# Leadless Pacemaker Betavoltaic Power Source

> **NIH NIH R44** · CITY LABS, INC. · 2023 · $41,924

## Abstract

PROJECT ABSTRACT
Leadless cardiac pacemakers (LCPs) represent a revolutionary leap forward in cardiac pacing technology
because they circumvent transvenous leads. The current size of lithium-carbon mono-fluoride (Li/CFX) batteries
results in an overall LCP device size of ~1 cc, and which only has a 10-year lifetime. LCPs are currently limited
to single-chamber pacing, representing only 10-20% of current pacemaker users. To achieve dual-chamber and
multi-chamber leadless pacing, a size reduction of the LCP is required. However, smaller batteries are required
to shrink the LCP. This Phase 2 effort will result in a betavoltaic battery for LCPs that is one-sixth the size of
Li/CFX batteries, enabling LCPs with a size of less than half the current LCP. Additionally, this new battery
technology will have greater than twice the energy capacity compared to Li/CFX batteries, and also will have
double the LCP lifespan, to a 20-year lifetime. This size reduction and increased longevity will allow for 2-3
implants over a patient’s lifetime, with minimal invasive overhead, facilitating mainstream use of LCPs, while
challenging traditional pacemakers. Dual or multi-chamber LCPs will dramatically increase the use of LCPs but
will require a ~0.1cc battery providing a consistent ≥3.8 microwatts for 20 years. Chemical-based batteries do
not have the energy density or reliability to meet this requirement, which the City Labs NanoTritiumTM betavoltaic
medical implant battery will effectively address. In Phase 2 the construction of the LCP betavoltaic battery will
comprise stacking ultrathin III-V betavoltaic cells that utilize a new, high beta-flux, tritium metal hydride film. The
betavoltaic battery will be ~0.1 cc with ≥14.9 microwatts power at beginning-oflife and have a 20-year projected
life at ≥ 3.8 microwatts. Phase 1 data shows that the target power density for a ~ 0.1 cc LCP battery will be
reached, resulting in a power density sufficient to meet pacemaker manufacturers’ performance goals, resulting
in continuous power output for 20 years within a ~0.1 cc formfactor. Tritium betavoltaic technology is a solid-
state power source that does not lose energy density with decreasing size, which occurs with lithium batteries.
Its principles of operation are similar to a solar cell, but in place of photons impinging on the semiconductor cell,
the electrons from the radioisotope’s beta decay are utilized. In the NHLBI SBIR Phase 2, City Labs will construct
a tritium betavoltaic battery consisting of ultra-thin stacked betavoltaic cell layers in a cylindrical form factor for
easy insertion into a leadless pacemaker package and deliver it to a pacemaker manufacturer to assess overall
system performance. Post Phase 2, integrated FDA testing and certification of the joint LCP and betavoltaic will
be performed by the pacemaker manufacturer through a Premarket Approval. A bioinert package with electrical
feedthroughs will be constructed. Packaging of the cell stack, seali...

## Key facts

- **NIH application ID:** 10741896
- **Project number:** 3R44HL145950-03S2
- **Recipient organization:** CITY LABS, INC.
- **Principal Investigator:** Peter Cabauy
- **Activity code:** R44 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2023
- **Award amount:** $41,924
- **Award type:** 3
- **Project period:** 2021-06-15 → 2024-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10741896

## Citation

> US National Institutes of Health, RePORTER application 10741896, Leadless Pacemaker Betavoltaic Power Source (3R44HL145950-03S2). Retrieved via AI Analytics 2026-05-29 from https://api.ai-analytics.org/grant/nih/10741896. Licensed CC0.

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