Syncope Time Frames for Adverse Events after Emergency Department Presentation: An Individual Patient Data Meta-Analysis.

Background and Objectives: Knowledge of the incidence and time frames of the adverse events of patients presenting syncope at the ED is essential for developing effective management strategies. The aim of the present study was to perform a meta-analysis of the incidence and time frames of adverse events of syncope patients. Materials and Methods: We combined individual patients' data from prospective observational studies including adult patients who presented syncope at the ED. We assessed the pooled rate of adverse events at 24 h, 72 h, 7-10 days, 1 month and 1 year after ED evaluation. Results: We included nine studies that enrolled 12,269 patients. The mean age varied between 53 and 73 years, with 42% to 57% females. The pooled rate of adverse events was 5.1% (95% CI 3.4% to 7.7%) at 24 h, 7.0% (95% CI 4.9% to 9.9%) at 72 h, 8.4% (95% CI 6.2% to 11.3%) at 7-10 days, 10.3% (95% CI 7.8% to 13.3%) at 1 month and 21.3% (95% CI 15.8% to 28.0%) at 1 year. The pooled death rate was 0.2% (95% CI 0.1% to 0.5%) at 24 h, 0.3% (95% CI 0.1% to 0.7%) at 72 h, 0.5% (95% CI 0.3% to 0.9%) at 7-10 days, 1% (95% CI 0.6% to 1.7%) at 1 month and 5.9% (95% CI 4.5% to 7.7%) at 1 year. The most common adverse event was arrhythmia, for which its rate was 3.1% (95% CI 2.0% to 4.9%) at 24 h, 4.8% (95% CI 3.5% to 6.7%) at 72 h, 5.8% (95% CI 4.2% to 7.9%) at 7-10 days, 6.9% (95% CI 5.3% to 9.1%) at 1 month and 9.9% (95% CI 5.5% to 17) at 1 year. Ventricular arrhythmia was rare. Conclusions: The risk of death or life-threatening adverse event is rare in patients presenting syncope at the ED. The most common adverse events are brady and supraventricular arrhythmias, which occur during the first 3 days. Prolonged ECG monitoring in the ED in a short stay unit with ECG monitoring facilities may, therefore, be beneficial.

Preprocedural imaging to guide transcoronary ethanol ablation for refractory septal ventricular tachycardia.

BACKGROUND: Radiofrequency ablation (RF) of ventricular tachycardia (VT) due to intramural foci has a high recurrence rate. Several techniques, such as bipolar ablation, irrigated needle ablation catheter, and retrograde coronary venous ethanol ablation have been suggested. Transarterial coronary ethanol ablation (TCEA) can also be effective. We present a case series of TCEA guided with preprocedural imaging to correlated coronary arteries and the intramural substrate. METHODS AND RESULTS: We present three consecutive patients with previous RF of septal VT (100% male; age, 72.6 ± 11.01 years; two patients with hypertrophic cardiomyopathy, one with mechanical aortic valve prosthesis) that underwent TCEA. Cardiac magnetic resonance was performed in two patients and cardiac CT in all patients. Correlation of septal arteries with intramural substrate was analyzed before the procedure so TCEA was attempted according to this analysis. After last TCEA (6.3 ± 2.08 months) the VT burden was reduced in all patients (sum of all implantable cardioverter-defibrillator therapies [antitachycardia pacing and shock] before and after TCEA, 15.8 ± 3.73 vs 0.97 ± 0.63 therapies/month; P = 0.02). No complications occurred during TCEA. CONCLUSIONS: TCEA completely guided with previous magnetic resonance imaging and computed tomography scan to select the coronary artery in relation to the substrate seems to be feasible as an alternative strategy in cases of intramural VT refractory to RF ablation.

Intra-atrial re-entrant tachycardia in congenital heart disease: types and relation of isthmus to atrial voltage.

