Comparison of Electroanatomic Contact and Noncontact Mapping of Ventricular Scar in a Chronic Post-infarct Ovine Model

Abstracts

288 High-density Mapping of the Human Sinus Node: The Effect of Atrial Remodelling Due to Atrial Flutter Martin Stiles ∗ , Anthony Brooks, Bobby John, Dennis Lau, Hany Dimitri, Lauren Wilson, Christopher Wong, Pawel Kuklik, Glenn Young, Prashanthan Sanders Cardiovascular Research Centre, Royal Adelaide Hospital and the Disciplines of Medicine and Physiology, University of Adelaide, Adelaide, Australia Introduction: Sinus node function is impaired following atrial flutter (AFL). Detailed evaluation of the sinus node complex in normal and diseased atria may help understand sinus node function. Methods: Sixteen patients with chronic AFL and 15 agematched controls were studied following ablation. A 20-pole catheter positioned along the crista terminalis (CT) and a multi-electrode array were used for mapping. Features of sinus node function were determined during sinus rhythm and following pacing. Results: Both earliest activation (EA) and sinus breakout (SBO) points were further from the SVC-RA junction in patients with AFL (EA: 15 ± 12 mm vs. 4 ± 5 mm; SBO: 23 ± 11 mm vs. 9 ± 6 mm, p < 0.001). Following pacing, caudal excursion was less for patients with AFL. EA 3 (IQR −4 to 11) vs. 10 (0–19 mm), p < 0.001; SBO 3 (0–6) vs. 7 (0–10 mm), p = 0.03. Patients with AFL demonstrated greater distance (21 ± 14 mm vs. 14 ± 9 mm, p = 0.001) and time (23 ± 8 ms vs. 15 ± 5 ms, p < 0.001) from EA to SBO. Conclusion: Remodelling of the sinus node complex due to AFL is characterised by more caudal activation and less excursion of early activity with lower voltage at this site. AFL

Control

P

Sinoatrial conduction time (ms)

150 ± 100

83 ± 33

Corrected sinus node recovery time (ms)

498 ± 409

252 ± 96

0.03

Sinus P-wave duration (ms)

147 ± 13

109 ± 13

<0.001

RA activation time (ms)

120 ± 15

92 ± 12

<0.001

Double potentials along CT Maximum duration CT potentials (ms)

5.4 ± 2.9 72 ± 14

2.1 ± 1.8 60 ± 15

Conduction block across CT; sinus rhythm

96%

62%

Anteroposterior delay CT (ms)

22 ± 9

17 ± 6

0.03

0.002 0.04 <0.001 0.006

Peak unipolar RA voltage (mV)

3.8 ± 3.1

5.3 ± 2.0

0.001

Voltage at SBO (mV)

1.5 ± 1.4

3.2 ± 1.5

<0.001

doi:10.1016/j.hlc.2008.05.289 289 Comparison of Electroanatomic Contact and Noncontact Mapping of Ventricular Scar in a Chronic Post-infarct Ovine Model Gopal Sivagangabalan ∗ , Jim Pouliopoulos, Kaimin Huang, Juntang Lu, Michael Barry, Aravinda Thiagalingam, Pramesh Kovoor Westmead Hospital, NSW, Australia Introduction: Substrate-based ablation is useful for post-infarct ventricular tachycardia which is not haemodynamically tolerated. We assessed the accuracy of the

S121

CARTO contact and ENSITE noncontact systems at identifying substrate in a chronic ovine model. Methods: Mapping was performed on eight male sheep with previous myocardial infarction. Up to 20 plunge needles were inserted into the left ventricle of each animal in visually identified areas of dense scar, scar border, and normal myocardium at thorocotomy. A simultaneous CARTO voltage map and ENSITE geometry were acquired using a single catheter. Pacing was performed at various sites to construct a ENSITE Dynamic Substrate Map (DSM). The needle electrode locations were registered on both systems. Tissue blocks around each plunge needle were sent for histological analysis and percentage of scar measured. Two classifications were used for scar percentage; (1) <50%, ≥50%, (2) <10%, ≥10%. Receiver operator characteristics (ROC) curves were constructed for ENSITE DSM, CARTO Bipolar voltages, unipolar PNV of needle electrodes, and compared to the histological classifications. Needles >40 mm from the ENSITE array were excluded. Results: For classification 1, the ROC area under the curve (AUC) for ENSITE DSM was 0.703, for CARTO bipolar voltage points was 0.700, and for needle PNV was 0.759. For classification 2, the ROC AUC for ENSITE DSM was 0.700, for CARTO bipolar voltage was 0.645, and for needle PNV was 0.827. Conclusion: Both the CARTO contact and ENSITE noncontact systems are moderately accurate in identifying post-infarct scar. doi:10.1016/j.hlc.2008.05.290 290 Incidence and Time Course of Pulmonary Vein Conduction Recovery Following Electrical Isolation Lauren Wilson ∗ , Anthony Brooks, Martin Stiles, Bobby John, Dennis Lau, Hany Dimitri, Glenn Young Cardiovascular Research Centre, Department of Cardiology, Royal Adelaide Hospital and the Disciplines of Medicine and Physiology, University of Adelaide, Adelaide, Australia Introduction: Pulmonary vein (PV) isolation is central to most strategies of atrial fibrillation (AF) ablation. Recovered conduction has been implicated as an important cause of recurrent arrhythmia. We aimed to determine the incidence and time course of early recovery of PV conduction after electrical isolation. Methods: Thirty-nine consecutive patients (27M; 55 ± 11 years) with paroxysmal/persistent AF undergoing ablation in sinus rhythm were studied. All patients underwent circumferential PV ablation with an end-point of PV isolation confirmed by circumferential mapping. Additional substrate modification was performed in patients with episodes of AF >48 h or with structural heart disease. Following ablation, PVs were evaluated for conduction recovery. Only PVs that were ablated in sinus rhythm were included in the study. Results: Recovery of PV conduction was evaluated at a median of 65 min (range 2–174 min) after initial isolation.

ABSTRACTS

Heart, Lung and Circulation 2008;17S:S1–S209