LAUSR

Successful catheter ablation is dependent on several factors, including patient specific characteristics, anatomical location of the ablation site, technology and equipment being utilized, as well as operator skill set and experience. In an ideal situation, the ablation procedure is performed with 100% success, no long term recurrence, and no patient complications. Of the above mentioned properties, some of them aremodifiable, whereby others are not. Of the modifiable factors, the use of increasingly sophisticated technology may improve ablation outcomes [1], at the expense of increasing the cost of the procedure. One of these technologies is contact force sensing catheters, which has been studied extensively in regards to atrial ablation in the context of patients with atrial fibrillation [2]. However, the utility of contact force catheters in ablation of other arrhythmia contexts such as WPW and AVNRT where the success rates with the conventional techniques are generally quite good is less clear and not well described in the published literature. In this issue of Indian Pacing and Electrophysiology, Choo et al. describe catheter-tissue contact force on several locations on both the tricuspid and mitral annulus. The locations chosen for assessment are frequent sites of accessory pathway location and therefore potential ablation sites. The authors collected data from 42 patients undergoing catheter ablation whose left atrial diameter was less than 4.5 cm. Operators, whowere blinded to the catheter measured contact force, also used a number of characteristics (including perceived tactile force, electrogram amplitude, and impedance) to provide a subjective assessment of contact force. The authors then compared the perceived contact force with the measured contact force at all the pre-specified tricuspid and mitral annular sites. Interestingly, the authors found that contact force was consistently lower on locations on the tricuspid annulus than the mitral annulus (6.1 g± 0.9 g vs. 9.8 g± 0.9 g, p1⁄4 0.0036). They postulated that this observation may be partly responsible for the lower long term success rate of right sided accessory pathway ablation as compared to left sided accessory pathway ablation [3]. Even more interesting however, is that mean contact force at different sites on the mitral and tricuspid annulus were similar despite having experienced operators quantify the perceived contact as good, moderate, or poor (mitral: 9.9 g, 9.3 g, 9.7 g, p1⁄4 0.959; tricuspid: 6.5 g, 4.9 g, 6.9 g, p1⁄4 0.671). What do these observations mean for the clinical practitioner? Successful catheter ablation relies on creating a durable lesion which is dependent on several modifiable factors including power, stability, time and catheter tissue contact force to name the key ones [4]. If perceived contact force does not correlate with measured contact force in ablation sites that have documented