Background: Intra-atrial re-entrant tachycardia (IART) is a frequent and severe complication in patients with congenital heart disease (CHD). Cavotricuspid isthmus (CTI)-related IART is the most frequent mechanism. However, due to fibrosis and surgical scars, non-CTI-related IART is also frequent. Objective: The main objective of this study was to describe the types of IART and circuit locations and to define a cut-off value for unhealthy tissue in the atria. Methods and results: This observational study included all consecutive patients with CHD who underwent a first ablation procedure for IART from January 2009 to December 2015 (94 patients, 39.4% female, age: 36.55 ± 14.9 years, 40.4% with highly complex cardiac disease). During the study, 114 IARTs were ablated (1.21 ± 0.41 IARTs per patient). Cavotricuspid isthmus-related IART was the only arrhythmia in 51% (n = 48) of patients, non-CTI-related IART was the only mechanism in 27.7% (n = 26), and 21.3% of patients (n = 20) presented both types of IART. In cases of non-CTI-related IART, the most frequent location of IART isthmus was the lateral or posterolateral wall of the venous atria, and a voltage cut-off value for unhealthy tissue in the atria of 0.5 mV identified 95.4% of IART isthmus locations. Conclusion: In our population with a high proportion of complex CHD, CTI-related IART was the most frequent mechanism, although non-CTI-related IART was present in 49% of patients (alone or with concomitant CTI-related IART). A cut-off voltage of 0.5 mV could identify 95.4% of the substrates in non-CTI-related IART.

Intra-atrial re-entrant tachycardia in patients with congenital heart disease: factors associated with disease severity.

Aim: Intra-atrial re-entrant tachycardia (IART) is a common complication in patients with congenital heart disease (CHD) and is related to increased morbidity and mortality. Few reports have been published about factors associated to IART severity. The aim of this study is to analyse factors associated to severe clinical presentation of IART. Methods and Results: Observational study of all consecutive CHD patients who underwent a first IART ablation from January 2009 to December 2015 (94 patients, 39.4% female, and age: 36.55 ± 14.9 years). Severe clinical presentation was defined as heart failure, syncope, shock, electromechanical dissociation (EMD), or aborted sudden death. The majority of patients had moderately or highly complex cardiac defect (90.4%). Types of IART included cavotricuspid isthmus(CTI) dependent in 51% (48), non-CTI-related in 22.3% (20), and both types in 27.7% (26). In 38 patients (40.4%), a severe event occurred and in 16 (17%), the symptoms included shock, syncope, sudden death, or EMD. In 21 (22.3%), severe symptoms were the first manifestation of IART. In multivariate analysis, transposition of the great arteries (TGA) with right systemic ventricle (OR 5.32, 95% C.I. 1.6-7.02, P = 0.0005) and severe dilation of the venous atrium (VsA) (OR 4.17; 95% CI 1.4-8.12, P = 0.0009) were factors independently associated with severity. Conclusion: In our series of 94 CHD patients with a high proportion of moderately to highly complex cardiac defects, severe consequences of IART were frequent. Transposition of the great arteries with systemic right ventricle and severe dilation of VsA were independently associated to severity. Early invasive procedures should be considered for these high-risk patients.

Limb-girdle myopathy and mild intellectual disability: The expanding spectrum of TANGO2-related disease.

TANGO2-related disease is an autosomal recessive multisystem disease associated with developmental delay and infancy-onset recurrent metabolic crises with early mortality. Several studies have reported dysfunction in endoplasmic reticulum-to-Golgi traffic and mitochondrial homoeostasis as the underlying pathophysiology. We report a 40-year-old woman affected by limb-girdle weakness and mild intellectual disability caused by the recurrent deletion of exons 3-9 in homozygosity in the TANGO2 gene. Physical examination revealed hyperlordosis, waddling gait, calf pseudohypertrophy, and Aquilian tendon retractions. Laboratory investigations revealed elevation of serum biomarkers suggestive of mitochondrial dysfunction together with hypothyroidism. At the age of 24, the patient suffered a metabolic crisis with severe rhabdomyolysis and malignant cardiac arrhythmia. After recovery, no metabolic or arrhythmic crisis has recurred. Muscle histology two years later revealed increased endomysial fibrosis and other myopathic changes. Our findings illustrate the mildest end of the phenotypic spectrum of TANGO2-related disease and reveal further aspects related to chronic muscle damage in this disorder.

Arrhythmic risk in single or recurrent episodes of unexplained syncope with complete bundle branch block.

