Zero-fluoroscopy ablation in patients with cardiac electronic implantable devices

INTRODUCTION

Utilizing a three-dimensional (3-D) mapping system and intracardiac echocardiography (ICE) has allowed ablation procedures with less or without fluoroscopy; however, there is limited data for patients with cardiac electronic implantable device (CIED) leads regarding the suspected risk of lead injury. Therefore, we sought to explore technics to perform safe trans-septal approach and catheter manipulation technique in patients with CIED leads.

METHODS AND RESULTS

This study comprised 49 consecutive patients (59% males, median 73 years old) with CIED who underwent catheter ablation for supraventricular tachycardia requiring the trans-septal approach, 15 without fluoroscopy (zero-fluoro group), and 34 with fluoroscopy (conventional-fluoro group), between July 2019 and April 2021. All procedures were performed under a 3-D mapping system and ICE guidance. We compared the differences in treatment and development of complications between the two groups. The procedures were for atrial fibrillation (82%) and atrial tachycardia (76%). Coronary sinus catheter insertion and the trans-septal procedure were successfully performed in all patients. The median time from venipuncture to trans-septal procedure (zero-fluoro vs. conventional-fluoro group: 28 [18-37] min vs. 24 [21-31] min, p = .70), total procedure time (231 [142-274] min vs. 175 [163-225] min, p = .63), and the acute procedural success rate (100% vs. 97%, p = 1.00) did not differ between both groups. No patient showed lead-related complications in both groups.

CONCLUSION

This is the first study to show zero-fluoro ablation for supraventricular arrhythmia using 3-D mapping and ICE in patients with CIED leads was feasible under careful catheter manipulation.

Genotype-Phenotype Correlation of SCN5A Genotype in Patients With Brugada Syndrome and Arrhythmic Events: Insights From the SABRUS in 392 Probands

BACKGROUND

Brugada syndrome (BrS) is associated with mutations in the cardiac sodium channel gene, SCN5A. However, genetic studies of patients with BrS with arrhythmic events have been limited. We sought to compare various clinical, ECG, and electrophysiological parameters according to SCN5A genotype in a large cohort of BrS probands with first arrhythmic event.

METHODS

Survey on Arrhythmic Events in Brugada Syndrome is a survey of 10 Western and 4 Asian countries, gathering 678 patients with BrS with first arrhythmic event. Only probands were included, and SCN5A genotype adjudicated. Patients without appropriate genetic data were excluded. Associations of genotype with clinical features were analyzed.

RESULTS

The study group comprised 392 probands: 92 (23.5%) SCN5A+(44 pathogenic/likely pathogenic [P/LP] and 48 variants of unknown significance) and 300 (76.5%) SCN5A-.SCN5A missense variants and the patients hosting them were similar regardless of adjudication. A higher proportion of patients with P/LP were pediatric (<16 years) compared with SCN5A- (11.4% versus 3%, P=0.023). The proportion of females was higher among patients with P/LP compared with SCN5A- (18.2% versus 6.3%, P=0.013). P/LP probands were more likely to have a family history of sudden cardiac death compared with SCN5A- (41.9% versus 16.8%, P<0.001). A higher proportion of patients with P/LP were White compared with SCN5A- (87.5% versus 47%, P<0.001). Ethnicity (odds ratio, 5.41 [2.8-11.19], P<0.001) and family history of sudden cardiac death (odds ratio, 2.73 [1.28-5.82], P=0.009) were independent variables associated with P/LP genotype following logistic regression.

CONCLUSIONS

The genetic basis of BrS has a complex relationship with gender, ethnicity, and age. Probands hosting a P/LP variant tended to experience their first arrhythmic event at a younger age and to have events triggered by fever compared with patients with SCN5A-. In addition, they were more likely to be White and to have family history of sudden cardiac death. Among females, a P/LP variant suggests an increased risk of being symptomatic. This association should be further studied on an ethnically specific basis in large prospectively collected international cohorts.

The association between late-phase early recurrence within the blanking period after atrial fibrillation catheter ablation and long-term recurrence: Insights from a large-scale multicenter study

BACKGROUND

The relationship between the timing of the first early recurrence and late recurrence after a single catheter ablation procedure for atrial fibrillation is controversial.

METHODS

The Efficacy of Short-Term Use of Antiarrhythmic Drugs After Catheter Ablation for Atrial Fibrillation trial followed 2038 patients who underwent radiofrequency catheter ablation for atrial fibrillation.

RESULTS

Of the patients, 907 (45%) had early recurrences within 90 days after the initial ablation. We divided these patients into two groups according to the timing of the first early recurrence episode, namely the ER₁ group (early recurrence during the early phase; 0-30 days, n = 814) and ER₂ group (early recurrence during the late phase; 31-90 days, n = 93). Three years after ablation, patients with early recurrences had a significantly lower event-free rate from late recurrences after a 90-day blanking period than patients without early recurrences (36.2% and 74.2%, respectively; log-rank, P < 0.0001). Three years after ablation, the event-free rate was significantly higher in the ER₁ than the ER₂ group (38.3% and 17.1%, respectively; log-rank, P < 0.0001). Moreover, the event-free rate at 3 years in the ER₂ group was extremely low (5.6%) in patient with non-paroxysmal atrial fibrillation.

CONCLUSION

Early recurrences were strongly associated with late recurrences, especially in patients with the first recurrence episode at >1 month within the blanking period after a single ablation procedure. Therefore, these patients should undergo close observation during follow-up, when they had especially with non-paroxysmal atrial fibrillation.

Echocardiographic predictors of cardioembolic stroke due to underlying atrial fibrillation: Reliable left atrial remodeling signs in acute stroke

INTRODUCTION

Atrial remodeling due to high-burden atrial fibrillation (AF) is associated with cardioembolic stroke (CES). As not all CESs is caused by AF, we analyzed the diagnostic values of each echocardiographic parameter to distinguish likely AF-related CES in acute stroke patients while in non-AF rhythm.

