Brugada syndrome in Japan and Europe: a genome-wide association study reveals shared genetic architecture and new risk loci.

BACKGROUND AND AIMS: Brugada syndrome (BrS) is an inherited arrhythmia with a higher disease prevalence and more lethal arrhythmic events in Asians than in Europeans. Genome-wide association studies (GWAS) have revealed its polygenic architecture mainly in European populations. The aim of this study was to identify novel BrS-associated loci and to compare allelic effects across ancestries. METHODS: A GWAS was conducted in Japanese participants, involving 940 cases and 1634 controls, followed by a cross-ancestry meta-analysis of Japanese and European GWAS (total of 3760 cases and 11 635 controls). The novel loci were characterized by fine-mapping, gene expression, and splicing quantitative trait associations in the human heart. RESULTS: The Japanese-specific GWAS identified one novel locus near ZSCAN20 (P = 1.0 × 10-8), and the cross-ancestry meta-analysis identified 17 association signals, including six novel loci. The effect directions of the 17 lead variants were consistent (94.1%; P for sign test = 2.7 × 10-4), and their allelic effects were highly correlated across ancestries (Pearson's R = .91; P = 2.9 × 10-7). The genetic risk score derived from the BrS GWAS of European ancestry was significantly associated with the risk of BrS in the Japanese population [odds ratio 2.12 (95% confidence interval 1.94-2.31); P = 1.2 × 10-61], suggesting a shared genetic architecture across ancestries. Functional characterization revealed that a lead variant in CAMK2D promotes alternative splicing, resulting in an isoform switch of calmodulin kinase II-δ, favouring a pro-inflammatory/pro-death pathway. CONCLUSIONS: This study demonstrates novel susceptibility loci implicating potentially novel pathogenesis underlying BrS. Despite differences in clinical expressivity and epidemiology, the polygenic architecture of BrS was substantially shared across ancestries.

Novel Compound Heterozygous Variants in Trans-2,3-Enoyl-Coenzyme A Reductase-Like Gene Associated With Catecholaminergic Polymorphic Ventricular Tachycardia.

A 10-year-old female patient experienced syncope while swimming, and electrocardiography revealed polymorphic ventricular tachycardia, leading to a diagnosis of catecholaminergic polymorphic ventricular tachycardia. No pathogenic variant was identified in RYR2. Additional comprehensive genetic testing revealed novel compound heterozygous variants in trans-2,3-enoyl-coenzyme A reductase-like gene, which caused a recessive form of catecholaminergic polymorphic ventricular tachycardia.

Right Atrial Septal Lead Enhances the Favorable Effects of the Adaptive Cardiac Resynchronization Therapy Algorithm.

The adaptive cardiac resynchronization therapy (CRT) algorithm provides synchronized left ventricular pacing (sLVP). However, ensuring a high sLVP rate is challenging. We assessed the association between the sLVP rate and pacing sites in the right atrium. We evaluated 71 patients who underwent CRT and in whom the adaptive CRT algorithm was applied (53 men; mean age, 66 ± 14 years; median follow-up period, 301 days; IQR: 212-596 days). The atrial pacing leads were positioned in the right atrial (RA) septum in 17 patients (septal group) and in the RA appendage in 54 patients (RA appendage group), with significantly higher sLVP rates in the septal group compared with the RA appendage group (81% ± 30% vs 63% ± 37%; P = 0.045). In patients with first-degree atrioventricular blocks, the sLVP rates tended to be higher in the septal group. Therefore, RA septal pacing increased sLVP rates in patients undergoing CRT.

Effect of adaptive cardiac resynchronization therapy in heart failure patients with pacemaker dependency.

