of Common Stock acquired by the Investors pursuant to the Securities Purchase Agreement and (ii) any other securities issued or issuable with respect to or in exchange for Registrable Securities; provided, that, a security shall cease to be a Registrable Security upon (A) sale pursuant to a Registration Statement or Rule 144 under the Act, or (B) such security becoming eligible for sale without notice or restriction (including without limitation any restriction relating to the availability of current public information about the Issuer and any volume restrictions) by the Investors pursuant to Rule 144.

Under the terms of the Registration Rights Agreement, NLV II and the Other Shareholders also have certain “piggy-back” rights, which provide if at any time following the date of the Registration Rights Agreement that any Registrable Securities remain outstanding (A) there is not one or more effective Registration Statements covering all of the Registrable Securities and (B) the Issuer proposes for any reason to register any shares of Common Stock under the Act (other than pursuant to a registration statement on Form S-4 or Form S-8 (or a similar or successor form)) with respect to an offering of Common Stock by the Issuer for its own account or for the account of any of its stockholders, it shall at each such time promptly give written notice to the holders of the Registrable Securities of its intention to do so and, to the extent permitted under the provisions of Rule 415 under the Act, include in such registration all Registrable Securities with respect to which the Issuer has received written requests for inclusion therein within fifteen days after receipt of the Issuer’s notice. Such notice shall offer the holders of the Registrable Securities the opportunity to register such number of shares of Registrable Securities as each such holder may request and shall indicate the intended method of distribution of such Registrable Securities. All registration rights terminate after the earlier of (i) the date on which all

CUSIP No. 980905301 13D Page 15 of 23 Pages

Registrable Securities covered by such registration statement as amended from time to time, have been sold, and (ii) the date on which all Registrable Securities covered by such registration statement may be sold without notice or restriction pursuant to Rule 144 of the Act, including, without limitation, any restriction relating to the availability of current public information about the Issuer and any volume restrictions.

To the knowledge of the Reporting Persons, except for the matters described herein, the Reporting Persons have no contract, arrangement, understanding or relationship (legal or otherwise) among the Reporting Persons or between the Reporting Persons and any other person with respect to any securities of the Issuer. The summaries of the terms of the Securities Purchase Agreement and the Registration Rights Agreement set forth herein are qualified in their entirety by reference to Exhibits 99.1 and 99.2, respectively.

Item 7. Material to be Filed as Exhibits.

Exhibit 99.1 – Securities Purchase Agreement.*

Exhibit 99.2 – Registration Rights Agreement.*

Exhibit 99.3 – Agreement regarding filing of joint Schedule 13D.

Exhibit 99.4 – Powers of Attorney regarding Schedule 13D filings.

* Incorporated by reference from the Form 8-K of the Issuer filed on January 22, 2010, Securities and Exchange Commission file number: 000-28882.

CUSIP No. 980905301 13D Page 16 of 23 Pages

SIGNATURE

After reasonable inquiry and to the best of its knowledge and belief, each of the undersigned certifies that the information set forth in this statement is true, complete and correct.

Date: February 4, 2010

NEW LEAF VENTURES II, L.P.
By:	NEW LEAF VENTURE ASSOCIATES II, L.P.
	General Partner
	By:	NEW LEAF VENTURE MANAGEMENT II, L.L.C.
		General Partner
		By:	/S/    CRAIG L. SLUTZKIN
			Craig L. Slutzkin
			Chief Financial Officer
NEW LEAF VENTURE ASSOCIATES II, L.P.
By:	NEW LEAF VENTURE MANAGEMENT II, L.L.C.
	General Partner
	By:	/S/    CRAIG L. SLUTZKIN
		Craig L. Slutzkin
		Chief Financial Officer
NEW LEAF VENTURE MANAGEMENT II, L.L.C.
	By:	/S/    CRAIG L. SLUTZKIN
		Craig L. Slutzkin
		Chief Financial Officer
*
Philippe O. Chambon
*
James Niedel
*
Vijay Lathi
*
Kathleen LaPorte

CUSIP No. 980905301 13D Page 17 of 23 Pages

*

Ronald Hunt

*

Srinivas Akkaraju

*

Jeani Delagardelle

/S/    CRAIG L. SLUTZKIN        

Craig L. Slutzkin

As attorney-in-fact

* This Schedule 13D was executed by Craig L. Slutzkin on behalf of the individuals listed above pursuant to Powers of Attorney, copies of which are attached as Exhibit 99.4.

CUSIP No. 980905301 13D Page 18 of 23 Pages

Exhibit 99.3

AGREEMENT

Pursuant to Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, the undersigned hereby agree that only one statement containing the information required by Schedule 13D need be filed with respect to the ownership by each of the undersigned of shares of stock of World Heart Corp.

