Prevalence, patterns and outcomes of cardiac involvement in Erdheim-Chester disease.

AIMS: Cardiac involvement of Erdheim-Chester disease (ECD), a rare L group histiocytosis, has been reported to be associated with poor outcomes, but systematic studies are lacking. The present study aimed to investigate the prevalence, clinical features, imaging features, and prognosis of cardiac involvement in ECD in a large series. METHODS AND RESULTS: All patients with ECD who underwent cardiac magnetic resonance (CMR) imaging between 2003 and 2019 at a French tertiary center were retrospectively included. Primary outcome was all-cause mortality. Secondary outcomes were pericarditis, cardiac tamponade, conduction disorders, device implantation and coronary artery disease (CAD). A total of 200 patients were included [63 (54-71) years, 30% female, 58% BRAFV600E mutated]. Median follow-up was 5.5 years (3.3-9 years). On CMR, right atrioventricular sulcus infiltration was observed in 37% of patients, and pericardial effusion was seen in 24% of patients. In total, 8 patients (4%) had pericarditis (7 acute, 1 constrictive), 10 patients (5%) had cardiac tamponade, 5 patients (2.5%) had ECD-related high-degree conduction disorders, and 45 patients (23%) had CAD. Overall, cardiac involvement was present in 96 patients (48%) and was associated with BRAFV600E mutation [Odds ratio (OR) = 7.4, 95% confidence interval (CI) (3.5-16.8), P < 0.001] and ECD-related clinical events [OR = 5, 95%CI (1.5-21.2), P = 0.004] but not with lower survival in multivariate analysis [adjusted hazard ratio (HR) = 1.4, 95% CI (0.8-2.5), P = 0.2]. CONCLUSION: Cardiac involvement is present in nearly half of ECD patients and is associated with BRAFV600E mutation and complications (pericarditis, cardiac tamponade, and conduction disorders) but not with lower survival.

Electrocardiographic findings in patients with arrhythmogenic cardiomyopathy and right bundle branch block ventricular tachycardia.

AIMS: Little is known about patients with right bundle branch block (RBBB)-ventricular tachycardia (VT) and arrhythmogenic cardiomyopathy (ACM). Our aims were: (i) to describe electrocardiogram (ECG) characteristics of sinus rhythm (SR) and VT; (ii) to correlate SR with RBBB-VT ECGs; and (iii) to compare VT ECGs with electro-anatomic mapping (EAM) data. METHODS AND RESULTS: From the European Survey on ACM, 70 patients with spontaneous RBBB-VT were included. Putative left ventricular (LV) sites of origin (SOOs) were estimated with a VT-axis-derived methodology and confirmed by EAM data when available. Overall, 49 (70%) patients met definite Task Force Criteria. Low QRS voltage predominated in lateral leads (n = 37, 55%), but QRS fragmentation was more frequent in inferior leads (n = 15, 23%). T-wave inversion (TWI) was equally frequent in inferior (n = 28, 42%) and lateral (n = 27, 40%) leads. TWI in inferior leads was associated with reduced LV ejection fraction (LVEF; 46 ± 10 vs. 53 ± 8, P = 0.02). Regarding SOOs, the inferior wall harboured 31 (46%) SOOs, followed by the lateral wall (n = 17, 25%), the anterior wall (n = 15, 22%), and the septum (n = 4, 6%). EAM data were available for 16 patients and showed good concordance with the putative SOOs. In all patients with superior-axis RBBB-VT who underwent endo-epicardial VT activation mapping, VT originated from the LV. CONCLUSIONS: In patients with ACM and RBBB-VT, RBBB-VTs originated mainly from the inferior and lateral LV walls. SR depolarization and repolarization abnormalities were frequent and associated with underlying variants.

Safety and efficacy of flecainide associated with beta-blockers in arrhythmogenic right ventricular cardiomyopathy.

