While much still remains to be understood about the pathophysiology of atrial fibrillation (AF|) and in particular the mechanisms of persistent atrial fibrillation, and atrial fibrillation occurring in young patients, much work has been driven towards creating better controlled lesions at the time of ablation. This push to improve both the immediate procedural success and the long term success of AF ablation, has been led by both independent researchers and industry.
The last few years has seen both a general standardisation of lesion sets and a trend towards using objective measures of lesion formation. Validation of these objective measures has been predominantly in the thigh prep model or ventricular tissue, with remarkably few validation studies in the atria due to the technical limitations of performing a large number of lesions in the models available. Despite the relatively limited data set, the use of tools such as the ablation index (Surpoint in the US) has rapidly been accepted by electrophysiologists across Europe where the proprietary algorithms and software was initially released. Initial studies have proved tantalising with improved medium term outcomes when using these objective measures of lesion formation and lesion spacing, for example the CLOSER study from the Bruges group.
As it has become easier to titrate lesion delivery, despite being unable to accurately determine atrial wall thickness at individual applications, so there appears to be a trend towards higher power delivery but over shorter time periods. While the appearance of objective numbers such as the ablation index or lesion size index may give reassurance to the operator, as power drifts higher, the further away from the animal models from which the formula were derived the less sure we can be about the accuracy and reproducibility of the formulae. The safety profile of AF ablation is perhaps improving as is highlighted in manuscripts featured on this site, but we should remain cautious; especially given our surveillance systems for detecting a change in rare complications, such as atrial osephageal fistula, across multiple centres are limited.
As the field of AF ablation matures, perhaps it is time to look outside electrogram characteristics, and at the broader picture of how patients can benefit from the advances that have been made. Still symptomatic patients who could realistically benefit from ablation outnumber the availability of electrophysiologists and catheter laboratories. The increases in productivity needed remain problematic. Standardisation of workflows and team working, both in and out of the lab remain key.
I hope you enjoy visiting this website and find it useful in your everyday practice.
Dr Matt Wright
08 March 2018
26 November 2014
25 September 2014
Higher contact force during radiofrequency ablation leads to a much larger increase in edema as compared to chronic lesion sizeSamuel Thomas, Josh Silvernagel, Nathan Angel, et al
Longer Duration Versus Increasing Power During Radiofrequency Ablation Yields Different Ablation Lesion CharacteristicsRyan T. Borne, William H. Sauer, Matthew M. Zipse, et al
Role of Contact Force Sensing in Catheter Ablation of Cardiac Arrhythmias: Evolution or History Repeating Itself?Nilshan Ariyarathna, Saurabh Kumar, Stuart P. Thomas, et al
Characteristics of Radiofrequency Catheter Ablation Lesion Formation in Real Time In Vivo Using Near Field Ultrasound ImagingMatthew Wright, Erik Harks, Szabolcs Deladi, et al
ThermoCool® SmartTouch® Catheter – The Evidence So Far for Contact Force Technology and the Role of VisiTag™ ModuleTina Lin, Feifan Ouyang, Karl-Heinz Kuck, et alArrhythmia & Electrophysiology Review 2013;3(1):44-7DOI: http://dx.doi.org/10.15420/articles/thermocool-smarttouch-catheter-evidence-so-far-contact-force-technology-and-role-visitag