INTRODUCTION AND OBJECTIVES: Patients with a single syncopal episode (SSE) and complete bundle branch block (cBBB) are frequently managed more conservatively than patients with recurrent episodes (RSE). The objective of this study was to analyze if there are differences between patients with single or recurrent unexplained syncope and cBBB in arrhythmic risk, the diagnostic yield of tests, and clinical outcomes. METHODS: Cohort study of consecutive patients with unexplained syncope and cBBB with a median follow-up time of 3 years. The patients were evaluated via a stepwise workup protocol based on electrophysiological study (EPS) and long-term follow-up with an implantable cardiac monitor. RESULTS: Of the 503 patients included in the study, 238 (47.3%) had had only 1 syncopal episode. The risk of an arrhythmic syncope was similar in both groups (58.8% in SSE vs 57.0% in RSE; P=.68), also after adjustment for possible confounding variables (HR, 1.06; 95%CI, 0.81-1.38; P=.674). No significant differences between the groups were found in the EPS results and implantable cardiac monitor diagnostic yield. A total of 141 (59.2%) patients with SSE and 154 (58.1%) patients with RSE required cardiac device implantation (P=.797). After appropriate treatment, 35 (7%) patients had recurrence of syncope. The recurrence rate and mortality were also similar in both groups. CONCLUSIONS: Patients with cBBB and unexplained syncope are at high risk of an arrhythmic etiology, even after the first syncopal episode. Patients with SSE and RSE have a similar arrhythmic risk and similar outcomes, and therefore there is no clinical justification for not managing them in the same manner.

Trends in the use of electrical cardioversion for atrial fibrillation: influence of major trials and guidelines on clinical practice.

BACKGROUND: The purpose of the present study was to assess the trends in the use of ECV following published studies that had compared rhythm and rate control strategies on atrial fibrillation (AF), and the recommendations included in the current clinical practice guidelines. METHODS: The REVERCAT is a population-based assessment of the use of electrical cardioversion (ECV) in treating persistent AF in Catalonia (Spain). The initial survey was conducted in 2003 and the follow-up in 2010. RESULTS: We observed a decrease of 9% in the absolute numbers of ECV performed (436 in 2003 vs. 397 in 2010). This is equivalent to 27% when considering population increases over this period. The patients treated with ECV in 2010 were younger, had a lower prevalence of previous embolism, a higher prevalence of diabetes, and increased body weight. Underlying heart disease factors indicated, in 2010, a higher proportion of NYHA ≥ II and left ventricular ejection fraction <30%. We observed a reduction in the number of ECV performed in 16 of the 27 (67%) participating hospitals. However, there was an increase of 14% in the number of procedures performed in tertiary hospitals, and was related to the increasing use of ECV as a bridge to AF ablation. Considering the initial number of patients treated with ECV, the rate of sinus rhythm at 3 months was almost unchanged (58% in 2003 vs. 57% in 2010; p=0.9) despite the greater use of biphasic energy in 2010 and a similar prescription of anti-arrhythmic drugs. CONCLUSIONS: Although we observed a decrease in the number of ECVs performed over the 7 year period between the two studies, this technique remains a common option for treating patients with persistent AF. The change in the characteristics of candidate patients did not translate into better outcomes.

Sex-Related Differences in Patients With Unexplained Syncope and Bundle Branch Block: Lower Risk of AV Block and Lesser Need for Cardiac Pacing in Women.

Objective: To analyze if there are sex-related differences in patients with unexplained syncope and bundle branch block (BBB). Background: Despite increasing awareness that sex is a major determinant of the incidence, etiology, and the outcomes of different arrhythmias, no studies have examined differences in presentation and outcomes between men and women with syncope and BBB. Methods: Cohort study of consecutive patients with unexplained syncope and BBB was included from January 2010 to January 2021 with a median follow-up time of 3.4 years [interquartile range (IQR) 1.7-6.0 years]. They were evaluated by a stepwise workup protocol based on electrophysiological study (EPS) and long-term follow-up with an implantable cardiac monitor (ICM). Results: Of the 443 patients included in the study, 165 (37.2%) were women. Compared with men, women had less diabetes (25.5 vs. 39.9%, p = 0.002) and less history of ischemic heart disease (IHD; 13.3 vs. 25.9%, p = 0.002). Left bundle branch block (LBBB) was more frequent in women (55.2 vs. 27.7%, p < 0.001) while right bundle branch block (RBBB) was more frequent in men (41.5 vs. 67.7%, p < 0.001). His to ventricle (HV) interval in the EPS was shorter in women (58 ms [IQR 52-71] vs. 60 ms [IQR 52-73], p = 0.035) and less women had an HV interval longer than 70 ms (28.5 vs. 38.1%, p = 0.039), however, EPS and ICM offered a similar diagnostic yield in both sexes (40.6 vs. 48.9% and 48.4% vs. 51.1%, respectively). Women had a lower risk of developing atrioventricular block (AVB) (adjusted odds ratio [OR] 0.44-95% CI 0.26-0.74, p = 0.002) and of requiring permanent pacemaker implantation (adjusted hazard ratio [HR] 0.72-95% CI: 0.52-0.99, p = 0.046). The mortality rate was lower in women (4.5 per 100 person-years [95% CI 3.1-6.4 per 100 person-years] vs. 7.3 per 100 person-years [95% CI 5.9-9.1 per 100 person-years]). Conclusions: Compared to men, women with unexplained syncope and BBB have a lower risk of AVB and of requiring cardiac pacing. A stepwise diagnostic approach has a similar diagnostic yield in both sexes, and it seems appropriate to guide the treatment and avoid unnecessary pacemaker implantation, especially in women.