METHODS

The data of consecutive patients with acute ischemic stroke in sinus rhythm between 2012 and 2015 were obtained. The echocardiographic parameters of patients with CES due to underlying AF (n = 61) and control patients (n = 319) with either large artery atherosclerosis or small-vessel occlusion were compared using receiver operating characteristic curves and logistic regression analyses. Each parameter was reassessed in acute stroke patients through a validation study using the same database with different periods of generalization.

RESULTS

CES patients with underlying AF showed a significantly larger left atrial volume index (LAVi), higher mitral inflow E wave (E), and lower A wave (A) than the controls. The area under the curve (AUC) (95% confidence interval) for diagnosing CES due to underlying AF was significantly higher for LAVi/A than for LAVi (0.785 versus 0.696, P < 0.01). Among patients aged >60 years, the E/A ratio had the highest AUC (0.857) of the parameters. The cut-off values were ≥ 0.70 (sensitivity, 55.7%; specificity, 90.9%) and ≥ 0.82 (sensitivity, 71.4%; specificity, 84.1%) for LAVi/A and the E/A ratio, respectively, in patients >60 years. The cut-off values of all parameters showed similar trends in a validation study.

CONCLUSION

LAVi/A is a useful indicator for distinguishing CES patients with underlying AF regardless of age, and the E/A ratio is reliable among patients aged >60 years in evaluation during acute stroke admission.

An anatomical approach to determine the location of the sinoatrial node during catheter ablation

INTRODUCTION

The sinoatrial node (SAN) should be identified before superior vena cava (SVC) isolation to avoid SAN injury. However, its location cannot be identified without restoring sinus rhythm. This study evaluated the usefulness of the anatomically defined SAN by comparing it with the electrically confirmed SAN (e-SAN) to predict the top-most position of e-SAN and thus establish a safe and more efficient anatomical reference for SVC isolation than the previously reported reference of the right superior pulmonary vein (RSPV) roof.

METHODS AND RESULTS

The e-SAN was identified as the earliest activation site in the electroanatomical map obtained during sinus rhythm. The anatomically defined SAN, the cranial edge of the crista terminalis (CT) visualized with intracardiac echocardiography (CT top), and the RSPV roof, which was obtained from the overlaid electroanatomical image of SVC and RSPV, were tagged on one map. The distance from the e-SAN to each reference was measured. Among 77 patients, the height of the e-SAN from the CT top was a median (interquartile range) of -2.0 (-8.0 to 4.0) mm. The e-SAN existed from 10 mm above the CT top or lower in 74 (96%) patients and from the RSPV roof or below in 73 (95%) patients. The reference of 10 mm above the CT top is more proximal to the right atrium than the RSPV roof and can provide longer isolatable SVC sleeves (30.0 [20.0-35.0] vs. 24.0 [18.0-30.0] mm, p < .001). The e-SAN tended to be found above the CT top when the heart rate during mapping was faster (adjusted odds ratio [95% confidence interval] per 10-bpm increase: 1.71 [1.20-2.43], p < .01).

CONCLUSION

The CT top is useful for predicting the upper limit of the e-SAN and can provide a better reference for SVC isolation than the RSPV roof.

Extracardiac Mass After Pericardiectomy: Mediastinal Fat Replacement Secondary to Progressive Constrictive Pericarditis

We describe an extracardiac mass in a 72-year-old man with a history of pericardiectomy for constrictive pericarditis. Imaging studies revealed that progressive shrinkage of the residual pericardium compressed mitral valve anteriority, and fat replacement of the secondarily enlarged posterior space of the atrioventricular groove appeared as a space-occupying lesion. (Level of Difficulty: Intermediate.).

A Pooled Analysis of the Prognostic Significance of Brugada Syndrome with Atrial Fibrillation

Background:

Guidelines have previously suggested that atrial fibrillation (AF) is associated with an increased risk of arrhythmic death in Brugada syndrome (BrS) patients. However, only two articles consisting of 17 AF patients with BrS supported these views. The risk stratification of BrS patients with AF remains controversial. Thus, a meta-analysis is used to estimate the risk stratification of BrS patients with AF.

Methods:

We searched for relevant studies published from 2000 to December 30, 2018. A total of 1712 patients with BrS from five studies were included: 200 patients (12%) were reported with AF, among whom 37 patients (19%) had arrhythmic events.

Results:

BrS patients with AF in all studies (OR 1.92, 95% CI:0.91to 4.04, P =0.09; Heterogeneity: P = 0.03, I2=61%) and some European studies (OR 1.12, 95% CI: 0.18 to 6.94, P=0.91; Heterogeneity: P = 0.006, I2=80%) did not display a higher risk of arrhythmic events than those without AF, but BrS patients with AF in Japanese studies (OR 2.32, 95% CI: 1.37 to 3.93, P=0.002; Heterogeneity: P = 0.40, I2=0%) had a higher risk of arrhythmic events than those without AF. The proportion of BrS patients with AF was greater in Japanese studies than in some European studies (16% vs. 9%, P<0.001).

Conclusions:

On the whole, BrS patients with AF showed no higher risk of arrhythmic events than those without AF, but BrS patients with AF in Japan had a higher risk of arrhythmic events than those without AF.

Characterization and Management of Arrhythmic Events in Young Patients With Brugada Syndrome

BACKGROUND

Information on young patients with Brugada syndrome (BrS) and arrhythmic events (AEs) is limited.

OBJECTIVES

The purpose of this study was to describe their characteristics and management as well as risk factors for AE recurrence.

METHODS

A total of 57 patients (age ≤20 years), all with BrS and AEs, were divided into pediatric (age ≤12 years; n = 26) and adolescents (age 13 to 20 years; n = 31).

RESULTS

Patients' median age at time of first AE was 14 years, with a majority of males (74%), Caucasians (70%), and probands (79%) who presented as aborted cardiac arrest (84%). A significant proportion of patients (28%) exhibited fever-related AE. Family history of sudden cardiac death (SCD), prior syncope, spontaneous type 1 Brugada electrocardiogram (ECG), inducible ventricular fibrillation at electrophysiological study, and SCN5A mutations were present in 26%, 49%, 65%, 28%, and 58% of patients, respectively. The pediatric group differed from the adolescents, with a greater proportion of females, Caucasians, fever-related AEs, and spontaneous type-1 ECG. During follow-up, 68% of pediatric and 64% of adolescents had recurrent AE, with median time of 9.9 and 27.0 months, respectively. Approximately one-third of recurrent AEs occurred on quinidine therapy, and among the pediatric group, 60% of recurrent AEs were fever-related. Risk factors for recurrent AE included sinus node dysfunction, atrial arrhythmias, intraventricular conduction delay, or large S-wave on ECG lead I in the pediatric group and the presence of SCN5A mutation among adolescents.

