Abstract Funding Acknowledgements Type of funding sources: None. Background Sleep-disordered breathing is highly prevalent in heart failure (HF) and it has been suggested as a risk factor for malignant ventricular arrhythmias. The Respiratory Disturbance Index (RDI) algorithm computed by select implantable cardioverter defibrillators (ICDs) can identify severe sleep apnea (SA). Purpose In the present analysis we evaluated the association between ICD-detected SA and the incidence of appropriate ICD therapy in patients with HF. Methods We enrolled 411 HF patients (age 69±10years, 77% male, ejection fraction 32±8%), implanted with an ICD endowed with an algorithm (ApneaScan, Boston Scientific) that calculates the RDI each night. In this analysis the weekly mean RDI value was considered. The endpoint was the first appropriate ICD shock. The median follow-up was 26 months [25th–75th percentile: 16-35]. Results During follow-up, one or more ICD shocks were documented in 58 (14%) patients. Patients with shocks were younger (66±13years versus 70±10years, p=0.038), and more frequently implanted for secondary prevention (21% versus 10%, p=0.026). The maximum RDI value calculated during the entire follow-up period did not differ between patients with and without shocks (55±15episodes/h versus 54±14episodes/h, p=0.539). However, the ICD-detected RDI showed a considerable variability during follow-up. The overall median of the weekly RDI was 33episodes/h [25th–75th percentile: 24-45]. Using a time-dependent Cox regression model, the continuously measured weekly mean RDI≥45episodes/h was independently associated with shock occurrence (HR:4.63, 95%CI:2.54-8.43, p<0.001), after correction for baseline confounders (age, secondary prevention). Conclusions In HF patients, patients were more likely to receive appropriate ICD shocks during periods of time when they exhibited more sleep-disordered breathing.

Abstract Funding Acknowledgements Type of funding sources: None. Background The recent introduction of Omnipolar Technology (OT) has the potential to improve ventricular substrate characterization. In fact, the amplitude of omnipolar electrograms is less dependent of the propagation direction of the recorded wavefront than that of bipolar electrograms, potentially increasing the sensitivity for the detection of viable myocardium by electroanatomical voltage mapping (EVM). Purpose To assess the presence and extension of dense scar regions and low-voltage areas in omnipolar voltage (OV) maps of the left ventricle (LV) as compared to standard bipolar endocardial maps and cardiac magnetic resonance (CMR)-derived pixel signal intensity (PSI) maps, among patients undergoing EVM-guided endomyocardial biopsy (EMB). Methods The study included 10 patients undergoing LV substrate mapping and EVM-guided EMB at our institution using the Advisor HD Grid mapping catheter. Before the procedure, contrast enhanced-CMR was obtained for each patient and PSI maps were derived from late gadolinium enhancement sequences with the ADAS-VT software. Scar core and border zone areas were measured in PSI endocardial (10-40% of wall thickness) maps and compared to dense scar regions (<0.5 mV) and low-voltage areas (0.5-1.5 mV) measured by standard bipolar endocardial mapping and OV endocardial mapping, respectively. Continuous variables were checked for normality with the Shapiro-Wilk test, and are reported as mean±standard deviation or median [1st-3rd quartile], as appropriate. Statistical comparisons among the three types of mapping (PSI mapping, standard bipolar, and OV) were performed with Friedman test with post-hoc sign test, as appropriate. P values<0.05 were considered statistically significant, and all analyses were performed with the software RStudio. Results The indication for EVM-guided EMB was a clinical suspicion of arrhythmogenic or inflammatory cardiomyopathy in all cases. Dense scar regions and low voltage areas detected by OV (dense scar: 2.2 [1.2-6.9] cm2; low voltage areas: 8±3.8 cm2) and standard bipolar mapping (dense scar: 3.4 [2.3-9.6] cm2; low voltage areas: 8.4±4 cm2) were similar to scar core and border zone areas shown by PSI maps (scar core: 1.6[0.6-2.9] cm2; border zone: 3.9[3.7-7.6] cm2; all p=NS). However, dense scar regions were less widespread with OV mapping that with standard bipolar mapping (Friedman test p=0.07; adjusted p=0.006, Figure). The diagnostic yield of EMB measured 80%, whereas mean procedural and fluoroscopy times were 136±30 min and 11±4 min, respectively. Conclusion OV mapping allowed a refinement of endocardial substrate maps of the LV as compared to standard bipolar mapping, by reducing the dependency of electrogram amplitude on the direction of propagation, thus allowing the detection of viable myocardium even in bipolar scar regions. Therefore, OV mapping may soon become a preferred approach for EVM-guided EMB.

