Impedance-guided Radiofrequency Ablation: Using Impedance to Improve Ablation Outcomes

Abstract

ABSTRACT. Despite the achievement of acute conduction block during catheter ablation, the recovery of conduction at previously ablated sites remains a primary factor implicated in arrhythmia recurrence after initial ablation. Real-time markers of adequate ablation lesion creation are needed to ensure durable ablation success. However, the assessment of acute lesion formation is challenging, and requires interpretation of surrogate markers of lesion creation that are frequently unreliable. Careful monitoring of impedance changes during radiofrequency catheter ablation has emerged as a highly specific marker of local tissue destruction. Ablation strategies guided by close impedance monitoring during ablation applications have been demonstrated to achieve high levels of success for ablation of atrial fibrillation. Impedance decrease during ablation may therefore be used as an additional endpoint beyond acute conduction block, in order to improve the durability of ablation lesions. In this manuscript, available methods of real-time lesion assessment are reviewed, and the rationale and technique for impedance-guided ablation are described.

Local impedance for the optimization of radiofrequency lesion delivery: A review of bench and clinical data

“…As described above, tissue heating by ablation results in a fall in GI 26,27 . Absent or suboptimal GI drop is therefore highly suggestive of ineffective current delivery 27 .…”

“…26,27 Absent or suboptimal GI drop is therefore highly suggestive of ineffective current delivery. 27 GI drops precede lesion maturation and may therefore result in premature termination of RF current. 28 After cessation of RF delivery, GI rises again, although it often remains below preablation levels.…”

Short-Time Impedance Spectroscopy Using a Mode-Switching Nonsinusoidal Oscillator: Applicability to Biological Tissues and Continuous Measurement

“…Thus, the absolute value and phase of bioimpedance are used to diagnose diseases, and this process is known as bioelectric impedance vector analysis [14][15][16][17][18][19]. Impedance measurement is also used in catheter ablation for treating arrhythmia [20][21][22][23]. By measuring the local impedance at an ablation site with electrodes integrated into an ablation catheter, the cauterization of myocardial tissue can be monitored.…”

Overcoming High Impedance in the Transitional Area of the Distal Great Cardiac Vein during Radiofrequency Catheter Ablation of Ventricular Arrhythmia

“…The appropriate impedance decrease is critical for effective ablation. Excessive decrease in impedance will increase the incidence of complications, while a decrease in impedance that is too low indicates ineffective treatment [ 20 , 21 ]. The impedance changes rapidly when emergencies such as steam pops occur.…”