The Radiological and Histological Phenotype of Skeletal Abnormalities in Fetal ARCN1-Related Syndrome.

Mutations in ARCN1 give rise to a syndromic disorder with rhizomelic short stature with microretrognathia and developmental delay. ARCN1 encodes the delta subunit of the coat protein I complex, which is required for intracellular trafficking of collagen 1 and which may also be involved in the endoplasmic reticulum (ER) stress response. In this paper we describe for the first time the skeletal histological abnormalities in an 18-week-old fetus with an ARCN1 mutation, and we suggest that the skeletal phenotype in ARCN1-related syndrome has more resemblance with ER stress than with a defect in collagen 1 metabolism.

Atrial electrophysiological characteristics of aging.

INTRODUCTION: Advancing age is a known risk factor for developing atrial fibrillation (AF), yet it is unknown which electrophysiological changes contribute to this increased susceptibility. The goal of this study is to investigate conduction disturbances and unipolar voltages (UV) related to aging. METHODS: We included 216 patients (182 male, age: 36-83 years) without a history of AF undergoing elective coronary artery bypass surgery. Five seconds of sinus rhythm were recorded intraoperatively at the right atrium (RA), Bachmann's bundle (BB), the left atrium and the pulmonary vein area (PVA). Conduction delay (CD), -block (CB), -velocity (CV), length of longest CB lines and UV were assessed in all regions. RESULTS: With aging, increasing conduction disturbances were found, particularly at RA and BB (RA: longest CB line rs = .158, p = .021; BB: CB prevalence rs = .206, p = .003; CV rs = -.239, p < .0005). Prevalence of low UV areas (UV <5th percentile) increased with aging at the BB and PVA (BB: rs = .237, p < .0005 and PVA: rs = .228, p = .001). CONCLUSIONS: Aging is accompanied by an increase in conduction disturbances during sinus rhythm and a higher prevalence of low UV areas, particularly at BB and in the RA. These electrophysiological alterations could in part explain the increasing susceptibility to AF development associated with aging.

Prediction of ventricular tachyarrhythmia in Brugada syndrome by right ventricular outflow tract conduction delay signs.

BACKGROUND: Brugada syndrome (BrS) is an autosomal dominant disease responsible for sudden cardiac death in young individuals without structural anomalies. The most critical part in the management of this channelopathy is identification of high-risk patients, especially asymptomatic subjects. Prior studies have shown that conduction delay in the right ventricular outflow tract (RVOT) is the main mechanism for developing ventricular tachyarrhythmia (VTA) in BrS patients. The aim of this study was to investigate the significance of electrocardiographic RVOT conduction delay parameters as predictors for development of VTA in patients with BrS. METHODS AND RESULTS: We retrospectively analyzed electrocardiograms obtained from 147 BrS patients (43 ± 15 years, 65% men) and assessed the following electrocardiographic parameters: (1) Tzou criteria (V1R > 0.15 mV, V6S > 0.15 mV, and V6S:R > 0.2), (2) prominent S wave in lead I, lead II, and lead III, (3) SII > SIII, and (4) prominent Q wave in lead III as possible predictors of VTA occurrences during follow-up. Prominent SI, SII, SIII, SII > SIII, QIII, and +ve Tzou criteria occurred more frequently in patients who either presented with VTA or developed VTA during the follow-up of 56 (IQR: 40-76) months. SII > SIII has the highest area under the curve for prediction of VTA (AUC: 0.84, sensitivity: 80%, specificity: 89%). Multivariable regression analysis showed that prominent S waves in lead I, SII > SIII and +ve Tzou criteria are independent predictors for VTA in BrS patients. CONCLUSION: Prominent S in lead I, SII > SIII and +ve Tzou criteria can be used as effective signs for predicting VTA in patients with BrS.

Progression of late postoperative atrial fibrillation in patients with tetralogy of Fallot.