Abstract Funding Acknowledgements Type of funding sources: None. Introduction To facilitate atrial fibrillation (AF) ablation procedures there is a variety of approaches for pre-procedural imaging of pulmonary veins (PV) and left atrium (LA), including CT angiography and cardiac MRI. Intra-procedural three-dimensional rotational angiography (3DRA) is the least employed method and it can be advantageous regarding efficiency and procedural logistics. Data supporting different practices is still evolving and there is an open question whether LA imaging could improve safety and outcomes of CB ablation. Purpose The aim of this study is to evaluate possible benefits of 3DRA for procedural success, safety and long-term outcomes of CB ablation. Methods We designed a single-centre unblinded randomised clinical trial and recruited 101 patients (65.3% male, 59.3±11.5 years) with paroxysmal (92%) and early-persistent AF. Patients were randomized to no imaging or 3DRA which was performed intra-procedurally after trans-septal puncture. Angiographic images were segmented and overlaid to the fluoroscopy screen to guide the ablation procedure. All patients are followed for 1 year and data concerning procedural characteristics, safety outcomes and AF recurrence are being collected. Results Of all the patients recruited, 48 (47%) underwent 3DRA. In patients who received no imaging (non-3DRA group) one PV couldn’t be isolated while in 3DRA group isolation of one PV could not be achieved in 3 patients (OR 3.47, 95% CI 0.35-34.51). The occurrence of left common PV, an anatomical variation that could have potential to influence results, was similar in both groups (25,4% in non-3DRA and 25.0% in 3DRA group). Procedure time was significantly longer when 3DRA was performed (87.4±27.7 min compared to 69.9±23.0 in non-3DRA group, p<0.001). Total radiation dose (148.2±177.7 vs 387.7±203.8 mGy, p<0.001) and contrast administration (42.5±27.1 vs 133.8±26.8 ml, p<0.001) were significantly lower in the control group. Only minor complications were reported in both groups. Three patients developed large haematoma (2 in 3DRA group vs 1 in control group). In each group there was one incident of transient phrenic nerve palsy. Conclusion 3DRA is a safe and efficient intra-procedural imaging method to guide CB ablation for AF. However, it significantly increases procedure duration, total radiation dose and contrast expenditure. In our trial it did not have any impact on the acute success rate of PV isolation. One-year follow up data is still being collected and will subsequently be presented.

Abstract Funding Acknowledgements Type of funding sources: None. Background Recently, a novel technology able to measure local tissue impedance (LI) and contact force (CF) aimed at validating ablation endpoints has become available for clinical use. Purpose This analysis explores the relationship between LI parameters, substrate characteristics and AF type during ablation in AF patients. Methods A novel ablation catheter with dedicated algorithm was used to measure LI at the distal electrode. Each ablation point was characterized in terms of RF delivery time, baseline LI and LI drop during ablation according to different voltages (above or below 0.5 mV) of the atrial substrate. Ablation endpoint was PVI as assessed by entrance and exit block with local capture. Data are reported as mean±SD. Results A total of 2032 RFC deliveries from 34 consecutive patients were analyzed (71% paroxysmal AF, 29% persistent AF). All PVs were successfully isolated with an overall procedure time of 128±33min (fluoroscopy time=15.6±9min, RF delivery time=9.6±4s, CF=11.1±7g). The baseline LI was 155±17Ω prior to ablation and 136±14Ω after ablation (p<0.0001, absolute LI drop of 21.0±8Ω) with a LI drop rate equal to 2.8±2Ω/s. Ablation spots were more frequently deployed in high-voltage areas (>0.5mv, n=1240, 61%). Baseline LI and LI drops were both higher when underlying atrial voltages were >0.5mV than when <0.5mV (156±18Ω vs 153.6±16Ω for starting LI, p=0.0032; 22.2±8Ω vs 19.1±8Ω for LI drop, p<0.0001, respectively). No differences were found in terms of both CF and LI after ablation between >0.5mV and <0.5mV (11.0±7g vs 11.2±7g for CF, p=0.3435; 136.4±13Ω vs 135.3±15Ω for ablated tissue LI, p=0.1521, respectively). Low-voltage areas were more frequently detected at ablated spots in persistent AF cases (n=288, 51.9%) than in paroxysmal AF cases (n=504, 35.1%, p<0.0001), however, no differences were found in terms of both baseline LI and LI drop between persistent and paroxysmal AF cases (156.3±17Ω vs 154.6±17Ω for starting LI, p=0.135; 20.7±8Ω vs 21.1±9Ω for LI drop, p=0.1722, respectively). Conclusions LI measurements well distinguished contact with high-voltage areas from low-voltage areas and were able to detect significant differences in LI drop during ablation according to the voltage level.

