AV Conduction Abnormalities Research Articles

PO-03-108 TEMPORAL COURSE OF CONDUCTION ABNORMALITIES AFTER PERCUTANEOUS AND SURGICAL AORTIC VALVE REPLACEMENT

Aortic valve replacement is an increasingly common procedure. With the advent of trans-catheter aortic valve implantation (TAVI), patients that would have previously been denied valve replacement are able to undergo intervention. The anatomic proximity of the aortic valve and the native conduction system can lead to significant conduction abnormalities requiring permanent pacemaker (PPM) implantation. This retrospective study aimed to compare the incidence, temporality and eventual recovery of conduction abnormalities in patients undergoing PPM implantation post TAVI and surgical aortic valve replacement (SAVR). During the 5-year study period, 1012 patients had aortic valve replacement, 746 underwent SAVR and 266 patients underwent TAVI. In this group, patients were screened for pacemaker implantation within 14 days post procedure and were included if the pacemaker implantation was due to new AV conduction abnormalities. Patients were excluded if they had a pacemaker prior to surgery or had alternate reasons for pacemaker implantation such as complications from infective endocarditis. The incidence of new AV conduction abnormalities requiring pacemaker implantation post-operatively was 5.3% (n=14) in TAVI patients and 3.4% (n=26) in SAVR patients. In the TAVI group PPM implantation occurred on average at 3.2 ± 2.1 days (median 3 days) post procedure. In the SAVR group the average time to implantation was 6 ± 3.1 days (median 5 days). To determine conduction recovery 36 patients had complete follow up, 26 patients in SAVR and 10 patients in TAVI group. After a mean follow-up of 3 months, 50% of patients in the TAVI group and 36.1% in SAVR group recovered 1:1 conduction. At 12 months, 60% of patients in the TAVI group and 41% in the SAVR group had improved conduction and by 24 months it was 50% and 34.5%, respectively. In patients who undergo PPM implant post TAVI a high rate of conduction recovery is observed during follow-up, probably emphasizing the need for better selection of pacing candidates.

535 CT SCAN AORTIC VALVE CALCIFICATION PATTERNS AND HEMODYNAMIC PERFORMANCE OF SELF-EXPANDING INTRA-ANNULAR TRANSCATHETER PROSTHESES

Abstract Introduction Aortic valve calcification (AVC) represents a negative prognostic factor in patients undergoing transcatheter aortic valve implantation (TAVI). Recent randomized clinical trials comparing commercially available self-expanding (SE) supra-annular and balloon-expandable (BE) devices with second-generation SE intra-annular devices demonstrated the clinical non-inferiority of the latter in terms of procedural success. However, no current data are available in vivo regarding the potential impact of AVC on SE intra-annular device performance and clinical outcomes. Purpose to evaluate the potential impact of different AVC patterns on SE intra-annular device performance in a consecutive cohort of patients undergoing TAVI. Methods this is an observational, non-randomized, prospective, single-center study preliminarily enrolling 53 consecutive patients who underwent TAVI with a SE intra-annular device (Portico - Abbott Structural Heart, St Paul, MN, USA) between 2019 and 2022 at our department. All patients underwent transthoracic echocardiography, contrast-enhanced multidetector row computed tomography (MDCT) with volumetric calcium score and coronary angiography before TAVI. Patients with bicuspid aortic valve and previous surgical aortic valve replacement eligible for valve-in-valve TAVI were excluded. AVC and left ventricle outflow tract (LVOT) calcification (up to 15 mm below the basal annular plane) were quantified in the contrast images by using a Hounsfield unit threshold of 850. Results Patients undergoing post-TAVI pacemaker implantation (19% of the overall study population) had higher AVC levels compared with those that did not show this complication (all three cusps AVA calcium score 270.6±409.6 vs 158.1±137.1, p=0.146; p=0.048, p=0.181 and p=0.346 for left cusp- LCC, right cusp – RCC- and non-coronary cusp-NCC, respectively). Severe LVOT calcification was also associated with a higher incidence of AV conduction abnormalities (37.9±44.5 vs 13.4±39.0 of patients without AV defects, p=0.045). Moreover, post-procedural moderate/severe aortic regurgitation occurred more frequently in patients with LCC calcification (183.7±87.0 vs 64.2±99.6, p=0.018) and RCC calcification (188.7±149.5 vs 58.7±120.8, p=0.019) rather than those with NCC or LVOT calcification. Conclusion(s) preliminary results of our observational registry highlight the potential impact of AVC patterns on the occurrence of aortic regurgitation and pacemaker implantation after a SE intra-annular device. A larger sample size is needed to better understand the impact of calcium patterns on each single outcome in order to identify patients at higher risk and to early manage these complications, improving long-term outcomes.