INTRODUCTION: ToF patients are at risk for ventricular deterioration at a relatively young age, which can be aggravated by AF development. Therefore, knowledge on AF development and its timespan of progression is essential to guide treatment strategies for AF. OBJECTIVE: We examined late postoperative AF onset and progression in ToF patients during long-term follow-up after ToF correction. In addition, coexistence of AF with regular supraventricular tachyarrhythmias (SVT) and ventricular tachyarrhythmias (VTA) was analyzed. METHODS AND RESULTS: ToF patients (N  =  29) with AF after ToF correction referred to the electrophysiology department between 2000 and 2015 were included. All available rhythm registrations were reviewed for AF, regular SVT, and VTA. AF progression was defined as transition from paroxysmal AF to (longstanding) persistent/permanent AF or from (longstanding) persistent AF to permanent AF. At the age of 44 ± 12 years, ToF patients presented with paroxysmal (N  =  14, 48%), persistent (N  =  13, 45%) or permanent AF (N  =  2, 7%). Age of AF development was similar among patients who either underwent initial shunt creation (N  =  15, 45 ± 11 [25-57] years) or primary total ToF correction (N  =  14, 43 ± 13 [26-66] years) (P  =  0.785). AF coexisted with regular SVT (N  =  18, 62%) and VTA (N  =  13, 45%). Progression of AF occurred in 11 patients (38%) within 5 ± 5 years after AF onset despite antiarrhythmic drug class II (AAD, P  =  0.052) or III (P  =  0.587) usage. CONCLUSIONS: AF in our ToF population developed at a young age and showed rapid progression. Rhythm control by pharmacological therapy was ineffective in preventing AF progression.

Intraoperative arrhythmias in children with congenital heart disease: transient, innocent events?

Aims: The significance and incidences of intraoperative arrhythmias occurring in the operating room (OR) in children with congenital heart disease (CHD) are unknown. Aims of this study were to determine incidences of intraoperative arrhythmias in children with CHD and to examine whether they are associated with persistent arrhythmias during follow-up. Methods and results: Continuous ECG recordings obtained from 134 consecutive paediatric CHD patients were manually examined from the moment the aortic cross-clamp (ACC) was removed [use of ACC and cardiopulmonary bypass (CPB)], when CPB was stopped (use of only CPB) or when the sternum was closed (no use of ACC and CPB) until departure from the OR. In the OR, 2nd (60%) and 3rd (34%) degree atrioventricular conduction block (AVB), ectopic atrial rhythm (30%), and junctional rhythm (32%) were most often observed in patients who underwent surgery with both ACC and CPB. Incidences of these arrhythmias decreased after cessation of CPB (P < 0.01). (Supra)ventricular premature beats were mostly observed between end of ACC time and sternum closure (64-84%), but decreased before departure from the OR (6-16%, P < 0.01). During a median follow-up of 37 months, 17 patients (13%) had new onset, late post-operative arrhythmias. Of these patients, 88% had intraoperative arrhythmias compared with 85% of patients without late post-operative arrhythmias (P = 1). Conclusion: Intraoperative arrhythmias, mainly 2nd degree AVB and (supra)ventricular premature beats, were frequently observed in children with CHD undergoing cardiac surgery with use of CPB and ACC. Most arrhythmias were short-lasting and transient and appeared not to be related to late post-operative arrhythmias.

Frequent atrial extrasystolic beats predict atrial fibrillation in patients with congenital heart defects.

Aims: Atrial fibrillation (AF) is increasingly observed in patients with congenital heart defects (CHDs) who survive nowadays into adulthood. Yet, predictors of AF are scarce in this high-risk population. This study therefore examined the predictive ability of atrial extrasystole (AES) for development of AF in CHD patients. Methods and results: Adult CHD patients who had a 24 h Holter registration were followed to determine who developed AF. A total of 573 patients (49% male, mean age 35 ± 12 years) were included; they had a simple/complete repaired CHD (n = 279), complex repaired CHD (n = 251), or univentricular heart (UVH, n = 43). Ageing (P < 0.0001), female gender (P = 0.028), UVH (P = 0.0010), and left atrial dilatation (P = 0.0025) were associated with the number of AES. During a median follow-up of 51.6 months (interquartile range 22.8-85.7), 29 patients (5%) developed de novo AF. An one-point increase in the number of logtotal-AES was associated with a two-fold higher risk of AF development (hazard ratio 1.95; 95% confidence interval 1.21-3.13; P = 0.016). C-statistic for left atrial dilatation, complexity, and age had a good discriminative ability for the incidence of AF with a C-statistic of 84.5%. The addition of the total number of AES/24 h to this model increased C-statistic to 88.4%. Conclusion: Atrial extrasystole occur relatively frequent in adult CHD patients compared with patients with other cardiac diseases. This is the first study that showed an association between an increased AES frequency and a higher risk of AF development in CHD patients.