CONCLUSIONS

Young BrS patients with AE represent a very arrhythmogenic group. Current management after first arrhythmia episode is associated with high recurrence rate. Alternative therapies, besides defibrillator implantation, should be considered.

Meta-Analysis of Risk Stratification of SCN5A With Brugada Syndrome: Is SCN5A Always a Marker of Low Risk?

Background: SCN5A with Brugada syndrome (BrS) is not commonly considered as an independent risk marker for subsequent cardiac events. However, the risk of SCN5A combined with other clinical characteristics has not been fully investigated. Objectives: The aim of this study is to investigate and evaluate risk stratification and related risk factors of SCN5A in BrS. Methods: The databases of PubMed, EMBASE, Cochrane Library, MEDLINE, Chinese National Knowledge Infrastructure (CNKI) and Wanfang Data were searched for related studies published from January 2002 to May 2018 followed by meta-analysis. The BrS patients who underwent SCN5A gene tests were included. The prognosis and risk stratification of SCN5A combined with symptoms and asymptoms diagnosis in BrS, electrophysiology study (EPS) were then investigated and evaluated. Outcomes were defined as ventricular tachycardia/fibrillation (VT/VF), sudden cardiac death (SCD). Results: Eleven suitable studies involving 1892 BrS patients who underwent SCN5A gene tests were identified. SCN5A (+) was not considered to be a significant predictor of future cardiac events (95% CI: 0.89-2.11; P = 0.15; I 2 = 0%). However, SCN5A (+) patients with symptoms at diagnosis revealed a higher prevalence of future VT/VF, SCD compared to SCN5A (-) patients with symptoms at diagnosis. (95% CI: 1.06-3.70; P = 0.03 I 2 = 0%) Among asymptomatic patients, the risk did not significantly differ between SCN5A (+) patients and SCN5A (-) patients. (95% CI: 0.51-4.72; P = 0.45 I 2 = 0 %). In an investigation involving patients in EPS (-) BrS electrocardiogram (ECG), the risk of SCN5A (+) is higher than that of SCN5A (-) (P < 0.001). Conclusions: In BrS patients with symptoms at diagnosis or EPS (-), the meta-analysis suggests that SCN5A (+) are at a higher risk of arrhythmic events than SCN5A (-).

Pooled Analysis of Risk Stratification of Spontaneous Type 1 Brugada ECG: Focus on the Influence of Gender and EPS

Aims: Risk stratification of patients with Brugada syndrome (BrS) is vital for accurate prognosis and therapeutic decisions. Spontaneous Type 1 ST segment elevation is generally considered to be an independent risk factor for arrhythmic events. Other risk factors include gender, syncope, sudden cardiac arrest (SCA), and positive electrophysiological study (EPS). However, the further risk stratification of spontaneous type 1 combined with the other risk factors remains unclear. The present study pooled data from 4 large trials aiming to systematically evaluate the risk of spontaneous Type-1 ECG when combined with one or more of these other recognized risk factors.

Methods: We searched for related studies published from November 2, 2002 to February 10, 2018 in PubMed, EMBASE, Cochrane Library, MEDLINE, Chinese National Knowledge Infrastructure (CNKI), and Wanfang Databases. The pooled data were evaluated combining each risk factor with the presence of a spontaneous Type-1 ECG. All analyses were performed using Review Manager, version 5.0.12.

Results: Four eligible studies involving 1,338 patients (85% males, mean age: 48.1 ± 18.1 years) were enrolled. Spontaneous Type-1 ECG was associated with higher risk for ventricular tachycardia/fibrillation (VT/VF) than cases with non-Type 1 ECG in males (odds ratio: 95% CI: 1.84–5.17; P < 0.0001), but not in females (P = 0.29). Among spontaneous Type-1 cases with syncope or with positive EPS, the difference was not statistically significant (P = 0.06 and 0.07, respectively). Patients with Type-1 ECGs and positive EPS were at higher risk than those with negative EPS (95% CI: 1.10–5.04; P = 0.03). Pooled analysis showed an association of Spontaneous Type-1 ECG, Type-1 ECGs combined with male, and Type-1 ECGs combined with positive EPS between increased risk of arrhythmic events.

Conclusion: Our results indicate that in BrS patients, a spontaneous Type-1 ECG is an independent risk factor for SCD in males, but not in females. A spontaneous Type-1 BrS is associated with a worse prognosis when combined with positive EPS

Gender Differences in Prognosis and Risk Stratification of Brugada Syndrome: A Pooled Analysis of 4,140 Patients From 24 Clinical Trials

Background: Male gender has been consistently shown to be a risk factor for a greater number of arrhythmic events in patients with Brugada Syndrome (BrS). However, there have been no large-scale comprehensive pooled analyses to statistically and systematically verify this association. Therefore, we conducted a pooled analysis on gender differences in prognosis and risk stratification of BrS with a largest sample capacity at present.

Methods: We searched PubMed, Embase, Medline, Cochrane Library databases, Chinese National Knowledge Infrastructure, and Wanfang Data for relevant studies published from 2002 to 2017. The prognosis and risk stratification of BrS and risk factors were then investigated and evaluated according to gender.

Results: Twenty-four eligible studies involving 4,140 patients were included in the analysis. Male patients (78.1%) had a higher risk of arrhythmic events than female patients (95% confidence interval: 1.46–2.91, P < 0.0001). Among the male population, there were statistical differences between symptomatic patients and asymptomatic patients (95% CI: 2.63–7.86, P < 0.00001), but in the female population, no statistical differences were found. In the female subgroup, electrophysiological study (EPS) positive patients had a tendency toward a higher risk of arrhythmic events than EPS-negative patients (95% CI: 0.93–29.77, P = 0.06).

