- Email: [email protected]
Thermal Characteristics of Standard Radiofrequency Ablation Catheters
S114
Heart, Lung and Circulation 2010;19S:S1–S268
Abstracts
ABSTRACTS
3 with CT. Pts did not suffer any long-term sequelae. Using TEE guidance there were no complications of TS and none of the 500 pts had tamponade, pericardial effusion or aortic root puncture associated with 1000 consecutive TS punctures. There were no cases of atrial esophageal fistula. LA/LAA thrombus was not observed. Conclusion: This study in 500 consecutive AF ablation procedures demonstrates the safety of routine use of GA and TEE during AF ablation. There were 3 TEE related complications (0.6%) without long-term sequelae. TEE was effective in guiding TS with no cases of cardiac perforation or aortic damage in 1000 consecutive punctures.
Conclusion: In AF, OSA is highly prevalent, and it’s severity is significantly correlated to AF duration and symptoms. In addition, there were more pts with severe OSA who had a history of stroke. These findings suggest the presence of significant atrial electrical and mechanical remodelling due to OSA. doi:10.1016/j.hlc.2010.06.934 268 Thermal Characteristics of Standard Radiofrequency Ablation Catheters
doi:10.1016/j.hlc.2010.06.933
W. Chik ∗ , S. Thavapalachandran, M. Barry, J. Pouliopoulos, T. Lim, S. Thomas, P. Kovoor, A. Thiagalingam
267
Westmead Hospital, University of Sydney, NSW, Australia
The Severity of Obstructive Sleep Apnoea Determines the Persistence and Symptoms of Atrial Fibrillation H. Dimitri 1,∗ , M. Ng 2 , A. Brooks 1 , N. Antic 3 , A. Thornton 2 , H. Abed 1 , M. Alasady 1 , D. Lau 1 , H. Lim 1 , D. McEvoy 3 , R. Antic 2 , P. Sanders 1 1 University of Adelaide and Cardiovascular Research Centre, Royal Adelaide Hospital, Australia 2 Sleep Unit, Department of Thoracic Medicine, Royal Adelaide Hospital, Australia 3 Adelaide Institute of Sleep Health, Repatriation General Hospital, Daw Park, SA, Australia
Background: The relationship between symptoms of AF pts presenting for ablation and OSA has not been characterized. Methods: 89 pts (60 M, 65% parox, 28% pers, 9% perm AF ablation pts) were studied by polysomnography. 20 randomly selected community controls were also studied. AF burden was quantified using the Atrial Fibrillation Severity Scale (AFSS) (duration, frequency, symptoms) and 7 day Holter. Results: 52% of AF pts (19% mod-sev (AHI ≥30), 33% mild-mod (AHI 15–30)) and none of the controls had OSA (mean AHI 8.35). The controls had lower BMI (25 ± 0.6 vs. 31 ± 0.9; p < 0.001). Pts with AF & OSA were asymptomatic on Epworth Sleepiness Scale. The 3 AF groups were similar for gender, neck circumference, HT, DM, structural heart disease, lung disease, anti-arrhythmic usage & LVEF. Pts with mod-sev OSA had more previous strokes/TIAs (p = 0.02). Despite no objective difference in AF burden on Holter, subjective AF severity was significantly greater in mod-sev OSA compared to the other groups. AFSS and AHI were associated (Std. coeff β = 0.319, p = 0.009) with pts with mod-sev OSA being more likely to have greater severity of AF (p = 0.002). AF duration was longer with increasing severity of OSA (p = 0.02) with OR for AF episodes >24 h of 2.4 (95%CI 1.1–3.8, p = 0.02) with OSA. LA size was larger in mod-sev OSA (27 ± 5 vs. 23 ± 5.2 cm2 ).