Electrocardiographic changes after TAVR and their clinical impact according to new ESC Pacing Guidelines

Abstract Conduction disturbances after transcatheter aortic valve replacement (TAVR) remain one of the most frequent complications. The aim of this study was to analyze ECG changes after TAVR using contemporary valves and to detect risk factors for the need of further clinical evaluation according to new ESC pacing guidelines to evaluate pacemaker implantation. In this retrospective analysis we included 850 patients (mean age 80±9 years, 51% female), who underwent TAVR in our institution from January 2019 until December 2020. A mean follow-up of 8.9±8.4 months and 217 (25.5%) patients was performed. 55% of the implanted valves were self-expandable, 45% balloon-expandable. After TAVR, 77 (9.1%) patients developed new LBBB and QRS >150ms, 26 (3.1%) new PR-time >240ms. Prolongation of PR-time and prolongation of QRS duration >20ms were seen in 20 (2.4%) and 90 (10.6%) patients with preexisting conduction disturbances. 152 (17.9%) patients needed pacemaker implantation post TAVR. Developing a PR-prolongation of >20ms was associated with calcification of the annulus (OR 1.2 CI 95% 1.004–1.4; p=0.04). New LBBB (OR 0.45; CI 95% 0.25–0.79; p=0.006) and pacemaker implantation (OR 0.4; CI 95% 0.2–0.8; p=0.009) were correlated with the implantation of a self-expandable valve. Coronary heart disease (OR 3, CI 95% 1.07–8.2; p=0.04) and peripheral arterial disease (OR 2.6 CI 95% 1.18–5.6; p=0.02) were associated with prolongation of QRS >20ms. New LBBB with QRS >150ms was seen more often after post-dilatation (OR 1.03, CI 95% 1.01–1.05; p=0.05). Pre-existing AV block I° (OR 2.8, CI 95% 1.4–5.6; p<0.001), pre-existing RBBB (OR 20.5, CI 95% 7.5–56; p<0.001), nicotine abuse (OR 2, CI 95% 1.05–3.8; p=0.04), prosthesis oversizing (OR 1.06, CI 95% 1.006–1.11; p=0.03) and implantation depth (OR 1.13, CI 95% 1.006–1.26; p=0.04) were independent risk factors for pacemaker implantation. During the follow-up 161 patients (18.9%) were hospitalized in 270 inpatient stays [cardiac decompensation (n=36, 13%), pacemaker implantation (n=9, 3.3%), acute coronary syndrome (n=12, 4.4%)]. 8 patients (80%) received a pacemaker implantation because of AV Block III° and 1 (10%) patient because of sick-sinus-syndrome (SSS). Analyzing the post TAVR ECG 5 (50%) had a new LBBB (3 (30%) with QRS >150ms) and 4 (40%) patients showed LBBB together with AV Block I°. According to new guidelines 213 (25.1%) patients would have needed further clinical evaluation (EP study or ECG monitoring) after TAVR. AV-conduction abnormalities were associated with annulus calcification. Self-expandable valves were associated with new LBBB and pacemaker implantation. There seems to be a correlation between arteriosclerotic diseases and QRS width post TAVR. Pre-existing RBBB, AV block I°, implantation depth and prosthesis oversizing are important risk factors for pacemaker implantation post TAVR. New LBBB after TAVR is associated with a higher risk for pacemaker implantation in the long-term analysis. Funding Acknowledgement Type of funding sources: None.

P299 CONDUCTION DISORDERS AS THE FIRST HALLMARK OF ISOLATED CARDIAC SARCOIDOSIS IN A HIGHLY ACTIVE INDIVIDUAL: A CASE REPORT

Abstract A 45–year–old highly active Caucasian individual was admitted to the emergency department complaining of slightly reduced physical performances: he reported a lack of increase of heart rate beyond 80–100 bpm at fitness tracker monitoring during physical activity during the previous week. He used to train 3–4 times/week. He had no previous medical concerns and he didn’t take any medication. Basal electrocardiogram (ECG) showed 2:1 atrioventricular block (AVB) and left axis deviation, with the exception of his 2:1 AVB, the other features on the ECG are common training related changes. Transthoracic echocardiogram was normal. Treadmill exercise test revealed paroxysmal 2:1 AVB and Mobitz I AVB at peak effort, then first degree AVB and isolated and coupled right infundibular premature ventricular complexes (PVC) in the recovery phase: exercise related AV–conduction improvement suggested supra–nodal AVB. Cardiac magnetic resonance (CMR) imaging reported two areas of late gadolinium enhancement (LGE) with midwall/subepicardial distribution: the first one in the basal anterior septal wall extending to basal anterior wall and the second one involving the basal and medium segment of inferior septum and inferior wall. LGE quantification was 6.0 g/m2 (9.5%). Short tau inversion recovery (STIR) acquisitions were negative for oedema (Figure 1). Subsequent FDG–PET imaging confirmed high uptake in the basal anterior septal wall, the anterior wall and in the basal inferior septal area (Figure 2). No other organ involvement was detected. Considering the FDG–PET, LGE and AV–conduction abnormalities, the patient was clinically diagnosed with symptomatic isolated CS. However, a definitive histologic diagnosis was not possible as no myocardial biopsy was performed. High dose corticosteroid therapy was startedand after few days of treatment ECG monitoring revealed an imrovement of cardiac conduction. The treadmill test was repeated and showed conduction improvement during effort, however the test was suspended due to the occurrence of ventricular couples and ventricular bigeminy during effort. For arrhythmic risk assessment, electrophysiological study (EPS) was performed and no arrhythmias were induced. We decided to defer ICD implantation. However, a loop–recorder for continuous arrhythmias monitoring was implanted. At three months, a new CMR was performed and was identical to the previous one, with no significant LGE reduction or increase detected.