AIMS: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy associated with a high risk of ventricular arrhythmia (VA). Current guidelines recommend beta-blockers as first-line medical therapy and if ineffective, sotalol or amiodarone. We describe our experience, as a tertiary centre for ARVC, with the effectiveness and tolerance of flecainide in addition to beta-blockers to prevent VA in ARVC. METHODS AND RESULTS: We retrospectively included 100 consecutive ARVC patients who received flecainide with beta-blockers between May 1999 and November 2017. Treatment persistence and related side effects were assessed, as was VA-free survival on treatment, 24-h Holter monitoring and programmed ventricular stimulation (PVS) off- and on-treatment. Tolerance was good, with 10% flecainide discontinuations (lack of efficacy in six, atrial fibrillation in one, and side effects in three). No Brugada-induced electrocardiography pattern on flecainide or haemodynamic impairment was reported. Premature ventricular contraction burden at 24-h Holter monitoring was significantly decreased under treatment [median 415 (interquartile range, IQR 97-730) vs. 2370 (1572-3400) at baseline, P < 0.0001, n = 46]. Among the 33 patients with PVS under treatment, PVS was positive in 40% on-treatment vs. 94% off-treatment (P < 0.001). During a median follow-up of 47 months (IQR 23-73), 22 patients presented sustained VA on treatment, corresponding to an event rate of 5% [95% confidence interval (CI) (0.6-9)] at 1 year and 25% [95% CI (14-35)] at 5 years under treatment. No patient died. CONCLUSION: This study suggests that flecainide and beta-blockers association is complementary to implantable cardioverter-defibrillator and catheter ablation and is safe for treating persistent symptomatic VA in patients with ARVC.

The prevalence of left and right bundle branch block morphology ventricular tachycardia amongst patients with arrhythmogenic cardiomyopathy and sustained ventricular tachycardia: insights from the European Survey on Arrhythmogenic Cardiomyopathy.

AIMS: In arrhythmogenic cardiomyopathy (ACM), sustained ventricular tachycardia (VT) typically displays a left bundle branch block (LBBB) morphology while a right bundle branch block (RBBB) morphology is rare. The present study assesses the VT morphology in ACM patients with sustained VT and their clinical and genetic characteristics. METHODS AND RESULTS: Twenty-six centres from 11 European countries provided information on 954 ACM patients who had ≥1 episode of sustained VT spontaneously documented during patients' clinical course. Arrhythmogenic cardiomyopathy was defined according to the 2010 Task Force Criteria, and VT morphology according to the QRS pattern in V1. Overall, 882 (92.5%) patients displayed LBBB-VT alone and 72 (7.5%) RBBB-VT [alone in 42 (4.4%) or in combination with LBBB-VT in 30 (3.1%)]. Male sex prevalence was 79.3%, 88.1%, and 56.7% in the LBBB-VT, RBBB-VT, and LBBB + RBBB-VT groups, respectively (P = 0.007). First RBBB-VT occurred 5 years after the first LBBB-VT (46.5 ± 14.4 vs 41.1 ± 15.8 years, P = 0.011). An implanted cardioverter-defibrillator was more frequently implanted in the RBBB-VT (92.9%) and the LBBB + RBBB-VT groups (90%) than in the LBBB-VT group (68.1%) (P < 0.001). Mutations in PKP2 predominated in the LBBB-VT (65.2%) and the LBBB + RBBB-VT (41.7%) groups while DSP mutations predominated in the RBBB-VT group (45.5%). By multivariable analysis, female sex was associated with LBBB + RBBB-VT (P = 0.011) while DSP mutations were associated with RBBB-VT (P < 0.001). After a median follow-up of 103 (51-185) months, death occurred in 106 (11.1%) patients with no intergroup difference (P = 0.176). CONCLUSION: RBBB-VT accounts for a significant proportion of sustained VTs in ACM. Sex and type of pathogenic mutations were associated with VT type, female sex with LBBB + RBBB-VT, and DSP mutation with RBBB-VT.

Purkinje-related monomorphic ventricular tachycardia as a mechanism for electrical storm in ischemic heart disease.

A 60-years-old male with remote anterior myocardial infarction (MI) was referred for catheter ablation of electrical storm related to monomorphic ventricular tachycardia (MVT). Radiofrequency applications targeting pre-systolic potentials abolished all clinical MVTs. Scar-associated Purkinje-related MVT mimicking fascicular VT is a rare mechanism of post-MI MVT. The surviving Purkinje cells within scar border zones, responsible for VF during acute MI, may also generate MVT after scar organization occurring with time or after VF ablation. Identification of this mechanism is useful as ablation of a limited area can rapidly eliminate several MVTs.

Sexual Dimorphisms, Anti-Hormonal Therapy and Cardiac Arrhythmias.