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Vinnova - The Swedish Agency for Innovation Systems. Region Stockholm Innovation Fund. Introduction Devices for long-term and ambulatory recording of heart rhythm have limited availability within health care systems worldwide, potentially leading to missed diagnoses and limitations in peri-procedural heart rhythm management. As smartphones are becoming ubiquitous the availability of heart rhythm diagnostics and management of atrial fibrillation (AF) using smartphone photoplethysmography (PPG) compared to electrocardiography (ECG) is increasing. Previous validation studies of smartphone-PPG applications have all been performed under supervision in healthcare settings. In addition, no previous study has validated smartphone-PPG compared to simultaneous ECG recordings, with manual heart rhythm interpretation of the PPG recordings nor have they included patients with atrial flutter (AFL). Purpose The aim of this study was to validate a novel smartphone-PPG method for heart rhythm diagnostics in patients with AF and/or AFL when in use unsupervised in an ambulatory setting. Methods Unselected patients undergoing direct current cardioversion at a University Hospital for treatment of AF or AFL were asked to perform one-minute heart rhythm recordings post-treatment at least twice daily for 30 days in their home environment. All included were provided with an unmodified iPhone 7 smartphone running the CORAI Heart Monitor PPG application simultaneously with a single-lead ECG recording (KardiaMobile). PPG and ECG recordings were interpreted independently by two readers. Results In total 280 patients, with median age of 69.0 years (31% women) were included from November 2018 to July 2020 and registered 18 005 simultaneous PPG and ECG recordings. Of the PPG recordings 96.9% had sufficient quality for diagnosis compared to 95.1% of the ECG recordings (p < 0.001). Precardioversion ECG recordings were interpreted as AF in 82.1%, AFL in 14.3% and as having insufficient quality for diagnosis in 3.6% of the patients. After removal of recordings with insufficient quality 69.7% of ECG recordings were interpreted as sinus rhythm, 28.2% as AF and 2.1 % as AFL. Manual interpretation of the PPG recordings diagnosed AF/AFL (sensitivity) in 97.7% and sinus rhythm (specificity) in 99.4% of the recordings compared to manually interpreted ECG recordings, with an overall accuracy of 98.9%. Results excluding recordings interpreted as AFL on ECG or PPG diagnosed AF (sensitivity) in 99.0% and sinus rhythm (specificity) in 99.7% of the recordings, with an overall accuracy of 99.5%. Conclusion A novel smartphone-PPG method can be used by patients unsupervised in their home environment for accurate heart rhythm diagnostics of AF and AFL with high sensitivity and specificity.

Abstract Funding Acknowledgements Type of funding sources: None. Elderly patients may be at great risk of complications and present a higher incidence of comorbidities which make challenging PM implant procedure. The use of leadless pacing systems has imposed itself to overcome peri- and post-procedural complications related to the presence of transvenous leads and the post-operative recovery, being a favorable option in elderly patients. The study aimed to investigate feasibility and long-term outcomes of M-TPS implant in a specific patient population, like the elderly, which represent a challenge for conventional cardiac pacing. Methods Between May 2014 and November 2021, 155 patients (120 males, mean age 78±9 y) underwent M-TPS implantation in our Center, targeting a non-apical site of delivery when feasible. A subgroup of 69 patients (52 males, 75.36%) were older than 80 years. All patients fulfilled standard criteria for PM implantation with specific indication to receive VVI pacing. Study population was divided into two groups according to age (group 1 < 79 years vs group 2≥80 years). The outcome evaluation included electrical performance (capture threshold, pacing impedance, R wave amplitude) before hospital discharge and then followed at 1, 6, and 12 months and then annually. Major complications were defined as life-threatening events, required surgical intervention or any event causing significant hemodynamic instability or resulting in death. Results In 69/155 cases (52 males, 75.36%) M-TPS was implanted in patients older than 80 years. There were no statistically significant differences between groups for demographics characteristics, except for age. The implant procedure was successful in all cases and no device-related events were registered during follow-up. In particular, no device infection and/or malfunction were reported. Patients were followed-up for an average of 24 months (median 18 months). No differences were observed between groups in procedure duration, single device delivery (group 1 vs group 2: 62.79% vs 65.22%, p=0.75), fluoroscopy time (group 1 vs group 2: 11.46 ±6.12 vs 11.37 ± 8.37 minutes, p=0.23), electrical performance at implant (group 1 vs group 2: pacing threshold 0.56 ± 0.37 V/0.24 ms vs 0.58 ± 0.31 V/0.24 ms, p=0.55; impedance 737.86 ± 173.50 Ohm vs 759.56 ± 255.35 Ohm, p=0.87; R wave amplitude 10.5 ± 5.18 mV vs 9.19 ± 4.45 mV, p=0.14) and at 18 [VB2] month F-U (group 1 vs group 2: pacing threshold 0.64 ± 0.55 V/0.24 ms vs 0.51 ± 0.1 V/0.24 ms, p=0.85; impedance 535.34 ± 102.53 Ohm vs 577.34 ± 69 Ohm, p=0.40; R wave amplitude 12.56 ± 4.56 mV vs 12.00 ± 5.8 mV, p=0.77[VB3] ). Conclusions The demand for cardiac pacing is strongly related to ageing, driving the clinical practice to look for the best solution for a considered fragile patient population. MTP-S implant is an effective and safe procedure in elderly patients, with similar electrical performance and outcome compared with younger patients at long-term follow.