BACKGROUND: An adaptive cardiac resynchronization therapy (aCRT) algorithm allows continuous adjustments of pacing timings of atrioventricular delays by periodic automatic evaluation of electrical conduction. This applies to patients with an atrioventricular block and is effective in cardiac resynchronization therapy (CRT) devices; however, whether this algorithm benefits patients with pacemaker dependency is uncertain. METHODS: This study examined the clinical impact of an aCRT algorithm in patients diagnosed with heart failure with reduced ejection fraction and pacemaker dependency. A total of 359 patients underwent CRT between January 2016 and December 2022. Patients undergoing pacemaker-dependent CRT with the aCRT algorithm function were selected. Sixty-four patients with pacemaker dependency (31 with aCRT algorithm and 33 without) were included. Pacemaker dependency was defined as the absence of spontaneous ventricular activity during the sensing test at VVI 30 bpm or prolonged atrioventricular delay (> 300 ms). The primary endpoint was the composite clinical outcome of all-cause death or hospitalization for heart failure. RESULTS: No significant differences were observed in baseline characteristics between groups. During a median follow-up of 1,067 days (interquartile range 553-1,776 days), aCRT reduced the risk of composite clinical outcomes in patients with pacemaker dependency (log-rank P = 0.028). In addition, using the aCRT algorithm was an independent predictor of the composite clinical outcomes in the multivariate analysis (hazard ratio 0.34, 95% confidence interval: 0.12-0.94, P = 0.038). CONCLUSION: The aCRT algorithm significantly reduced the risk of adverse clinical outcomes in patients with pacemaker dependency. This algorithm may be an important tool for managing such patients.

Evaluation of synchronized left ventricular pacing rate over biventricular pacing in cardiac resynchronization therapy.

BACKGROUND: The adaptive cardiac resynchronization therapy (aCRT) algorithm enables synchronized left ventricular pacing (sLVP) to achieve fusion with intrinsic right ventricular activation. Although sLVP presents benefits over biventricular pacing, the adequate sLVP rate for better clinical outcomes remains unclear. We aimed to assess the association between sLVP rates and clinical outcomes. METHODS: Our study cohort included 271 consecutive patients, who underwent CRT implantation between April 2016 and August 2021. RESULTS: We evaluated 63 patients on whom we applied the aCRT algorithm [48 men, mean age: 64 ±â€¯14 years; median follow-up period: 316 days (interquartile range: 212-809 days)]. At the 6-month follow-up after CRT implantation, the frequency of CRT responders was 71 % (n = 45). The sLVP rate was significantly higher in responders than in non-responders (75 ±â€¯30 % vs. 47 ±â€¯40 %, p = 0.003). Receiver operating characteristics curve analysis revealed that the optimal cut-off value during the sLVP rate was 59.4 % for the prediction of CRT responders (area under the curve, 0.70; sensitivity, 80 %; specificity, 61 %; positive predictive value, 84 %; and negative predictive value, 55 %). Kaplan-Meier analysis demonstrated that the higher-sLVP group (sLVP ≧59.4 %, n = 43) had a better prognosis (cardiac death and heart failure hospitalization) than the lower-sLVP group (sLVP <59.4 %, n = 20) (log-rank p < 0.001). Multivariate Cox hazard analysis revealed that a higher sLVP rate was associated with a good prognosis (p < 0.001). CONCLUSIONS: sLVP was associated with CRT response, and a higher sLVP rate (≧59.4 %) was important for good prognosis in patients with aCRT.

An international multicenter cohort study on implantable cardioverter-defibrillators for the treatment of symptomatic children with catecholaminergic polymorphic ventricular tachycardia.

BACKGROUND: Catecholaminergic polymorphic ventricular tachycardia (CPVT) may cause sudden cardiac death (SCD) despite medical therapy. Therefore, implantable cardioverter-defibrillators (ICDs) are commonly advised. However, there are limited data on the outcomes of ICD use in children. OBJECTIVE: The purpose of this study was to compare the risk of arrhythmic events in pediatric patients with CPVT with and without ICD. METHODS: We compared the risk of SCD in patients with RYR2 (ryanodine receptor 2) variants and phenotype-positive symptomatic patients with CPVT with and without ICD who were younger than 19 years and had no history of sudden cardiac arrest at phenotype diagnosis. The primary outcome was SCD; secondary outcomes were composite end points of SCD, sudden cardiac arrest, or appropriate ICD shocks with or without arrhythmic syncope. RESULTS: The study included 235 patients, 73 with ICD (31.1%) and 162 without ICD (68.9%). Over a median follow-up of 8.0 years (interquartile range 4.3-13.4 years), SCD occurred in 7 patients (3.0%), of whom 4 (57.1%) were noncompliant with medications and none had an ICD. Patients with ICD had a higher risk of both secondary composite outcomes (without syncope: hazard ratio 5.85; 95% confidence interval 3.40-10.09; P < .0001; with syncope: hazard ratio 2.55; 95% confidence interval 1.50-4.34; P = .0005). Thirty-one patients with ICD (42.5%) experienced appropriate shocks, 18 (24.7%) inappropriate shocks, and 21 (28.8%) device-related complications. CONCLUSION: SCD events occurred only in the no ICD group and in those not on optimal medical therapy. Patients with ICD had a high risk of appropriate and inappropriate shocks, which may be reduced with appropriate device programming. Severe ICD complications were common, and risks vs benefits of ICDs need to be considered.