Cardiac monitoring for patients with palpitations.

Palpitations are one of the most common reasons for medical consultation. They tend to worry patients and can affect their quality of life. They are often a symptom associated with cardiac rhythm disorders, although there are other etiologies. For diagnosis, it is essential to be able to reliably correlate the symptoms with an electrocardiographic record allowing the identification or ruling out of a possible rhythm disorder. However, reaching a diagnosis is not always simple, given that they tend to be transitory symptoms and the patient is frequently asymptomatic at the time of assessment. In recent years, electrocardiographic monitoring systems have incorporated many technical improvements that solve several of the 24-h Holter monitor limitations. The objective of this review is to provide an update on the different monitoring methods currently available, remarking their indications and limitations, to help healthcare professionals to appropriately select and use them in the work-up of patients with palpitations.

Cardiac biometric variables and arrhythmic events during COVID-19 pandemic lockdown in patients with an implantable cardiac monitor for syncope work-up.

Aim: To assess the changes induced by the COVID-19 lockdown on cardiac biometric variables recorded using an implantable cardiac monitor (ICM) in a patient population monitored for syncope work-up, as well to assess whether there has been an effect on arrhythmic events among the patients. Methods: Longitudinal cohort study. We included 245 adult patients monitored with an ICM indicated for the investigation of syncope. The records from days 1 to 12 March 2020 (prior to the institution of lockdown by the state government) with days 16 to 28 March 2020 were compared. Results: Daily physical exercise reduced markedly after the imposition of lockdown (132 [55-233] minutes vs. 78 [21-154] minutes). The mean daytime HR prior to lockdown was 77 [69-85] bpm, whereas during lockdown it was 74 [66-81] bpm. During the lockdown period, a drop in the variability in heart rate (114 [94-136] ms vs. 111 [92-133] ms) was observed. Although the incidence of AF was similar over both periods, the daily AF burden was significantly higher post-lockdown (405 [391-425] minutes vs. 423 [423-537] minutes). No differences in the number of other arrhythmias were found. Conclusions: The establishment of mandatory lockdown has led to a marked drop in daily physical activity in this population which probably explains changes observed in other cardiac biometric variables. Although, in the short term, we have not documented an increased risk of arrhythmia, we cannot rule out an effect in the medium to long term or in other populations of at-risk patients.

Objetivo: Evaluar los cambios inducidos por el confinamiento durante la pandemia de COVID-19 en las variables biométricas cardiacas registradas, utilizando un monitor cardíaco implantable (ICM) en una población de pacientes monitorizada para el diagnóstico de síncope, así como evaluar si ha habido un efecto sobre los eventos arrítmicos. Métodos: Estudio de cohorte prospectivo. Se incluyeron 245 pacientes adultos monitorizados con un ICM indicado para la investigación del síncope. Se compararon los registros de los días uno al 12 de marzo del 2020 (antes del establecimiento del confinamiento por parte del gobierno estatal) con los días 16 al 28 de marzo del 2020. Resultados: El ejercicio físico diario se redujo notablemente después de la imposición del confinamiento (132 [55 a 233] vs. 78 [21 a 154] min). La frecuencia cardiaca diurna media antes del confinamiento fue de 77 (69 a 85) lpm, mientras que durante el mismo fue de 74 (66 a 81) lpm. Durante el período de confinamiento, se observó una disminución de la variabilidad de la frecuencia cardiaca (114 [94 a 136] vs. 111 [92 a 133] ms). Aunque la incidencia de fibrilación auricular (FA) fue similar en ambos períodos, la carga diaria de FA fue significativamente mayor después del bloqueo (405 [391 a 425] vs. 423 [423 a 537] min). No se encontraron diferencias en el número de otras arritmias. Conclusiones: El establecimiento de un confinamiento obligatorio ha provocado un marcado descenso de la actividad física diaria en esta población, lo que probablemente explica los cambios observados en otras variables biométricas cardiacas. Si bien, a corto plazo, no se ha documentado un aumento del riesgo de arritmia, no podemos descartar un efecto a medio-largo plazo o en otras poblaciones de pacientes de riesgo.

