Role of Contact Force Sensing in Catheter Ablation of Cardiac Arrhythmias

Abstract

Adequate catheter-tissue contact facilitates efficient heat energy transfer to target tissue. Tissue contact is thus critical to achieving lesion transmurality and success of radiofrequency (RF) ablation procedures, a fact recognized more than 2 decades ago. The availability of real-time contact force (CF)-sensing catheters has reinvigorated the field of ablation biophysics and optimized lesion formation. The ability to measure and display CF came with the promise of dramatic improvement in safety and efficacy; however, CF quality was noted to have just as important an influence on lesion formation as absolute CF quantity. Multiple other factors have emerged as key elements influencing effective lesion formation, including catheter stability, lesion contiguity and continuity, lesion density, contact homogeneity across a line of ablation, spatiotemporal dynamics of contact governed by cardiac and respiratory motion, contact directionality, and anatomic wall thickness, in addition to traditional ablation indices of power and RF duration. There is greater appreciation of surrogate markers as a guide to lesion formation, such as impedance fall, loss of pace capture, and change in unipolar electrogram morphology. In contrast, other surrogates such as tactile feedback, catheter motion, and electrogram amplitude are notably poor predictors of actual contact and lesion formation. This review aims to contextualize the role of CF sensing in lesion formation with respect of the fundamental principles of biophysics of RF ablation and summarize the state-of-the-art evidence behind the role of CF in optimizing lesion formation.

Bipolar ablation of refractory atrial and ventricular arrhythmias: Importance of temperature values of intracardiac return electrodes

“…Radiofrequency delivery can be impaired when arrhythmia substrate is of pathological morphology (ie, ischemic or postinflammatory scar), surrounded by anatomical obstacles such as substantial epicardial fat or is located close to coronary arteries or His‐Purkinje system. Thus, despite technological progress in unipolar approach (irrigation catheters and contact force measurements) standard energy sources in some situations may be insufficient for creating an effective transmural lesion . In case of failure, a common scenario consist of RFCA performed at higher power settings and prolonged applications.…”

“…In case of failure, a common scenario consist of RFCA performed at higher power settings and prolonged applications. Extended unipolar RF, however, may increase the risk of complications, such as steam‐pop, pericardial effusion, tamponade or intramural hematoma . Thus, methods are sought to improve lesion formation and to minimize the risk of adverse events …”

Eliminating the effects of motion during radiofrequency lesion delivery using a novel contact‐force controller

“…A recent meta‐analysis, summarizing all randomized controlled trials investigating contact force in AF ablation, reports that contact force variability, rather than average force alone, has emerged as a critical element that governs lesion size and ablation outcomes . The EFFICAS II trial demonstrated durable pulmonary vein isolation (PVI) using a contact‐force target of 20 g , with a narrow range between 10 and 30 g .…”

Radiofrequency catheter ablation of premature ventricular contractions from the mitral annulus in patients without structural heart disease

“…However, unfortunately, in two patients (5%), successful results could not be achieved even though RFCA using an open irrigated ablation catheter from the various approach sites described in Figures 2B‐F was performed. The recent advancements in the new technologies, including contact force catheters, 10 which can facilitated a more stable lesion creation, were not used in this study, and they might have improved and helped during the RFCA procedure in those unsuccessful patients.…”