Histological evidence of a connection between true and false lumen in spontaneous coronary artery dissection.

The pathophysiological mechanism underlying spontaneous coronary artery dissection remains unclear. Although an endothelial-intimal disruption is assumed to be involved as either a primary or secondary event, the presence of a tear in the coronary intima has not been histologically presented, to our knowledge. We present three autopsy cases of spontaneous coronary artery dissection in which histopathological examination revealed an intimal tear and connection between true and false lumen in the area of the dissection.

Identification of Low-Voltage Areas: A Unipolar, Bipolar, and Omnipolar Perspective.

[Figure: see text].

First-in-children epicardial mapping of the heart: unravelling arrhythmogenesis in congenital heart disease.

Patients with congenital heart disease (CHD) are prone to develop atrial and ventricular arrhythmias. Multiple factors throughout life contribute to arrhythmogenicity substrate such as (i) (longstanding) volume and/or pressure overload, (ii) scar tissue, (iii) ageing-related structural remodelling, (iv) cardiovascular risk factors and (v) tachycardia-induced remodelling. At present, it is unknown whether, and to what extent, paediatric patients with CHD have atrial or ventricular conduction disorders early in life and whether there is a correlation between duration of volume/pressure overload and extensiveness of conduction disorders. To investigate this, we initiated high-resolution intraoperative epicardial mapping in paediatric patients with CHD undergoing primary open-heart surgery.

Outcomes of Atrial Arrhythmia Surgery in Patients With Congenital Heart Disease: A Systematic Review.

Background The improved life expectancy of patients with congenital heart disease is often accompanied by the development of atrial tachyarrhythmias. Similarly, the number of patients requiring redo operations is expected to continue to rise as these patients are aging. Consequently, the role of arrhythmia surgery in the treatment of atrial arrhythmias is likely to become more important in this population. Although atrial arrhythmia surgery is a well-established part of Fontan conversion procedures, evidence-based recommendations for arrhythmia surgery for macroreentrant atrial tachycardia and atrial fibrillation in other patients with congenital heart disease are still lacking. Methods and Results Twenty-eight studies were included in this systematic review. The median reported arrhythmia recurrence was 13% (interquartile range, 4%-26%) during follow-up ranging from 3 months to 15.2 years. A large variation in surgical techniques was observed. Based on the acquired data, biatrial lesions are more effective in the treatment of atrial fibrillation than exclusive right-sided lesions. Right-sided lesions may be more appropriate in the treatment of macroreentrant atrial tachycardia; evidence for the superiority of additional left-sided lesions is lacking. There are not enough data to support the use of exclusive left-sided lesions. Theoretically, prophylactic atrial arrhythmia surgery may be beneficial in this population, but evidence is currently limited. Conclusions To be able to provide recommendations for arrhythmia surgery in patients with congenital heart disease, future studies should report outcomes according to the type of preoperative arrhythmia, underlying congenital heart disease, lesion set, and energy source. This is essential for determining which surgical techniques should ideally be applied under which circumstances.

Distribution of Conduction Disorders in Patients With Congenital Heart Disease and Right Atrial Volume Overload.