Atrioventricular Block Necessitating Chronic Ventricular Pacing After Tricuspid Valve Surgery in Patients With a Systemic Right Ventricle: Long-Term Follow-Up.

BackgroundPatients with transposition of the great arteries (TGA) after an atrial switch or congenitally corrected TGA (ccTGA) are prone to systemic right ventricular (sRV) failure. Tricuspid valve (TV) regurgitation aggravates sRV dysfunction. Timely TV surgery stabilizes sRV function, yet the development of atrioventricular (AV)-conduction disturbances in the course of sRV failure can contribute to sRV dysfunction through pacing-induced dyssynchrony. This study aims to explore the incidence, timing, and functional consequences of AV-block requiring ventricular pacing after TV surgery in patients with sRV.MethodsConsecutive adolescent and adult patients with an sRV who underwent TV surgery between 1989 and 2020 and followed-up at our center were included in this observational cohort study.ResultsThe data of 28 patients (53% female, 57% ccTGA, and a mean age at surgery 38 ± 13 years) were analyzed. The mean follow-up was 9.7 ± 6.8 years. Of the remaining 22 patients at the risk of developing high degree AV-block after TV surgery, 9 (41%) developed an indication for chronic ventricular pacing during follow-up, of which 5 (56%) within 24 months postoperatively (3 prior to hospital discharge). The QRS duration, a surrogate marker for dyssynchrony, was significantly higher in patients with chronic left ventricular pacing than in patients with native AV-conduction (217 ± 24 vs. 116 ± 23 ms, p = 0.000), as was the heart failure biomarker NT-pro-BNP [2,746 (1,242–6,879) vs. 495 (355–690) ng/L, p = 0.004] and the percentage of patients with ≥1 echocardiographic class of deterioration of systolic sRV function (27 vs. 83%, p = 0.001). Of the patients receiving chronic subpulmonary ventricular pacing (n = 12), 9 (75%) reached the composite endpoint of progressive heart failure [death, ventricular assist device implantation, or upgrade to cardiac resynchronization therapy (CRT)]. Only 4 (31%) patients with native AV-conduction (n = 13) reached this composite endpoint (p = 0.027).ConclusionPatients with a failing sRV who undergo TV surgery are prone to develop AV-conduction abnormalities, with 41% developing an indication for chronic ventricular pacing during 10 years of follow-up. Patients with chronic subpulmonary ventricular pacing have a significantly longer QRS complex duration, have higher levels of the heart failure biomarker NT-pro-BNP, and are at a higher risk of deterioration of systolic sRV function and progressive heart failure.

Pacing for complete heart block in pregnancy

Whereas sinus tachycardia and paroxysmal supraventricular tachycardia are common during pregnancy, bradyarrhythmias are infrequent. Moreover, bradyarrhythmias are generally well tolerated during pregnancy. Nevertheless, a 12-lead ECG is indicated for pregnant women who present with bradycardia, to rule out sinoatrial (SA) node dysfunction or AV conduction abnormalities. Third-degree AV block (complete heart block, CHB) requires multidisciplinary care during pregnancy, with combined input from Cardiologists and Obstetricians. As CHB is associated with increased mortality and morbidity if left untreated, permanent pacing is usually indicated during pregnancy, even if the patient remains asymptomatic. However, not all pregnant patients with CHB require urgent pacing. In a pregnant patient who has CHB with an escape rhythm with narrow QRS complexes and rate of >50bpm, permanent pacemaker implantation can be delayed until after delivery, as described in this case report.

Emery-Dreifuss muscular dystrophy presenting as a heart rhythm disorders in children

