Safety
Contact force enacted on tissue is linked to the potential for complications like cardiac perforations. In an ex-vivo porcine study, minimal contact forces needed for perforation were ranging from 131g for the right atrium to 227g for the left ventricle17. In another study on human heart specimens, previously ablated tissue had a 2-fold reduced minimal force when compared to healthy tissue and the minimal force needed for perforation was as low as 38g18. An underestimation of high contact forces could therefore lead to an increased risk for perforations. Here, Smarttouch® and AcQblate® Force showed significant underestimation at 30° and 45°.
Combining the evidence for efficacy and safety, a range of 10g to 40g is generally considered appropriate for clinical ablation. The accuracy within this range was good for all models with a mean absolute error of <3g and should therefore not affect the estimation of lesion formation by much as long as forces are kept within this range.