OBJECTIVES: This study sought to quantify characteristics of atrial conduction disorders in patients with right atrial (RA) volume overload. BACKGROUND: Patients with an interatrial shunt are prone to developing atrial fibrillation (AF), which may be related to conduction disorders occurring due to atrial stretch. METHODS: Thirty-one patients undergoing surgery for an interatrial shunt (49 ± 14 years of age) underwent epicardial sinus rhythm mapping of the RA, Bachmann's bundle (BB), and left atrium (LA). Conduction delay (CD) was defined as interelectrode conduction time (CT) of 7 to 11 ms and conduction block (CB) as CT ≥12 ms. Prevalence of CD or CB (percentage of mapped region), length of lines, and severity of CB (75th percentile of CTs ≥12 ms) were analyzed. RESULTS: All patients had some degree of CD and CB. Prevalence of CD and CB was higher in the RA and BB than in the LA (p < 0.0083 after Bonferroni correction). The longest CB line within each patient was found in the RA in most patients (52%). Interindividual variation in prevalence and lengths of lines was considerable. CB was more severe in the RA than in the LA (p < 0.0083). Within the RA, conduction disorders were more prevalent and more severe in the intercaval region than in the RA free wall (p < 0.05). CONCLUSIONS: In patients with an interatrial shunt, conduction disorders during sinus rhythm are most pronounced in the RA-particularly the intercaval region-and BB. Knowledge of the conduction during sinus rhythm is essential to determine the relevance of conduction disorders for initiation and perpetuation of AF.

Concomitant pulmonary vein isolation and percutaneous closure of atrial septal defects: A pilot project.

BACKGROUND: Patients with an atrial septal defect (ASD) are at increased risk of developing atrial fibrillation (AF). Currently percutaneous ASD closure is the preferred therapeutic strategy and although pulmonary vein isolation (PVI) for AF is feasible after ASD closure, the transseptal puncture can be technically challenging and probably increases the perioperative risk. A staged approach, with PVI several months before ASD closure, has been recommended for patients already scheduled for closure, but no data are available on combined procedures. PURPOSE: This pilot study evaluates the feasibility of a combined procedure of PVI and ASD closure in patients with a hemodynamic important ASD and documented AF. METHODS: In one procedure, PVI was performed prior to placement of the ASD closure device. Transseptal access for PVI was obtained via wire passage through the ASD in all patients. Patients were followed with 5-day-holter monitoring at 3, 6, and 12 months. Recurrence of AF was defined as a documented, symptomatic episode of AF. RESULTS: The study population consisted of five patients (four females, mean age: 58 (±3) years). Acute PVI was achieved in all patients. Only one patient had a small residual ASD after closure. Besides a small groin hematoma in two patients, no complications occurred. After 12-month follow-up, three patients were free of AF recurrence (60%). CONCLUSION: This study shows that a combined PVI with ASD closure is feasible with an acceptable success rate of AF free survival. These preliminary results in a small patient group warrants a larger trial.

Ventricular Dysrhythmias During Long-Term Follow-Up in Patients With Inherited Cardiac Arrhythmia.

Reports on development of frequent ventricular premature complexes (fVPC), (non)sustained ventricular tachycardias ([n]sVT), or ventricular fibrillation (VF) and their interrelationship in patients with different inherited cardiac arrhythmia (ICA) have sofar not been reported. The aim of this study is therefore to examine incidences and recurrences rates of sVT and VF ("malignant ventricular tachyarrhythmias, VTA") in addition to the incidence of fVPC and nsVT ("ventricular dysrhythmias, VDR") in patients with various ICA during long-term follow up. Patients (N = 167, 88 male, age 45 ± 15 years) with ICA including definite/borderline arrhythmogenic right ventricular cardiomyopathy (ARVC, N = 47), Brugada syndrome (BrS, N = 71), catecholaminergic polymorphic ventricular tachycardia (CPVT, N = 7), long QT syndrome (LQTS, N = 41) or short QT syndrome (SQTS, N = 1) who had frequent 24-hour Holter monitoring during a follow-up period of 4.6 ± 4.4 years. During the initial screening visit, 15 patients had a history of malignant VTA. fVPC and nsVT was observed in respectively 19% (OHCA/VF/sVT: N = 9) and 13% (OHCA/VF/sVT: N = 4) of all patients. Compared with the ARVC group, patients with BrS and LQTS had less frequent fVPC and nsVT (fVPC: odds ratio [OR] 0.20, 95% confidence interval [CI] 0.08 to 0.49, p <0.000 and OR 0.09, 95% CI 0.02 to 0.33, p <0.000; nsVT:OR 0.17, 95% CI 0.06 to 0.50, p = 0.001 and OR 0.09, 95% CI 0.02 to 0.46, p = 0.003). The recurrence rate of malignant VTA was 33%. In conclusion, variety of VDR and malignant VTA were found during long-term follow-up in patients with ICA. During nearly a 5 years follow-up period, the recurrence rate of malignant VTA was considerable. fVPC, nsVT, and malignant VTA were most often found in patients with an ARVC.

