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Non Uniform Ventricular Remodelling Following CRT—Insights From Quadrapolar Leads
CSANZ 2013 Abstracts
Methods: We prospectively assessed phrenic nerve function during balloon cryoablation procedures using a novel technique. A quadrapolar pacing catheter was positioned posterior to the left sternoclavicular junction in the left subclavian vein. High output pacing was delivered to a widely spaced bipole (poles 1 and 4 at 25 mA) (Micropace EPS 320 cardiac stimulator, Sydney, Australia). Pacing output was then decreased until reliable capture (assessed by diaphragmatic contraction) was lost. Pacing was delivered at twice diastolic threshold during left sided cryoablation. Results: In 20 consecutive patients capture was easily achieved, with excellent stability. Pacing electrode instability resulting in temporary loss of capture did not occur in any patient. The median capture current was 2 mA (range 0.8–15 mA). Phrenic nerve dysfunction did not occur during the initial 20 cases (10 cases Arctic Front, 10 cases Arctic Front Advance). Phrenic nerve stimulation at low outputs, above the capture threshold resulted in weak diaphragmatic movement suggesting that capture was not an all-or-nothing phenomenon. Conclusion: Left phrenic nerve stimulation is a novel technique which allows the monitoring of left phrenic nerve function, during balloon cryoablation. http://dx.doi.org/10.1016/j.hlc.2013.05.272 272 This abstract has been withdrawn 273 Marked Variation in Catheter-Tissue Contact Force During Cavotricuspid Isthmus Ablation Using Traditional Markers of Good Contact S. Kumar 1,∗ , J. Kalman 1
Morton 1 , M.
Wong 1 , P.
Kistler 2 , J.
1 The
Royal Melbourne Hospital and University of Melbourne, Australia 2 The Alfred Hospital and Baker IDI, Melbourne, Australia Introduction: Catheter-tissue contact force (CF) determines radiofrequency (RF) lesion size. We characterised CF during cavotricuspid isthmus (CTI) ablation using traditional markers of “good” contact. Methods: 503 lesions (16 pts) using a novel CF-sensing catheter were assessed for average CF (g), force-time integral (FTI, g*s). Experienced operators were instructed to obtain “good” contact based on catheter tip motion on fluoroscopy, electrogram (EGM) quality, EGM abatement and impedance fall with ablation, whilst remaining blinded to 3D mapping and CF measurements. CTI was divided into annular, mid and caval regions for analysis. Results: There was significant variability in CF within and between different CTI regions (P < .001). 41% of lesions delivered had average CF < 10 g despite “good” contact using traditional markers. Lowest CF was at the annulus followed by the mid and the caval CTI (P < .001). Number of lesions with low average CF (<10 g) or low FTI (<500 g) strongly and linearly correlated with RF time to achieve CTI block (r2 = .8, P < .001). Average CF and FTI were sig-
S115
nificantly higher in lesions causing persistent CTI block vs. lesions resulting in recovered conduction (P < .05). Each 1 g increase in CF was associated with a 16% reduction in risk of recovered CTI conduction (95% CI: 4–27%, P = .01) Conclusions: The use of traditional markers of “good” contact results in marked variability in real-time CF and nearly half of all lesions delivered with low CF during CTI ablation. Low CF was implicated in longer time to achieve CTI block and increased risk of acute CTI reconnection. http://dx.doi.org/10.1016/j.hlc.2013.05.274 274 Non Uniform Ventricular Remodelling CRT—Insights From Quadrapolar Leads
Following
R. Spencer 1,∗ , H. Sugumar 2 , T. Lin 3 , D. Flannery 1 , P. Rae 1 , D. O’Donnell 1 1 Austin
Health, Victoria, Australia Health, Victoria, Australia 3 Kardiologie, St. Georg, Hamburg, Germany 2 Western
Introduction: Structural remodelling has been reported following cardiac resynchronisation therapy (CRT). Electrical remodelling has been less well evaluated. This study evaluated intracardiac electrograms (EGM) from multipolar leads to determine the degree and uniformity of electrical remodelling following CRT. Methods: Fifty-eight consecutive patients in sinus rhythm undergoing CRT for recognised indications were included. EGM and echocardiographic measures were performed at implant, 24 h and at 3, 6 and 12 months post implant. EGM’s were recorded from each of the four electrodes of a quadrapolar lead during intrinsic rhythm (Int RV-LV) during RV pacing (RVp-LV) and during LV pacing (LVp-RV). Response to CRT was defined as an improvement of EF > 10% and a reduction in LVEDD by >15%. Results: Fifty-five patients completed follow up with a response rate of 78%. Overall there was a reduction in Int RV-LV delay (15 ± 10 ms), LVp-RV (27 ± 12 ms) and the RVp-LV (16 ± 21 ms). The reduction in Int RV-LV was greater in responders 31 ± 11 ms compared with nonresponders 8 ± 6 ms (p < 0.01). In individual patients there were significant differences in EGM variation at different electrode sites. The mean maximal difference in LVp-RV in individual patients improved from 35 ± 13 ms to 21 ± 12 ms in the responders and from 33 ± 11 ms to 31 ± 12 ms in the non-responders (p < 0.01). Conclusions: Electrical remodelling, measured by intracardiac EGMs, correlates with response to CRT and structural remodelling. The electrical remodelling is not uniform with significant regional variation seen across the four electrodes of a quadrapolar LV lead. http://dx.doi.org/10.1016/j.hlc.2013.05.275
ABSTRACTS
Heart, Lung and Circulation 2013;22:S1–S125
Methods: We prospectively assessed phrenic nerve function during balloon cryoablation procedures using a novel technique. A quadrapolar pacing catheter was positioned posterior to the left sternoclavicular junction in the left subclavian vein. High output pacing was delivered to a widely spaced bipole (poles 1 and 4 at 25 mA) (Micropace EPS 320 cardiac stimulator, Sydney, Australia). Pacing output was then decreased until reliable capture (assessed by diaphragmatic contraction) was lost. Pacing was delivered at twice diastolic threshold during left sided cryoablation. Results: In 20 consecutive patients capture was easily achieved, with excellent stability. Pacing electrode instability resulting in temporary loss of capture did not occur in any patient. The median capture current was 2 mA (range 0.8–15 mA). Phrenic nerve dysfunction did not occur during the initial 20 cases (10 cases Arctic Front, 10 cases Arctic Front Advance). Phrenic nerve stimulation at low outputs, above the capture threshold resulted in weak diaphragmatic movement suggesting that capture was not an all-or-nothing phenomenon. Conclusion: Left phrenic nerve stimulation is a novel technique which allows the monitoring of left phrenic nerve function, during balloon cryoablation. http://dx.doi.org/10.1016/j.hlc.2013.05.272 272 This abstract has been withdrawn 273 Marked Variation in Catheter-Tissue Contact Force During Cavotricuspid Isthmus Ablation Using Traditional Markers of Good Contact S. Kumar 1,∗ , J. Kalman 1
Morton 1 , M.