Significant variations from the normal QT interval range of 350 to 450 milliseconds (ms) in men and 360 to 460 ms in women increase the risk for ventricular arrhythmias. This difference in the QT interval between men and women has led to the understanding of the influence of sex hormones on the role of gender-specific channelopathies and development of ventricular arrhythmias. The QT interval, which represents the duration of ventricular repolarization of the heart, can be affected by androgen levels, resulting in a sex-specific predilection for acquired and inherited channelopathies such as acquired long QT syndrome in women and Brugada syndrome and early repolarization syndrome in men. Manipulation of the homeostasis of these sex hormones as either hormonal therapy for certain cancers, recreational therapy or family planning and in transgender treatment has also been shown to affect QT interval duration and increase the risk for ventricular arrhythmias. In this review, we highlight the effects of endogenous and exogenous sex hormones in the physiological and pathological states on QTc variation and predisposition to gender-specific pro-arrhythmias.

A novel gain-of-function mutation in SCN5A responsible for multifocal ectopic Purkinje-related premature contractions.

Recently, four SCN5A mutations have been associated with Multifocal Ectopic Purkinje-related Premature Contractions (MEPPC), a rare cardiac syndrome combining polymorphic ventricular arrhythmia with dilated cardiomyopathy (DCM). Here, we identified a novel heterozygous mutation in SCN5A (c.611C>A, pAla204Glu) in a young woman presenting with polymorphic premature ventricular contractions (PVCs) and DCM. After failure of antiarrhythmic drugs and an attempt of radiofrequency catheter ablation showing three exit-sites of PVCs, all with presystolic Purkinje potentials, a treatment by hydroquinidine was tried, leading to an immediate and spectacular disappearance of all PVCs and normalization of cardiac function. Electrophysiological studies showed that Nav 1.5-A204E mutant channels exhibited a significant leftward shift of 8 mV of the activation curve, leading to a larger hyperpolarized window current when compared to wild-type. Action potential modeling using Purkinje fiber and ventricular cell models predicted an arrhythmogenic effect predominant in Purkinje fibers for the A204E mutation. Comparison with other MEPPC-associated Nav 1.5 mutations revealed a common electrophysiological pattern of abnormal voltage-dependence of activation leading to a larger hyperpolarized window current as a shared biophysical mechanism of this syndrome. These features of the mutant sodium channels are likely to be responsible for the hyperexcitability of the fascicular-Purkinje system observed in patients with MEPPC.

Androgenic Effects on Ventricular Repolarization: A Translational Study From the International Pharmacovigilance Database to iPSC-Cardiomyocytes.

BACKGROUND: Male hypogonadism, arising from a range of etiologies including androgen-deprivation therapies (ADTs), has been reported as a risk factor for acquired long-QT syndrome (aLQTS) and torsades de pointes (TdP). A full description of the clinical features of aLQTS associated with ADT and of underlying mechanisms is lacking. METHODS: We searched the international pharmacovigilance database VigiBase for men (n=6 560 565 individual case safety reports) presenting with aLQTS, TdP, or sudden death associated with ADT. In cardiomyocytes derived from induced pluripotent stem cells from men, we studied electrophysiological effects of ADT and dihydrotestosterone. RESULTS: Among subjects receiving ADT in VigiBase, we identified 184 cases of aLQTS (n=168) and/or TdP (n=68; 11% fatal), and 99 with sudden death. Of the 10 ADT drugs examined, 7 had a disproportional association (reporting odds ratio=1.4-4.7; P<0.05) with aLQTS, TdP, or sudden death. The minimum and median times to sudden death were 0.25 and 92 days, respectively. The androgen receptor antagonist enzalutamide was associated with more deaths (5430/31 896 [17%]; P<0.0001) than other ADT used for prostate cancer (4208/52 089 [8.1%]). In induced pluripotent stem cells, acute and chronic enzalutamide (25 µM) significantly prolonged action potential durations (action potential duration at 90% when paced at 0.5 Hz; 429.7±27.1 (control) versus 982.4±33.2 (acute, P<0.001) and 1062.3±28.9 ms (chronic; P<0.001), and generated afterdepolarizations and/or triggered activity in drug-treated cells (11/20 acutely and 8/15 chronically). Enzalutamide acutely and chronically inhibited delayed rectifier potassium current, and chronically enhanced late sodium current. Dihydrotestosterone (30 nM) reversed enzalutamide electrophysiological effects on induced pluripotent stem cells. CONCLUSIONS: QT prolongation and TdP are a risk in men receiving enzalutamide and other ADTs. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT03193138.

