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Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Grant project AZV NU20-02-00244 from the Ministry of Health of the Czech Republic and European Union's Horizon 2020 research and innovation program under grant agreement No 945119. Introduction Stereotactic body radiotherapy (SBRT) is a novel treatment for otherwise resistant ventricular tachycardias (VTs). Different mechanisms of SBRT for VT suppression were proposed that include radiation-induced fibrosis but also SBRT-triggered increase in myocardial conduction velocities without significant fibrotic changes. Purpose The study compared the morphologies and cycle lengths (CLs) of inducible VTs during re-do catheter ablation after SBRT with VTs before SBRT. Methods We investigated patients that underwent SBRT (a single session of 25 Gy) for refractory VT and subsequent electrophysiology study / reablation for recurrences of VTs. All inducible VTs were analysed concerning morphology and CL. Results A total of 9 patients (2 women, aged 60 ± 13 years) were included. Two patients had ischemic heart disease, six patients had nonischemic cardiomyopathy, and one had a cardiac fibroma. All patients were on chronic amiodarone treatment. The mean ejection fraction of the left ventricle was 35 ± 12%. The mean planning target volume for SBRT was 39 ± 21 ml. Electrophysiology study/reablation was performed at a mean interval of 8 months (interquartile range: 2-10months) after SBRT. A total of 23 and 27 distinct VT morphologies were inducible before and after SBRT, respectively. Twelve pairs of VTs (44%) were identified that had identical morphology before and after SBRT. The mean CL of these VT pairs decreased from 399 ± 98 ms to 472 ± 74 ms (P = 0.01) after SBRT. Overall, 15/27 of all VT morphologies induced after SBRT originated from the irradiated region. Conclusions Recurrent VTs after SBRT had commonly origin in the irradiated region. In pairwise comparison, the CL of VTs has prolonged after the SBRT. This suggests that SBRT results in radiation-induced fibrosis rather than an increase in conduction velocity.

Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The study was supported by the Ministry of Health of the Czech Republic. Background Atrial fibrillation (AF) and other atrial tachycardias (ATs), including typical atrial flutter (AFL), are common in patients with pulmonary hypertension. Frequently, several supraventricular arrhythmias are successively observed in individual patients. Purpose We investigated the hypothesis of whether more extensive radiofrequency catheter ablation of the bi-atrial arrhythmogenic substrate instead of clinical arrhythmia ablation alone results in superior clinical outcomes in patients with PH and AF / AT. Methods Patients with combined post- and pre-capillary or isolated pre-capillary PH and AF / AT indicated to catheter ablation were enrolled in 3 centers and randomized 1:1 into two parallel treatments arms: (A) Clinical arrhythmia ablation and (B) Clinical arrhythmia plus substrate-based ablation. The primary endpoint was arrhythmia recurrence >30 s without antiarrhythmic drugs after the 3-month blanking period. Results A total of 77 patients (mean age 67 ± 10 years; 41 males) were enrolled. The presumable clinical arrhythmia was AF in 38 and AT in 36 patients, including typical AFL in 23 patients. During the median follow-up period of 13 (IQR: 12; 19) months, the primary endpoint occurred in 15 patients (42 %) vs. 17 patients (45 %) in the group B vs. A (hazard ratio: 0.97, 95% confidence interval: 0.49-2.0). There was no excess of procedural complications and clinical follow-up events including an all-cause death in group B. Conclusion Extensive ablation, compared with a limited approach, was not beneficial in terms of arrhythmia recurrence in patients with AF / AT and pulmonary hypertension.

Funding Acknowledgements Type of funding sources: None. Background Radiofrequency (RF) catheter ablation is an established treatment method in patients with structural heart disease (SHD) and recurrent ventricular tachycardia (VT). Due to underlying SHD, concomitant heart failure and a high burden of comorbidities, these patients are at considerable risk of periprocedural complications including acute hemodynamic decompensation (AHD) with a reported rate of up to 11%. The PAINESD score [sum of 5, 3, 6, 6, 3, 5, and 3 points for chronic obstructive pulmonary disease (COPD), age >60 years, ischemic cardiomyopathy (ICM), NYHA Class >2, LV ejection fraction (LVEF) Purpose The single-centre, retrospective study investigated the incidence of AHD in large-volume, tertiary referral EP centre and the predictive power of the PAINESD score. Methods We included patients who had their first ablation for SHD-related VT between August 2006 and December 2020. The procedure was performed under conscious sedation except for patients who were on mechanical ventilation because of hemodynamical or electrical instability before the ablation. Substrate mapping/ablation was performed primarily during spontaneous rhythm or right-ventricular pacing. Induced VTs were terminated by overdrive pacing or cardioverted. Activation and entrainment mapping were used rarely – only in well-tolerated VTs. The goal of ablation was to abolish all inducible VTs. A purposely established institutional registry for complications of invasive procedures was used to collect all periprocedural complications that were subsequently adjudicated using the source medical records. AHD triggered by ablation procedure was defined as intraprocedural or early post-procedural ( Results The study cohort consisted of 1143 patients (age: 63±13 years, males: 87%, ICM: 67%, ES: 25%, NYHA Class: 2.1±1.0, LVEF: 34±13%, DM: 32%, COPD: 12%). Their PAINESD score was 11.4±6.6 (median: 12, interquartile range: 6–17). The ablation procedure (total duration 187±78 min, RF time: 23±15 min) was complicated by AHD in 13/1143 = 1.1% patients and these adverse events were not predicted by PAINESD score (Figure). Conclusions We observed a substantially lower rate (1.1%) of AHD than previously reported (up to 11%). These events did not accumulate in patients with upper-tertile PAINESD score in whom the highest AHD risk was reported (up to 24%). This observation may be explained by careful substrate-based ablation under conscious sedation that prevents prolonged low-output state related to repeated VT induction and mapping in general anaesthesia.

Funding Acknowledgements Type of funding sources: None. Background Radiofrequency catheter (RF) ablation of the superior ganglionated plexus (RAGP) that modifies parasympathetic innervation of the sinus node (SAN) is used for the treatment of functional bradyarrhythmias. The RAGP is usually targeted from the endocardial aspect of both the right and left atria. Purpose To investigate the acute effect of a minimized biatrial set of ablation lesions aimed at denervating the SAN. Methods In patients with cardioinhibitory reflex syncope (n=25) or symptomatic functional sinus bradycardia (n=7), a minimum of 2x2 and a maximum of 2x3 RF lesions (at the discretion of the operator) were created from both sides of the superior interatrial septum with a setting of 30 W / 30 s and strictly contralateral configuration. The response to extracardiac vagus nerve stimulation (ECVS) was assessed before and after ablation. This response was quantified by the ratio of the maximum induced P-P interval and the cycle length of the current sinus rhythm (MaxPPratio). Results In 32 patients (41±13 years, 56% men), ablation of RAGP (2x3 and 2x2 lesions in 23 and 9 patients, respectively) resulted in attenuation of the response to ECVS from 7.9±3.5 s to 0.9±0.2 s (Figure, left panel). After ablation, only 9 patients had MaxPPratio >1.1 and none of the patients had MaxPPratio >1.6 (Figure, right panel). In 6 patients with MaxPPratio >1.3, the extension of original lesions easily suppressed the residual responsiveness of SAN to ECVS. Conclusion Biatrial RAGP ablation with a total RF time of 2-3 minutes resulted acutely in virtually complete SAN denervation in 72% of patients. Highly significant, but incomplete SAN denervation in remaining patients was successfully treated by extension of original ablation clusters. The long-term durability of SAN denervation associated with this ablation strategy remains to be investigated.