Wong 1 , P.
Kistler 2 , J.
1 The
Royal Melbourne Hospital and University of Melbourne, Australia 2 The Alfred Hospital and Baker IDI, Melbourne, Australia Introduction: Catheter-tissue contact force (CF) determines radiofrequency (RF) lesion size. We characterised CF during cavotricuspid isthmus (CTI) ablation using traditional markers of “good” contact. Methods: 503 lesions (16 pts) using a novel CF-sensing catheter were assessed for average CF (g), force-time integral (FTI, g*s). Experienced operators were instructed to obtain “good” contact based on catheter tip motion on fluoroscopy, electrogram (EGM) quality, EGM abatement and impedance fall with ablation, whilst remaining blinded to 3D mapping and CF measurements. CTI was divided into annular, mid and caval regions for analysis. Results: There was significant variability in CF within and between different CTI regions (P < .001). 41% of lesions delivered had average CF < 10 g despite “good” contact using traditional markers. Lowest CF was at the annulus followed by the mid and the caval CTI (P < .001). Number of lesions with low average CF (<10 g) or low FTI (<500 g) strongly and linearly correlated with RF time to achieve CTI block (r2 = .8, P < .001). Average CF and FTI were sig-
S115
nificantly higher in lesions causing persistent CTI block vs. lesions resulting in recovered conduction (P < .05). Each 1 g increase in CF was associated with a 16% reduction in risk of recovered CTI conduction (95% CI: 4–27%, P = .01) Conclusions: The use of traditional markers of “good” contact results in marked variability in real-time CF and nearly half of all lesions delivered with low CF during CTI ablation. Low CF was implicated in longer time to achieve CTI block and increased risk of acute CTI reconnection. http://dx.doi.org/10.1016/j.hlc.2013.05.274 274 Non Uniform Ventricular Remodelling CRT—Insights From Quadrapolar Leads
Following
R. Spencer 1,∗ , H. Sugumar 2 , T. Lin 3 , D. Flannery 1 , P. Rae 1 , D. O’Donnell 1 1 Austin
Health, Victoria, Australia Health, Victoria, Australia 3 Kardiologie, St. Georg, Hamburg, Germany 2 Western
Introduction: Structural remodelling has been reported following cardiac resynchronisation therapy (CRT). Electrical remodelling has been less well evaluated. This study evaluated intracardiac electrograms (EGM) from multipolar leads to determine the degree and uniformity of electrical remodelling following CRT. Methods: Fifty-eight consecutive patients in sinus rhythm undergoing CRT for recognised indications were included. EGM and echocardiographic measures were performed at implant, 24 h and at 3, 6 and 12 months post implant. EGM’s were recorded from each of the four electrodes of a quadrapolar lead during intrinsic rhythm (Int RV-LV) during RV pacing (RVp-LV) and during LV pacing (LVp-RV). Response to CRT was defined as an improvement of EF > 10% and a reduction in LVEDD by >15%. Results: Fifty-five patients completed follow up with a response rate of 78%. Overall there was a reduction in Int RV-LV delay (15 ± 10 ms), LVp-RV (27 ± 12 ms) and the RVp-LV (16 ± 21 ms). The reduction in Int RV-LV was greater in responders 31 ± 11 ms compared with nonresponders 8 ± 6 ms (p < 0.01). In individual patients there were significant differences in EGM variation at different electrode sites. The mean maximal difference in LVp-RV in individual patients improved from 35 ± 13 ms to 21 ± 12 ms in the responders and from 33 ± 11 ms to 31 ± 12 ms in the non-responders (p < 0.01). Conclusions: Electrical remodelling, measured by intracardiac EGMs, correlates with response to CRT and structural remodelling. The electrical remodelling is not uniform with significant regional variation seen across the four electrodes of a quadrapolar LV lead. http://dx.doi.org/10.1016/j.hlc.2013.05.275
ABSTRACTS
Heart, Lung and Circulation 2013;22:S1–S125