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Streeter, A. J.

Publications and source records attributed to Streeter, A. J..

2 recordsLinked to original sources
bioRxiv2018

Assessment of the transmural unipolar electrogram morphology change radius during contact force-guided pulmonary vein isolation using the VISITAG™ Module and CARTOREPLAY™

AimsTo investigate the radius of transmural (TM) ablation effect at the left atrial posterior wall (LAPW) during contact force (CF)-guided pulmonary vein isolation (PVI), using pure R unipolar electrogram (UE) morphology change - a histologically validated marker of radiofrequency (RF)-induced TM atrial ablation.\n\nMethodsFollowing PVI in 24 consecutive patients (30W, continuous RF), VISITAG Module and CARTOREPLAY (Biosense Webster Inc.) RF and UE data at left and right-sided LAPW annotated sites 1 and 2 were analysed.\n\nResultsAcutely durable PVI without spontaneous / dormant recovery was achieved following 15s and 10-11s RF, at sites 1 and 2, respectively (p<0.0001). At site 1, RS UE morphology was noted pre-ablation, with RF-induced pure R UE morphology change in 47/48 (98%). Left and right-sided second RF site annotation was at 5.8mm and 5.2mm from site 1 respectively (p=0.64), yet immediate pure R UE morphology was noted in 35/48 (73%). For second-annotated sites, 30 demonstrated inter-ablation site transition time [&le;]17ms; pure R UE morphology was noted at annotation onset in 22/30 (73%), with overall median time to pure R morphology change significantly shorter than at site 1 - 0.0s, versus 4.1s and 5.3s, for left and right-sided first-annotated LAPW sites, respectively (p<0.0001).\n\nConclusionWhen the first and second-annotated LAPW RF sites were within 7mm, 73% second-annotated sites demonstrated immediate pure R UE morphology change. These analyses support a paradigm of shorter RF duration at immediately adjacent sites during continuous RF application, and may usefully inform the further development of \"tailored\" approaches towards CF-guided PVI.\n\nWhats known?O_LIThe VISITAG Module and CARTOREPLAY permit investigations into the tissue effects of RF energy delivery in vivo, via objective annotation methodology and retrospective evaluation of histologically validated unipolar electrogram (UE) criteria for transmural (TM) atrial ablation.\nC_LIO_LIGreater RF energy effect is seen at left compared to right-sided first-annotated left atrial posterior wall (LAPW) sites during pulmonary vein isolation (PVI).\nC_LI\n\nWhats new?O_LIFollowing [~]15s RF delivery at first-annotated LAPW sites and aiming for [&le;]6mm inter-ablation site distance during continuous RF delivery, 73% second-annotated sites demonstrated immediate TM UE morphology change.\nC_LIO_LIAt second-annotated sites, [~]10s RF resulted in acutely durable PVI in all. Greater left-sided RF energy effect was observed, not explained by differences in RF duration, mean CF or catheter position stability.\nC_LIO_LIThe radius of TM RF effect may be determined at the LAPW following CF and VISITAG Module-guided PVI.\nC_LI

physiology↗
bioRxiv2017

Transmural unipolar electrogram morphology is achieved within 7s at the posterior left atrial wall during pulmonary vein isolation: VISITAG&trade; Module-based lesion assessment during radiofrequency ablation

AimsTo assess the occurrence of a histologically validated measure of transmural (TM) atrial ablation - pure R unipolar electrogram (UE) morphology change - at first-ablated left atrial posterior wall (LAPW) sites during contact force (CF)-guided pulmonary vein isolation (PVI).\n\nMethods and resultsExported VISITAG Module and CARTOREPLAY (Biosense Webster Inc.) UE morphology data was retrospectively analysed in 23 consecutive patients undergoing PVI under general anaesthesia. PVI without spontaneous / dormant recovery was achieved in all, employing 16.3[3.2] minutes (mean [SD]) of temperature-controlled RF at 30W. All first-ablated LAPW sites demonstrated RS UE morphology pre-ablation, with RF-induced pure R UE morphology change in 98%. Time to pure R UE morphology was significantly shorter at left-sided LAPW sites (4.9[2.1] s versus 6.7[2.5] s; p=0.02), with significantly greater impedance drop (median 13.5{Omega} versus 9.9{Omega}; p=0.003). Importantly, neither the first-site RF duration (14.9 versus 15.0s) nor the maximum ablation catheter tip distance moved (during RF) were significantly different, yet the mean CF was significantly higher at right-sided sites (16.5g versus 11.2g; p=0.002). Concurrent impedance and objectively annotated bipolar electrogram (BE) data demonstrated ~6-8{Omega} impedance drop and ~30% BE decrease at the time of first pure R UE morphology change.\n\nConclusionUsing objective ablation site annotation, TM UE morphology change was typically achieved within 7s at the LAPW, with significantly greater ablative effect evident at left-sided sites. The methodology described in this report represents a novel and scientifically more rigorous foundation towards future research into the biological effects of RF ablation in vivo.\n\nCondensed abstractThrough appropriate use of the VISITAG Module and CARTOREPLAY, unipolar electrogram morphology change indicative of histologically confirmed transmural atrial ablation in animal models, was proven to occur typically within 7s, during first-site contact force-guided ablation at the left atrial posterior wall during pulmonary vein isolation.

physiology↗