Background Atrial fibrillation (AF) and related atrial tachycardias (ATs) are common arrhythmias in patients with pulmonary hypertension (PH). They are currently assessed in a multicentre randomized trial investigating extensive radiofrequency catheter ablation of the arrhythmogenic substrate on top of selective ablation of clinical arrhythmia alone. Purpose Irrespective of the randomization scheme, we compared clinical and procedural characteristics in patients with AF versus those with right-sided ATs. Methods Out of 74 patients with combined post- and pre-capillary or isolated pre-capillary PH, two study subgroups were composed: AF group included 40 patients and AT group included 31 patients: 24 with typical atrial flutter (AFL) and 7 with other right-sided ATs (2 upper loop reentry ATs, 2 focal ATs from coronary sinus ostium, 1 focal AT from terminal crest, and 2 polymorphic ATs from high right atrium). Three patients with inducible AV nodal reentrant tachycardia were excluded from this analysis. Biatrial electroanatomic mapping was performed in all patients. The data are presented as medians (interquartile range) and compared by the Mann-Whitney U test. Results The clinical and procedural characteristics of AF and AT groups are shown in Table. Cycle length (CL) of both induced and spontaneous AFL was 302 (267; 324) ms. Non-CTI-dependent ATs had CL 425 (350; 480) ms. In patients with AF, the dominant CL was 183 (152; 221) and 191 (154; 210) ms in right and left atrial appendage, respectively. In the whole cohort, pulmonary vein isolation was done in 49 (66%), left atrial substrate ablated in 23 (31%), cavotricuspid isthmus block achieved in 46 (62%), superior vena cava isolation completed in 28 (39%), intercaval line ablated in 26 (36%), and right atrial substrate or focal activity ablated in 8 (11%) cases. The procedure was technically successful in 72 (97%) patients. Conclusion Patients with right-sided ATs had expectedly more dilated right atrium. This was not, however, associated with a higher prevalence of right atrial low-voltage areas. Left atrial electroanatomic remodelling in AF patients was concordant with that frequently observed in non-PH patients with AF. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Health of the Czech Republic.

Background The progression of parasympathetic denervation of the atrioventricular node (AVN) during cardioneuroablation (CNA) can be evaluated by extracardiac vagal stimulation (ECVS). The right vagus nerve is usually used for stimulation (R-ECVS) because the right jugular vein is easily accessible. However, the AVN node is predominantly under the control of the left vagus nerve. Purpose To highlight the importance of left vagus stimulation (L-ECVS) for effective AVN denervation. Methods Both R-ECVS and L-ECVS (frequency: 50 Hz; pulse width: 0.05 ms; output 1 V / 1 kg; max. 70 V, duration 5 s) was attempted in 80 patients (age: 41±12 years, 45% men) undergoing CNA with stepwise strategy consisting of ablation of right anterior ganglionated plexus (RAGP) followed by ablation of posteromedial left ganglionated plexus (PMLGP). The study objective was the AVN response to L-ECVS (evaluated as the max. R-R interval during stimulation train) at the point when AVN non-reactivity to R-ECVS was achieved. Results A total of 59 patients were suitable for the analysis. Of the remaining 21 patients, left (n=14) or right (n=2) jugular veins were not accessible, AVN non-reactivity to L-ECVS was achieved before non-reactivity to R-ECVS (n=4), or AVN denervation was not achieved at all (n=1). At baseline, the AVN response was identical for R-ECVS (max. R-R median: 6.9 s, interquartile range [IQR]: 5.7–8.2 s) and L-ECVS (median: 7.1 s, IQR: 6.0–8.3 s), P=0.44. AVN non-reactivity to R-ECVS was present already at baseline (n=2); was achieved after ablation of RAGP (n=14), after ablation PMLGP (n=38), or after extensive ablation (n=5). At the point of AVN non-reactivity to R-ECVS, the response of AVN to L-ECVS was as follows: none (n=25), 2: 1 AV block (n=13) or complete AV block (n=21). The corresponding median of max. R-R interval was: 1.2 s, IQR: 0.6–4.8 s distributed as shown in Figure 1. Conclusions In 34/59 (58%) patients, significant AVN response to L-ECVS persists after reaching AVN non-reactivity to R-ECVS. Stimulation of both vagal nerves tightens the procedural endpoint and may increase the clinical efficacy of CNA, especially in patients with dominant AVN disorder. Funding Acknowledgement Type of funding sources: None.

Background Radiofrequency catheter ablation of posteromedial left ganglionated plexus is a critical step to eliminate the vagal input to the atrioventricular node (AVN) for the treatment of symptomatic episodes of functional AV block. This ganglionated plexus can be effectively targeted from the coronary sinus (CS) or from the endocardial aspect of the right (RA) and left (LA) atria. Purpose We investigated the effect of ablation at individual sites on the suppression of parasympathetic modulation of AVN. Methods The study included 20 patients (age: 42±13 years, 45% males) who underwent cardioneuroablation in general anesthesia. Posteromedial left ganglionated plexus was ablated from [1] the CS (proximal 2-cm segment), [2] the RA aspect (between the fossa ovalis and inferior vena cava), and [3] the LA aspect (middle bottom part adjacent to inferior rim of fossa ovalis). Patients were randomly (1:1) assigned to CS-to-RA or RA-to-CS ablation order. LA ablation was always the last step. The response to extracardiac vagus nerve stimulation (ECVS; 50 Hz, 0.05 ms, 1 V/kg [ Results Temporal development of outcome measure with the progression of ablation is shown in Figure 1. CS ablation resulted in much stronger AV nodal denervation compared to RA ablation (P=0.02). However, RA ablation still provided some effect on top of CS ablation. The combination of CS + RA ablation resulted in complete AVN denervation in 8 (40%) patients. Subsequent LA ablation increased the number of denervated patients to 14 (70%). Two more patients were subsequently denervated by ablation elsewhere. In four patients, AVN denervation was not achieved but their responsiveness to ECVS was significantly suppressed compared to the baseline. Conclusions All ablation clusters targeting posteromedial ganglionated plexus convey complementary effects. Biatrial cardioneuroablation seems essential for efficacious suppression of parasympathetic modulation of AVN. Funding Acknowledgement Type of funding sources: None.

