Fehmi Keçe

Chapter 9 186 catheter ablation, cardiac tamponade remains an important complication compared to balloon-based techniques. Due to three-dimensional mapping the procedural duration has been shortened and with the development of high-power short duration ablation further shortening of the duration is expected. For cryoballoon ablation the incidence of phrenic nerve palsy is of importance and higher compared to radiofrequency ablation. Improvement of the cryoballoon ablation system led to shorter procedural and fluoroscopy times with similar efficacy and complication rates. Other single shot devices are in development with unknown safety profiles. A potential drawback of non-irrigated multi- electrode catheters is the association with asymptomatic cerebral embolism of which the clinical significance is not yet clarified. Together with the improvement of ablation devices also the ablation protocol is improved with implementation of safety maneuvers for the prevention of complications and pre-selection of patients undergoing ablation. In chapter 3 a randomized controlled trial on the incidence and clinical significance of cerebral embolism during AF ablation with the duty-cycled phased radiofrequency catheter versus a cooled radiofrequency catheter is described. With the first generation pulmonary vein ablation catheter (PVAC), the incidence of asymptomatic cerebral embolism was up to 42%on cerebral magnetic resonance imaging. Studies suggested that temperature overshoot during intermittent catheter-tissue contact and an electrical short-circuit between electrode 1 and 10 were the main causes of these cerebral infarcts in the pulmonary vein ablation catheter. The technical development of the next generation PVAC-Gold consisted therefore by substitution of platinum electrodes by gold to prevent temperature overshoot and removal of electrode 10 to prevent short-circuiting. Furthermore, the ablation protocol was optimized by aiming at higher Activated Clotting Time (ACT) values and submersion of the catheter in saline before introduction tominimize air embolism. In this chapter we show that the incidence of asymptomatic cerebral embolism/cerebral infarctions with this new catheter and ablation protocol is still higher (23%) compared to an irrigated catheter (6%). While both ablation technologies induced a similar increase in the procoagulant state, we observed a significantly higher number of micro-emboli on transcranial doppler with the PVAC-Gold catheter. Themedian concentration of micro-embolic-signals during the total procedure was 8 [IQR, 5 to 17] MES/minwith the pulmonary vein ablation catheter versus 4 [IQR 3 to 5] MES/ min with the irrigated catheter. We detected no cognitive decline in patients using extensive neuropsychological testing. As the purpose of the redesigned catheter was to reduce the high incidence of asymptomatic cerebral embolism, we state that the improvement of this device was only partly successful with only a 45% reduction of ACE and MES compared to the first generation device. As the incidence is still higher compared to point-by-point ablation, the manufacturer should continue to improve the device.