Conclusions: Male patients are at a higher risk of arrhythmic events than female patients. Within the male population, symptomatic patients have a significantly higher risk profile compared to asymptomatic patients, but no such differences are evident within the female population. Consequently, in the female population, the risk of asymptomatic patterns cannot be underestimated.

Development of Heart Failure From Transient Atrial Fibrillation Attacks in Responders to Cardiac Resynchronization Therapy

OBJECTIVES

This study aimed to clarify the clinical impact of transient atrial fibrillation (AF) attacks themselves and the efficacy of cardiac resynchronization therapy (CRT) in patients with intermittent AF.

BACKGROUND

The benefit of CRT in patients with intermittent AF, especially the effect of the AF attacks themselves, remains unclear.

METHODS

Among our cohort of 269 consecutive CRT patients, we compared the percent of biventricular pacing (BIVP%) and other clinical characteristics between patients with intermittent AF and those with sinus rhythm (SR).

RESULTS

During a median follow-up of 942 days (interquartile range: 379 to 1,464 days) a total of 22 patients, including 59% of CRT responders, developed heart failure (HF) due to a transient AF attack itself, and that accounted for 21% of all HF events. The BIVP% during the AF attacks was significantly lower than that during SR (p < 0.05). When compared to the SR groups, patients with intermittent AF had a significantly higher risk of developing HF or death (hazard ratio: 2.2; 95% confidence interval: 1.3 to 3.8). However, the patients who received a BIVP% of ≥90% during AF attacks were comparable to those with SR (hazard ratio: 1.2; 95% confidence interval: 0.4 to 3.0).

CONCLUSIONS

A substantial number of patients developed HF due to transient AF attacks themselves even in the CRT responders, and the reason was mainly due to the loss of the BIVP%.

HCN4-Overexpressing Mouse Embryonic Stem Cell-Derived Cardiomyocytes Generate a New Rapid Rhythm in Rats with Bradycardia

A biological pacemaker is expected to solve the persisting problems of an artificial cardiac pacemaker including short battery life, lead breaks, infection, and electromagnetic interference. We previously reported HCN4 overexpression enhances pacemaking ability of mouse embryonic stem cell-derived cardiomyocytes (mESC-CMs) in vitro. However, the effect of these cells on bradycardia in vivo has remained unclear. Therefore, we transplanted HCN4-overexpressing mESC-CMs into bradycardia model animals and investigated whether they could function as a biological pacemaker. The rabbit Hcn4 gene was transfected into mouse embryonic stem cells and induced HCN4-overexpressing mESC-CMs. Non-cardiomyocytes were removed under serum/glucose-free and lactate-supplemented conditions. Cardiac balls containing 5 × 10³ mESC-CMs were made by using the hanging drop method. One hundred cardiac balls were injected into the left ventricular free wall of complete atrioventricular block (CAVB) model rats. Heart beats were evaluated using an implantable telemetry system 7 to 30 days after cell transplantation. The result showed that ectopic ventricular beats that were faster than the intrinsic escape rhythm were often observed in CAVB model rats transplanted with HCN4-overexpressing mESC-CMs. On the other hand, the rats transplanted with non-overexpressing mESC-CMs showed sporadic single premature ventricular contraction but not sustained ectopic ventricular rhythms. These results indicated that HCN4-overexpressing mESC-CMs produce rapid ectopic ventricular rhythms as a biological pacemaker.

Age of First Arrhythmic Event in Brugada Syndrome

Background

Data on the age at first arrhythmic event (AE) in Brugada syndrome are from limited patient cohorts. The aim of this study is 2-fold: (1) to define the age at first AE in a large cohort of patients with Brugada syndrome, and (2) to assess the influence of the mode of AE documentation, sex, and ethnicity on the age at first AE.

Methods and Results

A survey of 23 centers from 10 Western and 4 Asian countries gathered data from 678 patients with Brugada syndrome (91.3% men) with first AE documented at time of aborted cardiac arrest (group A, n=426) or after prophylactic implantable cardioverter–defibrillator implantation (group B, n=252). The vast majority (94.2%) of the patients were 16 to 70 years old at the time of AE, whereas pediatric (<16 years) and elderly patients (>70 years) comprised 4.3% and 1.5%, respectively. Peak AE rate occurred between 38 and 48 years (mean, 41.9±14.8; range, 0.27–84 years). Group A patients were younger than in Group B by a mean of 6.7 years (46.1±13.2 versus 39.4±15.0 years; P <0.001). In adult patients (≥16 years), women experienced AE 6.5 years later than men ( P =0.003). Whites and Asians exhibited their AE at the same median age (43 years).

Conclusions

SABRUS (Survey on Arrhythmic Events in Brugada Syndrome) presents the first analysis on the age distribution of AE in Brugada syndrome, suggesting 2 age cutoffs (16 and 70 years) that might be important for decision-making. It also allows gaining insights on the influence of mode of arrhythmia documentation, patient sex, and ethnic origin on the age at AE.

Persistent increase in cardiac troponin T at hospital discharge predicts repeat hospitalization in patients with acute decompensated heart failure

Background

High-sensitive cardiac troponin T (hsTnT) is a sensitive biomarker of myocardial damage and predictor of acute decompensated heart failure (ADHF). However, there is little information on changes over time in hsTnT level during ADHF management. The aim of this prospective study was to evaluate changes in hsTnT levels between admission and at discharge in patients with ADHF, and identify factors that determine such levels and their prognostic significance.

Methods and results

We evaluated 404 ADHF patients with abnormal hsTnT levels (≥0.0135 ng/ml) on admission. The median (interquartile ranges) hsTnT levels on admission, at discharge, and percent changes in hsTnT levels were 0.038 (0.026 to 0.065), 0.032 (0.021 to 0.049) ng/ml, and -12.0 (-39.8 to 7.4) % respectively. The numbers of patients with falling (hsTnT decrease > -15%), stable (hsTnT change between -15 and +15%) and rising (hsTnT increase > +15%) hsTnT level at discharge were 190, 146, and 68, respectively. The percent change in B-type natriuretic peptide (BNP) levels was greater in the falling group, compared to the stable (p<0.001) and rising groups (p<0.001). Changes in hsTnT levels correlated significantly with changes in BNP levels (ρ = 0.22, p<0.001). Multivariate Cox regression analysis identified rising or stable hsTnT at discharge as a significant predictor of heart failure-related rehospitalization (hazard ratio: 1.69; 95% confidence interval: 1.06 to 2.70; p = 0.03).