Local dispersion of repolarization in the occurrence of ventricular fibrillation in Brugada syndrome: Possibility of phase 2 reentry?

To date, there have been no reports of recording epicardial electrograms at the onset of spontaneous ventricular fibrillation (VF) in patients with Brugada syndrome (BrS). In the case of BrS, unipolar and bipolar electrogram recording on the right ventricular epicardium revealed that dispersion of repolarization with delayed potential was associated with spontaneous occurrence of VF. Phase 2 reentry associated with shortening and dispersion of action potential could have been recorded for the first time in BrS. Epicardial unipolar mapping can guide accurate and appropriate ablation for the elimination of arrhythmia substrate in J wave syndrome.

Implications of ventricular arrhythmia after cardiac resynchronization therapy.

BACKGROUND: Conflicting data are available on whether ventricular arrhythmia (VA) or shock therapy increases mortality. Although cardiac resynchronization therapy (CRT) reduces the risk of VA, little is known about the prognostic value of VA among patients with CRT devices. OBJECTIVES: The purpose of this study was to evaluate the implications of VA as a prognostic marker for CRT. METHODS: We investigated 330 CRT patients within 1 year after CRT device implantation. The primary endpoint was the composite endpoint of all-cause death or hospitalization for heart failure. RESULTS: Forty-three patients had VA events. These patients had a significantly higher risk of the primary endpoint, even among CRT responders (P = .009). Fast VA compared to slow VA was associated with an increased risk of the primary endpoint (hazard ratio [HR] 2.14; 95% confidence interval [CI] 1.06-4.34; P = .035). Shock therapy was not associated with a primary endpoint (shock therapy vs antitachycardia pacing: HR 1.49; 95% CI 0.73-3.03; P = .269). The patients with VA had a lower prevalence of response to CRT (23 [53%] vs 202 [70%]; P = .031) and longer left ventricular paced conduction time (174 ± 23 ms vs 143 ± 36 ms; P = .003) than the patients without VA. CONCLUSION: VA occurrence within 1 year was related to paced electrical delay and poor response to CRT. VA could be associated with poor prognosis among CRT patients.

Clinical Significance of Atrial Tachyarrhythmia Duration for Ventricular Arrhythmia in Patients With Cardiac Resynchronization Therapy.

BACKGROUND: Atrial tachyarrhythmias (ATAs) are reportedly associated with ventricular arrhythmias (VAs). However, little is known about the association between ATA duration and the risk of VA. We investigated the relationship between ATA duration and subsequent VA in patients with a cardiac resynchronization therapy defibrillator (CRT-D).Methods and Results: We investigated associations between the longest ATA duration during the first year after cardiac resynchronization therapy (CRT) implantation and VA and VA relevant to ATA (VAATA) in 160 CRT-D patients. ATAs occurred in 63 patients in the first year. During a median follow-up of 925 days from 1 year after CRT implantation, 40 patients experienced 483 VAs. Kaplan-Meier analysis showed a significantly higher risk of VA in patients with than without ATA in the first year (log rank P=0.0057). Hazard ratios (HR) of VA (HR 2.36, 2.10, and 3.04 for ATA >30s, >6 min and >24 h, respectively) and only VAATA (HR 4.50, 5.59, and 11.79 for ATA >30s, >6 min and >24 h, respectively) increased according to the duration of ATA. In multivariate analysis, ATA >24 h was an independent predictor of subsequent VA (HR 2.42; P=0.02). CONCLUSIONS: Patients with ATA >24 h in the first year after CRT had a higher risk of subsequent VA and VAATA. The risk of VA, including VAATA, increased with the longest ATA duration.

Fatal Arrhythmic Risks in Cardiac Sarcoidosis With Mildly Impaired Cardiac Function.