QRS Vector Magnitude as Predictor of Ventricular Arrhythmia in Patients With Brugada Syndrome.

Risk stratification is the most challenging part in management of patients with Brugada syndrome (BrS). Conduction delay in the right ventricular outflow tract (RVOT) is the major mechanism underlying ventricular tachyarrhythmia (VTA) in BrS. However, QRS duration was not useful in stratifying high-risk patients in large registries. Reconstructing the traditional 12-lead electrocardiogram into QRS vector magnitude can be used to quantify depolarization dispersion and identify high-risk BrS patients. The aim of the study is to test the significance of the QRSvm as a predictor for VTA in patients with BrS. In this retrospective cohort, we included 136 patients (47 ± 15 years, 66% male) who visited outpatient clinic for cardiogenetic screening. All medical records were examined, all 12- lead electrocardiograms were reconstructed into QRSvm using Kors' quasiorthogonal method and were assessed for the presence of electrocardiographic signs indicative of RVOT conduction delay including R wave sign, deep SI, SII >SIII pattern, and Tzou criteria. QRSvm was significantly lower in patients who either presented with VTA or developed VTA during follow-up (1.24 ± 0.35 vs 1.78 ± 0.42 mV, p < 0.001). Positive RVOT conduction delay signs occurred more frequently in symptomatic patients (20% vs 7%, p < 0.001).The area under receiver operator characteristic curve for QRSvm was 0.85 (95% confidence interval [CI] 0.77 to 0.92). Using QRSvm cutoff of 1.55 mV, sensitivity and specificity were 89% and 71%, respectively. Multivariate regression analysis showed that QRSvm and RVOT signs are independent predictors for VTA in BrS patients (QRS vector magnitude: odds ratio 3.68, 95% CI 2.4 to 6.2, p = 0.001; RVOT: odds ratio 2.6, 95% CI 1.4 to 4.9, p = 0.001). In conclusion, not only electrocardiographic signs indicative of RVOT conduction delay but also QRSvm can be used as a predictor for VTA events in BrS patients.

Arrhythmia Mechanisms and Outcomes of Ablation in Pediatric Patients With Congenital Heart Disease.

BACKGROUND: In contrast to the adult population with congenital heart disease (CHD), arrhythmia mechanisms and outcomes of ablation in pediatric patients with CHD in recent era have not been studied in detail. Aims of this study were to determine arrhythmia mechanisms and to evaluate procedural and long-term outcomes in pediatric patients with CHD undergoing catheter ablation. METHODS: Consecutive patients <18 years of age with CHD undergoing catheter ablation over an 11-year period (2007-2018) were included. Procedural outcome included complete or partial success, failure or empirical ablation. Long-term outcome included arrhythmia recurrence and burden according to a 12-point clinical arrhythmia severity score. RESULTS: The study population consisted of 232 patients (11.7 years [0.01-17.8], 33.5 kg [2.2-130.1]). The most common diagnoses were Ebstein's anomaly (n=44), septal defects (n=39), and single ventricle (n=36). Arrhythmia mechanisms included atrioventricular reentry tachycardia (n=104, 90 patients), atrioventricular nodal reentry tachycardia (n=33, 29 patients), twin atrioventricular nodal tachycardia (n=3, 2 patients), macroreentrant atrial tachycardia (n=59, 56 patients), focal atrial tachycardia (n=33, 25 patients), ventricular ectopy (n=10, 8 patients), and ventricular tachycardia (n=15, 13 patients). Fifty-six arrhythmias (39 patients) were undefined. Outcomes included complete success (n=189, 81%), partial success (n=7, 3%), failure (n=16, 7%), or empirical ablation (n=20, 9%). Over 3.6 years (0.3-10.7) arrhythmia recurred in 49%. Independent of arrhythmia recurrence, arrhythmia scores decreased from 4 (0-10) at baseline to 0.5 (0-8) at 4 years follow-up (P<0.001). In 23/51 repeat procedures (45%), a different arrhythmia substrate was found. Overall adverse event rate was 9.4%, although only 1.6% (n=4) were of major severity and 0.8% (n=2) of moderate severity. CONCLUSIONS: Pediatric patients with CHD demonstrate a broad spectrum of arrhythmia mechanisms. Despite recurrence and emergence of novel mechanisms after a successful procedure, ablation can be performed safely and successfully resulting in decreased arrhythmia burden.