[Cardiac biometric variables and arrhythmic events during COVID-19 pandemic lockdown in patients with an implantable cardiac monitor for syncope work-up]. / Variables biométricas cardiacas y eventos arrítmicos durante el confinamiento por la pandemia de COVID-19 en pacientes portadores de un monitor cardiaco implantable para el diagnóstico de síncope.

AIM: To assess the changes induced by the COVID-19 lockdown on cardiac biometric variables recorded using an implantable cardiac monitor (ICM) in a patient population monitored for syncope work-up, as well to assess whether there has been an effect on arrhythmic events among the patients. METHODS: Longitudinal cohort study. We included 245 adult patients monitored with an ICM indicated for the investigation of syncope. The records from days 1 to 12 March 2020 (prior to the institution of lockdown by the state government) with days 16 to 28 March 2020 were compared. RESULTS: Daily physical exercise reduced markedly after the imposition of lockdown (132 [55-233] minutes vs. 78 [21-154] minutes). The mean daytime HR prior to lockdown was 77 [69-85] bpm, whereas during lockdown it was 74 [66-81] bpm. During the lockdown period, a drop in the variability in heart rate (114 [94-136] ms vs. 111 [92-133] ms) was observed. Although the incidence of AF was similar over both periods, the daily AF burden was significantly higher post-lockdown (405 [391-425] minutes vs. 423 [423-537] minutes). No differences in the number of other arrhythmias were found. CONCLUSIONS: The establishment of mandatory lockdown has led to a marked drop in daily physical activity in this population which probably explains changes observed in other cardiac biometric variables. Although, in the short term, we have not documented an increased risk of arrhythmia, we cannot rule out an effect in the medium to long term or in other populations of at-risk patients.

Etiology and prognosis of patients with unexplained syncope and mid-range left ventricular dysfunction.

BACKGROUND: Syncope in patients with mid-range left ventricular ejection fraction (LVEF) can be due to potentially serious arrhythmic causes. However, there is no clear consensus on the best way to manage these patients. OBJECTIVES: The objectives of this study were to determine the causes of syncope and assess the diagnostic yield and safety of a stepwise workup protocol in this population. METHODS: This was a prospective observational study. A stepwise workup protocol was applied to patients with LVEF 35%-50% and unexplained syncope after the initial assessment (step 1). RESULTS: One hundred four patients were included {median age 75.6 years; (interquartile range [IQR] 67.6-81.2 years); median LVEF 45% (IQR 40%-48%); median follow-up 2.0 years (IQR 0.7-3.3 years). In 71 patients (68.3%), a diagnosis was reached: 55 (77.5%) in step 2 (hospital admission and electrophysiology study) and 16 (36.5%) in step 3 (implantable cardiac monitor). Arrhythmic causes were the most common etiology (45.2% auriculoventricular block and 9.6% ventricular tachycardia). Sixty patients (57.7%) required the implantation of a cardiac device and 11 had a defibrillation function. Patients diagnosed in step 3 had a higher global risk of recurrence of syncope (hazard ratio 6.5; 95% confidence interval 2.3-18.0). The mortality rate was 8.1 per 100 person-years, and the sudden or unknown death rate was 0.9 per 100 person-years. CONCLUSION: In patients with mid-range left ventricular dysfunction and syncope of unknown cause, a systematic diagnostic strategy based on electrophysiology study and/or implantable cardiac monitor implantation allows a diagnosis to be reached in a high proportion of cases and guides the treatment. Arrhythmia is the most common cause of syncope in this population, particularly auriculoventricular block.

Risk stratification of ventricular arrhythmias in repaired tetralogy of Fallot.