Background: The prognosis and later fatal arrhythmia in cardiac sarcoidosis (CS) with relatively preserved cardiac function were unclear. Objectives: This study aimed to evaluate the prognosis and arrhythmic events in patients with CS and mildly impaired cardiac function. Methods: Data were collected from a nationwide Japanese cohort survey conducted in 57 hospitals (n = 420); 322 patients with CS with left ventricular ejection fraction (LVEF) >35% were investigated. Results: Ventricular tachycardia (VT) manifestation was present in 50 patients (16%) and absent in 272 (84%), of whom 36 (72%) and 46 (17%), respectively, had an implantable cardioverter-defibrillator (ICD). Over a median of 5 years, 23 all-cause deaths and 31 appropriate ICD discharges were observed. In Kaplan-Meier analysis, all-cause death did not differ between patients with and without VT manifestation (P = 0.660), although appropriate ICD therapy was significantly less used in patients without VT manifestation than in those with VT manifestation (P < 0.001). Of the 272 patients without VT manifestation, 18 had ventricular arrhythmic events (VAEs), including 3 sudden cardiac deaths and 15 appropriate ICD discharges. In multivariate analysis, concomitant nonsustained ventricular tachycardia (NSVT) with atrioventricular block (AVB), lower LVEF, abnormal gallium-67 scintigraphy or 18F-fluorodeoxyglucose positron emission tomography of the heart (Ga/PET), and concomitant NSVT with abnormal Ga/PET at CS diagnosis were independent predictors of VAEs (P = 0.008, P = 0.021, P = 0.049, and P = 0.024, respectively). Conclusions: If concomitant NSVT with AVB, concomitant NSVT with abnormal Ga/PET, or abnormal Ga/PET is observed in patients with CS and mildly impaired cardiac function (LVEF >35%), ICD should be considered as primary prevention.

N-terminal pro atrial natriuretic peptide as a prognostic marker of cardiac resynchronization therapy recipients.

Background: Although the dynamic changes of atrial natriuretic peptide (ANP) expressions in a failing heart are well-documented, the clinical implications of detailed measurements of each ANP molecular form processed from proANP remain unclear. Methods: Patients screening was conducted on patients who were eligible for cardiac resynchronization therapy (CRT) between 2014 and 2019 in our institution. Blood samples and echocardiographic parameters were collected on the day before and six months after implantation. Total ANP, proANP, and N-terminal fragment of proANP (NT-proANP) were examined as predictive biomarkers for cardiac death, left ventricular assist device implantation, and heart failure hospitalization following CRT implantation. Results: A total of 86 subjects (mean age 70 years, 64 males) who underwent successful CRT implantation were enrolled. Plasma levels of total ANP, proANP, and NT-proANP were not normally distributed [25.8 pM (interquartile range: 11.1-53.1), 2.2 pM (1.0-5.4), and 4.1 nM (2.4-7.1), respectively]. Over a median follow-up of 2.7 years, 31 patients (2 deaths and 29 heart failure hospitalizations) reached the endpoints. Among the different ANP forms, only NT-proANP emerged as an independent predictor of the composite outcome (adjusted odds ratio of 2.542 in those with levels above vs. below the median, 95 % confidence interval 1.151-5.615, p = 0.021). NT-proANP levels were associated with left atrial volume and left diastolic functional parameters and decreased in response to echocardiographic improvements at six months post-implantation (16 ± 44 % decrease in responders vs 18 ± 60 % increase in non-responders, p = 0.005). Conclusion: Pre-implantation NT-proANP levels could serve as a predictive factor for clinical outcomes in recipients of CRT.

Flecainide Is Associated With a Lower Incidence of Arrhythmic Events in a Large Cohort of Patients With Catecholaminergic Polymorphic Ventricular Tachycardia.