EXECUTED this 4th day of February, 2010.

NEW LEAF VENTURES II, L.P.
By:	NEW LEAF VENTURE ASSOCIATES II, L.P.
	General Partner
	By:	NEW LEAF VENTURE MANAGEMENT II, L.L.C.
		General Partner
		By:	/s/ Craig L. Slutzkin
			Craig L. Slutzkin
			Chief Financial Officer
NEW LEAF VENTURE ASSOCIATES II, L.P.
By:	NEW LEAF VENTURE MANAGEMENT II, L.L.C.
	General Partner
	By:	/s/ Craig L. Slutzkin
		Craig L. Slutzkin
		Chief Financial Officer
NEW LEAF VENTURE MANAGEMENT II, L.L.C.
	By:	/s/ Craig L. Slutzkin
		Craig L. Slutzkin
		Chief Financial Officer
*
Philippe O. Chambon
*
James Niedel
*
Vijay Lathi
*
Kathleen LaPorte

CUSIP No. 980905301 13D Page 19 of 23 Pages

        *

Ronald Hunt

        *

Srinivas Akkaraju

        *

Jeani Delagardelle

    /s/ Craig L. Slutzkin

Craig L. Slutzkin

As attorney-in-fact

* This Schedule 13D was executed by Craig L. Slutzkin on behalf of the individuals listed above pursuant to Powers of Attorney, copies of which are attached as Exhibit 99.4.

CUSIP No. 980905301 13D Page 20 of 23 Pages

Exhibit 99.4

POWER OF ATTORNEY

KNOWN ALL MEN BY THESE PRESENTS, that the undersigned hereby constitutes and appoints CRAIG L. SLUTZKIN as her true and lawful attorney-in-fact and agent with full power of substitution and re-substitution for her and in her name, place and stead, in any and all capacities, to sign any and all documents relating to any and all Securities and Exchange Commission filings which may be required, granting unto said attorney-in-fact and agent full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises, as fully to all intents and purposes as she might or could do in person, thereby ratifying and confirming all that said attorney-in-fact may lawfully do or cause to be done by virtue hereof.

This power shall continue in effect until terminated in writing.

By:	/s/ Kathleen LaPorte
	Kathleen LaPorte

Dated: November 18, 2004

CUSIP No. 980905301 13D Page 21 of 23 Pages

POWER OF ATTORNEY

KNOWN ALL MEN BY THESE PRESENTS, that the undersigned hereby constitutes and appoints CRAIG L. SLUTZKIN as his true and lawful attorney-in-fact and agent for him and in his name, place and stead, in any and all capacities, to sign any and all documents relating to any and all Securities and Exchange Commission filings which may be required, granting unto said attorney-in-fact and agent full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises, as fully to all intents and purposes as he might or could do in person, thereby ratifying and confirming all that said attorney-in-fact may lawfully do or cause to be done by virtue hereof.

This power shall continue in effect until terminated in writing.

By:	/s/ Vijay K. Lathi
	Vijay K. Lathi
By:	/s/ James Niedel
	James Niedel

Dated: October 5, 2005

CUSIP No. 980905301 13D Page 22 of 23 Pages

POWER OF ATTORNEY

KNOWN ALL MEN BY THESE PRESENTS, that the undersigned hereby constitutes and appoints CRAIG L. SLUTZKIN as his/her true and lawful attorney-in-fact and agent for him/her and in his/her name, place and stead, in any and all capacities, to sign any and all documents relating to any and all Securities and Exchange Commission filings which may be required, granting unto said attorney-in-fact and agent full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises, as fully to all intents and purposes as he/she might or could do in person, thereby ratifying and confirming all that said attorney-in-fact may lawfully do or cause to be done by virtue hereof.

This power shall continue in effect until terminated in writing.

By:	/s/ Philippe O. Chambon
	Philippe O. Chambon
By:	/s/ Jeani Delagardelle
	Jeani Delagardelle
By:	/s/ Ronald Hunt
	Ronald Hunt

Dated: September 29, 2006

CUSIP No. 980905301 13D Page 23 of 23 Pages

POWER OF ATTORNEY

KNOWN ALL MEN BY THESE PRESENTS, that the undersigned hereby constitutes and appoints CRAIG L. SLUTZKIN as his true and lawful attorney-in-fact and agent for him and in his name, place and stead, in any and all capacities, to sign any and all documents relating to any and all Securities and Exchange Commission filings which may be required, granting unto said attorney-in-fact and agent full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises, as fully to all intents and purposes as he might or could do in person, thereby ratifying and confirming all that said attorney-in-fact may lawfully do or cause to be done by virtue hereof.

This power shall continue in effect until terminated in writing.

By:	/s/ Srinivas Akkaraju
	Srinivas Akkaraju

Dated: February 2, 2009