INTRODUCTION AND OBJECTIVES: Risk stratification of ventricular arrhythmias in patients with repaired tetralogy of Fallot (rTOF) remains unresolved. We aimed to identify right ventricular (RV) electrophysiological parameters potentially associated with a higher risk of ventricular arrhythmias in patients with rTOF. METHODS: We included all consecutive patients with rTOF who underwent RV electroanatomical mapping at a single tertiary center. We used logistic regression modeling to identify those variables associated with an increased risk of clinical or induced ventricular tachycardia (VT), or clinical VT exclusively. RESULTS: Twenty-one of the 56 patients included had clinical or induced VT. A high-frequency of premature ventricular contractions/nonsustained VT (OR, 11.34; 95%CI, 1.50-85.97; P=.019), an HV interval > 55 ms (OR, 21.20; 95%CI, 3.12-144.14; P=.002), and RV activation time (ms) (OR [per 10ms intervals], 1.34; 95%CI, 1.02-1.75; P=.035) proved to be associated with clinical or induced VT. The model including this information had good discrimination ability, with an area under the curve of 0.884 (95%CI, 0.79-0.97; P <.001). When considering only clinical VT as the outcome of interest, only an HV interval > 55ms (OR, 9.65; 95%CI, 1.41-66.14; P=.021) and high-frequency of premature ventricular contractions/nonsustained VT (OR, 13.14; 95%CI, 1.95-88.54; P=.008) were independently associated (area under the curve of 0.836 [95%CI, 0.663-1.000; P=.002]). CONCLUSIONS: High-frequency of premature ventricular contractions/nonsustained VT, an HV interval> 55ms and RV activation time are factors associated with an increased risk of ventricular arrhythmias in patients with rTOF.

Syncope in Patients With Severe Aortic Stenosis: More Than Just an Obstruction Issue.

BACKGROUND: Severe aortic stenosis (AoS) is considered a primary cause of syncope. However, other mechanisms may be present in these patients and accurate diagnosis can have important clinical implications. The aim of this study is to assess the different etiologies of syncope in patients with severe AoS and the impact on prognosis of attaining a certain or highly probable diagnosis for the syncope. METHODS: Out of a cohort of 331 patients with AoS and syncope, 61 had severe AoS and were included in the study. Main cause of syncope and adverse cardiac events were assessed. RESULTS: In 40 patients (65.6%), we reached a certain or highly probable diagnosis of the main cause of the syncope. AoS was considered the primary cause of the syncope in only 7 patients (17.5% of the patients with known etiology). Atrioventricular block (14 patients, 35.0%) and vasovagal syncope (6 patients, 15.0%) were the most frequently diagnosed causes. The presence of a known cause for syncope during the admission was not associated with a lower incidence of recurrence during follow-up (hazard ratio [HR] 0.69, 95% confidence interval [CI] 0.20-2.40). Syncope of unknown etiology was independently associated with greater mortality during 1-year follow-up (HR 5.4, 95% CI 1.3-21.6) and 3-year follow-up (HR 3.5, 95% CI 1.2-10.3). CONCLUSIONS: In a high proportion of patients with severe AoS admitted for syncope, the valvulopathy was not the main cause of the syncope. Syncope in two-thirds of this population was caused by either bradyarrhythmia or reflex causes. Syncope of unknown cause was associated with increased short- and medium-term mortality, independently from treatment of the valve disease. An exhaustive work-up should be conducted to determine the main cause for syncope.

Substrate characterization of the right ventricle in repaired tetralogy of Fallot using late enhancement cardiac magnetic resonance.

BACKGROUND: Three-dimensional (3D) substrate characterization by high-resolution late gadolinium enhancement cardiac magnetic resonance (LE-CMR) is useful for guiding ventricular tachycardia ablation of the left ventricle in ischemic heart disease. OBJECTIVE: The purpose of this study was to validate the substrate characterization and 3D reconstruction of LE-CMR images of the right ventricle (RV) in patients with repaired tetralogy of Fallot (rTOF) and to identify the algorithm that best fits with electroanatomic mapping (EAM). METHODS: RV LE-CMR images were compared with RV EAM in 10 patients with rTOF. RV LE-CMR images were postprocessed and analyzed to identify fibrotic tissue on 3D color maps. The 3D RV substrate reconstructions were created using an adjustable percentage of the maximum voxel signal intensity (MSI) of the scar region to define the threshold between core, transitional zone (TZ), and healthy tissue. Extensions of the core and TZ areas were compared with the scar (<0.5 mV) and low-voltage (0.5-1.5 mV) areas obtained by RV EAM. Agreement on anatomic isthmi identification was quantified. RESULTS: The best match between core and scar was obtained at 65% MSI cutoff (mean areas 17.4 ± 9.9 cm2 vs 16.9 ± 10.0 cm2, respectively; r = 0.954; P <.001). Agreement on anatomic isthmi identification was best at 60% MSI cutoff, which identified 95% of isthmi and achieved a total fit in 90% of patients. CONCLUSION: This study demonstrates that characterization of the RV substrate by postprocessing LE-CMR images in rTOF patients is feasible and validates the technique against RV EAM, which could help in planning target ablation.