Development and Validation of a New Risk Prediction Score for Life-Threatening Ventricular Tachyarrhythmias in Laminopathies.

BACKGROUND: An accurate estimation of the risk of life-threatening (LT) ventricular tachyarrhythmia (VTA) in patients with LMNA mutations is crucial to select candidates for implantable cardioverter-defibrillator implantation. METHODS: We included 839 adult patients with LMNA mutations, including 660 from a French nationwide registry in the development sample, and 179 from other countries, referred to 5 tertiary centers for cardiomyopathies, in the validation sample. LTVTA was defined as (1) sudden cardiac death or (2) implantable cardioverter defibrillator-treated or hemodynamically unstable VTA. The prognostic model was derived using the Fine-Gray regression model. The net reclassification was compared with current clinical practice guidelines. The results are presented as means (SD) or medians [interquartile range]. RESULTS: We included 444 patients, 40.6 (14.1) years of age, in the derivation sample and 145 patients, 38.2 (15.0) years, in the validation sample, of whom 86 (19.3%) and 34 (23.4%) experienced LTVTA over 3.6 [1.0-7.2] and 5.1 [2.0-9.3] years of follow-up, respectively. Predictors of LTVTA in the derivation sample were: male sex, nonmissense LMNA mutation, first degree and higher atrioventricular block, nonsustained ventricular tachycardia, and left ventricular ejection fraction (https://lmna-risk-vta.fr). In the derivation sample, C-index (95% CI) of the model was 0.776 (0.711-0.842), and the calibration slope 0.827. In the external validation sample, the C-index was 0.800 (0.642-0.959), and the calibration slope was 1.082 (95% CI, 0.643-1.522). A 5-year estimated risk threshold ≥7% predicted 96.2% of LTVTA and net reclassified 28.8% of patients with LTVTA in comparison with the guidelines-based approach. CONCLUSIONS: In comparison with the current standard of care, this risk prediction model for LTVTA in laminopathies significantly facilitated the choice of candidates for implantable cardioverter defibrillators. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT03058185.

Extracorporeal Membrane Oxygenation to Support Life-Threatening Drug-Refractory Electrical Storm.

OBJECTIVES: Despite rapid implementation of anti-arrhythmic treatment and sedation and controlling the triggering event, rare patients develop treatment-refractory electrical storm and their hemodynamic instability prevents emergency catheter ablation. In that context, venoarterial extracorporeal membrane oxygenation could rapidly restore hemodynamics and tissue perfusion and reduce myocardial oxygen consumption, until adequate anti-arrhythmic drug levels are reached to safely perform catheter ablation. DESIGN: Retrospective, multicenter study over an 8-year period. SETTING: Two French tertiary care centers. PATIENTS: Eighty-three consecutive adults with venoarterial extracorporeal membrane oxygenation-supported treatment-refractory electrical storm (median [interquartile range] age, 55 yr [48-63 yr]). MEASUREMENTS AND MAIN RESULTS: Fifty-nine percent of these patients had acute ischemic cardiomyopathy and 66% underwent cardiopulmonary resuscitation prior to venoarterial extracorporeal membrane oxygenation initiation, with 18% cannulated during it. Fifty patients (60%) had ventricular tachycardia and/or ventricular fibrillation alternating with short periods of sinus rhythm and 33 (40%) had refractory ventricular tachycardia and/or ventricular fibrillation. Twelve patients (15%) underwent safe catheter ablation under venoarterial extracorporeal membrane oxygenation. After a median of 3 days (1-13 d) on extracorporeal membrane oxygenation support, 37 patients (45%) were successfully weaned off and 42% were alive 6 months post-ICU admission. Multivariable analysis retained ventricular tachycardia and/or ventricular fibrillation episodes alternating with short periods of sinus rhythm (odds ratio, 0.18; 95% CI, 0.06-0.52; p = 0.002) and age less than 50 years (odds ratio, 0.32; 95% CI, 0.18-0.89; p = 0.002) as being independent protective factors with 6-month survival, regardless of the underlying electrical storm cause. CONCLUSIONS: Among venoarterial extracorporeal membrane oxygenation-supported drug-refractory electrical storm patients, 42% survived 6 months post-ICU admission. Ventricular tachycardia and/or ventricular fibrillation episodes alternating with short periods of sinus rhythm and age less than 50 years were independently associated with better survival.

Crossroads or "Flyovers" novel insights into ventricular tachycardia mechanisms: The path is twisting.