Introduction Obesity and atrial fibrillation (AF) pose a significant burden on healthcare systems worldwide. Reduction of body weight has been documented to reduce the risk of AF. Little is known about the effect of different weight-reducing interventions including bariatric surgery in obese individuals on the risk of arrhythmia recurrence following catheter ablation (CA) for AF, and about the pathophysiological mechanisms linking these two conditions. Methods The Effect of complex weigHt-reducing interventiOns on rhythm control in oBese subjects wITh Atrial Fibrillation (HOBIT-AF) is a single-blinded, parallel-group randomised controlled trial with 18-month follow-up to assess the effect of complex weight-reducing interventions supported by the use of smart technologies and bariatric surgery on the arrhythmia burden in obese individuals following CA for AF. One hundred and sixty individuals (age 18–70 years, body mass index ≥ 30 kg/m2) will be randomised in a 1:1 fashion to undergo a structured weight reduction programme and sleeve gastrectomy (when indicated and preferred by the patient) aiming to achieve greater than 10% weight reduction from baseline (intervention group) or standard post-ablation medical care (control group). Two-week continuous ECG monitoring will be used 3 and 18 months after CA to assess the arrhythmia burden. Other investigations will include transthoracic echocardiography with quantification of epicardial adipose tissue, and markers of low-grade inflammation and circulating adipokines. Planned Outcomes The main objective is to assess the effect of complex weight-reducing interventions on the arrhythmia burden and quality of life. Subgroup analyses to identify patient subgroups preferentially benefiting from weight loss related to a decrease in arrhythmia burden will be performed. Exploratory objectives will include investigation of potential mechanisms linking weight reduction with amelioration of arrhythmia burden such as changes in markers of low-grade inflammation, circulating adipokines, cytokines, monocytes or reduction of epicardial adipose tissue volume. Trial Registration NCT04560387

Funding Acknowledgements Type of funding sources: None. Background The most frequent complications of catheter ablation for atrial fibrillation (AF) are related to vascular access. Purpose Vascular complication rates of ultrasound-guided venipuncture (USGV) were analyzed and compared to historical controls (CTRL) with an anatomical landmark-guided approach. Methods The study cohort included 4646 consecutive patients (2330 and 2316 patients in USGV and CTRL groups, respectively). Clinical characteristics were as follows: age of 61±10 years, 67% males, 66% paroxysmal AF, CHA2DS2-VASc score of 2.0±1.4, 27% reablation, and procedure time of 208±69 min. Both femoral veins were cannulated with 2 and 2 sheaths (7, 11, and 2x 8.5 French) in the majority (>95%) of procedures. Major complications were defined as those requiring intervention (surgery, thrombin injection, or transfusion), or hematoma/bleeding with hemoglobin drop >30g/l, or condition prolonging hospitalization and/or resulting in re-hospitalization. They were extracted from the institutional tracking system for complications of invasive procedures and by a review of medical reports within the first 3 months of follow-up. Results There were 32 (1.38%) vs. 62 (2.66%) major complications related to vascular access in USGV and CTRL groups, respectively (Yates corrected Chi-square P=0.003), i.e. relative reduction of -48% in the USGV group. Surgical intervention was needed in 6 (0.26%) vs. 18 (0.77%) patients, respectively (Fisher exact test P=0.02), i.e. relative reduction of -64% in the USGV group. The differences remained significant after adjustment for baseline clinical characteristics. Multivariate analysis revealed that USGV strategy (P=0.0005), male gender (P=0.003), and less advanced age (P=0.0002) were significantly associated with lower complication rates. Conclusions USGV was associated with a statistically significant reduction of major vascular complications after catheter ablation for AF. This strategy also decreased the need for surgical correction of vascular complications. Ultrasound guidance can be recommended to improve the safety of femoral venous access.

Funding Acknowledgements Type of funding sources: None. Background Pulmonary vein isolation (PVI) by thermal energy (radiofrequency energy or cryoenergy) results in collateral ganglionic plexi ablation. On the contrary, pulsed electric field (PEF) energy presumably spares neural tissue. Purpose We investigated and compared the effect of PVI on parasympathetic input into the sinus node (SAN) and AV node (AVN) when four different ablation strategies were used. Methods A study enrolled 49 patients who underwent PVI in general anesthesia (age: 57 ± 13 years, 71% males). In 17 patients, point-by-point radiofrequency energy delivery by the irritated-tip catheter was used for ablation while 7 patients were ablated using a second-generation cryoballoon catheter. In 7 patients, PEF energy was delivered using a single-shot Farawave catheter while 18 patients were ablated using Sphere9 lattice-tip catheter (Affera, Inc.); both subgroups with manufacturer-specific PEF settings. Before and after PVI, the responsiveness of the SAN and AVN was assessed by extracardiac vagal nerve stimulation (ECVS) via a diagnostic catheter in the right internal jugular vein. Five-second stimulation trains were delivered with a frequency of 50 Hz, pulse width of 0.05 ms, and output of 1 V/kg ( Results At baseline, physiological response to ECVS (long sinus arrest and/or AV block) was demonstrated. After PVI, a substantial reduction of SAN response was observed in 21/24 (88%) patients after thermal PVI and 7/25 (25%) patients after non-thermal PVI (P = 0.0001). Similarly, a substantial reduction of AVN response was observed in 21/24 (88%) patients after thermal PVI and 9/25 (36%) patients after non-thermal PVI (P = 0.0003). The Figure shows on the continuous scale the post-PVI pauses in sinus rhythm (maximum P-P interval) and atrial pacing (maximum R-R interval) induced by ECVS. Conclusion Vagal responses of SAN and AVN are preserved in most AF patients after non-thermal PVI. This contrasts with the much stronger effect of thermal PVI. Whether this may influence the clinical outcome of AF ablation procedures remains to be investigated in future studies.

Funding Acknowledgements Type of funding sources: None. Introduction Ablation of superior parasympathetic ganglia is associated with acceleration of sinus rhythm (SR). This has been considered a favorable sign during cardioneuroablation (CNA) for the treatment of functional bradyarrhythmias. Aim We studied whether the relative increase in SR frequency (DeltaSR) during CNA is a reliable predictor of significantly reduced parasympathetic modulation of the sinus node (SAN). Methods In patients undergoing CNA under general anesthesia, the gradual reduction in parasympathetic modulation of SAN during the procedure was assessed by extracardiac right vagal nerve stimulation (ECVS). The response to ECVS was quantified by the ratio of the maximum P-P interval (induced by ECVS) and the baseline SR cycle length (MaxPPratio). The ECVS was performed repeatedly after partial ablation steps, and therefore several pairs of DeltaSR and MaxPPratio values were obtained in the course of the single procedure. A MaxPPratio Results The study included 64 patients (mean age: 42 ± 16 years, 48% men). A total of 188 intraprocedural pairs of DeltaSR and MaxPPratio (2.9 ± 2.1 pairs per procedure) covering the wide distribution of their values (19 ± 14 bpm for DeltaSR and 2.9 ± 2.8 for MaxPPratio) were obtained. One half of ECVS tests (51%) met the criterion of MaxPPratio Conclusion Acceleration of SR during CNA is not a relevant surrogate of significantly reduced parasympathetic modulation of SAN. Elimination or significant suppression of responses of SAN to ECVS serves as an excellent procedural endpoint that might contribute to the favorable clinical outcome of the CNA.