The ability to characterise thermal profile of radiofrequency (RF) lesions is critical for optimising the balance between transmural lesion creation and complications arising from excessive thermal energy delivery. We utilised thermochromic liquid crystals (TLC) to demonstrate the thermal profiles of standard Non-irrigated (NI), Thermocool (TC: distal tip irrigation only) and Coolpath Duo (CPD: both proximal and distal irrigation) ablation catheters. Methods: The myocardial phantom was constructed from a vertical sheet of TLC film embedded within transparent gel layers. TLC showed colour from 50.5 ◦ C (red) to 78 ◦ C (dark blue) and provided 2.5 ◦ C isotherms on hue analysis. Normal saline, impedance titrated to blood values at 37 ◦ C, was used as supernatant. Standard ablations were performed (30 W, 60 s, 100 W and 17 ml/min irrigation). Results: Proximal electrode temp was higher for both TC and NIC. This gradient is less marked for CPD due to lower surface temperatures. NIC had the highest (72.5 ◦ C) maximum temperature (Tmax) and CPD lowest (65 ◦ C). Tmax for irrigated tip catheters were over 20–30 ◦ C hotter than thermocouple reading. Conclusions: (1) Proximal surface temp are greater than distal tip for both TC and NIC. This implies a potentially higher risk for thermal complications. (2) CPD “spares” the endocardial surface proximally and distally by effective cooling. (3) Thermocouple temperature readings from irrigated catheters grossly under-estimate the true surface temperature at the lesion due to cooling from irrigation at the thermocouple tip.
Abstracts
S115
mizing complications arising from excessive thermal energy delivery to the surface. (3) A deeper “hot zone” may reduce surface overheating and risks of thermal complications.
doi:10.1016/j.hlc.2010.06.935 269
doi:10.1016/j.hlc.2010.06.936
Thermal Characteristics of the Novel Virtual Electrode in a Direct Visualisation Ablation Catheter W. Chik 1,∗ , S. Thavapalachandran 1 , M. Barry 1 , T. Lim 1 , J. Pouliopoulos 1 , S. Thomas 1 , Z. Malchano 2 , V. Saadat 2 , P. Kovoor 1 , A. Thiagalingam 1 1 Westmead 2 Voyage
Hospital, University of Sydney, NSW, Australia Medical, Redwood City, CA, USA
The Virtual Electrode within the direct visualization catheter delivers radiofrequency (RF) energy for ablation via a unique distal hood aperture utilising saline irrigation as a “bridge” to the targeted endocardial surface. We used a myocardial phantom using thermochromic liquid crystals (TLC) to demonstrate the thermal profiles of the saline bridge ablation catheter. Methods: The phantom was constructed from a vertical sheet of TLC film embedded within transparent gel layers. The TLC illustrated color range between 50.5 ◦ C (red) and 78 ◦ C (dark blue) and provided isotherms on hue analysis. Normal saline, impedance titrated to blood values at 37 ◦ C, was used as supernatant. VE ablations were performed using 10–30 W power with irrigation at 25 ml/min for 60 s. Standard Thermocool (TC) catheter ablations using 30 W for 60 s at 17 ml/min irrigation was performed. Results: VE lesions were larger in size at lower power settings compared to TC lesions. Lower maximum surface temperature reached in VE lesions with no significant gradient. Max overall temp was deeper from surface in VE than TC. Conclusions: (1) VE is a more energy efficient method of RF delivery to create ablation lesions than TC. (2) More even surface cooling and no significant temperature gradient across the surface attributable to central hood aperture irrigation, potentially mini-
270 Twin Left Atrial Flutters Using a Common Scar Isthmus Presenting with Tachycardia of Alternating Cycle Length H. Lim ∗ , B. John, D. Lau, H. Dimitri, P. Sanders Cardiovascular Research Centre, Royal Adelaide Hospital, University of Adelaide, Australia Introduction: The importance of conduction barriers and scar areas in left atrial (LA) flutters is well known. There has only been one report after ablation in which alternating cycle length (CL) tachycardia was found to use different gaps in the same scar to result in identical activation patterns—“twin flutters”. We present the first case of twin flutters in the absence of prior surgery. Methods and results: A 61yo female presented with recurrent LA flutter. Echocardiography was normal. During electrophysiology study she had a tachycardia with alternating CLs of 350 and 310 ms (Figure). 3D mapping revealed a spontaneous anterior LA wall scar. Individual activation maps demonstrated both tachycardias rotating counter-clockwise around the scar. Adjacent to this scar, a low voltage area with continuous atrial activity (256 ms) was demonstrated. Ablation at this site terminated both tachycardias. The scar area was anchored to the isolated left upper pulmonary vein. She has remained arrhythmia free 9 months post ablation. Possible explanations include a single tachycardia with alternating conduction across 2 gaps with differing refractory periods/conduction velocities; or 2 distinct conduction times through a single gap similar to AVRT with CL alternans due to AH interval variation. Conclusion: This is the first case we are aware of whereby a spontaneous region of LA scar sustained a flutter with alternating CLs.
