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ThermoCool ®

ThermoCool ®
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ThermoCool® SF Catheter provides “uniform cooling” with a reduced volume load. Case Report: anti-arrhythmic drug resistant atrial fibrillation ablation in a chronic end-stage renal failure patient. Dipen Shah, MD Service de Cardiologie, Hôpital Cantonal de Genève,Rue Gabriel-Perret-Gentil, 4 1211 Genève 14 Switzerland Summary A new irrigated tip design delivers uniform saline cooling surrounding the entire tip electrode, providing more effective cooling to decrease embolic potential and allowing a lower volume* load to the patient. Patients with left ventricular dysfunction or renal failure are particularly susceptible and would benefit from a lower volume load. The effective volume load delivered to the patient may essentially be reduced by about 50%* depending upon the precise ablation protocol and delivered radiofrequency (RF) power. The new ThermoCool® SF Catheter (Figure 1) is an open irrigated radio-frequency energy ablation catheter, available in either bidirectional or unidirectional steering, with a 3.5 mm tip electrode and three 1mm ring electrodes. The new tip ablation electrode incorporates 56 small diameter (0.0035”) irrigation holes distributed all around the electrode surface, which are connected to a central reservoir within the distal electrode and linked by tubing inside the catheter shaft to the external roller pump. It is known that during in vivo RF energy delivery, the passage of current produces tissue heating, which can result in the generation of heparin insensitive coagulum (predominantly denatured plasma proteins) and even char, with significant embolic potential. Compared to non irrigated catheters, open irrigated tip catheters allow the delivery of RF energy, while reducing the incidence of thrombus and char formation, by cooling the electrode tissue interface with saline infused through holes in the distal electrode. The original ThermoCool® Catheter design incorporates 6 circumferentially equally spaced irrigation holes at the distal end of the distal 3,5 mm ablation electrode. This design has been shown to be effective, achieving lower rates of coagulum and char formation as well as higher efficacy rates for atrial fibrillation* and typical flutter# ablation, when compared to non-irrigated catheters. A 17or 30ml/min saline infusion rate, depending on the type of procedure, is required in order to achieve effective control of coagulum and char on the ablation electrode resulting in the potential for significant volume loads to the patient during complex and lengthy procedures. Some patients who undergo ablation have co-morbidities that reduce their ability to handle a large volume load, making them susceptible to developing pulmonary edema or heart failure during or after the ablation procedure. Patients with left ventricular dysfunction and/or renal failure are particularly susceptible and would benefit from a lower volume load. The tip design of the open irrigated tip catheter has been recently improved in order to provide uniform cooling surrounding the entire tip at reduced flow rates with comparable or potentially better protection against heat induced coagulum and char formation when compared to the precedent open irrigated design catheter device. *When compared to the THERMOCOOL® Catheter Figure 1. Uniform distribution of saline around the ablation electrode of the ThermoCool® SF Catheter As with all irrigated catheters, the electrode tip temperature is a poor indicator of tissue temperature compared to non irrigated catheters. The superior cooling efficiency of the ThermoCool® SF Catheter design further reduces the thermocouple sensed temperature feedback from tissue heating as a result of energy delivery. Typically the electrode tip temperature remains below 40°C and therefore the physician must continue to utilize clinical indicators and tools such as electrograms, fluoroscopy and, to a lesser degree, impedance to assess adequate tissue contact during RF delivery. Bi-directional steerability allows for the potential use of two different curves on either side (asymmetric), resulting in the dual benefits of being able to reach target tissue further away on one side and closer to the catheter shaft (because of a tighter curve) on the other. Additionally, bidirectional steering allows the operator to achieve high contact force even when straightening the catheter. This feature can be a significant advantage when ablating along the roof of the left atrium or 2011 – 4806 11USExt

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on the mitral isthmus line. We describe below the clinical use of the ThermoCool® SF Catheter to perform pulmonary vein isolation in a patient with chronic end-stage renal failure and paroxysmal atrial fibrillation. Case Report A 67 year old woman with chronic end-stage renal failure (autosomal dominant hepatorenal polycystic disease, high blood pressure and congenital maxillo- facial syndrome) on maintenance hemodialysis and awaiting a renal transplant was referred for catheter ablation of symptomatic anti-arrhythmic drug resistant atrial fibrillation (AF). A routine hemodialysis was...

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