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High-density Mapping to Characterize Dominant Frequency Sites in Permanent Atrial Fibrillation: Effect of Ablation
Abstracts
effects resulted in a 1.5–2-fold global reduction of λ for VT(+) compared to VT(−) sheep (p = 0.036). Conclusions: Electrical remodeling differs between groups studied. Reentrant VT is not enhanced specifically by scar but may be associated with head–tail interaction of propagation caused by prolongation of refractoriness resulting in reduction of λ. doi:10.1016/j.hlc.2009.05.336 335 HIGH-DENSITY MAPPING TO CHARACTERIZE DOMINANT FREQUENCY SITES IN PERMANENT ATRIAL FIBRILLATION: EFFECT OF ABLATION P. De Sciscio, A.G. Brooks, P. Kuklik, M.K. Stiles, C.X. Wong, B. John, H. Dimitri, L. Wilson, G.D. Young, P. Sanders Cardiovascular Research Centre, Department of Cardiology, Royal Adelaide Hospital and the Disciplines of Medicine and Physiology, University of Adelaide, South Australia, Adelaide, Australia Introduction: Localized areas of high frequency are suggested to maintain AF. A retrospective study has suggested that ablation at high dominant frequency (DF) sites is associated with slowing/termination of paroxysmal AF. We evaluate the characteristics of high DF sites predictive of an impact during permanent AF ablation. Methods: 10 patients (10M; 56 ± 14 years) undergoing ablation of permanent AF (16 ± 15 months) were studied. Bi-atrial high-density mapping (885 ± 146 pts/pt) was performed during AF using a PentaRay catheter. Data was collected by sequentially acquiring 15 simultaneous electrograms for 8 s. DF was calculated by FFT, filtered by RI > 0.2 and ranked in descending order. Stepwise ablation was performed with a random order targeting high DF sites. Electrograms corresponding to DF sites were characterized by: fractionation; voltage; local CL; local activation gradient; and signal stability. Ablation impact was defined by AF slowing (>5ms CL increase) or termination. Results: Ablation targeting 40 DF sites (4/pt) resulted in AF termination in 2 (5%) and slowing in 5 (12.5%). Table 1 shows DF site characteristics. The presence of a local activation gradient was the only independent predictor of favourable DF sites (p = 0.002). Other electrogram characteristics were not significantly different between sites (Table 1). Table 1. Impact (n = 7) Fractionation (CFE-mean) Voltage (mV) Local CL (ms) Local activation gradient, n (%) Signal stability (ratio)
111 ± 36
No impact (n = 33) 92 ± 25
0.41 ± 0.33 135 ± 29 5 (71)
0.48 ± 0.28 166 ± 33 1 (3%)
0.26 ± 0.11
0.31 ± 0.12
Univariate analysis
Multivariate analysis
0.092 0.556 0.043* .003* 0.304
0.18 0.002*
S149
Conclusion: High-density mapping allows identification of high DF sites during perm AF. Ablation of 17.5% of these sites demonstrates an impact on AF. High DF sites displaying a local activation gradient were more predictive of AF slowing/termination. doi:10.1016/j.hlc.2009.05.337 336 HIGH-DENSITY NON-CONTACT MAPPING TO CHARACTERISE ATRIAL REMODELLING DUE TO CHRONIC ATRIAL FLUTTER M.K. Stiles 1 , A.G. Brooks 2 , B. John 2 , D.H. Lau 2 , H. Dimitri 2 , C.X. Wong 2 , P. Kuklik 2 , L. Wilson 2 , G.D. Young 2 , P. Sanders 2 1 Waikato
Hospital and the University of Auckland, New Zealand 2 Royal Adelaide Hospital and the University of Adelaide, South Australia, Australia Background: Atrial electrical remodelling has been demonstrated in patients with recent atrial flutter (AFL). However, important structural changes underlying the substrate for arrhythmia are increasingly recognised. We sought to characterise this atrial substrate with highdensity non-contact mapping techniques. Methods: Sixteen patients with chronic AFL and 15 controls were studied immediately post-ablation. 20-pole catheters at the crista terminalis and multi-electrode balloon arrays recorded right atrial (RA) electrical activity. We measured RA activation time, conduction characteristics at the crista terminalis, sinus node function and regional/global voltage. Results: Patients with AFL demonstrated the following differences compared to controls: longer P wave duration (147 ± 13 versus 109 ± 13 ms, p < 0.001); longer RA activation time (120 ± 15 versus 92 ± 12 ms, p < 0.001); greater site-specific conduction abnormalities at the crista terminalis (number of double potentials 5.4 ± 2.9 versus 2.1 ± 1.8, p = 0.002); lower likelihood of conduction through the crista terminalis (4 versus 38%, p < 0.001); longer activation delay from the anterior to posterior aspect of the crista terminalis when conduction was blocked (24 ± 7 versus 17 ± 6 ms, p = 0.02); greater RA surface area (163 ± 34 versus 132 ± 12 cm2 , p = 0.003); longer SACT (150 ± 100 versus 83 ± 33 ms, p = 0.03); and longer CSNRT (498 ± 409 versus 253 ± 96 ms, p = 0.03). Mean RA voltage trended lower with AFL (1.4 ± 0.6 versus 1.8 ± 0.6 mV, p = 0.1) and lower mean voltage was seen in the region of the crista terminalis (1.3 ± 0.6 versus 1.9 ± 0.6 mV, p = 0.009). Conclusions: Atrial remodelling seen with chronic AFL is associated with widespread changes characterised by generalised and site-specific conduction abnormalities, sinus node dysfunction and decreased voltage. These features provide insight into the structural changes underlying the substrate predisposing to and maintaining AFL. doi:10.1016/j.hlc.2009.05.338