Abstract Funding Acknowledgements Type of funding sources: None. The reduction of the risk of stroke in patients with AF is achieved with the help of continuous administration of oral anticoagulants (OAC). The presence of cognitive impairment in a patient may be a significant risk factor for low adherence to antithrombotic therapy, therefore, the medico-social significance of impaired cognitive functions in patients with AF is high. At the same time, it is still unclear which neurophysiological mechanisms and areas of the brain are responsible for the development of cognitive disorders in this pathology. Thus, further studies are needed to assess the state of higher cortical functions in patients with AF. Materials and methods The study included 50 patients with nonvalvular AF and a high risk of hemorrhagic and ischemic events, with a risk of thromboembolic complications on the CHA2DS2-VASc scale of at least 2 points and a risk of bleeding on the HAS-BLED scale of at least 3 points. The control group consisted of 17 relatively healthy individuals. Research results The analysis of indicators of extended neuropsychological testing made it possible to establish that, compared with healthy individuals of the same age, patients with AF perform worse on tests of neurodynamics, attention and short-term memory, Table. Patients with AF have a lower rate of complex sensorimotor reactions, a greater number of errors, especially in tests with biofeedback (brain performance test). Also, patients with AF have worse performance indicators and higher focused attention depletion (characterized by the number of characters processed in the 1st and 4th minutes of the proofreading test, respectively). As for the indicators of short-term memory, healthy subjects were superior to patients with AF in memorizing meaningless syllables and words, but not numbers. The power indicators of the theta EEG rhythms at rest with eyes closed were taken. The factors were identified - GROUP (2 levels: patients with AF; healthy individuals), AREA (5 levels: (frontal, central, temporal, parietal, occipital) and LATERALITY (2 levels: left, right hemisphere). In patients with cardiac arrhythmias, the increase in the power of the theta-2 rhythm biopotentials in the direction from the anterior to the posterior cortex is significantly pronounced (p = 0.000001), while in healthy individuals the gradient curve is flatter (p = 0.009). Conclusions It was found that about half of the examined AF patients have syndrome mild cognitive impairment (MCI). The most significant cognitive decline in these patients compared with relatively healthy individuals was noted for the speed of sensorimotor response, performance control indicators, and short-term memory, while decreased cognitive test scores were associated with a greater representation of slow waves in the resting EEG, mainly in the posterior regions of the cerebral cortex.

Abstract Funding Acknowledgements Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Unrestricted educational grants Background Increasing evidence supports a link between myocardial fibrosis (MF) and ventricular arrhythmias. We sought to determine whether presence of MF on visual assessment (MFVA) and gray zone fibrosis (GZF) mass predicts SCD and ventricular fibrillation / sustained ventricular tachycardia after cardiac implantable electronic device (CIED) implantation. Methods In this prospective study, total fibrosis and GZF mass, quantified using cardiovascular magnetic resonance, was assessed in relation to the primary endpoint of sudden cardiac death (SCD) and the secondary, arrhythmic endpoint of SCD or ventricular arrhythmias after CIED implantation. Results Among 700 patients (age 68.0 ± 12.0yrs [mean ± SD]), 27 (3.85%) experienced a SCD and 121 (17.3%) met the arrhythmic endpoint over 6.93 yrs (median; interquartile range 5.82-9.32). MFVA predicted SCD (hazard ratio [HR]: HR:26.3 [95% confidence interval [CI] 3.70-3337]; negative predictive value: 100%). In competing risks analyses, MFVA also predicted the arrhythmic endpoint (subdistribution [sHR]: 19.9 [95% CI 6.40-61.9]; negative predictive value:98.6%). Compared with no MFVA, a GZF mass measured with the 5SD method (GZF5SD) > 17 g was associated with highest risk of SCD (HR: 44.6;95% CI 6.12-5685) and the arrhythmic endpoint (sHR: 30.3 [95% CI 9.60-95.8]). Adding GZF5SD mass to MFVA led to reclassification of 39% for SCD and 50.2% for the arrhythmic endpoint. In contrast, LVEF did not predict either endpoint. Conclusions In CIED recipients, MFVA excluded patients at risk of SCD and virtually excluded ventricular arrhythmias. Quantified GZF5SD mass added predictive value in relation to SCD and the arrhythmic endpoint.