BACKGROUND: In severely affected patients with catecholaminergic polymorphic ventricular tachycardia, beta-blockers are often insufficiently protective. The purpose of this study was to evaluate whether flecainide is associated with a lower incidence of arrhythmic events (AEs) when added to beta-blockers in a large cohort of patients with catecholaminergic polymorphic ventricular tachycardia. METHODS: From 2 international registries, this multicenter case cross-over study included patients with a clinical or genetic diagnosis of catecholaminergic polymorphic ventricular tachycardia in whom flecainide was added to beta-blocker therapy. The study period was defined as the period in which background therapy (ie, beta-blocker type [beta1-selective or nonselective]), left cardiac sympathetic denervation, and implantable cardioverter defibrillator treatment status, remained unchanged within individual patients and was divided into pre-flecainide and on-flecainide periods. The primary end point was AEs, defined as sudden cardiac death, sudden cardiac arrest, appropriate implantable cardioverter defibrillator shock, and arrhythmic syncope. The association of flecainide with AE rates was assessed using a generalized linear mixed model assuming negative binomial distribution and random effects for patients. RESULTS: A total of 247 patients (123 [50%] females; median age at start of flecainide, 18 years [interquartile range, 14-29]; median flecainide dose, 2.2 mg/kg per day [interquartile range, 1.7-3.1]) were included. At baseline, all patients used a beta-blocker, 70 (28%) had an implantable cardioverter defibrillator, and 21 (9%) had a left cardiac sympathetic denervation. During a median pre-flecainide follow-up of 2.1 years (interquartile range, 0.4-7.2), 41 patients (17%) experienced 58 AEs (annual event rate, 5.6%). During a median on-flecainide follow-up of 2.9 years (interquartile range, 1.0-6.0), 23 patients (9%) experienced 38 AEs (annual event rate, 4.0%). There were significantly fewer AEs after initiation of flecainide (incidence rate ratio, 0.55 [95% CI, 0.38-0.83]; P=0.007). Among patients who were symptomatic before diagnosis or during the pre-flecainide period (n=167), flecainide was associated with significantly fewer AEs (incidence rate ratio, 0.49 [95% CI, 0.31-0.77]; P=0.002). Among patients with ≥1 AE on beta-blocker therapy (n=41), adding flecainide was also associated with significantly fewer AEs (incidence rate ratio, 0.25 [95% CI, 0.14-0.45]; P<0.001). CONCLUSIONS: For patients with catecholaminergic polymorphic ventricular tachycardia, adding flecainide to beta-blocker therapy was associated with a lower incidence of AEs in the overall cohort, in symptomatic patients, and particularly in patients with breakthrough AEs while on beta-blocker therapy.

Interference of cardiac implantable electronic devices and computed tomography imaging in the current era with a phantom model.

Introduction: Cardiac implantable electronic devices are used in patients with cardiac rhythm disorders. Computed tomography irradiation is not prohibited for patients with cardiac implantable electronic devices, despite adverse events being reported. Hence, appropriate preparation and knowledge are required before computed tomography irradiation can be carried out in these patients. Since there is limited knowledge or literature about the influence of computed tomography irradiation in cases with recent cardiac implantable electronic devices, we aimed to evaluate the adverse events and elucidate the necessary and sufficient safety measures associated with this therapy. Methods and Results: We placed cardiac implantable electronic devices on an anthropomorphic phantom model and observed their electrical activity in electrograms, while various protocols of computed tomography irradiation were implemented and adverse events evaluated. Oversensing with pauses of up to 3.2 s was observed in standard computed tomography protocols, but ventricular tachyarrhythmia or other clinically significant events could not be confirmed. Oversensing with pauses of up to 8.0 s was observed and ventricular tachyarrhythmia was detected in the maximum-dose protocols. However, treatments such as antitachycardia pacing or shock therapy for ventricular tachyarrhythmia were not observed because of their absence. Conclusion: Computed tomography irradiation for patients using cardiac implantable electronic devices is highly unlikely to cause clinically significant adverse events with the device settings and computed tomography protocols currently being used. Changing or monitoring the device settings routinely before computed tomography irradiation is not necessarily required for most patients.

Clinical presentation of calmodulin mutations: the International Calmodulinopathy Registry.