ABSTRACTS
Heart, Lung and Circulation 2010;19S:S1–S268
Heart, Lung and Circulation 2010;19S:S1–S268
Abstracts
ABSTRACTS
3 with CT. Pts did not suffer any long-term sequelae. Using TEE guidance there were no complications of TS and none of the 500 pts had tamponade, pericardial effusion or aortic root puncture associated with 1000 consecutive TS punctures. There were no cases of atrial esophageal fistula. LA/LAA thrombus was not observed. Conclusion: This study in 500 consecutive AF ablation procedures demonstrates the safety of routine use of GA and TEE during AF ablation. There were 3 TEE related complications (0.6%) without long-term sequelae. TEE was effective in guiding TS with no cases of cardiac perforation or aortic damage in 1000 consecutive punctures.
Conclusion: In AF, OSA is highly prevalent, and it’s severity is significantly correlated to AF duration and symptoms. In addition, there were more pts with severe OSA who had a history of stroke. These findings suggest the presence of significant atrial electrical and mechanical remodelling due to OSA. doi:10.1016/j.hlc.2010.06.934 268 Thermal Characteristics of Standard Radiofrequency Ablation Catheters
doi:10.1016/j.hlc.2010.06.933
W. Chik ∗ , S. Thavapalachandran, M. Barry, J. Pouliopoulos, T. Lim, S. Thomas, P. Kovoor, A. Thiagalingam
267
Westmead Hospital, University of Sydney, NSW, Australia
The Severity of Obstructive Sleep Apnoea Determines the Persistence and Symptoms of Atrial Fibrillation H. Dimitri 1,∗ , M. Ng 2 , A. Brooks 1 , N. Antic 3 , A. Thornton 2 , H. Abed 1 , M. Alasady 1 , D. Lau 1 , H. Lim 1 , D. McEvoy 3 , R. Antic 2 , P. Sanders 1 1 University of Adelaide and Cardiovascular Research Centre, Royal Adelaide Hospital, Australia 2 Sleep Unit, Department of Thoracic Medicine, Royal Adelaide Hospital, Australia 3 Adelaide Institute of Sleep Health, Repatriation General Hospital, Daw Park, SA, Australia
Background: The relationship between symptoms of AF pts presenting for ablation and OSA has not been characterized. Methods: 89 pts (60 M, 65% parox, 28% pers, 9% perm AF ablation pts) were studied by polysomnography. 20 randomly selected community controls were also studied. AF burden was quantified using the Atrial Fibrillation Severity Scale (AFSS) (duration, frequency, symptoms) and 7 day Holter. Results: 52% of AF pts (19% mod-sev (AHI ≥30), 33% mild-mod (AHI 15–30)) and none of the controls had OSA (mean AHI 8.35). The controls had lower BMI (25 ± 0.6 vs. 31 ± 0.9; p < 0.001). Pts with AF & OSA were asymptomatic on Epworth Sleepiness Scale. The 3 AF groups were similar for gender, neck circumference, HT, DM, structural heart disease, lung disease, anti-arrhythmic usage & LVEF. Pts with mod-sev OSA had more previous strokes/TIAs (p = 0.02). Despite no objective difference in AF burden on Holter, subjective AF severity was significantly greater in mod-sev OSA compared to the other groups. AFSS and AHI were associated (Std. coeff β = 0.319, p = 0.009) with pts with mod-sev OSA being more likely to have greater severity of AF (p = 0.002). AF duration was longer with increasing severity of OSA (p = 0.02) with OR for AF episodes >24 h of 2.4 (95%CI 1.1–3.8, p = 0.02) with OSA. LA size was larger in mod-sev OSA (27 ± 5 vs. 23 ± 5.2 cm2 ).
