Sec Form 4 Filing - Lightcap Jeffrey C @ Heartflow, Inc. - 2026-03-24

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Lightcap Jeffrey C 2. Issuer Name and Ticker or Trading Symbol Heartflow, Inc. [ HTFL] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O HEARTFLOW, INC., 331 E. EVELYN AVENUE 3. Date of Earliest Transaction (MM/DD/YY) 03/24/2026 (Street) MOUNTAIN VIEW, CA94041 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 03/24/2026 J 206,261 ( 1 ) A $ 0 246,261 D Common Stock 833,075 I By HealthCor Partners Fund II, L.P. ( 2 ) Common Stock 1,248,939 I By HealthCor Partners Fund, L.P. ( 2 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Lightcap Jeffrey C C/O HEARTFLOW, INC. 331 E. EVELYN AVENUE MOUNTAIN VIEW, CA94041 X Signatures /s/ Nga Van by power of attorney 03/26/2026 Signature of Reporting Person Date

Explanation of Responses:

( 1 )On March 24, 2026, HCPCIV 1, LLC ("HCPCIV") effected a pro rata in-kind distribution of Heartflow, Inc. common stock to its members in accordance with its operating agreement, including 206,261 shares allocable to Mr. Lightcap based on his indirect interest in HCPCIV immediately prior to the distribution. Following the distribution, HCPCIV is being dissolved. After giving effect to the distribution, Mr. Lightcap's beneficial ownership is held directly (and no longer indirectly through HCPCIV) to the extent of the shares received. ( 2 )Mr. Lightcap is a controlling member of each of HealthCor Partners Fund II, L.P. and HealthCor Partners Fund, L.P. and may be deemed to have voting and dispositive power with respect to the shares. Mr. Lightcap disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of all of the reported shares for purposes of Section 16 or for any other purpose.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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