Conclusions

Persistent increase in hsTnT levels at discharge correlated with inadequate decrease of BNP levels, and was a predictor of poor clinical outcome, with repeat heart failure hospitalizations.

Local Left Ventricular Epicardial J Waves and Late Potentials in Brugada Syndrome Patients with Inferolateral Early Repolarization Pattern

Background: Brugada syndrome (BrS) is characterized by J-point or ST-segment elevation on electrocardiograms (ECGs) and increased risk of ventricular fibrillation (VF). In BrS, epicardial depolarization abnormality with delayed potential on the right ventricular outflow tract is reportedly the predominant mechanism underlying VF. Yet VF occurrence is also associated with early repolarization (ER) pattern in the inferolateral ECG leads, which may represent the inferior and/or left lateral ventricular myocardium. The aim of this study was to examine epicardial electrograms recorded directly at the left ventricle (LV) in BrS patients after VF episodes.

Methods: In 12 BrS patients who had experienced VF episodes and 17 control subjects, a multipolar catheter was introduced into the left lateral coronary vein for unipolar and bipolar electrogram recordings at the LV epicardium. Both inferior and lateral ER patterns on ECG were observed in three BrS patients and six control subjects.

Results: In the epicardium, prominent J waves were detected using unipolar recording, and potentials after the QRS complex were detected using bipolar recording in three of the 12 BrS patients. These three patients also showed both inferior and lateral ER patterns on ECG. Neither prominent J waves nor potentials after the QRS complex were recorded at the endocardium of the LV in any of these three patients; nor were they seen at the epicardium in any of the control subjects. These features were accentuated on pilsicainide administration (n = 2) but diminished on constant atrial pacing (n = 3) and isoproterenol administration (n = 1). The J waves observed through unipolar recording coincided with the potentials after QRS complex observed through bipolar recording and with the inferolateral ER patterns on ECG.

Conclusions: We recorded prominent J waves in unipolar electrogram and potentials after QRS complex in bipolar electrogram at the LV epicardium in BrS patients with global ER pattern. The prominent J waves coincided with the potentials after QRS complex and the inferolateral ER pattern on ECG. The characteristics of the inferolateral ER pattern on ECG in these patients primarily represent depolarization feature.

Utility of High-Resolution Magnetocardiography to Predict Later Cardiac Events in Nonischemic Cardiomyopathy Patients With Normal QRS Duration

BACKGROUND

Nonischemic dilated cardiomyopathy (NIDCM) patients, even those with a narrow QRS, are at increased risk for major adverse cardiac events (MACE). We hypothesized that 64-channel magnetocardiography (MCG) would be useful to detect prognostic left intraventricular disorganized conduction (LiDC) by overcoming the limitations of fragmented QRS (fQRS, qualitative definitions, low specificity) and late potential (abnormality undetectable in earlier QRS).Methods and Results:We evaluated LiDC on MCG, defined as significant deviation from a global clockwise left ventricular (LV) activation pattern, and conventional noninvasive predictors of MACE, including fQRS and late potential, in 51 NIDCM patients with narrow QRS (LV ejection fraction, 22±7%; QRS duration, 99±11 ms). MACE was defined as cardiac death, lethal ventricular arrhythmias, or LV assist device (LVAD) implantation. LiDC was present in 22 patients. Baseline characteristics were comparable between patients with and without LiDC, except for the ratio of positive late potential. During a mean follow-up of 2.9 years, MACE developed in 16 NIDCM patients (3 cardiac deaths, 9 lethal ventricular arrhythmias, and 4 LVAD). MACE was more incident in patients with LiDC (13/22) than in those without (3/29, P<0.001). Multivariate analysis revealed LiDC, but not fQRS or late potential, as the strongest independent predictor of MACE (hazard ratio 4.28, 95% confidence interval 1.30-19.39, P=0.015).

CONCLUSIONS

MCG accurately depicts LiDC, a promising noninvasive predictor of MACE in patients with NIDCM and normal QRS.

Diagnosis and treatment of cardiac sarcoidosis

Sarcoidosis is a systemic granulomatous disease of unknown aetiology. The frequency of cardiac involvement (cardiac sarcoidosis (CS)) varies in the different geographical regions, but it has been reported that it is an absolutely important prognostic factor in this disease. Complete atrioventricular block is the most common, and ventricular tachycardia/ventricular fibrillation the second most common arrhythmia in this disease, both of which are associated with cardiac sudden death. Diagnosing CS is sometimes difficult because of the non-specific ECG and echocardiographic findings, and CS is sometimes misdiagnosed as dilated cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy or an idiopathic ventricular aneurysm, and therefore, endomyocardial biopsy is important, but has a low sensitivity. Another problem is the recognition of isolated types of CS. Recently, MRI and (18)F-fluorodeoxyglucose positron emission tomography have been demonstrated to be useful tools for the non-invasive diagnosis of CS as well as therapeutic evaluation tools, but are still unsatisfactory. Treatment of CS is usually done by corticosteroid therapy to control inflammation, prevent fibrosis and protect from any deterioration of the cardiac function, but the long-term outcome is still in debate. Despite the advancement of non-pharmacological approaches for CS (pacing, defibrillators and catheter ablation) to improve the prognosis, there are still many issues remaining to resolve diagnosing and managing CS. Here, we attempt a review of the clinical evidence, with special focus on the current understanding of this disease and showing the current strategies and remaining problems of diagnosing and managing CS.

Efficacy of Antiarrhythmic Drugs Short-Term Use After Catheter Ablation for Atrial Fibrillation (EAST-AF) trial

AIMS

Substantial portion of early arrhythmia recurrence after catheter ablation for atrial fibrillation (AF) is considered to be due to irritability in left atrium (LA) from the ablation procedure. We sought to evaluate whether 90-day use of antiarrhythmic drug (AAD) following AF ablation could reduce the incidence of early arrhythmia recurrence and thereby promote reverse remodelling of LA, leading to improved long-term clinical outcomes.

