Note 17. Related Parties

Prior to the Merger, David A. Jenkins, the Company’s current Executive Chairman of the Board and Chief Executive Officer, and Old Catheter’s Chairman of the Board of Directors, and his affiliates held approximately $25.1 million of Old Catheter’s Convertible Promissory Notes ("Notes"), that were converted into 7,856.251 shares of Series X Convertible Preferred Stock in connection with the Merger (see Note 12, Preferred Stock). As of December 31, 2025, all of the Series X Preferred Stock received by these related parties had been converted into shares of common stock. In consideration for forgiving the interest accrued but remaining unpaid under the Notes in an aggregate amount of approximately $13.9 million, Mr. Jenkins and his affiliates also received royalty rights equal to approximately 12% of the net sales, if any, of LockeT, commencing upon the first commercial sale and through December 31, 2035. The Company entered into an additional royalty agreement for the LockeT device with Auston Locke, who is the son of Robert Locke, VP of Product Development. Under this agreement, the Company will pay a 5% royalty rate on net sales up to $1 million in cumulative royalties. In April 2025, a US patent was granted by the United States Patent and Trademark Office, after which the Company is obligated to pay an additional royalty of 2% of net sales only after the initial $1 million of 5% royalties has been paid, up to a maximum of $10 million in additional royalties. 

On December 31, 2025, pursuant to the Exchange Agreement, Mr. Jenkins and his affiliate converted their aforementioned royalty rights and accrued royalty amounts into an aggregate of 9,490 shares of the Company’s newly designated Series J Convertible Preferred Stock. As of December 31, 2025, 9,490 shares of Series J Convertible Preferred Stock were held by these related parties. Refer to Note 2, Summary of Significant Accounting Policies, and Note 8, Royalties Payable, for additional information over the royalties payable due to these related parties. Refer to Note 12, Preferred Stock, for additional information over the Series J Convertible Preferred Stock.

In addition to the shares described above that were issued in connection with the Notes, Mr. Jenkins and his affiliates received 1,325.838 shares of Series X Convertible Preferred Stock in the Merger, and Mr. Jenkins’ adult children received 1,284.344 shares of Series X Convertible Preferred Stock in the Merger, all in exchange for their equity interests in Old Catheter in accordance with the Merger exchange ratio. As of  December 31, 2025, all of  the Series X Preferred Stock held by these related parties had been converted into shares of common stock.

Mr. Jenkins’ daughter, the Company’s non-executive Chief Operating Officer, received options to purchase 757 shares of the Company’s common stock upon the closing of the Merger in exchange for her options to purchase shares of Old Catheter common stock, converted based on the exchange ratio in the Merger. Of the total options to purchase 757 shares of the Company’s common stock, 17 options have expired as of  December 31, 2025, and the remaining 740 options have an exercise price of $112.10 per share.

On May 1, 2024, Marie-Claude Jacques, the Company’s then Chief Commercial Officer, received a non-plan option to purchase 1,315 shares of the Company’s common stock. The options have an exercise price of $101.10 per share, vest at 20% per year for 5 years and expire in May 2034.  On January 29, 2025, Ms. Jacques received an incentive stock option to purchase 13,154 shares of the Company's common stock. The options had an exercise price of $7.98 per share, 1,315 options vested on the grant date and an additional 1,315 options were to vest annually for 4 years, 1,644 options were to vest quarterly upon achievement of quarterly sales targets during 2025 and expire in January 2035. Ms. Jacques’ employment was terminated on June 2, 2025, and all unexercised options were cancelled, consisting of 1,315 unexercised non-plan options and 13,154 unexercised incentive stock options.

During the year ended December 31, 2024, the Company entered into various short-term promissory notes with various related parties (the “Related Party Notes”). These Related Party Notes had a maturity date of August 30, 2024 and interest rates of 8% per annum. On August 23, 2024, the Notes were amended to extend the maturity date to January 31, 2026 and increase the interest rate to 12% per annum effective August 31, 2024. On December 31, 2025, the Notes were amended a second time to extend the maturity date of the notes payable to the Jenkins Family Charitable Institute to January 31, 2028, and the notes payable to FatBoy Capital, L.P. and Mr. Jenkins to January 31, 2029. In connection with the second amendment of the Notes, the Company transferred its Perikard membership interests to Mr. Jenkins for de minimis proceeds and issued an aggregate of 340,000 Series M Warrants to FatBoy Capital, L.P. and Mr. Jenkins with a fair value of $509 thousand. See Note 7, Notes Payable, Note 14, Asset Acquisitions, and Note 11, Equity Offerings, for additional information regarding the second amendment, the Perikard transfer, and the Series M Warrants.  

On July 11, 2025, two short-term promissory notes with a face value of $150 thousand each were issued by KardioNav to the Company's Chief Executive Officer and Lifestim, Inc., a company controlled by the Company's Chief Executive Officer. The promissory notes have a maturity date of July 11, 2026, and interest rates of 4.2% per annum, payable upon maturity. See Note 7, Notes Payable, for further information.

The related parties and the amounts owed to each related party as of  December 31, 2025 are summarized in the following table (in thousands):

On September 3, 2024, the Jenkins Family Charitable Institute also invested approximately $500,000 in the Company’s public offering and received 13,947 shares of common stock; 12,368 pre funded warrants with an exercise price of $0.0019 and no expiration date; 26,316 Series H Warrants with an exercise price of $19.00 per share that expired on March 3, 2025; 26,316 Series I Warrants with an exercise price of $19.00 per share that expire on March 3, 2026; and 26,316 Series J Warrants with an exercise price of $19.00 per share that expire on September 3, 2029. 

On October 28, 2024, the Jenkins Family Charitable Institute exercised all 12,368 pre funded warrants and received 12,368 shares of common stock of the Company. On December 31, 2024, the Jenkins Family Charitable Institute distributed 23,684 Series J warrants to its trustee and two advisors, who are daughters of Mr. Jenkins. 

On January 6, 2025, Philip Anderson, the Company's Chief Financial Officer, received a non-plan option to purchase 26,315 shares of the Company's common stock. The options have an exercise price of $10.07 per share, vest monthly over 36 months and expire in January 2035.

In February 2025, Catheter formed its subsidiary Cardionomix. The capitalization structure of the newly formed entity included 82% of the common stock of Cardionomix held by the Company, 5% of the common stock of Cardionomix held by Mr. Jenkins, 7% of the common stock by affiliates of Mr. Jenkins, and the remaining 6% held by third parties.

On June 20, 2025, Catheter formed a new subsidiary, KardioNav. The capitalization structure of the newly formed entity included 57% of the common stock of KardioNav held by the Company, 33% of the common stock of KardioNav held by Chelak iECG, Inc., an unrelated third party, 3% of the common stock of KardioNav held by Mr. Jenkins and 7% of the common stock of KardioNav held by affiliates of Mr. Jenkins.