Abstract Introduction Emery-Dreifuss muscular dystrophy (EDMD) is an inherited muscle dystrophy often accompanied by cardiac abnormalities in the form of supraventricular arrhythmias, conduction defects, sinus node dysfunction. Cardiac phenotype typically arises years after skeletal muscle presentations, though, can be severe and life-threatening. The disease usually manifests during the third decade of life with elbow joint contractions and progressive muscle weakness and atrophy. Objective To present our clinical experience of diagnosis and treatment of arrhythmias in children with Emery-Dreifuss muscular dystrophy Materials and methods We enrolled 5 patients with different forms of EDMD (X-linked and autosomal dominant) linked to the mutations in EMD and LMNA genes, presented with early onset of cardiac abnormalities and no leading skeletal muscle phenotype. The predominant forms of cardiac pathology were atrial flutter, atrial fibrillation and conduction disturbances that progress over time. Clinical examination included physical examination, 12-lead electrocardiography, Holter ECG monitoring (HM), transthoracic echocardiography, neurological examination and biochemical and hormone tests. Also we performed CMR, electrophysiological study (EPS), treadmill test of some patients. One patient underwent an endomyocardial biopsy to exclude inflammatory heart disease. Target sequencing was performed using a panel of 108 or 172 genes Results We observed five patients with EDMD and cardiac debut during first-second decades of life: 3 with 1st subtype (variants in EMD gene) and 2 with 2nd subtype (variants in LMNA gene). All patients were males. The mean age of cardiac manifestation was 13,2±3,11 (from 9 to 16 y.o.). The mean follow-up period was 7,4±2,6 years. All patients presented with sinus node dysfunction and four out of five with AV conduction abnormalities. The leading arrhythmic phenotypes included various types of supraventricular arrhythmias: multifocal atrial tachycardia (AT) (n=4), premature atrial captures (PACs) (n=4), atrial flutter, (AF) (n=3), atrial fibrillation (AFib) (n=3) and AV nodal recurrent tachycardia (AVRNT). Heart rhythm disorders were the first manifestation in all three patients with 1st EDMD subtype. Radiofrequency ablation was performed in 2 patients, one of them received permanent pacemaker implantation. Conclusions In conclusion, while being the rare cases, heart rhythm disorders can represent the first and for a long time, the only clinical symptom of EDMD even in the pediatric group of patients. Therefore, thorough laboratory and neurological screening along with genetic studies, are of importance in each pediatric patient presenting with complex heart rhythm disorders of primary supraventricular origin to exclude EDMD or other neuromuscular disorders. Funding Acknowledgement Type of funding sources: None.

Atrioventricular-block necessitating ventricular pacing after tricuspid valve surgery in patients with a systemic right ventricle: long term follow-up

Abstract Background Patients with transposition of the great arteries (TGA) after atrial switch or congenitally corrected TGA (ccTGA) are prone to systemic right ventricular (sRV) failure. Atrioventricular (AV)-conduction disturbances and tricuspid regurgitation aggravate the course of sRV dysfunction. Timely tricuspid valve (TV) surgery stabilizes sRV function. However, TV surgery is an independent risk for AV-block and ventricular pacing in non-congenital cardiothoracic surgery patients. Chronic subpulmonary ventricular pacing-induced dyssynchrony further contributes to sRV failure, potentially reducing the beneficial effects of the tricuspid valve surgery. Purpose The aim of this study is to explore the incidence, timing and functional consequences of AV-conduction block requiring ventricular pacing after TV surgery in sRV patients. Methods Consecutive adolescent and adult patients with a sRV who underwent TV surgery in the period 1989–2020 and follow-up at our tertiary care center were included in this observational cohort study. Patients who were <10 years of age at the time of operation and/or died in perioperative, in-hospital, setting were excluded from analysis (n=5). Demographic and clinical data was collected from the patient records. Results Data of 28 patients (54% female, 57% ccTGA) was analysed (Figure). The mean age at surgery was 38±13 years, 5 patients (18%) received chronic ventricular pacing preoperatively. Mean follow-up was 9.7±6.8 years, during which 7 patients (25%) died and 3 (11%) underwent ventricular assist device implantation (VAD). Two patients died awaiting VAD/HTx, one patient died awaiting CRT upgrade. Seven (25%) patients underwent a re-operation, of which 3 (11%) TV replacement, 3 (11%) VAD and 1 (4%) pulmonary valve replacement. Of the 23 patients at risk of developing AV-block, 11 (48%) developed an indication for chronic ventricular pacing, of which 6 within 24 months postoperatively (4 before hospital discharge). Of the 21 patients with a device, 7 (25%) had successful resynchronization therapy (2 before TV surgery). Patients with chronic ventricular pacing had a wider QRS-duration (mean 121 ms vs 194 ms in those without pacing, p<0.001) and 43% had a severely reduced sRV function (vs 36% in those without pacing) at latest follow-up. Conclusions Patients with a failing sRV who undergo TV surgery are prone to AV-conduction abnormalities with 48% of this group developing an indication for chronic ventricular pacing during follow-up. Pacing-induced dyssynchrony can further contribute to sRV dysfunction. Implantation of an epicardial sRV lead at the time of TV surgery for future CRT may be considered to attenuate the detrimental effects of subpulmonary ventricular pacing in this heart failure prone patient group with complex anatomy, limiting transvenous possibilities. Funding Acknowledgement Type of funding sources: None.

