Affera: Dual-Energy Lattice-Tip Ablation for Atrial Arrhythmias

Atrial arrhythmias, including atrial fibrillation and atrial tachycardia, pose significant challenges in cardiovascular medicine, often requiring catheter-based ablation for management. Traditional methods use either radiofrequency or cryoablation, but limitations in lesion durability and procedural efficiency have driven the development of new technologies.

Affera’s dual-energy lattice-tip ablation system enhances precision and effectiveness in treating complex arrhythmias. By integrating advanced energy delivery with a unique catheter design, this technology optimizes lesion formation while ensuring procedural safety.

Dual-Energy Concept

The Affera system combines radiofrequency (RF) and pulsed field energy (PFE) within a single catheter, allowing tailored energy delivery based on tissue characteristics. RF energy generates heat through resistive heating, causing controlled coagulative necrosis, while PFE uses high-voltage, short-duration electrical pulses to create nanopores in cell membranes, inducing nonthermal cell death via irreversible electroporation. This dual-energy approach enhances adaptability in targeting arrhythmogenic substrates.

One key advantage is its ability to overcome limitations of conventional ablation techniques. RF ablation, though effective, can lead to complications such as char formation, steam pops, and excessive thermal injury to adjacent structures. PFE provides a nonthermal alternative that preserves extracellular matrix integrity, reducing risks like pulmonary vein stenosis when applied near critical structures. The ability to transition seamlessly between these energy modalities allows electrophysiologists to customize lesion characteristics in real time, optimizing depth and uniformity.

Early clinical studies suggest that combining RF and PFE may improve procedural efficiency by reducing the need for extensive lesion overlap, a common necessity in traditional RF ablation. PFE’s selective impact on cardiomyocytes while sparing connective tissue may contribute to better long-term outcomes, particularly in patients with complex arrhythmogenic substrates. Preliminary data indicate this approach may lower recurrence rates compared to single-energy ablation strategies, though larger randomized trials are needed for confirmation.

Lattice-Tip Characteristics

The Affera catheter’s lattice-tip design departs from conventional solid-tip electrodes, offering advantages in energy delivery and lesion formation. Unlike traditional catheters relying on single-point or circumferential contact, the lattice structure consists of an open, multi-electrode framework that enhances surface area interaction with the myocardium. This configuration ensures more uniform energy dispersion, improving both resistive heating during RF ablation and electric field distribution during PFE application. By reducing focal overheating, the lattice-tip mitigates risks such as excessive thermal injury or tissue charring.

A key benefit of this design is its ability to deliver energy more evenly, leading to greater lesion consistency. Traditional solid-tip electrodes often create variations in lesion depth and width due to uneven energy application, requiring overlapping ablation sites to ensure conduction block. The lattice structure minimizes these inconsistencies by allowing simultaneous multi-electrode energy transfer, producing broader, contiguous lesions with fewer applications. This efficiency is particularly valuable in complex arrhythmias where durable, transmural lesions are essential. Preclinical studies show this design accelerates lesion formation, potentially shortening procedure duration.

The lattice-tip also enhances catheter stability and tissue contact. Effective lesion creation requires a consistent electrode-tissue interface, but traditional catheters often struggle with variable contact pressure, affecting lesion depth and efficacy. The multi-electrode lattice design adapts better to the myocardial surface, distributing force evenly and reducing excessive pressure at a single point. This is particularly beneficial in anatomically complex regions, such as the pulmonary veins and posterior left atrium, where stable contact can be challenging.

Biological Basis Of Ablation

Ablation therapy for atrial arrhythmias modifies myocardial tissue to disrupt aberrant electrical circuits sustaining irregular rhythms. The extent and nature of this injury depend on the type of energy applied, duration of exposure, and tissue characteristics. Effective lesion formation balances sufficient tissue disruption to achieve conduction block while minimizing unintended damage to adjacent structures.

RF ablation employs resistive heating to cause protein denaturation and coagulative necrosis, resulting in fibrotic scar tissue that blocks electrical signals. The degree of tissue destruction depends on catheter contact force, blood flow dynamics, and tissue thickness. Incomplete lesions may allow electrical reconnection, increasing arrhythmia recurrence risk, while excessive heating can cause complications such as steam pops, endothelial damage, and collateral injury.

PFE, a nonthermal alternative, induces irreversible electroporation by applying high-voltage, short-duration electrical pulses that create nanopores in cell membranes. Unlike RF ablation, which affects both cardiomyocytes and connective tissue, PFE selectively targets electrically active cells while preserving extracellular matrix components. This approach is particularly advantageous near critical structures like the pulmonary veins, where excessive fibrosis can lead to stenosis and long-term complications.

Tissue Considerations In Persistent Atrial Arrhythmia

Persistent atrial arrhythmia presents unique challenges due to progressive structural and electrical remodeling of the atrial myocardium. Unlike paroxysmal cases, which often have focal triggers, persistent forms involve widespread fibrosis, altered conduction pathways, and heterogeneous myocardial substrate. These changes complicate ablation, as diseased tissue varies in excitability, conductivity, and responsiveness to energy delivery. Fibrotic regions interspersed with viable myocytes create reentry circuits that sustain arrhythmia, requiring a more comprehensive lesion strategy.

The extent of atrial fibrosis significantly affects procedural success. Late gadolinium-enhanced cardiac MRI helps assess fibrosis burden, with studies linking higher scarring levels to increased post-ablation recurrence rates. Patients with extensive fibrosis may require more extensive lesion sets to achieve durable conduction block, though excessive ablation can promote further arrhythmogenic substrate formation. Striking a balance between effective arrhythmia termination and preserving atrial function remains crucial, especially in cases where atrial transport function is already compromised.