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Cardiac conduction disease and sudden cardiac death is known to be associated with Myotonic Dystrophy type 1 (MD). Patients often require device implantation to prevent sudden cardiac death. It is not known how frequently device implantation occurs and how quickly conduction disease progresses. Objective To define the rate and type of device implantation, rate of pacing and outcome in MD patients managed in a single specialist centre. Method Retrospective analysis of pacing and outcome data on consecutive MD patients managed at Specialist Centre in the UK between 2011 and 2021. Results 24/119 MD patients were implanted with a cardiac device. Male:Female 13:11. At implant, patients had a mean age of 56 (95% CI 52 to 59), mean PR interval 217 ms (95% CI 203 to 230), mean QRSd 123ms (95% CI 109 to 137). Devices implanted included 16 DDDR, 4 CRT-D, 1 CRT-P, 1- ICD and 2 VVI pacemakers. 10 (42%) died during follow up of 10 years. 12 out of 19 (63%) with an atrial pacing lead required a mean increase in atrial pacing of 15% (95% CI 5 to 25) during follow up. 12 out of 24 (50%) of patients required mean increase of 13% (95% CI 5 to 22) in Ventricular pacing. 7 (88%) patients who died had evidence of progressive conduction disease prior to death. Conclusion In our cohort of myotonic dystrophy patients 20% required device implantation. There was a higher incidence of progressive atrial rather than ventricular pacing, despite the known concern about progressive AV block. Despite pacing, mortality remained high and was more frequent in patients with progressive conduction disease. Increases in pacing demand could be early indicator of disease progression.

Abstract Funding Acknowledgements Type of funding sources: None. Introduction/Background: Implantation of cardioverter defibrillators (ICD) to prevent sudden death is common in patients with left ventricular dysfunction (LVD) (1).However, these devices are expensive and there is increasing controversy about their cost benefit ratio. More agreement is present about the benefits of cardiac resynchronization therapy (CRT) in patients with LVD and concurrent heart failure (HF) and left bundle branch block (LBB) (2). Nevertheless, LVD often presents without one these two conditions which may only develop at follow up. This makes unclear the benefits of CRT at the time of ICD implantation (CRT-D) in these patients. Some have advocated implanting a CRT-D without the left ventricle lead instead of a conventional single/dual chamber ICD which would give the possibility to add CRT pacing without replacing the device generator at follow-up. However, this practice has been never evaluated and it is unclear its potential impact on cost. Methods This study included all CRT devices implanted in our institution since 2005. Patients with LVD but just heart failure (HF) or left bundle branch block (LBB) were considered for CRT-D implantation without the left lead. The number of patients who needed implantation of a LV lead at follow-up was analyzed. Only patients who needed device replacement due to battery depletion were included in the final analysis Results A total of 913 CRT devices were implanted of which 115 (12.59%) were implanted without a left ventricular lead. The left ventricular lead was not implanted due to technical reasons in 46 cases (5%) and electively in the remaining. CRT device replacement (due to Elective Replacement Indicator (ERI) activation) was necessary in 38 patients of the latter and a LV lead had been never implanted in 32 (84.21%) of them during follow-up (7 +/- 2 years). In patients who needed a LV lead added, device replacement (because of battery depletion) was necessary during left ventricular lead implant procedure in 2 (6.25%). Using the average cost of these devices in our institution (22,000 euros), around 384,000 euros could have been saved if the CRT-D had not been implanted until left ventricular lead was. Conclusions Implantation of a CRT-D without the left ventricle lead instead of a conventional single/dual chamber ICD in patient with border line indication for CRT is not cost effective and does not result is significant savings in ICD generators.