METHODS AND RESULTS

A total of 2038 patients who had undergone radiofrequency catheter ablation for paroxysmal, persistent, or long-lasting AF were randomly assigned to either 90-day use of Vaughan Williams class I or III AAD (1016 patients) or control (1022 patients) group. The primary endpoint was recurrent atrial tachyarrhythmias lasting for >30 s or those requiring repeat ablation, hospital admission, or usage of class I or III AAD at 1 year, following the treatment period of 90 days post ablation. Patients assigned to AAD were associated with significantly higher event-free rate from recurrent atrial tachyarrhythmias when compared with the control group during the treatment period of 90 days [59.0 and 52.1%, respectively; adjusted hazard ratio (HR) 0.84; 95% confidence interval (CI) 0.73-0.96; P = 0.01]. However, there was no significant difference in the 1-year event-free rates from the primary endpoint between the groups (69.5 and 67.8%, respectively; adjusted HR 0.93; 95% CI 0.79-1.09; P = 0.38).

CONCLUSION

Short-term use of AAD for 90 days following AF ablation reduced the incidence of recurrent atrial tachyarrhythmias during the treatment period, but it did not lead to improved clinical outcomes at the later phase.

Enhancement of Spontaneous Activity by HCN4 Overexpression in Mouse Embryonic Stem Cell-Derived Cardiomyocytes - A Possible Biological Pacemaker

BACKGROUND

Establishment of a biological pacemaker is expected to solve the persisting problems of a mechanical pacemaker including the problems of battery life and electromagnetic interference. Enhancement of the funny current (If) flowing through hyperpolarization-activated cyclic nucleotide-gated (HCN) channels and attenuation of the inward rectifier K+ current (IK1) flowing through inward rectifier potassium (Kir) channels are essential for generation of a biological pacemaker. Therefore, we generated HCN4-overexpressing mouse embryonic stem cells (mESCs) and induced cardiomyocytes that originally show poor IK1 currents, and we investigated whether the HCN4-overexpressing mESC-derived cardiomyocytes (mESC-CMs) function as a biological pacemaker in vitro.

METHODS AND RESULTS

The rabbit Hcn4 gene was transfected into mESCs, and stable clones were selected. mESC-CMs were generated via embryoid bodies and purified under serum/glucose-free and lactate-supplemented conditions. Approximately 90% of the purified cells were troponin I-positive by immunostaining. In mESC-CMs, expression level of the Kcnj2 gene encoding Kir2.1, which is essential for generation of IK1 currents that are responsible for stabilizing the resting membrane potential, was lower than that in an adult mouse ventricle. HCN4-overexpressing mESC-CMs expressed about a 3-times higher level of the Hcn4 gene than did non-overexpressing mESC-CMs. Expression of the Cacna1h gene, which encodes T-type calcium channel and generates diastolic depolarization in the sinoatrial node, was also confirmed. Additionally, genes required for impulse conduction including Connexin40, Connexin43, and Connexin45 genes, which encode connexins forming gap junctions, and the Scn5a gene, which encodes sodium channels, are expressed in the cells. HCN4-overexpressing mESC-CMs showed significantly larger If currents and more rapid spontaneous beating than did non-overexpressing mESC-CMs. The beating rate of HCN4-overexpressing mESC-CMs responded to ivabradine, an If inhibitor, and to isoproterenol, a beta-adrenergic receptor agonist. Co-culture of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) with aggregates composed of mESC-CMs resulted in synchronized contraction of the cells. The beating rate of hiPSC-CMs co-cultured with aggregates of HCN4-overexpressing mESC-CMs was significantly higher than that of non-treated hiPSC-CMs and that of hiPSC-CMs co-cultured with aggregates of non-overexpressing mESC-CMs.

CONCLUSIONS

We generated HCN4-overexpresssing mESC-CMs expressing genes required for impulse conduction, showing rapid spontaneous beating, responding to an If inhibitor and beta-adrenergic receptor agonist, and having pacing ability in an in vitro co-culture system with other excitable cells. The results indicated that these cells could be applied to a biological pacemaker.

Adenosine triphosphate-guided pulmonary vein isolation for atrial fibrillation: the UNmasking Dormant Electrical Reconduction by Adenosine TriPhosphate (UNDER-ATP) trial

AIMS

Most of recurrent atrial tachyarrhythmias after pulmonary vein isolation (PVI) for atrial fibrillation (AF) are due to reconnection of PVs. The aim of the present study was to evaluate whether elimination of adenosine triphosphate (ATP)-induced dormant PV conduction by additional energy applications during the first ablation procedure could reduce the incidence of recurrent atrial tachyarrhythmias.

METHODS AND RESULTS

We randomly assigned 2113 patients with paroxysmal, persistent, or long-lasting AF to either ATP-guided PVI (1112 patients) or conventional PVI (1001 patients). The primary endpoint was recurrent atrial tachyarrhythmias lasting for >30 s or those requiring repeat ablation, hospital admission, or usage of Vaughan Williams class I or III antiarrhythmic drugs at 1 year with the blanking period of 90 days post ablation. Among patients assigned to ATP-guided PVI, 0.4 mg/kg body weight of ATP provoked dormant PV conduction in 307 patients (27.6%). Additional radiofrequency energy applications successfully eliminated dormant conduction in 302 patients (98.4%). At 1 year, 68.7% of patients in the ATP-guided PVI group and 67.1% of patients in the conventional PVI group were free from the primary endpoint, with no significant difference (adjusted hazard ratio [HR] 0.89; 95% confidence interval [CI] 0.74-1.09; P = 0.25). The results were consistent across all the prespecified subgroups. Also, there was no significant difference in the 1-year event-free rates from repeat ablation for any atrial tachyarrhythmia between the groups (adjusted HR 0.83; 95% CI 0.65-1.08; P = 0.16).

CONCLUSION

In the catheter ablation for AF, we found no significant reduction in the 1-year incidence of recurrent atrial tachyarrhythmias by ATP-guided PVI compared with conventional PVI.

