QMODE+ ablation mode: optimal parameter setting and impedance-adapted strategies.

Area of Science:

• Electrophysiology
• Medical Devices
• Cardiac Ablation

Background:

• A novel QDOT-MICRO catheter facilitates high-power short-duration (vHPSD) ablation.
• This technology enables advanced ablation techniques like QMODE+.

Purpose of the Study:

• To optimize lesion formation using QMODE+ ablation with the QDOT-MICRO catheter.
• To clarify the impact of key ablation parameters on lesion characteristics.
• To develop impedance-adapted strategies for consistent lesion creation.

Main Methods:

• Radiofrequency (RF) ablation was performed on porcine myocardium using the QDOT-MICRO catheter in QMODE+ mode.
• Key parameters investigated included contact force (CF), power, RF duration, interlesion distance, contact angle, and impedance.
• Optimal parameters were identified, and strategies for managing varying impedances were explored.

Main Results:

• Lesion size increased with higher CF, longer RF duration, and greater power, but decreased with elevated impedance.
• Optimal lesion formation was observed with CF < 25g, perpendicular contact, and 5mm interlesion distance.
• Adjustments in QMODE+ and QMODE modes allowed for consistent lesion formation across different impedance levels (90Ω to 150Ω).

Conclusions:

• Routine QMODE+ ablation with specific parameters (90W, 4s, CF<25g, 5mm distance, perpendicular contact) achieves optimal lesion formation.
• Adjusting QMODE+ parameters at low impedance and switching to QMODE at high impedance ensures consistent lesion creation.
• Parallel contact can be used to reduce lesion depth in fragile tissues or under low impedance conditions.