Funding Acknowledgements Type of funding sources: None. Background Cardioneuroablation (CNA) has been proposed as a new therapeutic approach in selected patients with recurrent neurally mediated syncope and documented cardioinhibitory component. Purpose We report on procedural data and clinical outcomes of consecutive patients who underwent anatomically-guided CNA at our center in the period of 2014 - 2021. Methods A study investigated 145 otherwise healthy patients (age: 40 ± 14 years, 56% males) with recurrent reflex syncope and the physiological result of the atropine test. Biatrial radiofrequency (RF) ablation was performed under general anesthesia by irrigated-tip catheter at empirical sites of ganglionated plexi (GP) with the navigation by CARTO-3 system and intracardiac echocardiography. Anterior right GP and posteromedial left GP were always targeted to modulate the innervation of both sinoatrial (SAN) and atrioventricular (AVN) nodes, irrespective of clinical manifestation of the disease. The loss of responsiveness of both nodes to extracardiac vagus nerve stimulation was the procedural endpoint. Right vagus or bilateral vagus nerve stimulation was used in 86% and 54% of procedures, respectively. Results Enrolled patients had documented cardioinhibitory disorder of SAN (59%), AVN (30%), or both nodes (11%). CNA (duration: 157 ± 31 min; RF time: 15 ± 6 min; radiation dose: 84 ± 135 µGy.m²) resulted in sinus rate acceleration by 28 ± 12 bpm, shortening of AH interval by 15 ± 31 ms, an increase of Wenckebach point by 28 ± 33 bpm, shortening of AVN effective refractory period by 110 ± 115 ms, and sinus node recovery time by 508 ± 666 ms. During a median follow up of 26 (IQR: 12-39) months, CNA was repeated in 9 patients and is scheduled in 3 other (total 8%). Pacemaker was implanted only in 4 (3%) patients after single (n = 2) or repeated CNA (n = 2). Corresponding Kaplan-Meier curves are provided in the Figure. Any-syncope-free survival is comparable to that reported in active arms of historical and recent pacemaker studies. Conclusions CNA is a reasonably effective treatment option for patients with functional cardioinhibitory syncope. CNA can be performed by anatomically-guided ablation at empirical GP sites. Our study corroborates the clinical utility of CNA as a viable alternative to pacemaker implant in selected patients.

Funding Acknowledgements Type of funding sources: None. Background Catheter ablation (CA) is a well-established treatment strategy for the management of drug-refractory ventricular tachycardia (VT) in patients with structural heart disease. Stereotactic body radiotherapy (SBRT) was proposed recently as a treatment option for cases of failed CA. Purpose This study reports overall experience with the SBRT from two Czech centers. Methods Since 2014, we enrolled consecutive patients who underwent at least one prior CA for recurrent scar-related VT and had subsequent VT recurrences due to inaccessible substrate. Single-session SBRT for VT was performed without the use of general anesthesia or sedation. A dose of 25 Gy was delivered. Results The study investigated 33 patients (3 women) with a mean age of 66 ± 9 years. Underlying heart disease was ischemic (58%) and nonischemic (39%) cardiomyopathy; one patient had large cardiac fibroma. The mean left ventricular ejection fraction was 31 ± 8%. Seventy-six percent of patients were on amiodarone. Before SBRT, they underwent a median of 2 (IQR: 1-3; range: 1-5) CA that included epicardial access in 42% of patients. Following SBRT with a planned target volume of 42.6 ± 22.8 ml, the immediate effect was not observed in any patient, VT burden gradually decreased over weeks or months. Seventeen (52%) patients died (2 of them suddenly) during the mean follow up of 29 ± 23 months mainly due to the progression of heart failure (Figure 1). One patient died due to bleeding associated with esophagopericardial fistula that developed 9 months after SBRT. Overall, the number of DC shocks after a single procedure decreased significantly from 0.9 ± 1.9 per month in the period of 6 months before SBRT to 0.1 ± 0.3 per month in the period of 6-12 months after SBRT (P=0.008, Figure 2). However, 14 patients (42%) had to undergo additional CA due to VT recurrences at a mean interval of 13 ± 14 months after SBRT. Three patients underwent repeated SBRT (after 3, 29, and 38 months), which was successful in 2 of them. Conclusions SBRT in patients with refractory VT is feasible but the long-term mortality after the procedure is high and reflects mainly the severity of the underlying disease. The treatment effect of SBRT is delayed and additional CA is often necessary for VT suppression. At present, SBRT should be offered as only a bailout procedure for otherwise intractable VT.

Background There are controversial reports on QT interval response to ganglionic plexi ablation that are selectively targeted during cardioneuroablation (CNA) or occurs as collateral lesion during left atrial ablation procedures. Both shortening or prolongation of the heart-rate corrected QT interval (QTc) with therapeutic or safety implications were described. Purpose In this retrospective study, we investigated longitudinal changes of QTc after CNA. Methods The study included 108 patients (age: 39±12 years, 60% males) who underwent biatrial cardioneuroablation (radiofrequency time: 15.5±6.7 min) for symptomatic functional bradyarrhythmias. Surface ECG examinations were performed on the day before the CNA (N=108), 1 hour after the CNA (N=106), on the 1st post-ablation day (N=50), at the 3-month (N=99), and 1-year (N=63) follow-up visits. Automated measurements of QT interval were employed for the analysis. Four formulas (Bazett, Framingham, Fridericia, and Hodges) were used for the correction of QT interval to instant heart rate. Results QTc significantly prolonged immediately after the CNA with rapid return to baseline values (Figure and Table). This was particularly valid for QT correction by Framingham formula (and similarly for Fridericia and Hodges formulas). The QTc by Bazett formula, which is known to overestimate QT at higher heart rates, returned to baseline more slowly and incompletely. Several mechanisms may contribute to observed QTc dynamics: (1) direct effect of autonomic denervation with recovery phenomenon; (2) QT hysteresis with an extremely long time constant; or (3) artifact due to suboptimum QT correction to a substantial change of heart rate. Conclusions The study suggests that CNA produces acute prolongation of QTc interval with rapid decay and virtual normalization in 3 months. CNA in otherwise healthy subjects is not likely associated with substantial long-term risk of long-QT-associated arrhythmias. In the same way, we cannot confirm earlier observations of clinically significant QTc shortening effect of ganglionated plexi ablation. Funding Acknowledgement Type of funding sources: None. Figure 1Table 1