Comparison of outcomes in patients with probable versus definite cardiac sarcoidosis

Patients with probable cardiac sarcoidosis (CS) who satisfy only clinical cardiac findings for CS are not uncommon. The aim of this study was to compare outcomes between patients with probable CS and those with definite CS treated with steroids. The study population consisted of 101 consecutive patients who satisfied clinical cardiac findings for CS. Patients with definite CS were defined as having histologic or clinical confirmation of CS according to the guidelines and were treated with steroids. Patients with probable CS were defined as having only clinical cardiac findings but not definite CS because of no histologic confirmation or extracardiac sarcoidosis and were not treated with steroids. The end point was major adverse cardiac events. Forty-seven patients had definite CS, and the other 54 had probable CS. Except for serum angiotensin-converting enzyme levels and left ventricular dysfunction, clinical characteristics were similar between the 2 groups. Over a median follow-up period of 15 months, major adverse cardiac events occurred more frequently in patients with probable CS than in those with definite CS (74% vs 53%, p=0.029). The event-free survival rate was worse in patients with probable CS than in those with definite CS (log-rank test, p=0.006). Cox proportional-hazards analysis showed that probable CS was an independent predictor of major adverse cardiac events. In conclusion, outcomes were worse in patients with probable CS than in those with definite CS treated with steroids. The initiation of steroid treatment may be considered for patients who satisfy only clinical cardiac findings for CS.

Risk stratification in patients with Brugada syndrome without previous cardiac arrest – prognostic value of combined risk factors

BACKGROUND

Risk stratification in patients with Brugada syndrome for primary prevention of sudden cardiac death is still an unsettled issue. A recent consensus statement suggested the indication of implantable cardioverter defibrillator (ICD) depending on the clinical risk factors present (spontaneous type 1 Brugada electrocardiogram (ECG) [Sp1], history of syncope [syncope], and ventricular fibrillation during programmed electrical stimulation [PES+]). The indication of ICD for the majority of patients, however, remains unclear.

METHODS AND RESULTS

A total of 218 consecutive patients (211 male; aged 46 ± 13 years) with a type 1 Brugada ECG without a history of cardiac arrest who underwent evaluation for ICD including electrophysiological testing were examined retrospectively. During a mean follow-up period of 78 months, 26 patients (12%) developed arrhythmic events. On Kaplan-Meier analysis patients with each of Sp1, syncope, or PES+ suffered arrhythmic events more frequently (P=0.018, P<0.001, and P=0.003, respectively). On multivariate analysis Sp1 and syncope were independent predictors of arrhythmic events. When dividing patients according to the number of these 3 risk factors present, patients with 2 or 3 risk factors experienced arrhythmic events more frequently than those with 0 or 1 risk factor (23/93 vs. 3/125; P<0.001).

CONCLUSIONS

Syncope, Sp1, and PES+ are important risk factors and the combination of these risks well stratify the risk of later arrhythmic events.

Electrical storm in patients with brugada syndrome is associated with early repolarization

BACKGROUND

Electrical storms (ESs) in patients with Brugada syndrome (BrS) are rare though potentially lethal.

METHODS AND RESULTS

We studied 22 men with BrS and ES, defined as ≥3 episodes/d of ventricular fibrillation (VF) and compared their characteristics with those of 110 age-matched, control men with BrS without ES. BrS was diagnosed by a spontaneous or drug-induced type 1 pattern on the ECG in the absence of structural heart disease. Early repolarization (ER) was diagnosed by J waves, ie, >0.1 mV notches or slurs of the terminal portion of the QRS complex. The BrS ECG pattern was provoked with pilsicainide. A spontaneous type I ECG pattern, J waves, and horizontal/descending ST elevation were found, respectively, in 77%, 36%, and 88% of patients with ES, versus 28% (P<0.0001), 9% (P=0.003), and 60% (P=0.06) of controls. The J-wave amplitude was significantly higher in patients with than without ES (P=0.03). VF occurred during undisturbed sinus rhythm in 14 of 19 patients (74%), and ES were controlled by isoproterenol administration. All patients with ES received an implantable cardioverter defibrillator and over a 6.0±5.4 years follow-up, the prognosis of patients with ES was significantly worse than that of patients without ES. Bepridil was effective in preventing VF in 6 patients.

CONCLUSIONS

A high prevalence of ER was found in a subgroup of patients with BrS associated with ES. ES appeared to be suppressed by isoproterenol or quinidine, whereas bepridil and quinidine were effective in the long-term prevention of VF in the highest-risk patients.

Successful lung transplantation in a case with diffuse pulmonary arteriovenous malformations and hereditary hemorrhagic telangiectasia

Diffuse pulmonary arteriovenous malformations (AVMs) are associated with a poor prognosis and the therapeutic strategy remains controversial. We describe a pediatric patient with diffuse pulmonary AVMs associated with hereditary hemorrhagic telangiectasia (HHT), who presented with two cerebral AVMs in the parietal and occipital lobes as well. Of note, successful bilateral lung transplantation not only improved the hypoxemia but also resulted in size reduction of the cerebral AVMs. Although it is essential to consider involvements other than pulmonary AVMs, especially brain AVMs, to decide the indication, lung transplantation can be a viable therapeutic option for patients with diffuse pulmonary AVMs and HHT.

Cardiac dysfunction and prolonged hemodynamic deterioration after implantable cardioverter-defibrillator shock in patients with systolic heart failure

BACKGROUND

We investigated the acute effects of implantable cardioverter-defibrillator shock on myocardium, cardiac function, and hemodynamics in relation to left ventricular systolic function.