Pulmonary and Cardiac Sarcoidosis - Diagnosis and Therapy

Sarcoidosis occurs predominantly in younger adults and may involve multiple organ systems. Although classical features such as bihilar lymphadenopathy, low grade fever, fatigue, pulmonary opacities, ocular lesions and arthritis occur frequently it must be kept in mind that sarcoidosis is able to mimic virtually any other disease. A thorough and systematic diagnostic strategy is warranted since even the histological hallmark of non-caseating granulomas occurs in a variety of other granulomatous diseases and even malignancies. A firm diagnosis is based on a match of clinical features, imaging results and histopathological findings. The Scadding classification describes four different types, not stages, of thoracic sarcoidosis based on mediastinal lymph node and lung parenchyma involvement. Medical treatment of pulmonary sarcoidosis is indicated only in patients exhibiting progressive disease and/or organ function impairment. Cardiac sarcoidosis manifests itself by clinical signs of heart failure, impaired cardiac function and arrhythmias including ventricular tachycardia, ventricular fibrillation and AV-conduction abnormalities. Patients with symptomatic or suspected cardiac sarcoidosis require rapid and elaborate diagnostic testing including cardiac MRI and PET imaging. Referral to a specialized center should be considered to establish a firm diagnosis and to initiate medical treatment and eventual device implantation. Oral corticosteroids, as the initial medical treatment of choice, carry side effects that must be weighed carefully against clinical benefits. Immunosuppressive therapy with methotrexate, azathioprine or TNF-blockers is usually reserved for patients that are either not responsive or intolerant to systemic steroids or that require steroid maintenance therapy above the cushing threshold. Diagnosed early and treated correctly, pulmonary and cardiac sarcoidosis mostly carry a favorable prognosis.

Recurrent syncope in patients with a pacemaker and bradyarrhythmia

Abstract Objectives To investigate the risk of recurrent syncope and all-cause mortality after implantation of a pacemaker in patients with bradyarrhythmia. Background A pacemaker is generally recommended when syncope is caused by bradyarrhythmias to prevent a new syncope. However, the occurrence and risk of recurrent syncope in patients with bradyarrhythmia after pacemakerimplantation are still unknown. Methods Patients with a prior syncope and an implantation of pacemaker were identified. Cumulative incidences of 5-years were estimated for the outcomes stratified into groups according to the type of bradyarrhythmia; and type of pacemaker. The risk of recurrent syncope and all-cause mortality were estimated using adjusted cox proportional hazard regressions. Results We identified 8,663 patients with a prior syncope and pacemaker implantation (median age of 78,1 years (SD 69,1–84,8) and 55,1% males). The 5-year cumulative incidence of recurrent syncope was 19,3% (95% confidence intervals (CI) 18,4–20,2). Factors associated with a significant increased risk of recurrent syncope were male sex, age 80 years and above, alcohol related disease, bleeding, chronic obstructive pulmonary disease, chronic kidney disease, stroke, and malignancy. Atrial fibrillation was associated with a significantly decreased risk of recurrent syncope. Patients with an advanced AV conduction abnormality had a lower associated risk of syncope compared to patients with sinus node dysfunction (HR 0,85, 95% CI 0,76–0,94, p=0,003). Conclusions One fifth of the cohort had a recurrence syncope after five years. Besides older age and male sex, several comorbidities were found to be associated with a higher risk of recurrence of syncope. Clinicians need to be attentive that a large proportion of patients with bradyarrhythmia suffer from syncope even when treated with a pacemaker. Funding Acknowledgement Type of funding source: None

Functional modulation of atrio-ventricular conduction by enhanced late sodium current and calcium-dependent mechanisms in Scn5a1798insD/+ mice.

Aims SCN5A mutations are associated with arrhythmia syndromes, including Brugada syndrome, long QT syndrome type 3 (LQT3), and cardiac conduction disease. Long QT syndrome type 3 patients display atrio-ventricular (AV) conduction slowing which may contribute to arrhythmogenesis. We here investigated the as yet unknown underlying mechanisms.Methods and resultsWe assessed electrophysiological and molecular alterations underlying AV-conduction abnormalities in mice carrying the Scn5a1798insD/+ mutation. Langendorff-perfused Scn5a1798insD/+ hearts showed prolonged AV-conduction compared to wild type (WT) without changes in atrial and His-ventricular (HV) conduction. The late sodium current (INa,L) inhibitor ranolazine (RAN) normalized AV-conduction in Scn5a1798insD/+ mice, likely by preventing the mutation-induced increase in intracellular sodium ([Na+]i) and calcium ([Ca2+]i) concentrations. Indeed, further enhancement of [Na+]i and [Ca2+]i by the Na+/K+-ATPase inhibitor ouabain caused excessive increase in AV-conduction time in Scn5a1798insD/+ hearts. Scn5a1798insD/+ mice from the 129P2 strain displayed more severe AV-conduction abnormalities than FVB/N-Scn5a1798insD/+ mice, in line with their larger mutation-induced INa,L. Transverse aortic constriction (TAC) caused excessive prolongation of AV-conduction in FVB/N-Scn5a1798insD/+ mice (while HV-intervals remained unchanged), which was prevented by chronic RAN treatment. Scn5a1798insD/+-TAC hearts showed decreased mRNA levels of conduction genes in the AV-nodal region, but no structural changes in the AV-node or His bundle. In Scn5a1798insD/+-TAC mice deficient for the transcription factor Nfatc2 (effector of the calcium-calcineurin pathway), AV-conduction and conduction gene expression were restored to WT levels.ConclusionsOur findings indicate a detrimental role for enhanced INa,L and consequent calcium dysregulation on AV-conduction in Scn5a1798insD/+ mice, providing evidence for a functional mechanism underlying AV-conduction disturbances secondary to gain-of-function SCN5A mutations.