AIMS: Calmodulinopathy due to mutations in any of the three CALM genes (CALM1-3) causes life-threatening arrhythmia syndromes, especially in young individuals. The International Calmodulinopathy Registry (ICalmR) aims to define and link the increasing complexity of the clinical presentation to the underlying molecular mechanisms. METHODS AND RESULTS: The ICalmR is an international, collaborative, observational study, assembling and analysing clinical and genetic data on CALM-positive patients. The ICalmR has enrolled 140 subjects (median age 10.8 years [interquartile range 5-19]), 97 index cases and 43 family members. CALM-LQTS and CALM-CPVT are the prevalent phenotypes. Primary neurological manifestations, unrelated to post-anoxic sequelae, manifested in 20 patients. Calmodulinopathy remains associated with a high arrhythmic event rate (symptomatic patients, n = 103, 74%). However, compared with the original 2019 cohort, there was a reduced frequency and severity of all cardiac events (61% vs. 85%; P = .001) and sudden death (9% vs. 27%; P = .008). Data on therapy do not allow definitive recommendations. Cardiac structural abnormalities, either cardiomyopathy or congenital heart defects, are present in 30% of patients, mainly CALM-LQTS, and lethal cases of heart failure have occurred. The number of familial cases and of families with strikingly different phenotypes is increasing. CONCLUSION: Calmodulinopathy has pleiotropic presentations, from channelopathy to syndromic forms. Clinical severity ranges from the early onset of life-threatening arrhythmias to the absence of symptoms, and the percentage of milder and familial forms is increasing. There are no hard data to guide therapy, and current management includes pharmacological and surgical antiadrenergic interventions with sodium channel blockers often accompanied by an implantable cardioverter-defibrillator.

Transvenous lead extraction versus surgical lead extraction or conservative treatment for cardiac implantable electronic device infections: Propensity score-weighted analyses of a nationwide claim-based database.

INTRODUCTION: Infection is one of the most important complications associated with cardiac implantable electronic device (CIED) therapy. The number of reports comparing the outcomes of transvenous lead extraction (TLE), surgical lead extraction, and conservative treatment for CIED infections using a real-world database is limited. This study investigated the association between the treatment strategies for CIED infections and their outcomes. METHODS: We performed a retrospective analysis of 3605 patients with CIED infections admitted to 681 hospitals using a nationwide claim-based database collected between April 2012 and March 2018. RESULTS: We divided the 3605 patients into TLE (n = 938 [26%]), surgical lead extraction (n = 182 [5.0%]), and conservative treatment (n = 2485 [69%]) groups. TLE was performed more frequently in younger patients and at larger hospitals (p for trend < .001 for both). The rate of TLE increased during the study period, whereas that of surgical lead extraction decreased (p for trend < .001 for both). TLE was associated with lower in-hospital mortality (vs. surgical lead extraction: odds ratio [OR], 0.20; 95% CI, 0.06-0.70; vs. conservative treatment: OR, 0.45; 95% CI: 0.22-0.94) and lower 30-day readmission rates (vs. surgical lead extraction: OR, 0.18; 95% CI: 0.06-0.56; vs. conservative treatment: OR, 0.06; 95% CI, 0.03-0.13) in propensity score-weighted analyses. CONCLUSIONS: Only 26% of patients hospitalized for CIED infections received TLE. TLE was associated with significantly lower in-hospital mortality and 30-day recurrence rates than surgical lead extraction and conservative treatment, suggesting that TLE should be more widely recommended as a first-line treatment for CIED infections.

Significance of effective cardiac resynchronization therapy pacing for clinical responses: An analysis based on the effective cardiac resynchronization therapy algorithm.

BACKGROUND: High percent ventricular pacing maximizes cardiac resynchronization therapy (CRT) response. An effective CRT algorithm classifies each left ventricular (LV) pace as effective or ineffective on the basis of the detection of QS or QS-r morphology on the electrogram; however, the relationship between percent effective CRT pacing (%e-CRT) and responses is unclear. OBJECTIVE: We aimed to clarify the association between %e-CRT and clinical outcomes. METHODS: Of the 136 consecutive CRT patients, 49 using the adaptive and effective CRT algorithm with percent ventricular pacing > 90% were evaluated. The primary and secondary outcomes were heart failure (HF) hospitalization and prevalence of CRT responders, defined as patients with an improvement in LV ejection fraction of ≥10% or a reduction in LV end-systolic volume of ≥15% after CRT device implantation, respectively. RESULTS: We divided the patients into the effective group (n = 25) and the less effective group (n = 24) by the median value of %e-CRT (97.4% [93.7%-98.3%]). During the median follow-up period of 507 days (interquartile range 335-730 days), the effective group had a significantly lower risk of HF hospitalization than the less effective group as revealed by Kaplan-Meier analysis (log-rank, P = .016). Univariate analysis revealed %e-CRT ≥ 97.4% (hazard ratio 0.12; 95% confidence interval 0.01-0.95; P = .045) as a predictor of HF hospitalization. The effective group had a higher prevalence of CRT responders than the less effective group (23 [92%] vs 9 [38%]; P < .001). Univariate analysis revealed that %e-CRT ≥ 97.4% (odds ratio 19.20; 95% confidence interval 3.63-101.00; P < .001) was a predictor of CRT response. CONCLUSION: High %e-CRT is associated with high CRT responder prevalence and low HF hospitalization risk.