METHODS AND RESULTS

We studied 50 patients who underwent implantable cardioverter-defibrillator implantation and defibrillation threshold (DFT) testing: 25 patients with left ventricular ejection fraction (LVEF) ≥ 45% and 25 patients with LVEF <45%. We measured cardiac biomarkers (creatine kinase, creatine kinase-MB, myoglobin, cardiac troponin T and I, and N-terminal probrain natriuretic peptide). Left ventricular relaxation was assessed by global longitudinal strain rate during the isovolumetric relaxation period using speckle-tracking echocardiography. Blood sampling and echocardiography were performed before, immediately after, and 5 minutes and 4 hours after DFT testing. Mean arterial pressure was measured directly during DFT testing. Cardiac biomarkers showed no significant changes in either group. LVEF was decreased until 5 minutes after DFT testing and had recovered to the baseline at 4 hours in the group with reduced LVEF (P<0.001), whereas LVEF reduction was not observed in the group with preserved LVEF (P=0.637). Global isovolumetric relaxation period was decreased until 5 minutes after DFT testing and had recovered to the baseline at 4 hours in both groups (preserved LVEF: 0.39 ± 0.14 versus 0.23 ± 0.13* versus 0.23 ± 0.13* versus 0.40 ± 0.13 s(-1), *P<0.001 versus baseline; reduced LVEF: 0.15 ± 0.05 versus 0.08 ± 0.04† versus 0.09 ± 0.04† versus 0.15 ± 0.05 s(-1), †P<0.001 versus baseline, repeated-measures ANOVA). Time to recovery of mean arterial pressure to the baseline was prolonged in the group with reduced LVEF (P<0.001).

CONCLUSIONS

Implantable cardioverter-defibrillator shock transiently impairs cardiac function and hemodynamics especially in patients with systolic dysfunction, although significant tissue injury is not observed.

Intermittent arm ischemia induces vasodilatation of the contralateral upper limb

Intermittent arm ischemia before percutaneous coronary intervention induces remote ischemic preconditioning (RIPC) and attenuates myocardial injury in patients with myocardial infarction. Several studies have shown that intermittent arm ischemia increases coronary flow and is related to autonomic nerve system. The aim of this study was to determine whether intermittent arm ischemia induces vasodilatation of other arteries and to assess changes in the autonomic nerve system during intermittent arm ischemia in humans. We measured change in the right brachial artery diameter during intermittent left arm ischemia through three cycles of 5-min inflation (200 mmHg) and 5-min deflation of a blood-pressure cuff using a 10-MHz linear array transducer probe in 20 healthy volunteers. We simultaneously performed power spectral analysis of heart rate. Ischemia-reperfusion of the left arm significantly dilated the right brachial artery time-dependently, resulting in a 3.2 ± 0.4% increase after the 3rd cycle. In the power spectral analysis of heart rate, the high-frequency domain (HF), which is a marker of parasympathetic activity, was significantly higher after the 3rd cycle of ischemia-reperfusion than baseline HF (P = 0.02). Intermittent arm ischemia was accompanied by vasodilatation of another artery and enhancement of parasympathetic activity. Those effects may play an important role in the mechanism of RIPC.

Impact of hypertriglyceridemia on endothelial dysfunction during statin ± ezetimibe therapy in patients with coronary heart disease

Despite the use of statin therapy and achieving the target for low-density lipoprotein cholesterol, a substantial number of coronary events are not prevented, and residual risk factors remain unsettled. Recently, ezetimibe has been shown to reduce not only low-density lipoprotein cholesterol but also triglyceride (TG) levels. The aim of this study was to investigate the associations of residual risk factors, mainly hypertriglyceridemia, with endothelial function during statin therapy in patients with coronary heart disease and examine the effect of ezetimibe add-on therapy. A total of 109 consecutive patients with coronary heart disease during statin therapy were enrolled. Lipid profile was measured and endothelial function was assessed by flow-mediated dilation (FMD) of the brachial artery in a fasting state. Next, 32 patients with high TG levels (≥150 mg/dl) were prospectively assigned to the ezetimibe add-on group or the no-ezetimibe group, and endothelial function was assessed after 3 months. Multivariate linear regression analysis demonstrated that serum TG and high-density lipoprotein cholesterol levels were independent determinants of percentage FMD (β = -0.210 and 0.208, respectively, p <0.05). In patients with high TG levels, ezetimibe add-on therapy significantly improved percentage FMD (from 3.3 ± 1.1% to 4.0 ± 1.1%, p <0.005), whereas no significant change was observed in the no-ezetimibe group. Moreover, the improvement in percentage FMD was significantly associated with reduction in serum TG levels (β = -0.387, p <0.05) independent of the change in serum low-density lipoprotein cholesterol levels. In conclusion, hypertriglyceridemia is independently associated with endothelial dysfunction in patients with coronary heart disease during statin therapy. Ezetimibe add-on therapy improves endothelial function in these high-risk populations.

Ezetimibe improves postprandial hyperlipemia and its induced endothelial dysfunction

OBJECTIVE

Postprandial hyperlipemia has been shown to impair endothelial function and contribute to the development of atherosclerosis. We investigated the association between postprandial lipid profiles and endothelial function, and we examined the effects of ezetimibe on postprandial hyperlipemia and lipemia-induced endothelial dysfunction.

METHODS

A randomized prospective trial in which 10 mg/day of ezetimibe was administered to 10 subjects for 4 weeks and not administered to 10 subjects (control group) was performed. Lipid profiles and endothelial function, assessed by brachial artery flow-mediated dilation (FMD) during a fasting state and at 2, 4, 6 and 8 h after an oral cookie loading test, were determined before and after treatment for 4 weeks.

RESULTS

In all subjects before treatment, the maximum reduction in postprandial %FMD was significantly correlated with the maximum increases in postprandial triglyceride (TG) (r=-0.499, P<0.05) and apolipoprotein B-48 (apoB-48) concentrations (r=-0.551, P<0.05). Ezetimibe treatment for 4 weeks significantly suppressed postprandial elevation in TG (area under the incremental curve, from 1419±594 to 968±32 1 mg h/dl, P<0.05), remnant lipoprotein cholesterol (from 66.9±27.6 to 38.9±15.4 mg h/dl, P<0.01) and apoB-48 (from 58.8±27.5 to 36.2±17.0 μg h/ml, P<0.05) concentrations, and postprandial endothelial dysfunction assessed by %FMD (maximum reduction in %FMD, from -2.6±1.1% to -1.2±0.8%, P<0.05), whereas no significant changes were observed in the control group.

CONCLUSION

Postprandial hyperlipemia is closely correlated with transient endothelial dysfunction. Ezetimibe improves postprandial hyperlipemia and its induced endothelial dysfunction.