Background In patients with atrial fibrillation (AF), pulmonary vein isolation (PVI) by radiofrequency (RF) energy is associated with a significant change of cardiac autonomic regulations due to collateral ganglionic plexi ablation. Pulse-field (PF) ablation energy presumably spares neural tissue. Purpose We compared the effect of PVI by PF and RF energy on cardiac autonomic function. Methods A study enrolled 23 patients who underwent PVI in general anaesthesia. In 12 patients, a novel lattice-tip catheter and PF energy were used for ablation while 11 patients were ablated using a conventional irrigated-tip catheter and RF energy. The response of the sinus node (SAN) and atrioventricular node (AVN) to extracardiac high-frequency vagal stimulation (ECVS) was tested before and after PVI (via right internal jugular vein; stimulation frequency of 50 Hz; pulse width of 0.05 ms; output of 1 V/kg ( Results At baseline, physiological massive response to ECVS (sinus arrest and/or AV block) was demonstrated in the majority of patients. After PVI, complete loss of autonomic response of the SAN in 11/11 (100%) and 3/12 (25%) patients (p=0.003), and the AVN in 9/11 (82%) and 3/12 (25%) patients (p=0.01) was observed in RF and PF groups, respectively. The figure shows the maximum duration of the pause in sinus rhythm (maximum P-P interval) and AVN block (maximum R-R interval during atrial pacing) induced by ECVS after PVI. Conclusion Cardiac vagal response is preserved in a considerable proportion of AF patients after PF ablation which is in contrast with a significantly stronger effect of RF energy. This may influence the clinical outcome of AF ablation procedures. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Institute for Clinical and Experimental Medicine, Prague

Background Nonischaemic cardiomyopathy (NICM) represents a heterogenic disorder with a variable arrhythmogenic substrate. Its location is often epicardial and catheter ablation in this location proved to be an effective therapeutic modality in NICM patients with recurrent ventricular tachycardias (VTs). Purpose To determine the impact of the type of genetic mutation on the long-term outcome of endo-epicardial ablation in patients with NICM. Methods We investigated 82 patients (age 47±15 years, 10 women) with NICM who underwent endo-epicardial ablation for frequent VTs. Of them, 59% had a history of failed endocardial ablation. Patients had a left ventricular ejection fraction of 44±14% and all were implanted with cardioverter-defibrillator. One hundred candidate genes were examined using the new generation sequencing technique. Results Mutation in genes coding desmosomal complex (genes: PKP2, DSC, DSP, and DSG) was found in 30% of patients (“desmosomal” group). In 23% of patients, other gene mutations (genes: LMNA/C, MYH7, DES, TTN, RYR2, TPM1, MYPN, FLNC, and SCN5A) were detected (“non-desmosomal” group). In 46% of subjects no pathogenic mutation could be identified (“none” group). During a mean follow up of 34±33 months, patients in the “non-desmosomal” group were at significantly higher risk of VT recurrence and death/heart transplant compared to patients in the “desmosomal” group (Figure 1). Conclusion Potentially pathogenic mutation can be detected in about half of patients with NICM undergoing endo-epicardial VT ablation. Most commonly, mutations can be found in genes coding desmosomal complex and the endo-epicardial ablation is then associated with a satisfactory low VT recurrence rate and excellent survival in the long-term. On the other hand, patients with a mutation in non-desmosomal genes have poor outcomes despite endo-epicardial ablation. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Supported by Ministry of Health of the Czech Republic, grant nr. NV18-02-00237 Figure 1

Background We evaluated the differences in the anatomy of the cavotricuspid isthmus (CTI) by assessing image loops provided by intracardiac echocardiography (ICE) in patients who underwent ablation for atrial flutter and/or atrial fibrillation. Purpose CTI is an essential component of the reentrant circle in isthmus–dependent atrial flutter (CTI-AFL) and a target for catheter ablation. In some patients, CTI anatomy may be responsible for a difficult procedure. The aim of this study is to describe in details the anatomical variants of this structure. Methods We included a group of 138 patients, who underwent cardiac ablation for atrial flutter and/or atrial fibrillation between August 2020 and January 2021. Intracardiac echocardiography was employed during the intervention to evaluate the morphology of CTI. Analysis was focused on size, shape, presence of sub-eustachian pouch (excavation more than 5 mm) or presence of prominent Eustachian ridge (ER, embryologic remnant of the valve of the IVC) and mobility of the structure. Results The length of CTI measured during ventricular systole averaged at 38,4mm (min 22,5mm, max 60mm). The most frequent pattern was a flat CTI without sub-eustachian excavation or with excavation less than 5mm (71 patients; 51.4%). A pouch (excavation more than 5mm) was observed in 41 pts (29.7%), where the deepest pouch reached 10,5mm. Prominent ER was present in 58 pts (42%). The remaining 26 of CTIs (18.8%) were classified in the “unclassifiable” category with deviations from common anatomic variants - substantial convexity, pronounced trabeculation of isthmus or double pouch. We observed 14 CTIs (10.1%), where the structure was partially or in full extent detached from the diaphragm, sliding during cardiac contractions. In addition to the described morphology, Chiari's network was observed in 18 pts (13%). In reference to mobility, 53 pts (38.4%) presented with hypermobile CTI with a difference in size of more than 1/3 between the diastole and systole. Moreover, we looked into differences of CTI related to BMI, left atrial volume index (LAVi) and ejection fraction of the left ventricle. A positive correlation was found between LVEF and mobility of CTI. Hypermobile CTI was present in 42.2% of pts with normal LVEF compared to only 18.9% of pts with reduced EF (EF less than 50%). Similar results were observed in pts with non-dilated LA, where hypermobile CTI was present in 51.9% of pts compared to only 35.1% of pts with dilated LA with LAVi >28 ml/m2 (see table below). Conclusions We observed a substantial differences in the anatomy of the CTI, which could play an important role in catheter ablation of this structure. Besides the prominent ER, significant sub-eustachian pouch and hypermobility appear to be variants predisposing to difficult ablation. Funding Acknowledgement Type of funding sources: None. CTI variants related to EFLV, BMI, LAViCTI detached from the diaphragm

Funding Acknowledgements Type of funding sources: None. Background Radiofrequency catheter ablation of superior paraseptal ganglionic plexus is an important step to eliminate the vagal modulation of sinus node for the treatment of neurally-mediated syncope. The reasonable effect can be achieved by targeting this plexus from the endocardial aspect of both right (RA) and left (LA) atria. Purpose We investigated the efficacy of RA and LA ablation in terms of sinus nodal denervation. Methods The study included 24 patients (age: 42 ± 13 years, 50% males) who underwent cardioneuroablation for recurrent cardioinhibitory syncope in general anesthesia. Right atrial semicircular lesion at the posteroseptal quadrant of superior vena cava ostium was composed of 5-6 equidistantly distributed ablation sites (30 W, 30 s, 20 ml/min). Left atrial lesion of comparable size was placed strictly contralaterally across the interatrial septum in the anterior vestibulum of a right superior pulmonary vein. Patients were randomly (1:1) assigned to RA-to-LA or LA-to-RA ablation. Sinus rate and the response to extracardiac right vagal nerve high-frequency stimulation (50 Hz, 0.05 ms, 1 V/kg [ Results Study protocol ablations overall resulted in sinus acceleration (81 ± 13 vs. 59 ± 12 bpm, P Conclusions Neither RA nor LA approach is preferable for targeting the superior paraseptal ganglionic plexus. Both ablation clusters convey complementary and, in part, mutually independent effects. Biatrial cardioneuroablation seems essential for efficacious sinus nodal denervation. Abstract Figure.

Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): IKEM Background Pulmonary vein isolation (PVI) is an established treatment modality for patients with atrial fibrillation (AF). PVI performed by radiofrequency (RF) energy results in parasympathetic denervation of the heart by collateral ganglionic plexi ablation. Pulse field (PF) is a novel nonthermal energy source for PVI that selectively ablates atrial myocardium while preserving cardiac autonomic nerves, which may affect the outcome after PVI. Purpose The study compared the effect of PVI between RF and PF ablation on cardiac autonomic function and a short-term AF recurrence rate. The resting heart rate (HR) was evaluated as a simple index of sinus nodal parasympathetic innervation. Methods We investigated 45 patients (aged 64 ± 7 years, 4 women) who underwent PVI by novel three-dimensional electroanatomical mapping/ablation system (lattice electrode ablation system). PVI was performed by either high-energy RF (n = 21) or PF (n = 24) energy using the identical ablation catheter. Resting HR assessed by standard ECG was recorded the day before the procedure and at the 3-month visit. Arrhythmia recurrences were analysed by 24-Holter at the 3-month visit. Results All PVs were acutely isolated in all patients. The HR data are shown in the Table. The baseline HR did not differ between both groups. A significant increase in HR was observed only in the RF ablation subgroup. The between-group difference remained significant even after adjustment for age, gender, and baseline HR. There was no difference in arrhythmia recurrences at the 3-month visit between study groups. Conclusions Parasympathetic denervation effects on HR after the PF ablation are virtually absent. Comparable AF recurrence rate at 3-month visit after RF and PF ablation suggests that preservation of autonomic innervation has no impact on AF recurrence during short-term follow-up. Table RF PVI (n = 21) PF PVI (n = 24) P Baseline HR (bpm) 60.0 ± 7.1 63.8 ± 9.4 n.s. HR change - 3-month visit (bpm) 14.4 ± 6.9 0.3 ± 8.6 P

Background Intracardiac echocardiography (ICE) is routinely used for guiding cardiac ablation procedures. However, the potential of ICE for measurement of renal artery (RA) blood flow (RABF) has not been fully exploited. Aims To investigate the feasibility of ICE for the assessment of RABF and to evaluate its reproducibility in humans. Methods The study included 15 patients undergoing catheter ablation of atrial fibrillation guided by ICE (age: 61±14 years, body mass index: 30±5 kg/m2, left ventricular ejection fraction: 57±6%, serum creatinine: 80±29 μmol/l). During sinus rhythm, the ICE probe was withdrawn from the right atrium to the inferior vena cava until the right RA with its ostium became visible. Blood flow in the RA was visualized by colour flow mapping. The RA diameter was measured at 10 mm from the ostium. RABF at this location was measured by pulse wave Doppler. Velocity-time integral (VTI) was delineated manually and averaged over five consecutive beats. RABF was calculated by the formula: RABF = (RA radius)2 x π x VTI x heart rate. To assess reproducibility of the method, the ICE probe was repositioned in the right atrium and the measurement of RABF was repeated by the same operator. Results The right RA was visualized in all 15 patients. No procedure-related clinical complications occurred. The mean RA radius was 2.5±0.4 mm. In all cases, the angle of incidence during the measurement of VTI was Conclusions This study demonstrated that measurement of RABF by ICE is feasible and has reasonable intra-observer reproducibility. The method can be used to study RABF during various interventions and hemodynamic conditions. Figure 1. Intra-individual reproducibility Funding Acknowledgement Type of funding source: None

Background Radiofrequency catheter ablation of inferior atrial ganglionic plexi frequently results in vagal denervation of the atrioventricular (AV) node. The effective sites are, however, considerably variable. Purpose We prospectively sought the left atrial (LA) ablation site with the maximum effect on AV nodal modulation. Methods The study included 16 patients (age: 46±14 years, 56% males) who underwent cardioneuroablation for recurrent reflex cardioinhibitory syncope in general anesthesia. After targeting the superior paraseptal ganglionic plexi and achieving the denervation of the sinus node, study ablations were performed at the bottom of the LA to accomplish the AV nodal denervation (Figure). Five equidistantly distributed ablation lesions (30W / 30s / 20ml/min) were created on the virtual line connecting inferior ostium of right inferior pulmonary vein (RIPV) and inferior mitral annulus (MA). Lesions were centered symmetrically relative to the posterior mid-left-atrial line. They were numbered in ascending order from #1 (more septal, closer to the RIPV) to #5 (more lateral, closer to the MA). Patients were randomly (1:1) assigned to mutually opposite direction of ablation (from site #1 to #5 or from site #5 to #1). The response of heart rhythm to extracardiac vagal nerve high-frequency stimulation (50Hz/0.05ms/1V/kg [ Results Study protocol ablations overall resulted in elimination or attenuation of inducible AV block (maximum R-R interval: 2.9±2.8 vs. 5.2±2.4s, P Conclusion Ablation of perimitral region of the inferior LA conveyed the maximum effect in terms of AV nodal denervation. Funding Acknowledgement Type of funding source: None

Background Catheter ablation is an established treatment modality for atrial fibrillation (AF). The risk of procedural complications is not negligible. Some studies suggested that female patients have a higher risk of complications. Purpose To identify gender-specific predictors of major complications (MCs) in patients undergoing catheter ablation for AF in a tertiary ablation centre. Methods A total of 4733 catheter ablations for AF (65% paroxysmal, 26% repeated procedures) were performed at our centre between January 2006 and August 2018. Patients (71% males) aged 60±10 years and had body mass index of 29±4 kg/m2 at the time of the procedure. Radiofrequency point-by-point ablation was employed in 96.3% procedures with the use of 3D navigation systems and facilitated by intracardiac echocardiography. Pulmonary vein isolation was mandatory; cavotricuspid isthmus and left atrial substrate ablation were performed in 22% and 38% procedures, respectively. MCs were defined as those that resulted in permanent injury, required intervention or prolonged hospitalization. Variables were assessed by uni- and multivariate analysis, two-sided α Results A total of 160 (3.4%) MCs were detected - 60 (4.4%) in females and 100 (2.9%) in males (P=0.012). Both lower body height and the presence of bundle branch block (BBB) were associated with MCs only in females; for left bundle branch block (LBBB), the effect size was higher. On the contrary, higher left ventricular end-diastolic diameter (LVEDd) and persistent AF were associated with MCs in males (Table). Conclusion Females have a higher risk of MCs during catheter ablation for AF. Body height, AF type, BBB, and LVEDd may belong among gender-specific risk factors for MCs in AF ablation procedures. Whether BBB and LVEDd represent true risk factors warrants a validation in further studies. Funding Acknowledgement Type of funding source: None