Incremental pacing for the diagnosis of complete cavotricuspid isthmus block during radiofrequency ablation of atrial flutter.

BACKGROUND: Complete conduction block of the cavotricuspid isthmus (CTI) reduces atrial flutter recurrences after ablation. Incremental rapid pacing may distinguish slow conduction from complete CTI conduction block. METHODS AND RESULTS: Fifty-two patients (67 +/- 9 years) undergoing 55 CTI ablation procedures were included. With ablation, double potentials (DPs) separated by an isoelectric line of > or =30 ms were obtained. Incremental atrial pacing (600-250 ms) was performed from coronary sinus (CS) and low lateral right atrium (LLRA). A <20 ms increase in the DPs distance during incremental pacing was indexed as complete CTI block. In 8 patients, an initial <20 ms DPs distance increase was noted; direct complete isthmus block was suggested and no additional ablation performed. In the remaining, the CTI line was remapped for conduction gaps and additional radiofrequency energy pulses applied. Complete block, as indexed by incremental pacing, occurred in 46 of 55 procedures, with one flutter recurrence (follow-up 8 +/- 2 months): DPs interval variation of 116 +/- 20 to 123 +/- 20 ms (CS), P = 0.21; and 122 +/- 25 to 135 +/- 35 ms (LLRA), P = 0.17. The remaining 9 patients (persistent rate-dependent DPs increase) presented 3 flutter recurrences, P = 0.01: DP distance from 127 +/- 15 to 161 +/- 18 ms (CS), P < 0.001; and 114 +/- 24 to 142 +/- 10 ms (LLRA), P = 0.007. CONCLUSION: Incremental pacing distinguishes complete CTI block from persistent conduction. Such identification, accompanied by additional ablation to achieve block, should minimize flutter recurrences after ablative therapy.

High incidence of subclinical atrial fibrillation in patients with syncope monitored with implantable cardiac monitor.

OBJECTIVE: The use of implantable cardiac monitors (ICM) is highly useful in syncope workup. Latest-generation devices can detect asymptomatic episodes of atrial fibrillation. The main objective of this study was to determine the incidence of subclinical atrial fibrillation (AF) detected in a patient population undergoing prolonged electrocardiographic monitoring with an ICM for the etiological workup of syncope. METHODS: Prospective observational study carried out in a tertiary hospital from April 2014 to October 2019. All consecutive adult patients monitored with a latest-generation ICM for syncope with no prior history of AF were included in the analysis. RESULTS: Of a total of 509 ICMs implanted during the study period, 208 patients fulfilled the inclusion criteria. 42 patients (20.2%) were found to have AF on ICM. The incidence of AF was 11.7 cases per 100 person-years (95% CI: 8.7-15.9 per 100 person-years). The median burden of AF was 0.2% (IQR 0-0.8%). Age, the presence of hypertension, chronic kidney disease, the size of the septum and left atrium on electrocardiogram and the presence of broad QRS on baseline electrocardiogram were predictors for the appearance of AF in the univariate analysis. CONCLUSION: The incidental finding of atrial fibrillation in patients with syncope monitored with ICM is common. The burden of AF is low, and it is generally subclinical. These findings create added value for the use of ICM in the workup for syncope, although further studies are needed to determine the clinical benefit of documenting subclinical AF.

Management of Heart Failure with Reduced Ejection Fraction after ESC 2016 Heart Failure Guidelines: The Linx Registry.