Case of successful treatment of second-degree AV block in patient with gastroesophageal reflux disease associated with hiatal hernia

Clinical observation of a young patient without an organic pathology of the heart, who repeatedly sought medical help in connection with complaints of episodes of dizziness, lability of blood pressure and pulse numbers, is presented. The medical survey revealed a link between clinical symptoms and progressive retardation of AV conduction (from first-degree AV block to second-degree Mobitz II), and therefore the patient was recommended to be implanted with permanent artificial cardiac pacemaker. To clarify the nature of the conduction disorders, an invasive electrophysiology study was performed, which revealed a proximal AV block due to vagal influences. As the most likely cause of stimulation n. vagus was considered identified in a patient gastroesophageal reflux disease associated with hiatal hernia. Surgical treatment (laparoscopic fundoplication) led to a regression of the clinical and electrocardiographic picture, avoiding the implantation of permanent artificial cardiac pacemaker. The tactic chosen is consistent with the algorithm for managing patients with AV conduction abnormalities (2018 ACC / AHA / HRS Guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay), which involves eliminating potentially reversible causes of bradyarrhythmia before deciding whether to install permanent artificial cardiac pacemaker.

285Arrhythmias after transcatheter closure of persistent foramen ovale are related to the type and size of the implanted device

Abstract Transient supraventricular arrhythmias may occur in patients following persistent foramen ovale (PFO) closure. Therefore, the aim of the study was to prospectively perform 24-hour ECG monitoring to assess the electrocardiographic effects of transcatheter closure of PFO depending on the type of implanted devices. Material and methods 351 consecutive adult subjects (196 F, 155M; mean age: 40.9±15.3) were enrolled into the study to undergo PFO closure with an Amplatzer Septal Occluder - ASO (157 pts: 117 occluders – size 25; 40 pts – size 30), and Cardia device (194 pts: 163 occluders – size 25; 31 – size 30). Holter monitoring was performed on all patients before, at 1 and 12 months after the procedure. Results The success rate of PFO closure was 97.8% (351 cases from 359 qualified in TEE), in 8 cases the PFO tunnels were too small to be forced by a catheter, in one case the PFO device caused an injury of the septum and an ASD Amplatzer device was implanted. During the procedure in 3 (0.85%) cases transient supraventricular arrhythmia and in 1 (0.28%) case bradycardia to 27 bpm occurred. At 1 month: in 7 (2%) pts changes in AV conduction occurred: 1 pt (0.28%) had complete AV dissociation, 6 (1.7%) pts intermittent first degree AV block; paroxysmal atrial fibrillation (pAF) occurred in 6 (1.7%) pts, 2 of whom had pAF prior to closure. A significant increase in the number of SVE premature beats/24h was noted at 1 month after the procedure: 1167.9±409 (27–9976) compared to baseline data 60.2±44 (0–601) (p<0.0001), at 12 months the SVE number decreased to 57.2±51 (7–752) and did not differ significantly from the baseline data. There was no change in the mean number of ventricular arrhythmias/24h after the procedure. There was a significant correlation between SVE premature beats/24h at 1 month after the procedure and device size (p<0.001 r=97211). Pts with ASO device had a significantly higher number of SVE ectopy at 1 month after PFO closure (19123.9±70) compared to pts with Cardia device (811.9±324), p<0.0001. Conclusions 1. Transcatheter closure of PFO is associated with a transient increase in supraventricular premature beats and a small risk of AV conduction abnormalities and paroxysmal atrial fibrillation in the early follow-up. There is regression of periprocedural arrhythmias after 12 months of PFO closure. 2. Transcatheter closure of PFO with Cardia device is related to a lower risk of supraventricular arrhythmias in the early follow-up. 3. The smaller device is implanted the lower risk of periprocedural arrhythmias is expected.

The effects of septal myectomy and alcohol septal ablation for hypertrophic cardiomyopathy on the cardiac conduction system.

