Radiofrequency Energy: Irrigation and Alternate Catheters Andreas Pflaumer
Irrigated tip RF ablation Irrigated tip How does it work? Potential benefits? Potential risks? How is this relevant to pediatric and congenital patients
Biophysics of RF Ablation M. Houmsse and E. G. Daoud, Expert Rev Med Devices, vol. 9, no. 1, pp. 59 70, Jan. 2012.
Open and closed irrigation Navarro 2013
Influences on lesions size and quality (experimental studies) Higher saline flow increases the lesion size ( magic number 17ml/min) for up to 30 W Higher contact pressure increases lesion size Parallel instead of perpendicular orientation decreases lesion volume by 25%
Potential complications Steam pop higher probability with closed loop catheters Thrombus formation (again higher probability with closed looped catheters) Injury of coronary arteries, esophagus and phrenic nerve Increased mural swelling, especially in scarred / infarcted area
Better effectiveness proven in Endocardial ablation for VT (Soejima, E. Circulation, vol. 103, no. 14, pp. 1858 1862, Apr. 2001.) Epicardial ablation for VT (d Avila et. Al. Circulation. 2004; 109: 2363-2369 ), especially with epicardial fat
Eur Heart J, vol. 25, no. 11, pp. 963 969, Jun. 2004. 80 patients randomized to 4 groups, irrigated (internal and external), and conventional 8mm with different sensor technique Endpoint CTI block after 12min of ablation The differences were statistically significant for the following compari- sons: externally irrigated versus internally cooled and internally cooled versus 8-mm single sensor
No difference in conventional and irrigated catheters: Acta Cardiol. 2011 Oct;66(5):613-8. Irrigated-tip vs. conventional-tip catheters for primary ablation of posteroseptal and right free-wall accessory pathways: a prospective randomized study. Circulation 2004;110:1030-1035 Effect of Isthmus Anatomy and Ablation Catheter on Radiofrequency Catheter Ablation of the Cavotricuspid Isthmus
M. H. Kanj et al. Pulmonary vein antral isolation using an open irrigation ablation catheter for the treatment of atrial fibrillation: a randomized pilot study., J Am Coll Cardiol, vol. 49, no. 15, pp. 1634 1641, Apr. 2007.
What about the use in pediatrics?
(Am J Cardiol 2013;111:569-573)
Atrial wall thickness Right atrium wall thickness In children less than 1 mm between the pectinated muscles The free wall 2mm and the crista terminalis up to 6mmm Septum Limbus 4-8mm depending on age Left atrium 1-3mm thickness
Ventricular wall thickness RV 3-5 mm free wall 1-2 mm RVOT Septum 8-15mm LV 9-15mm
Coronary Arteries Asirvatham, IPEJ, 8,(Suppl. 1): S55-S74 (2008)
Effect in pediatric patients irrigated vs. non irrigated Joachim Will et al, PediatricCardiology 2012, 33, 1348-1354
Wall thickness in congenital heart disease Examples of RA wall thickness A) control patient: mean RA wall thickness = 1.6 mm; B) patient with tricuspid atresia: Fontan operation at age 9 years and death 3 months after surgery, mean RA thickness = 7.0 mm; (bar scale = 10 mm in both panels) Wolf et al., Am J Cardiol. 2009 December 15; 104(12): 1737 1742.
Heart Rhythm Journal, vol. 2, no. 7, pp. 700 705, Jul. 2005. Heart Rhythm Journal, vol. 1, no. 3, pp. 268 275, Sep. 2004.
Irrigated Catheter in CHD Studies: Tanner: Comparison with historical group Less number of ablations needed Average power delivered with each lesion higher in irrigation group
?More uniform cooling Conventional 6 holes irrigated tip CoolFlex Smart tip 21
More stable anatomical conformability? The Smart tip might absorb movement and might improve tissue wall contact better in the beating heart 22
Force measurement Heart Rhythm Journal, vol. 9, no. 11, pp. 1789 1795, Nov. 2012. All patients treated with an average CF of 10 g (5 of 5 patients) experienced recurrences, whereas 80% of the patients treated with an average CF of 20 g (8 of 10 patients) were free from AF recurrence at 12 months. The analysis of the average force-time integral showed that 75% of the patients treated with 500 gs were recurrent whereas only 31% of the patients treated with 1000 gs had recurrences at 12 months.
Chik et. al, J Cardiovasc Electrophysiol, vol. 23, no. 1, pp. 88 95, Jan. 2012.
Wright et. al Real-time lesion assessment using a novel combined ultrasound and radiofrequency ablation catheter., Heart Rhythm Journal, vol. 8, no. 2, pp. 304 312, Feb. 2011.
Correlation of measurements Wright et. al Real-time lesion assessment using a novel combined ultrasound and radiofrequency ablation catheter., Heart Rhythm Journal, vol. 8, no. 2, pp. 304 312, Feb. 2011
Potential Disadvantages Fluid overload Price Thicker, less flexible catheter Higher risk of air embolism
Potential damage Coronary artery rupture or stenosis Pulmonary vein stenosis Esophageal damage Mitral valve/papillary muscle Phrenic nerve damage
Potential advantages Energy delivered more effectively and independent of blood flow Higher energy delivery without the risk of steam pops (comparing same size electrodes) Deeper lesion (transmural)
Conclusion Irrigated tip ablation has it s role in congenital heart disease It might be very useful in pediatric patients if one is able to control the lesion size Need for more studies