Diverging channels of activation may be observed in some ventricular tachycardia (VT) using ultra-high-density mapping. We present here cases of such diverging activation patterns as observed from 60 consecutive VT activation maps using the Rhythmia system™ (Boston Scientific, Marlborough, MA, USA). Diverging directions of activation in the same area with "crossroads" or "flyover" pattern can be traced, implying recording of independent multilayer channels. Adaptation of current automated recording by the 3D mapping system is mandatory for better investigating this phenomenon.

Mode and Characteristics of Arrhythmia Initiation in Idiopathic Ventricular Fibrillation: A THESIS Substudy.

BACKGROUND: There is limited information on the mode of arrhythmia initiation in idiopathic ventricular fibrillation (IVF). A non-pause-dependent mechanism has been suggested to be the rule. OBJECTIVES: The aim of this study was to assess the mode and characteristics of initiation of polymorphic ventricular tachycardia (PVT) in patients with short or long-coupled PVT/IVF included in THESIS (THerapy Efficacy in Short or long-coupled idiopathic ventricular fibrillation: an International Survey), a multicenter study involving 287 IVF patients treated with drugs or radiofrequency ablation. METHODS: We reviewed the initiation of 410 episodes of ≥1 PVT triplet in 180 patients (58.3% females; age 39.6 ± 13.6 years) with IVF. The incidence of pause-dependency arrhythmia initiation (prolongation by >20 ms of the preceding cycle length) was assessed. RESULTS: Most arrhythmias (n = 295; 72%) occurred during baseline supraventricular rhythm without ambient premature ventricular complexes (PVCs), whereas 106 (25.9%) occurred during baseline rhythm including PVCs. Nine (2.2%) arrhythmias occurred during atrial/ventricular pacing and were excluded from further analysis. Mode of PVT initiation was pause-dependent in 45 (15.6%) and 64 (60.4%) of instances in the first and second settings, respectively, for a total of 109 of 401 (27.2%). More than one type of pause-dependent and/or non-pause-dependent initiation (mean: 2.6) occurred in 94.4% of patients with ≥4 events. Coupling intervals of initiating PVCs were <350 ms, 350-500 ms, and >500 ms in 76.6%, 20.72%, and 2.7% of arrhythmia initiations, respectively. CONCLUSIONS: Pause-dependent initiation occurred in more than a quarter of arrhythmic episodes in IVF patients. PVCs having long (between 350 and 500 ms) and very long (>500 ms) coupling intervals were observed at the initiation of nearly a quarter of PVT episodes.

Clinical course of arrhythmogenic right ventricular cardiomyopathy with end-stage heart failure and outcome after heart transplantation.

BACKGROUND: Few data exist on the characteristics and outcomes of patients with arrhythmogenic right ventricular cardiomyopathy and advanced heart failure who undergo heart transplantation. AIM: To explore the pretransplant course and outcomes of patients with arrhythmogenic right ventricular cardiomyopathy after heart transplantation. METHODS: This observational retrospective monocentric study included all consecutive patients with arrhythmogenic right ventricular cardiomyopathy who underwent heart transplantation during a 13-year period (2006-2019) at Pitié-Salpêtrière University Hospital (Paris). RESULTS: A total of 23 patients with arrhythmogenic right ventricular cardiomyopathy underwent heart transplantation between 2006 and 2019. The median time from diagnosis to heart transplantation was 9 years, and the median age at transplantation was 50 years. At diagnosis, half of the patients had left ventricular dysfunction, 59% had extensive T-wave inversion and 43% had a history of sustained ventricular tachycardia. Only five patients were involved in intensive sport activity. Indications for heart transplantation were end-stage biventricular dysfunction in 13 patients, end-stage right ventricular heart failure in seven and electrical storm in three. Only three patients had pulmonary hypertension, and half of the patients had atrial arrhythmias. The survival rate 1 year after heart transplantation was 74% (95% confidence interval 53-88%). Eight patients experienced primary graft dysfunction needing extracorporeal membrane oxygenation. CONCLUSIONS: Patients with arrhythmogenic right ventricular cardiomyopathy who eventually needed heart transplantation mostly exhibited extended disease with biventricular dysfunction at diagnosis. Intensive sport activity did not seem to be a major determinant. Advanced heart failure usually occurred late in the course of the disease. Primary graft dysfunction after heart transplantation was frequent, and should be anticipated. Additional data are needed to identify the optimal timing for heart transplantation and predictors of end-stage heart failure in patients with arrhythmogenic right ventricular cardiomyopathy.