Dysrhythmias in patients with a complete atrioventricular septal defect: From surgery to early adulthood.

OBJECTIVE: Outcomes after surgical repair of complete atrioventricular septal defect (cAVSD) have improved. With advancing age, the risk of development of dysrhythmias may increase. The aims of this study were to (1) examine development of sinus node dysfunction (SND), atrial and ventricular tachyarrhythmias, and (2) study progression of atrioventricular conduction abnormalities in young adult patients with repaired cAVSD. STUDY DESIGN: In this retrospective multicenter study, 74 patients (68% female) with a cAVSD repaired in childhood were included. Patients' medical files were evaluated for occurrence of SND, atrioventricular conduction block (AVB), atrial and ventricular tachyarrhythmias. RESULTS: Median age at repair was 6 months (interquartile range 3-10) and median age at last follow-up was 24 years (interquartile range 21-28). SND occurred after a median of 17 years (interquartile range 11-19) after repair in 23% of patients, requiring pacemaker implantation in two patients (12%). Regular supraventricular tachycardia was observed in three patients (4%). Atrial fibrillation and ventricular tachyarrhythmias were not observed. Twenty-seven patients (36%) had first-degree AVB, which was self-limiting in 16 (59%) and persistent in 10 (37%) patients. One patient developed third-degree AVB 7 days after left atrioventricular valve replacement. Spontaneous type II second-degree AVB occurred in a 28-year-old patient. Both patients underwent pacemaker implantation. CONCLUSIONS: Clinically significant dysrhythmias were uncommon in young adult patients after cAVSD repair. However, three patients required pacemaker implantation for either progression of SND or spontaneous type II second-degree AVB. Longer follow-up should point out whether dysrhythmias will progress or become more prevalent with increasing age.

Time course and interrelationship of dysrhythmias in patients with surgically repaired atrial septal defect.

BACKGROUND: Atrial fibrillation (AF) and other supraventricular tachycardias (SVTs) are known complications after surgical repair of atrial septal defect (ASD), but sinus node dysfunction (SND) and complete atrioventricular conduction block (cAVB) may also occur. OBJECTIVE: The aim of this study was to examine time course and interrelationship of various dysrhythmias in patients with ASD. METHODS: Adult patients (N = 95) with surgically repaired secundum ASD (n = 40), partial atrioventricular septal defect (n = 37) or sinus venosus defect (n = 18), and documented SND, cAVB, AF, and/or other SVT were included. The median age at repair was 13 years (interquartile range [IQR] 6-45 years), and patients were followed for 26 years (IQR 15-37 years) after ASD repair. RESULTS: SND was observed in 34 patients (36%), cAVB in 14 (14%), AF in 48 (49%), and SVT in 44 (45%); 37 patients (39%) had ≥2 dysrhythmias. All dysrhythmias presented most often after ASD repair (P < .01), with a median duration of 12 years (IQR 17 days - 32 years) to 16 years (IQR 4 - 28 years) between repair and onset. Development of SND and cAVB late after ASD repair was not related to a redo procedure in 100% and 60% of patients, respectively. SND preceded atrial tachyarrhythmias in 50% (P = .31) and SVT preceded AF in 68% (P = .09) of patients with both dysrhythmias. CONCLUSION: A substantial number of dysrhythmias presented (very) late after ASD repair. In most patients, development of late SND and cAVB was not related to redo procedures. In patients with multiple dysrhythmias, a specific order of appearance was not observed.

Impact of Supraventricular Tachyarrhythmia in Patients With Inherited Cardiac Arrhythmia.