Clinical Predictors of Pacing Device Implantation in Implantable Cardiac Monitor Recipients for Unexplained Syncope.

Background: Implantable cardiac monitors (ICMs) help investigate the cause of unexplained syncope, but the probability and predictors of needing a pacing device thereafter remain unclear. Methods: We retrospectively analyzed the data of patients who received ICM insertion for unexplained syncope with suspected arrhythmic etiology. The data were obtained from a nationwide database obtained between April 1, 2012 and March 31, 2020. Multivariable mixed-effects survival analysis was performed to identify predictors of pacing device implantation (PDI), and a risk score model was developed accordingly. Results: In total, 2905 patients (age: 72 years [range: 60-78]) implanted with ICMs to investigate the cause of syncope were analyzed. During the median follow-up period of 128 days (range: 68-209) days, 473 patients (16%) underwent PDI. Older age, history of atrial fibrillation, bundle branch block (BBB), and diabetes were independent predictors of PDI in multivariable analysis. A risk score model was developed with scores ranging from 0 to 32 points. When patients with the lowest quartile score (0-13 points) were used as a reference, those with higher quartiles had a higher risk of PDI (second quartile: 14-15 points, hazard ratio [HR]: 3.86, 95% confidence interval [CI]: 2.62-5.68; third quartile: 16-18 points, HR: 4.67, 95% CI: 3.14-6.94; fourth quartile: 19-32 points, HR: 6.59, 95% CI: 4.47-9.71). Conclusions: The 4 identified predictors are easily assessed during the initial evaluation of patients with syncope. They may help identify patients with a higher risk of requiring permanent PDI.

Contexte: Les moniteurs cardiaques implantables (MCI) aident à déterminer la cause d'une syncope inexpliquée, mais la probabilité et les facteurs prédictifs du besoin d'un dispositif de stimulation cardiaque par la suite demeurent incertains. Méthodologie: Nous avons analysé de façon rétrospective les données de patients s'étant fait implanter un MCI après une syncope inexpliquée et chez lesquels une étiologie d'arythmie était soupçonnée. Les données proviennent d'une base de données nationale et s'étendent du 1er avril 2012 au 31 mars 2020. Une analyse de survie multivariable à effets mixtes a été effectuée pour cibler les facteurs prédictifs de l'implantation d'un dispositif de stimulation cardiaque (IDSC), et un modèle de score de risque a été conçu en conséquence. Résultats: Au total, les cas de 2905 patients (âge : 72 ans [écart interquartile (ÉI) : 60-78]) ayant reçu un MCI pour déterminer la cause de la syncope ont été analysés. Durant la période de suivi médiane de 128 jours (ÉI : 68-209), 473 patients (16 %) ont subi une IDSC. L'âge avancé, les antécédents de fibrillation auriculaire, le bloc de branche et le diabète étaient des facteurs prédictifs indépendants de l'IDSC dans l'analyse multivariable. Un modèle de score de risque a été conçu, les scores allant de 0 à 32 points. Lorsque les patients ayant un score dans le quartile inférieur (0 à 13 points) étaient utilisés à titre de référence, ceux ayant un score dans les quartiles supérieurs avaient un risque plus élevé d'IDSC (deuxième quartile : 14-15 points, rapport des risques instantanés [RRI] : 3,86, intervalle de confiance [IC] à 95 % de 2,62 à 5,68; troisième quartile : 16-18 points, RRI : 4,67, IC à 95 % de 3,14 à 6,94; quatrième quartile : 19-32 points, RRI : 6,59, IC à 95 % de 4,47 à 9,71). Conclusions: Les quatre facteurs prédictifs ciblés sont faciles à évaluer durant l'évaluation initiale des patients ayant subi une syncope. Ils peuvent aider à repérer les patients présentant un risque plus élevé d'avoir besoin d'un dispositif de stimulation cardiaque permanent.