Correlations Between Endocardial Voltage Mapping, Diagnosis, and Genetics in Patients With Arrhythmogenic Right Ventricular Cardiomyopathy.

The relations between endocardial voltage mapping and the genetic background of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) have not been investigated so far. A total of 97 patients with proved or suspected ARVC who underwent 3-dimensional endocardial mapping and genetic testing have been retrospectively included. Presence, localization, and size of scar areas were correlated to ARVC diagnosis and the presence of a pathogenic variant. A total of 78 patients (80%) presented with some bipolar or unipolar scar on endocardial voltage mapping, whereas 43 carried pathogenic variants (44%). Significant associations were observed between presence of endocardial scars on voltage mapping and previous or inducible ventricular tachycardia, right ventricular function and dimensions, or electrocardiogram features of ARVC. A total of 60 of the 78 patients (77%) with an endocardial scar fulfilled the criteria for a definitive arrhythmogenic right ventricular dysplasia diagnosis versus 8 of 19 patients (42%) without scar (p = 0.003). Patients with a definitive diagnosis of ARVC had more scars from any location and the scars were larger in patients with ARVC. In the 68 patients with a definitive diagnosis of ARVC, the presence of any endocardial scar was similar whether an ARVC-causal mutation was present or not. Only scar extent was significantly greater in patients with pathogenic variants. There was no difference in the presence and characteristics of scars in PKP2 mutated versus other mutated patients. The 3-dimensional endocardial mapping could have an important role for refining ARVC diagnosis and may be able to detect minor forms with otherwise insufficient criteria for diagnosis. The trend for larger scar extent were observed in mutated patients, without any difference according to the mutated genes.

Assessment of atrial fibrillation in European emergency departments: insights from a prospective observational multicenter study.

BACKGROUND: The diagnosis and management of atrial fibrillation (AF) in emergency departments (EDs) have not been well described in France, with limited EU research. This study aimed to describe the diagnosis, management, and prognosis of AF patients in French EDs. METHODS: A prospective, observational 2-month study in adults diagnosed with AF was conducted at 32 French EDs. Data regarding patient characteristics, diagnosis, and treatment at EDs were collected, with 12-month follow-up. RESULTS: The study included a total of 1369 patients diagnosed with AF at an ED: 279 patients (20.4%) with idiopathic AF (no identified cause of the AF) and 1090 (79.6%) with secondary AF (with a principal diagnosis identified as the cause of AF). Patients were aged 84 years (median) and 51.3% were female. Significantly more idiopathic AF patients than secondary AF patients underwent CHA2DS2-VASc assessment (67.8% vs. 52.1%,) or echocardiography (21.2% vs. 8.3%), or received an oral anticoagulant and/or antiarrhythmic (62.0% vs. 12.9%). Idiopathic AF patients also had significantly higher rates of discharge to home (36.4% vs. 20.4%) and 3-month cardiologist follow-up (67.0% vs. 41.1%). At 12 months, 96% of patients with follow-up achieved sinus rhythm. The estimated Kaplan-Meier 12-month mortality rate was significantly lower with idiopathic AF than secondary AF (11.9% vs. 34.5%). CONCLUSIONS: Patients diagnosed with idiopathic or secondary AF at the ED presented heterogeneous characteristics and prognoses, with those with secondary AF having worse outcomes. Further studies are warranted to optimize patients' initial evaluation in EDs and provide appropriate follow-up.

Temporary transvenous VDD pacing as a bridge to permanent pacemaker implantation in patients with sepsis and haemodynamically significant atrioventricular block.

AIMS: Permanent pacemaker (PM) implantation is temporarily contraindicated in patients (pts) with sepsis. In patients with symptomatic atrioventricular (AV) block and infection, prolonged VVI pacing is therefore usually ensured by a ventricular pacing lead (PL) connected to an external PM generator. In patients with normal sinus function and heart failure, the VVI mode can exacerbate haemodynamic dysfunction. A single AV PL can be attractive to achieve physiological pacing. This study was designed to assess the efficacy and safety of temporary VDD pacing as a bridge to permanent PM implantation in patients with complete AV block until control of infection. METHODS AND RESULTS: This study included eight patients with complete AV block and sepsis with negative blood culture. Due to the presence of congestive heart failure, a single bipolar AV PL connected to an external VDD PM generator. At VDD implantation, P-wave amplitude was 1.9 ± 1.6 mV and R-wave was 11.3 ± 5.2 mV. The ventricular pacing threshold was 0.53 ± 0.1 V for a 0.5 ms pulse. Antibiotic therapy was instituted in all patients. A permanent VDD or DDD PM was implanted after 8 ± 2.5 days of temporary VDD pacing. At permanent PM implantation, the mean brain natriuretic peptide level had decreased and sepsis was controlled in all patients. No recurrence of sepsis was observed with a mean follow-up of 15.8 ± 5.3 months. CONCLUSION: Temporary VDD pacing is a safe and effective method to achieve prolonged AV physiological pacing in patients with AV block until infection has been controlled.