The ability to characterise thermal profile of radiofrequency (RF) lesions is critical for optimising the balance between transmural lesion creation and complications arising from excessive thermal energy delivery. We utilised thermochromic liquid crystals (TLC) to demonstrate the thermal profiles of standard Non-irrigated (NI), Thermocool (TC: distal tip irrigation only) and Coolpath Duo (CPD: both proximal and distal irrigation) ablation catheters. Methods: The myocardial phantom was constructed from a vertical sheet of TLC film embedded within transparent gel layers. TLC showed colour from 50.5 ◦ C (red) to 78 ◦ C (dark blue) and provided 2.5 ◦ C isotherms on hue analysis. Normal saline, impedance titrated to blood values at 37 ◦ C, was used as supernatant. Standard ablations were performed (30 W, 60 s, 100 W and 17 ml/min irrigation). Results: Proximal electrode temp was higher for both TC and NIC. This gradient is less marked for CPD due to lower surface temperatures. NIC had the highest (72.5 ◦ C) maximum temperature (Tmax) and CPD lowest (65 ◦ C). Tmax for irrigated tip catheters were over 20–30 ◦ C hotter than thermocouple reading. Conclusions: (1) Proximal surface temp are greater than distal tip for both TC and NIC. This implies a potentially higher risk for thermal complications. (2) CPD “spares” the endocardial surface proximally and distally by effective cooling. (3) Thermocouple temperature readings from irrigated catheters grossly under-estimate the true surface temperature at the lesion due to cooling from irrigation at the thermocouple tip.
Abstracts
S115
mizing complications arising from excessive thermal energy delivery to the surface. (3) A deeper “hot zone” may reduce surface overheating and risks of thermal complications.
doi:10.1016/j.hlc.2010.06.935 269
doi:10.1016/j.hlc.2010.06.936
Thermal Characteristics of the Novel Virtual Electrode in a Direct Visualisation Ablation Catheter W. Chik 1,∗ , S. Thavapalachandran 1 , M. Barry 1 , T. Lim 1 , J. Pouliopoulos 1 , S. Thomas 1 , Z. Malchano 2 , V. Saadat 2 , P. Kovoor 1 , A. Thiagalingam 1 1 Westmead 2 Voyage
Hospital, University of Sydney, NSW, Australia Medical, Redwood City, CA, USA
The Virtual Electrode within the direct visualization catheter delivers radiofrequency (RF) energy for ablation via a unique distal hood aperture utilising saline irrigation as a “bridge” to the targeted endocardial surface. We used a myocardial phantom using thermochromic liquid crystals (TLC) to demonstrate the thermal profiles of the saline bridge ablation catheter. Methods: The phantom was constructed from a vertical sheet of TLC film embedded within transparent gel layers. The TLC illustrated color range between 50.5 ◦ C (red) and 78 ◦ C (dark blue) and provided isotherms on hue analysis. Normal saline, impedance titrated to blood values at 37 ◦ C, was used as supernatant. VE ablations were performed using 10–30 W power with irrigation at 25 ml/min for 60 s. Standard Thermocool (TC) catheter ablations using 30 W for 60 s at 17 ml/min irrigation was performed. Results: VE lesions were larger in size at lower power settings compared to TC lesions. Lower maximum surface temperature reached in VE lesions with no significant gradient. Max overall temp was deeper from surface in VE than TC. Conclusions: (1) VE is a more energy efficient method of RF delivery to create ablation lesions than TC. (2) More even surface cooling and no significant temperature gradient across the surface attributable to central hood aperture irrigation, potentially mini-
270 Twin Left Atrial Flutters Using a Common Scar Isthmus Presenting with Tachycardia of Alternating Cycle Length H. Lim ∗ , B. John, D. Lau, H. Dimitri, P. Sanders Cardiovascular Research Centre, Royal Adelaide Hospital, University of Adelaide, Australia Introduction: The importance of conduction barriers and scar areas in left atrial (LA) flutters is well known. There has only been one report after ablation in which alternating cycle length (CL) tachycardia was found to use different gaps in the same scar to result in identical activation patterns—“twin flutters”. We present the first case of twin flutters in the absence of prior surgery. Methods and results: A 61yo female presented with recurrent LA flutter. Echocardiography was normal. During electrophysiology study she had a tachycardia with alternating CLs of 350 and 310 ms (Figure). 3D mapping revealed a spontaneous anterior LA wall scar. Individual activation maps demonstrated both tachycardias rotating counter-clockwise around the scar. Adjacent to this scar, a low voltage area with continuous atrial activity (256 ms) was demonstrated. Ablation at this site terminated both tachycardias. The scar area was anchored to the isolated left upper pulmonary vein. She has remained arrhythmia free 9 months post ablation. Possible explanations include a single tachycardia with alternating conduction across 2 gaps with differing refractory periods/conduction velocities; or 2 distinct conduction times through a single gap similar to AVRT with CL alternans due to AH interval variation. Conclusion: This is the first case we are aware of whereby a spontaneous region of LA scar sustained a flutter with alternating CLs.
ABSTRACTS
Heart, Lung and Circulation 2010;19S:S1–S268