AV conduction abnormalities are observed in 15-30% of patients with hypertrophic cardiomyopathy but are usually not severe enough to require permanent pacemaker implant. Both septal myectomy and alcohol septal ablation are effective options to relieve symptoms due to left ventricular outflow tract gradient in patients with hypertrophic cardiomyopathy but have procedure-specific effects on AV conduction and the His Purkinje system. Septal myectomy is associated with the development of LBBB in 50-100% of patients, while alcohol septal ablation is associated with RBBB in 37-70% of patients. Baseline abnormalities in the contralateral bundles and the presence of conduction disease have an important impact on the likelihood of the development of AV block for both of these therapies. AV block requiring permanent pacing occurs in approximately 2-3% of patients after septal myectomy and 10-15% of patients after alcohol septal ablation. Permanent pacemaker implant after alcohol septal ablation is more common in older patients (> 55years old 13 vs. < 55years old 5%; p = 0.06). Improved outcomes for septal myectomy and alcohol septal ablation are observed in experienced centers. Septal reduction therapies should be performed at medical centers with a dedicated hypertrophic cardiomyopathy program using a multidisciplinary approach.

Cardiogenic anorexia and underweighting in a child: case report.

IntroductionIn this case, we present a child with a diagnosis of anorexia and no known cardiac disease, who was referred to our clinic for a routine cardiac monitoring. ‘Asymptomatic’ high degree of atrioventricular block (AVB) was revealed. She underwent successful pacemaker (PM) implantation and losing of the weight stopped.Case presentationIn this case, the abrupt AVB with more than 6 s ventricular pauses without escape rhythm during the day-time most possible is a type of neurally mediated AVB which was presented by anorexia, underweighting, and refusing to eat in a 12-year-old girl. All symptoms disappeared after PM implantation, and weight gain was recorded during 6 months of follow-up.DiscussionThe causal link between AVB and anorexia is discussed. In this case, patient’s eating disorder was related to her AV conduction abnormality. The main reason of this case report is to emphasize, that in children with unexplained anorexia and underweighting cardiogenic origin must be excluded.

Electrocardiographic assessments and cardiac events after fingolimod first dose \u2013 a comprehensive monitoring study

BackgroundFirst dose observation for cardiac effects is required for fingolimod, but recommendations on the extent vary. This study aims to assess cardiac safety of fingolimod first dose. Individual bradyarrhythmic episodes were evaluated to assess the relevance of continuous electrocardiogram (ECG) monitoring.MethodsSTART is an ongoing open-label, multi-center study. At the time of analysis 3951 patients were enrolled. The primary endpoints are the incidence of bradycardia (heart rate < 45 bpm) and second-/third-degree AV blocks during treatment initiation. The relevance of Holter was assessed by matching ECG findings with the occurrence of clinical symptoms as well as by rigorous analysis of AV blocks with regard to the duration of pauses and the minimal heart rate recorded during AV block.ResultsThirty-one patients (0.8%) developed bradycardia (<45 bpm), 62 patients (1.6%) had second-degree Mobitz I and/or 2:1 AV blocks with a lowest reading (i.e. mean of ten consecutive beats) of 35 bpm and the longest pause lasting for 2.6 s. No Mobitz II or third-degree AV blocks were observed. Only one patient complained about mild chest discomfort and fatigue. After 1 week, there was no second-/third-degree AV block.ConclusionsContinuous Holter ECG monitoring in this large real-life cohort revealed that bradycardia and AV conduction abnormalities were rare, transient and benign. No further unexpected abnormalities were detected. The data presented here give an indication that continuous Holter ECG monitoring does not add clinically relevant value to patients’ safety.Trial registrationNCT01585298; registered April 23, 2012.

Advanced AV Conduction Abnormality in Acute Rheumatic Fever

Advanced AV Conduction Abnormality in Acute Rheumatic Fever

56-29: Functional permanent 2:1 atrioventricular block treated with cardioneuroablation:Casereport

A 54-year-old woman had undergone slow pathway ablation for AVNRT 3 years ago. Before admission she had started to present with recurrentdizziness and syncope due to 2:1 AV block and was referred for pacemaker implantation. She was asymptomatic and had no signs of AV conduction abnormalities until 2 weeks ago. AV conduction abnormality resolved with atropine infusion and at stage 2 of a treadmill exercise test. Electrophysiologic study showed suprahisian 2:1 AV block. Using a 4-mm open-tip irrigated RF catheter the 3-dimensional geometry of the right and the left atrium was created using a 3- dimensional electroanatomic mapping system. Bipolar endocardial electrograms were displayed at filter settings of 30–500Hz and 300–500 Hz (for EPS and online spectral analysis, respectively) and measured at a sweep speed of 400mm/s. Localization of the ganglia was detected by high-frequency stimulation. The ablation procedure was performed only via the RA. The RA sites showing a parasympathetic response and fibrillar atrial myocardium pattern were assigned as targets and ablated until atrial electrical potential was almost completely eliminated. A high degree AV block was seen during RF application at targeted sites. After AV node denervation by ablation of ganglia A and C via the RA approach, AV conduction resolved completely (Figure 2). The results of our case indicate that cardioneuroablation in patients with functional AV block is feasible and may be a valuable adjunctive therapy in patientswho cannot be adequately treated by conventional modalities and refuse pacemaker implantation.