External Validation of a Risk Prediction Model for Ventricular Arrhythmias in Arrhythmogenic Right Ventricular Cardiomyopathy.

The new 5-year ventricular arrhythmia (VA) occurrence risk model is a major breakthrough for arrhythmia risk stratification in the challenging population of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). In the original study, the model resulted in a 20.6% reduction in implantable cardioverter-defibrillator (ICD) placement compared with the 2015 consensus, for the same protection level. However, only internal validation was performed, limiting generalisation. We externally validated the model in a European tertiary care cohort of 128 patients with ARVC with restrictive indications for primary prevention ICD placement. Overall, 74% were men, none had VA history, and a single patient had an ICD at baseline. Median age at diagnosis was 38 years (interquartile range [IQR] 28-50). During a median follow-up of 7.8 years (IQR 6.1-9.7), 15 patients (12%) experienced VA. The model provided good discrimination, with a C-index for 5-year VA risk prediction of 0.84 (95% confidence interval 0.74-0.93). However, the model led to an overestimation of the 5-year VA risk when applying thresholds < 50%. With a < 10% predicted risk, no patient showed VA. With a 7.5% predicted risk, the ICD:VA ratio was 6.3 vs 3.4 in the original study. The model still outperformed the 2015 International Task Force Consensus. Overall, in a relatively large European ARVC cohort with restrictive indications for ICD placement, the ARVC model for VA prediction successfully identified ARVC patients with VA during follow-up. Yet, our study underscores the need for careful threshold selection, considering the model's associated risk overestimation in low- to intermediate-risk patients.

Arrhythmia-induced cardiomyopathy: A potentially reversible cause of refractory cardiogenic shock requiring venoarterial extracorporeal membrane oxygenation.

BACKGROUND: The most severe form of arrhythmia-induced cardiomyopathy in adults- refractory cardiogenic shock requiring mechanical circulatory support-has rarely been reported. OBJECTIVE: The purpose of this study was to describe the management of critically ill patients admitted for acute, nonischemic, or worsening of previously known cardiac dysfunction and recent-onset supraventricular arrhythmia who developed refractory cardiogenic shock requiring venoarterial extracorporeal membrane oxygenation (VA-ECMO). METHODS: This study is a retrospective analysis of prospectively collected data. RESULTS: Between 2004 and 2018, 35 patients received VA-ECMO for acute, nonischemic cardiogenic shock and recent supraventricular arrhythmia (77% atrial fibrillation [AF]). Cardiogenic shock was the first disease manifestation in 21 patients (60%). Characteristics at ECMO implantation [median (interquartile range)] were Sequential Organ Failure Assessment score 10 (7-13); inotrope score 29 (11-80); left ventricular ejection (LVEF) fraction 10% (10%-15%); and lactate level 8 (4-11) mmol/L. For 12 patients, amiodarone and/or electric cardioversion successfully reduced arrhythmia, improved LVEF, and enabled weaning off VA-ECMO; 11 had long-term survival without transplantation or long-term assist device. Eight patients experiencing arrhythmia-reduction failure underwent ablation procedures (7 atrioventricular node [AVN] with pacing, 1 atrial tachycardia) and were weaned off VA-ECMO; 7 survived. Of the remaining 15 patients without arrhythmia reduction or ablation, only the 6 bridged to heart transplantation or left ventricular (LV) assist device survived. CONCLUSION: Arrhythmia-induced cardiomyopathy, mainly AF-related, is an underrecognized cause of refractory cardiogenic shock and should be considered in patients with nonischemic cardiogenic shock and recent-onset supraventricular arrhythmia. VA-ECMO support allowed safe arrhythmia reduction or rate control by AVN ablation while awaiting recovery, even among those with severe LV dilation.