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Background Accurate delivery of transmural lesion is associated with improved durability of pulmonary vein isolation and reduced reconduction. Lesion quality depends on multiple parameters such as radiofrequency power, tissue-catheter contact, duration of energy application, and catheter tip temperature. Consequently, energy delivery parameters vary based on individual operators’ preferences and procedural needs. Purpose To characterize and compare the utilization of automated lesion marking feature and lesion delivery parameters used during paroxysmal atrial fibrillation ablation performed with a magnetic sensor enabled contact force-sensing catheter across European and U.S. centers. Methods Procedural data were prospectively collected in clinical cases performed with a new magnetic sensor enabled, contact force ablation catheter within the first 6 months of use at participating centers in Europe and the U.S. Use of bidirectional CF catheters, steerable sheaths, automated lesion marking software and associated lesion delivery parameters during paroxysmal atrial fibrillation ablation were evaluated. Results A total of 149 cases across 37 centers in 11 European countries, and 112 cases across 31 U.S. centers were analyzed. A bidirectional contact force catheter (56.4% and 90.2%), a steerable sheath (65.8% and 69.6%), and the automated lesion marking module (77.9% and 90.2%) were used in most European and U.S. cases, respectively. The most commonly reported energy delivery parameters were: lesion index (LSI), Force-Time Integral (FTI), and time from European cases; LSI, average force, and FTI for U.S. cases (Table). Target LSI values were recorded for 126 cases in Europe and 34 in the U.S, ranging from 3 to 6. In anterior/roof segments, most common LSI target values for anterior/roof and posterior/inferior segments were 6 (42.9%) and 5 (51.2%) in Europe, and 5.5 (44.1%) and 5 (54.5%) in the U.S. PVI was confirmed with an average of 20.3 minutes waiting period (69.1%) for European cases and exit block (57.1%) in U.S. cases. First pass PVI were 67.1% and 74.4% for European and U.S. cases, respectively. Conclusion Energy delivery parameters and PVI confirmation method varied considerably by geography during paroxysmal atrial fibrillation ablation using the magnetic sensor enabled, contact force ablation catheter. Further study on efficacy implication on these differences in practice should be examined. Energy delivery parameters used Paroxysmal AF N LSI FTI Time Imp Drop Avg Force Other N/A Europe 149 44.0 % 13.4 % 7.0 % 6.0 % 2.4 % 1.0 % 26.2 % U.S. 112 31.2% 17.9 % 6.2 % 8.0 % 23.2 % 11.7 % 1.8 % Energy delivery parameters used in paroxysmal AF ablation in Europe and U.S.

Background Although pulmonary vein isolation (PVI) is considered the standard approach of atrial fibrillation ablation worldwide, procedural practice during the ablation varies by geographical region. Using the same magnetic sensor enabled contact force-sensing ablation catheter for the treatment of de novo paroxysmal atrial fibrillation, a comparison of procedural detail between Europe and U.S operators can provide insights into geographic specific clinical practices. Purpose To characterize and compare procedural differences during paroxysmal atrial fibrillation ablation performed with a magnetic sensor enabled contact force-sensing catheter across European and U.S. centers. Methods Procedural data were prospectively collected in clinical cases performed with a new magnetic sensor enabled, contact force ablation catheter within the first 6 months of use at participating centers in Europe and the U.S. Procedure time, PVI time, PVI confirmation method, fluoroscopy usage and lesion delivery parameters were analyzed based on geographies. Results A total of 131 cases across 35 centers in 11 European countries, and 95 cases across 26 U.S. centers were analyzed. Target geometry was created with the ablation catheter in 94 out of 131 (71.8%) European cases, while only 5 out of 95 U.S. cases (5.3%) reported the use of the ablation catheter for model creation. Although a steerable sheath (64.1% and 67.3%) was commonly used with the ablation catheter in both geographies, difference in the utilization of bidirectional contact force catheter (52.7% and 90.5%) and the automated lesion marking module (76.3% and 81.1%) were observed in European and U.S. cases, respectively. The use of adenosine or isoproterenol to confirm PVI was reported in 25% and 64% of the European and U.S. cases. Average waiting periods were 18.2 minutes and 26.5 minutes from reported European and U.S. cases. Total procedural time, mapping time, and fluoroscopy time were similar between European and U.S. cases. (Table). First pass PVI were 66.4% and 72.6% for European and U.S. cases, respectively. Conclusion Total procedural time and RF time were similar between European and U.S. cases during de novo paroxysmal atrial fibrillation ablation using the same ablation catheter. Differences in workflow including the use of a mapping catheter for geometry creation and waiting period were observed between the two geographies. Summary of procedural details De novo PAF N Procedural time(min) Mapping time (min) PVI time (min) Total RF time (min) Fluoro time( min) Europe 131 144.0 ± 56.9 16.6 ± 17.1 69.8 ± 35.0 33.2 ± 15.6 11.6 ± 10.1 U.S. 95 137.6 ± 64.8 18.1 ± 23.5 58.8 ± 31.5 32.3 ± 22.2 12.0 ± 15.8