Abstract 18669: A Simple Noninvasive Score for Predicting Permanent Pacemaker Implantation Following Transcatheter Aortic Valve Replacement

Introduction: Cardiac conduction abnormalities requiring permanent pacemaker (PPM) are well-recognized complications of TAVR. However, a clinical prediction tool for assessing the risk of post-TAVR PPM placement is not available. Hypothesis: The purpose of this study was to create a novel clinical prediction tool for assessing the risk of PPM following TAVR. Methods: A total of 114 patients who underwent TAVR using the balloon-expandable Edwards SAPIEN valve at the University of Iowa Hospitals and Clinics were identified. We then excluded patients with a pre-existing PPM, who required conversion to an open/salvage procedure, and those without available CT data. Binomial logistic multivariate regression was performed to construct a scoring system. Results: A total of 84 patients were included in the study and PPM was placed in 9 patients (10.7%). From the binomial logistic regression analysis using RBBB, valve size to Sinus of Valsalva diameter ratio, and sex as predictors, pre-existing RBBB (odds ratio [OR]: 6.5, 95% confidence ratio [CI]: 1.1-37.1, p=0.035) and the ratio of valve size to diameter of Sinus of Valsalva (OR: 1.2, 95% CI: 1.03-1.3, p=0.012) were identified as significant predictors of PPM post-TAVR. We created a novel clinical prediction tool for PPM post-TAVR with patients being designated with score 0 if they had no RBBB and valve size to diameter of sinus of Valsalva ratio &lt; 81.4 (optimal cut-off based on ROC curve) and score 1 if they had RBBB, or valve size to diameter of sinus of Valsalva ratio ≥ 81.4, or both (OR: 12.6, 95% CI: 1.5-106.8, p=0.009; sensitivity, 0.90; specificity, 0.59). Conclusions: Our clinical prediction score for PPM following TAVR expands upon the available literature for pre-procedural risk-stratification. The components of the score have biological plausibility, as pre-existing conduction system disease and relative valve prosthesis oversizing would be expected to confer a higher risk of post-procedural AV block. Implantation of PPM prior to TAVR in patients at risk for high-grade AV conduction abnormalities, based on this simple risk score, could have important implications for morbidity/mortality, length of stay, and cost. Moving forward, this prediction score requires validation in multicenter cohorts.

Abstract 191: Deletion or Knockdown of Myotonic Dystrophy Protein Kinase Does Not Affect Cardiac Conduction or Ejection Fraction in Mice

Myotonic dystrophy type 1 (DM1), the most common form of muscular dystrophy in adults, causes dominantly-inherited muscle weakness, defects of cardiac conduction, variable LV dysfunction, and risk of sudden death. The genetic basis is an expanded CTG repeat in the 3’ untranslated region of DMPK. DM1 patients are functionally hemizygous for DMPK protein, due to nuclear retention of mRNA having expanded repeats. The cardiac aspects are attributed to DMPK loss, toxicity of RNA with expanded repeats, or both. Dmpk heterozygous (+/-) and homozygous knockout (-/-) mice were reported to show AV conduction abnormalities resembling DM1 (Berul et al, JCI, 1999). In an effort to reduce RNA toxicity, antisense oligonucleotides (ASOs) targeting DMPK mRNA have recently entered clinical trials. DM1 phenotypes in skeletal muscle were corrected by ASO knockdown of toxic RNA in mice (Wheeler et al, Nature, 2012). While ASOs may have similar potential to mitigate RNA toxicity in the heart, there is risk of aggravated DMPK deficiency. To reexamine the role of DMPK in the conduction system we studied mice with Dmpk gene deletion or ASO knockdown. We obtained ECGs and echocardiograms on Dmpk -/- and +/- mice, compared to WT littermates. The +/- mice were treated with Dmpk-targeting ASOs or saline. Subcutaneous injection of 50 mg/kg/wk ASO was started at age 2 months, then shifted to biweekly injections after 6 weeks. Dmpk expression in hearts of +/- mice was ~50% of WT, and was further reduced by ASOs (84 ± 3% decrease of mRNA, 93 ± 2% decrease of protein, relative to WT). Surface ECGs and echocardiography at 6 and 10 months showed no differences of heart rate, cardiac conduction, or ejection fraction in WT, saline-treated +/-, ASO-treated +/-, or -/- mice. Conscious, unrestrained ECGs obtained at 11-12 months by radiotelemetry showed no differences among WT, saline-treated +/-, ASO-treated +/-, or -/- mice. We conclude that ASOs can induce posttranscriptional silencing of Dmpk in murine hearts. Constitutive absence of DMPK did not impact cardiac conduction or contractility, and the same was true for ASO knockdown to levels &lt;15% of WT. Our data support the idea that cardiac dysfunction in DM1 results mainly from RNA toxicity, which potentially could be prevented or alleviated by ASOs.