Optimizing Energy Efficiency in Cardiac Rhythm Management

The performance of cardiac rhythm management (CRM) devices depends on the energy required to stimulate cardiac tissue. This energy is determined by the programmed pulse width and amplitude, as well as the voltage delivered between the electrodes—the anode and the cathode. Because the electrode surface directly influences how efficiently electrical energy is transferred to cardiac tissue, optimizing the electrode–tissue interface can reduce current drain and improve overall device efficiency. Clinically, improvements in this interface can contribute to extended battery life and longer device longevity.

Electrodes used in CRM devices, such as pacemakers, are metallic conductors that mediate the transition from electronic current within the electrode to ionic current in the surrounding tissue through electrochemical processes occurring at the electrode–tissue interface.

Why Material Choice Defines Device Longevity and Reliability

The materials used in implantable electrodes do more than conduct electrical current—they play a critical role in determining how reliably a device performs during long-term operation within the body.

Selecting materials and surface technologies for implantable electrodes requires careful consideration of material properties, surface microstructure, electrochemical behavior, and charge-transfer characteristics. The electrode surface must efficiently deliver electrical stimulation while also enabling accurate sensing of the cardiac response.

In cardiac rhythm management (CRM) devices, charge transfer ideally occurs through double-layer charging and discharging at the electrode–electrolyte interface. This capacitive charge-exchange mechanism is desirable because it avoids the generation or consumption of chemical species during a stimulation pulse. Achieving high charge-injection capacity therefore depends on electrode surfaces that provide large effective surface area, typically through porous microstructures or high-surface-area coatings.

Titanium nitride (TiN) coatings have long been used on platinum–iridium (Pt/Ir) electrodes in cardiac rhythm management (CRM) applications. TiN is a chemically stable, electrically conductive material with excellent biocompatibility that supports charge injection through the electrode–electrolyte double layer.

Electrodes incorporating high-surface-area TiN coatings can therefore achieve high charge-injection capacities. The surface microstructure of TiN coatings can also promote controlled tissue in-growth at the electrode–tissue interface, which may contribute to improved long-term stability and device performance.

At Pulse Technologies, TiN coatings are applied using precision physical vapor deposition (PVD) processes supported by extensive experience in implantable device manufacturing. These capabilities enable consistent coating quality, controlled surface morphology, and reliable electrochemical performance for OEM partners developing cardiac rhythm management and neurostimulation devices.

Engineered for Reliability and Long-Term Implant Performance

Our titanium nitride (TiN) coatings provide high capacitance and charge-injection capacity while reducing electrode impedance.

The diagrams below illustrate these effects, showing the increased charge-storage capacity (left) and lower impedance (right) achieved with TiN-coated electrodes.