ABSTRACTS
Heart, Lung and Circulation 2009;18S:S1–S286
effects resulted in a 1.5–2-fold global reduction of λ for VT(+) compared to VT(−) sheep (p = 0.036). Conclusions: Electrical remodeling differs between groups studied. Reentrant VT is not enhanced specifically by scar but may be associated with head–tail interaction of propagation caused by prolongation of refractoriness resulting in reduction of λ. doi:10.1016/j.hlc.2009.05.336 335 HIGH-DENSITY MAPPING TO CHARACTERIZE DOMINANT FREQUENCY SITES IN PERMANENT ATRIAL FIBRILLATION: EFFECT OF ABLATION P. De Sciscio, A.G. Brooks, P. Kuklik, M.K. Stiles, C.X. Wong, B. John, H. Dimitri, L. Wilson, G.D. Young, P. Sanders Cardiovascular Research Centre, Department of Cardiology, Royal Adelaide Hospital and the Disciplines of Medicine and Physiology, University of Adelaide, South Australia, Adelaide, Australia Introduction: Localized areas of high frequency are suggested to maintain AF. A retrospective study has suggested that ablation at high dominant frequency (DF) sites is associated with slowing/termination of paroxysmal AF. We evaluate the characteristics of high DF sites predictive of an impact during permanent AF ablation. Methods: 10 patients (10M; 56 ± 14 years) undergoing ablation of permanent AF (16 ± 15 months) were studied. Bi-atrial high-density mapping (885 ± 146 pts/pt) was performed during AF using a PentaRay catheter. Data was collected by sequentially acquiring 15 simultaneous electrograms for 8 s. DF was calculated by FFT, filtered by RI > 0.2 and ranked in descending order. Stepwise ablation was performed with a random order targeting high DF sites. Electrograms corresponding to DF sites were characterized by: fractionation; voltage; local CL; local activation gradient; and signal stability. Ablation impact was defined by AF slowing (>5ms CL increase) or termination. Results: Ablation targeting 40 DF sites (4/pt) resulted in AF termination in 2 (5%) and slowing in 5 (12.5%). Table 1 shows DF site characteristics. The presence of a local activation gradient was the only independent predictor of favourable DF sites (p = 0.002). Other electrogram characteristics were not significantly different between sites (Table 1). Table 1. Impact (n = 7) Fractionation (CFE-mean) Voltage (mV) Local CL (ms) Local activation gradient, n (%) Signal stability (ratio)
111 ± 36
No impact (n = 33) 92 ± 25
0.41 ± 0.33 135 ± 29 5 (71)
0.48 ± 0.28 166 ± 33 1 (3%)
0.26 ± 0.11
0.31 ± 0.12
Univariate analysis
Multivariate analysis
0.092 0.556 0.043* .003* 0.304
0.18 0.002*
S149
Conclusion: High-density mapping allows identification of high DF sites during perm AF. Ablation of 17.5% of these sites demonstrates an impact on AF. High DF sites displaying a local activation gradient were more predictive of AF slowing/termination. doi:10.1016/j.hlc.2009.05.337 336 HIGH-DENSITY NON-CONTACT MAPPING TO CHARACTERISE ATRIAL REMODELLING DUE TO CHRONIC ATRIAL FLUTTER M.K. Stiles 1 , A.G. Brooks 2 , B. John 2 , D.H. Lau 2 , H. Dimitri 2 , C.X. Wong 2 , P. Kuklik 2 , L. Wilson 2 , G.D. Young 2 , P. Sanders 2 1 Waikato
Hospital and the University of Auckland, New Zealand 2 Royal Adelaide Hospital and the University of Adelaide, South Australia, Australia Background: Atrial electrical remodelling has been demonstrated in patients with recent atrial flutter (AFL). However, important structural changes underlying the substrate for arrhythmia are increasingly recognised. We sought to characterise this atrial substrate with highdensity non-contact mapping techniques. Methods: Sixteen patients with chronic AFL and 15 controls were studied immediately post-ablation. 20-pole catheters at the crista terminalis and multi-electrode balloon arrays recorded right atrial (RA) electrical activity. We measured RA activation time, conduction characteristics at the crista terminalis, sinus node function and regional/global voltage. Results: Patients with AFL demonstrated the following differences compared to controls: longer P wave duration (147 ± 13 versus 109 ± 13 ms, p < 0.001); longer RA activation time (120 ± 15 versus 92 ± 12 ms, p < 0.001); greater site-specific conduction abnormalities at the crista terminalis (number of double potentials 5.4 ± 2.9 versus 2.1 ± 1.8, p = 0.002); lower likelihood of conduction through the crista terminalis (4 versus 38%, p < 0.001); longer activation delay from the anterior to posterior aspect of the crista terminalis when conduction was blocked (24 ± 7 versus 17 ± 6 ms, p = 0.02); greater RA surface area (163 ± 34 versus 132 ± 12 cm2 , p = 0.003); longer SACT (150 ± 100 versus 83 ± 33 ms, p = 0.03); and longer CSNRT (498 ± 409 versus 253 ± 96 ms, p = 0.03). Mean RA voltage trended lower with AFL (1.4 ± 0.6 versus 1.8 ± 0.6 mV, p = 0.1) and lower mean voltage was seen in the region of the crista terminalis (1.3 ± 0.6 versus 1.9 ± 0.6 mV, p = 0.009). Conclusions: Atrial remodelling seen with chronic AFL is associated with widespread changes characterised by generalised and site-specific conduction abnormalities, sinus node dysfunction and decreased voltage. These features provide insight into the structural changes underlying the substrate predisposing to and maintaining AFL. doi:10.1016/j.hlc.2009.05.338
ABSTRACTS
Heart, Lung and Circulation 2009;18S:S1–S286