Background Ablation of superior paraseptal ganglionic plexi is invariantly associated with the acceleration of sinus rhythm. This is considered a favourable sign during cardioneuroablation for the treatment of recurrent neurally-mediated cardioinhibitory syncope or symptomatic sinus bradycardia. Purpose In this retrospective study, we investigated whether the magnitude of sinus rhythm acceleration corresponds with directly assessed sinus nodal parasympathetic denervation. Methods The study included 48 patients (age: 39 ± 13 years, 58% males) who underwent cardioneuroablation in general anaesthesia. The procedural endpoint was non-responsiveness (i.e. loss of original cardioinhibitory response) of the sinus node to extracardiac high-frequency stimulation of the vagal nerve. The magnitude of sinus rhythm acceleration was compared between patients who reached or did not reach this endpoint. Results All patients had positive atropine test (baseline heart rate: 65 ± 14 bpm; post-atropine: 109 ± 22 bpm). Complete sinus nodal denervation as assessed by vagal nerve stimulation was achieved in 44/48 (92%) patients. Intraprocedurally, heart rate accelerated from 54 ± 11 to 85 ± 14 bpm (difference: 31 ± 10; median 29; interquartile range: 24–40; total range: 13–61 bpm). This change did not correlate with age and was not related to pre-procedural post-atropine sinus rhythm acceleration. There was no difference in heart rate acceleration between the patient with and without sinus nodal denervation (Figure). Conclusions Sinus rhythm acceleration is not reliable endpoint for cardioneuroablation. Guidance by extracardiac vagal nerve stimulation may help to tailor the procedures to increase the clinical success rate and, at the same time, to avoid patient overtreatment. Abstract Figure.

Background Cardiac resynchronization therapy (CRT) improves symptoms of heart failure (HF), morbidity and mortality in selected population. The aim of the study was to investigate the impact of cardiac magnetic resonance (CMR)-guided left ventricular (LV) lead placement on clinical outcomes and LV reverse remodelling in CRT recipients. Methods Patients with CRT indication were randomized for CMR-guided (CMR group) or electrophysiologically guided (EP group) LV lead placement between 2011 and 2014. The target site in the CMR group was defined as the most delayed, scar-free, in the EP group as the site with the longest interval between the QRS onset and local electrogram. The primary endpoint was a combination of cardiovascular death or HF hospitalization. Secondary endpoints were New York Heart Association (NYHA) Class improvement ≥1, LV endsystolic diameter reduction >10%, B-type natriuretic peptide reduction by ≥30%. Results A total of 99 patients (47 in the CMR and 52 in the EP group) were enrolled. During a median follow-up of 47 months, primary composite endpoint occurred in 5 patients in the CMR group and 14 patients in the EP group (HR = 0.46; 95% CI: 0.16–1.32). Patients with left bundle branch block and NYHA Class >2 had better clinical outcome in the CMR group (HR = 0.09; 95% CI: 0.01–0.75). Conclusions The use of CMR did not result in significant reduction of combined endpoint of cardiovascular death or HF hospitalization in the total study population. Significant clinical benefit from CMR-guided procedure was observed in a subgroup of optimum CRT candidates with advanced HF.

Left atrial (LA) volume (LAV) is used for the selection of patients with atrial fibrillation (AF) to rhythm control strategies. Calculation of LAV from the LA diameters and areas by two-dimensional (2D) echocardiography may result in significant error. Accuracy of atrial volume assessment has never been studied in patients with long-standing persistent AF (LSPAF) and significant atrial remodeling. This study investigated correlation and agreement between 2D echocardiographic (Simpson method) and electroanatomic (CARTO, Biosense Webster) left and right atrial (RA) volumes (LAV(ECHO) vs. LAV(CARTO) and RAV(ECHO) vs. RAV(CARTO)) in patients undergoing catheter ablation for LSPAF. The study enrolled 173 consecutive subjects (females: 21 %, age: 59+/-9 years). There was only modest correlation between LAV(ECHO) (92+/-31 ml) and LAV(CARTO) (178+/-37 ml) (R=0.57), and RAV(ECHO) (71+/-29 ml) and RAV(CARTO) (173+/-34 ml) (R=0.42), respectively. LAV(ECHO) and RAV(ECHO) underestimated LAV(CARTO) and RAV(CARTO) with the absolute bias (+/-1.96 standard deviation) of -85 (-148; -22) ml and -102 (-169; -35) ml, respectively, and with the relative bias of -48 (-75; -21) % and -59 (-88; -30) %, respectively (all P

INTRODUCTION Heart rate slowing agents are frequently prescribed to manage heart transplant (HTx) patients with the assumption that higher heart rate is a risk factor in cardiovascular disease. PATIENTS AND METHODS This prospective two-center study investigated early progression of cardiac allograft vasculopathy (CAV) in 116 HTx patients. Examinations by coronary optical coherence tomography and 24-hour ambulatory ECG monitoring were performed both at baseline (1 month after HTx) and during follow-up (12 months after HTx). RESULTS During the first post-HTx year, we observed a significant reduction in the mean coronary luminal area from 9.0 ± 2.5 to 8.0 ± 2.4 mm2 (P

Background Cardioneuroablation by targeting of atrial ganglionic plexi (GP) has been proposed as a new therapeutic option in selected patients with reflex syncope. Contribution of individual GPs to cardiac autonomic regulations is not fully established. Purpose Because consistent vagal responses have been observed during left superior pulmonary vein isolation in patients undergoing ablation for atrial fibrillation, we investigated whether standalone ablation of the superior left GP modifies the vagal input into the sinoatrial (SAN) and atrioventricular node (AVN). Methods Study hypothesis was investigated in otherwise healthy patients undergoing cardioneuroablation for symptomatic bradyarrhythmias. All had preprocedural atropine test suggesting functional disorder. Anatomically-navigated (CARTO-3) radiofrequency (RF) ablation (25–30 W/30 s/20 ml/min) at empirical GP sites was performed in general anaesthesia. Extracardiac high-frequency vagal nerve stimulation (25–60 V/30–50 Hz/0.05–0.1 ms) via right jugular vein was performed at baseline, after initial superior left GP ablation, and after the ablation of remaining septal and inferior GPs. High-frequency vagal nerve stimulation was always done in both sinus rhythm and atrial pacing. The elimination of all stimulation-induced vagal responses was the endpoint of the procedure. Results A study included 8 patients (34±8 years; 5 males). Six of them had recurrent syncope with cardioinhibitory response at the SAN (n=4), AVN (n=1) or both nodes (n=1); and 2 patients had symptomatic sinus bradycardia. At baseline, high-frequency vagal nerve stimulation induced long episodes of sinus arrest and advanced AV block in all patients. Cluster ablation at the superior left GP (RF time: 192±28 s) did not change the sinus rate (59±14 vs 60±15, NS), PQ interval (174±37 vs 173±37, NS), and did not induce any tangible change in SAN/AVN response to high-frequency vagal nerve stimulation. Subsequently, anterior right GP was targeted from the aspect of right atrium (n=7), from the anterior antrum of right pulmonary veins (n=6), and inferior GPs were targeted from the aspect of left atrium (n=7). This lesion set finally resulted in complete non-responsiveness of SAN and AVN to high-frequency vagal nerve stimulation in all patients. Ablation procedure overall (duration: 172±15 min; RF time: 988±306 s; radiation dose: 70±34 μGy·m2) led to sinus rate acceleration by a median of 29 (IQR: 18–38) bpm, increase of Wenckebach point by 21 (IQR: 9–28) bpm, and shortening of AVN effective refractory period by 40 (IQR: 15–73) ms. Conclusions Cardioneuroablation guided by extracardiac high-frequency vagal nerve stimulation can achieve complete denervation of SAN and AVN by ablation of postero(para)septal and inferior GPs only. Ablation of the superior left GP appears unnecessary and can be eliminated from the lesion set design.