Supraventricular tachyarrhythmia (SVT), especially atrial fibrillation (AF), has been observed in patients with inherited cardiac arrhythmia (ICA). Data on the time course of SVT and the occurrence of SVT other than AF is limited. In this study, we examined the prevalence, co-existence, and the time course of different types of SVT in patients with various ICAs. In this retrospective study, we selected 393 patients (median 49 years, range 17 to 87, 57% male) from a cohort of patients visiting the outpatient clinic for cardiogenetic screening of ICA. Patients' medical records were examined for the occurrence of AF and other SVT. AF/SVT was found in 49 patients (12%, 31 male, 42 ± 17 years). Patients presenting with only AF (n = 12, 3%) were older than patients presenting with only SVT (n = 28, 7%), respectively 52 ± 18 versus 37 ± 14, p = 0.007. Nineteen patients (5%) had multiple episodes of either AF (n = 7, 2%) or SVT (n = 12, 3%). Alternating episodes of AF and SVT occurred in 9 patients (2%). Intervals between second and third AF episodes were significantly shorter than between first and second episodes (p = 0.02). An implantable cardioverter defibrillator (ICD) was implanted in 158 patients (40.2%) and 26 patients (16%) had inappropriate ICD shocks (SVT 25, AF 1), particularly those with multiple SVT episodes (p = 0.003). In patients with a variety of ICAs, episodes of AF/SVT occurred in 12%. In patients with multiple AF episodes, intervals between consecutive episodes became significantly shorter over time. AF/SVT episodes are associated with inappropriate ICD shocks and aggressive therapy of AF/SVT is therefore justified.

Usefulness of the R-Wave Sign as a Predictor for Ventricular Tachyarrhythmia in Patients With Brugada Syndrome.

Brugada syndrome (BrS) is an autosomal dominant channelopathy which is responsible for a large number of sudden cardiac deaths in young subjects without structural abnormalities. The most challenging step in management of patients with BrS is identifying who is at risk for developing malignant ventricular tachyarrhythmia (VTA). In patients with BrS, conduction delay in the right ventricular outflow tract (RVOT) causes a prominent R wave in lead aVR. This electrocardiographic parameter can be useful to detect these high-risk patients. The goal of this study was to test the significance of R-wave elevation in lead aVR as a predictor for VTA in patients with BrS. In this retrospective study, we included 132 patients with BrS (47 ± 15 years, 65% men) who visited the outpatient clinic for cardiogenetic screening. Patients' medical records were examined for the presence of a positive R-wave sign in lead aVR and VTA. A positive R-wave sign in lead aVR was observed in 41 patients (31%). This sign was more frequently observed in patients who experienced VTA (n = 24) before the initial diagnosis, during electrophysiological studies, or during follow-up (p <0.001). The positive R-wave sign occurred more frequently in symptomatic patients with a history of an out of hospital cardiac arrest, VTA, or syncope than asymptomatic patients (60% vs 26%; p = 0.002). During the follow-up period, this sign was more frequently detected in patients who developed either de novo (50%) or recurrent VTA (80%) (p = 0.017). Multivariable regression analysis showed that R-wave sign is an independent predictor for VTA development (odds ratio 4.8, 95% confidence interval 1.79 to 13.27). The presence of a positive R-wave sign in lead aVR is associated with the development of VTA. In conclusion, positive R-wave sign in lead aVR can be used to identify patients with BrS at risk for malignant VTA.

Atrial tachyarrhythmias after atrial switch operation for transposition of the great arteries: Treating old surgery with new catheters.

The arterial switch operation has been the procedure of first choice for correction of transposition of the great arteries (TGA) for several decades now. However, a large number of adult patients with TGA nowadays were palliated previously by either a Mustard or a Senning procedure. Atrial tachyarrhythmias (ATs) are frequently observed during long-term follow-up of patients with TGA after these atrial switch corrections and are associated with both morbidity and mortality. Because of the complex postoperative anatomy in these patients, ablative therapy for these tachyarrhythmias can be challenging. The goals of this review are to discuss the most prevalent ATs in patients after the Mustard or Senning procedure and to summarize (long-term) outcomes of ablative therapy. In addition, recent developments in ablative therapy for ATs in this patient population are outlined.