Background In patients with non-ischemic cardiomyopathy (NICM), non-inducibility after catheter ablation has been associated with lower VT recurrence rates. We hypothesized that induced VT pleomorphism (PL-VT) may be indicative for a complex VT substrate that might be associated with poor ablation outcome independently of non-inducibility at the end of the procedure. Methods Consecutive patients with left-dominant NICM undergoing VT ablation (2008–2018) were included. All patients underwent genetic screening. PL-VT was defined as occurrence of ≥1 morphologically distinct QRS lasting for ≥6 consecutive beats during the same induced VT episode. Complete acute success was defined as non-inducibility of any VT at the end of procedure. Results Eighty-five patients (56±15 yrs, LVEF 38±12%), inducible for 365 VTs (median 3/patient, IQR 1–6) were included. PL-VT was observed in 29 patients (34%). Patients with PL-VT had more often anteroseptal substrates, a higher number of induced VTs, and larger endocardial bipolar ( Figure 1 Conclusions Induced PL-VT was not associated with acute outcome but higher VT recurrence rate after catheter ablation in patients with NICM. Moreover, co-existence of PL-VT and persistent VT inducibility identifies patients at highest risk for VT recurrence whereas non-inducible patients without PL-VT have a favorable prognosis.

1. Ca(2+) sensitizers enhance systolic function, but may impair relaxation in vitro; these effects may differ in stunned and normal myocardium. We therefore studied the effect of EMD 57033 on systolic and diastolic function of normal and stunned porcine myocardium in vivo. 2. Myocardial stunning by 15 min coronary occlusion and 30 min reperfusion abolished systolic shortening (SS) (baseline 13+/-1%) and decreased end-systolic elastance (E(es)) from 67+/-7 to 47+/-5 mmHg mm(-1) (both P0.05). Maximum rate of fall of myocardial elastance (dE/dt(min)) decreased from -850+/-100 to -320+/-30 mmHg mm(-1) s(-1), while the time constant tau(e) of the decay of elastance increased from 58+/-3 to 68+/-6 ms (both P0.05). End-diastolic elastance (E(ed)) was unchanged although the zero pressure intercept (L(0,ed)) had increased. 3. In the stunned region, EMD 57033 (0.2 mg kg(-1) min(-1) for 60 min, i.v., n=7) increased SS to 19+/-2%, E(es) to 287+/-40 mmHg mm(-1), dE/dt(min) to -3630+/-640 mmHg mm(-1) s(-1) and decreased tau(e) to 50+/-3 ms, while E(ed) remained unchanged. In the normal region, 4. EMD 57033 increased SS from 14+/-2 to 18+/-3%, E(es) from 59+/-4 to 263+/-23 mmHg mm(-1), dE/dt(min) from -480+/-70 to -2280+/-700 mmHg mm(-1) s(-1) and decreased tau(e) from 91+/-12 to 61+/-3 ms (all P0.05), while E(ed) remained unchanged. These responses were minimally affected by adrenoceptor blockade (n=7). Vehicle (n=7) had no effect on either region. EMD 57033 increased cardiac output (up to 27+/-8%) and LVdP/dt(max) (86+/-19%). Mean aortic pressure decreased (19+/-7%) due to systemic vasodilation that was not amenable to blockade of adrenoceptors or NO synthesis. 5. In conclusion, EMD 57033 restored systolic and diastolic function of stunned myocardium, and produced similar improvements in systolic and diastolic function in normal myocardium.