IntroductionThe aim of this study was to investigate the predictors of long-term clinical outcome of heart failure (HF) patients who survived first year after initiation of cardiac resynchronization therapy (CRT).MethodsThis was a single-center observational cohort study of CRT patients implanted because of symptomatic HF with reduced ejection fraction between 2005 and 2013. Left ventricle (LV) diameters and ejection fraction, New York Heart Association (NYHA) class, and level of N-terminal fragment of pro-brain natriuretic peptide (NT-proBNP) were assessed at baseline and 12 months after CRT implantation. Their predictive power for long-term HF hospitalization and mortality, and cardiac and all-cause mortality was investigated.ResultsA total of 315 patients with left bundle branch block or intraventricular conduction delay who survived >1 year after CRT implantation were analyzed in the current study. During a follow-up period of 4.8±2.1 years from CRT implantation, 35.2% patients died from cardiac (19.3%) or non-cardiac (15.9%) causes. Post-CRT LV ejection fraction and LV end-systolic diameter (either 12-month value or the change from baseline) were equally predictive for clinical events. For NT-proBNP, however, the 12-month level was a stronger predictor than the change from baseline. Both reverse LV remodeling and 12-month level of NT-proBNP were independent and comparable predictors of CRT-related clinical outcome, while NT-proBNP response had the strongest association with all-cause mortality. When post-CRT relative change of LV end-systolic diameter and 12-month level of NT-proBNP (dichotomized at -12.3% and 1230 ng/L, respectively) were combined, subgroups of very-high and very-low risk patients were identified.ConclusionThe level of NT-proBNP and reverse LV remodeling at one year after CRT are independent and complementary predictors of future clinical events. Their combination may help to improve the risk stratification of CRT patients.

In this article an international group of CRT specialists presents a comprehensive classification system for present and future schemes for optimising CRT. This system is neutral to the measurement technology used, but focuses on little-discussed quantitative physiological requirements. We then present a rational roadmap for reliable cost-effective development and evaluation of schemes. A widely recommended approach for AV optimisation is to visually select the ideal pattern of transmitral Doppler flow. Alternatively, one could measure a variable (such as Doppler velocity time integral) and "pick the highest". More complex would be to make measurements across a range of settings and "fit a curve". In this report we provide clinicians with a critical approach to address any recommendations presented to them, as they may be many, indistinct and conflicting. We present a neutral scientific analysis of each scheme, and equip the reader with simple tools for critical evaluation. Optimisation protocols should deliver: (a) singularity, with only one region of optimality rather than several; (b) blinded test-retest reproducibility; (c) plausibility; (d) concordance between independent methods; and (e) transparency, with all steps open to scrutiny. This simple information is still not available for many optimisation schemes. Clinicians developing the habit of asking about each property in turn will find it easier to win now down the broad range of protocols currently promoted. Expectation of a sophisticated enquiry from the clinical community will encourage optimisation protocol-designers to focus on testing early (and cheaply) the basic properties that are vital for any chance of long term efficacy.

Atrioventricular (AV) conduction turbulence, biphasic dromotropic response of AV node to single ventricular premature contraction (VPC), consists of early shortening and later prolongation of AV conduction intervals due to the direct electrophysiological mechanisms and perturbation in autonomic modulation. We investigated the acute effect of radiofrequency catheter ablation of slow pathway on AV turbulence. The electrophysiological study was performed in 18 patients (7 men, mean age 49 ± 15 years) undergoing catheter ablation for AV nodal reentrant tachycardia. The stimulation protocol consisting of series of isolated VPC (coupling interval of 273 ± 23 ms) delivered from right ventricle apex during constant atrial pacing at 100 bpm was performed immediately prior to and 8 ± 4 min after successful slow-pathway ablation. Averaged post-VPCs profiles of AV conduction intervals were analyzed by purpose-written software. The descriptors of AV turbulence, turbulence onset (TOAV), turbulence slope (TSAV), and AV recovery (R AV) were assessed. Slow-pathway ablation suppressed the AV nodal responsiveness to VPC as evidenced by significant reduction of AV turbulence indices: TOAV: −6.4 ± 7.5 % vs. −4.3 ± 6.1 % (p

Aims Clinical benefit from ablation for long-standing persistent atrial fibrillation has remained unknown. We hypothesized that successful ablation of long-standing persistent atrial fibrillation would improve haemodynamics, functional status, and quality of life. Methods and results A total of 160 patients (aged 59 +/- 9 years, 23% females) undergoing ablation of long-standing (median of 28 months) persistent atrial were enrolled in this prospective study. Morphological and functional echocardiographic parameters, N-terminal prohormone of brain natriuretic peptide (NT-proBNP), maximum oxygen consumption during exercise test (VO2 max), and quality of life were assessed at baseline and 1 year after the ablation. At the 1-year follow-up visit, 81% patients were examined in sinus rhythm (after repeat ablation in 38% patients). Left atrial appendage outflow velocity increased from 44 +/- 20 to 58 +/- 23 cm/s, left ventricular ejection fraction from 54 +/- 9 to 59 +/- 5%, and VO2 max from 20.4 +/- 6.4 to 23.7 +/- 8.1 mL/kg/min; NT-proBNP decreased from median 897 (interquartile range 603 1424) to 230 (interquartile range 120 420) pg/mL (all P < 0.0001). These beneficial effects of ablation were predominantly associated with the presence of sinus rhythm. Quality of life (range 0-100) increased significantly (EQ-5D index: from 68.8 +/- 12.5 to 75.4 +/- 14.4; EQ-VAS score: from 62.8 +/- 13.2 to 70.6 +/- 13.8; both P < 0.0001). Conclusion Ablation of long-standing persistent atrial fibrillation was associated with significant recovery of haemodynamics and exercise capacity that projected onto the long-term improvement in quality of life.

Ventricular outpouchings include acquired abnormalities (aneurysms and pseudoaneurysms) and congenital ventricular diverticula (CVD). CVD represent rare cardiac pathologies. Although CVD is often associated with other cardiac and extracardiac congenital anomalies, it can also be incidentally observed in otherwise healthy subjects. CVD may lead to significant morbidity and even have lethal consequences. We describe a case of arrhythmogenic left ventricle (LV) apical CVD revealed by cardiac magnetic resonance imaging (CMRI) after being initially overlooked by echocardiography. The paper includes the review of the literature also. This clinical case highlights the possible association of this pathology with recurrent ventricular tachycardia and stroke, and illustrates the importance of multimodal imaging approach in differential diagnosis.