AIMS: In May 2016, a new version of the European Society of Cardiology (ESC) Guidelines for the management of heart failure (HF) was released. The aim of this study was to describe the management of HF with reduced ejection fraction after the publication of ESC Guidelines. METHODS AND RESULTS: The Linx registry is a multicentre, observational, cross-sectional study from 14 Catalan hospitals that enrolled 1056 patients with HF and reduced left ventricular ejection fraction (≤40%) from 1 February to 30 April 2017 in outpatient cardiology clinics. Results were compared between hospitals according to their level of complexity in our own registry and compared with previously published registries similar to ours. Sacubitril/valsartan was prescribed to 23.9% of patients in our population, as a consequence, use of angiotensin-converting enzyme inhibitor and angiotensin receptor blockers in monotherapy decreased to 48.1% and 16.9%, respectively, and prescription of beta-blockers (91.8%), mineralocorticoid receptor antagonists (72.7%), and ivabradine (21.4%) remained similar to previous registries. Target doses of beta-blockers (25.4%), angiotensin-converting enzyme inhibitors (24.9%), angiotensin receptor blockers (7.7%), sacubitril/valsartan (8.1%), and mineralocorticoid receptor antagonists (19.7%) were accomplished in a low proportion of patients. Our results also suggest that prescription and up-titration of class I HF drugs were greater in hospitals with higher level of complexity. CONCLUSIONS: The Linx registry shows an appropriate adherence to pharmacological recommendations from ESC HF Guidelines despite a low proportion of patients reached target doses. Almost one-quarter of patients were under treatment with sacubitril/valsartan a few months after ESC HF Guidelines recommendations.

Diagnostic Yield and Economic Assessment of a Diagnostic Protocol With Systematic Use of an External Loop Recorder for Patients With Palpitations.

INTRODUCTION AND OBJECTIVES: To assess the diagnostic yield and cost-effectiveness of a diagnostic protocol based on the systematic use of latest-generation external loop recorders (ELRs) compared with the classic diagnostic strategy for patients with recurrent unexplained palpitations. METHODS: Two cohorts of consecutive patients referred for diagnosis of unexplained palpitations to the outpatient clinic of the arrhythmia unit were compared: a prospective cohort after the implementation of a new diagnostic protocol based on the systematic use of ELRs, and another, retrospective, cohort before the implementation of the protocol. The cost of diagnosis was calculated based on the number of complementary examinations, visits to outpatient clinics, or emergency department visits required to reach a diagnosis, and its costs according the prices published for the local health system. RESULTS: One hundred and forty-nine patients were included (91 in the ELR group, 58 in the control group). The diagnostic yield was higher in the ELR group (79 [86.8%] definitive diagnoses in the ELR group vs 12 [20.7%] in the control group, P < .001). The cost per diagnosis was €375.13 in the ELR group and €5184.75 in the control group (P < .001). The cost-effectiveness study revealed that the systematic use of ELR resulted in a cost reduction of €11.30 for each percentage point of increase in diagnosis yield. CONCLUSIONS: In patients with recurrent unexplained palpitations, evaluation by means of a study protocol that considers the systematic use of a latest-generation ELR increases diagnostic yield while reducing the cost per diagnosis.

Flecainide Versus Procainamide in Electrophysiological Study in Patients With Syncope and Wide QRS Duration.

OBJECTIVES: This study sought to compare the differences between procainamide and flecainide to stress the His-Purkinje system during electrophysiological study (EPS) in patients with syncope and bundle branch block (BBB). BACKGROUND: Patients with syncope and BBB are at risk of developing atrioventricular block. EPS is recommended including class I drug challenge to unmask His-Purkinje disease in cases with baseline normal His-ventricular interval. There is little data on differences between different class I drugs. METHODS: This was a prospective study of all consecutive patients undergoing EPS for syncope and BBB at a single center (January 1, 2012 to June 30, 2017). Of those patients with negative baseline EPS, 2 cohorts were compared: group A (historical cohort: procainamide) and group B (flecainide). RESULTS: During the study, 271 patients (age 73.9 ± 12.1 years, 64.9% male, QRS duration: 139.4 ± 13.9 ms) underwent EPS. In 166, baseline EPS was negative and class I drug challenge was performed (90 procainamide, 76 flecainide). The final value and percentage increase in the His-ventricular interval (76 ± 16 ms vs. 64 ± 10 ms and 22.5 ± 6.2% vs. 11.8 ± 5.3%; p < 0.001) and diagnostic yield (14.5% vs. 7.8%, p = 0.04) were higher with flecainide. No differences were found in baseline characteristics. During follow-up (25.8 ± 6.3 months), 39 patients (24.8%) with negative EPS (19.2% with flecainide vs. 30.1% with procainamide: relative risk: 5.1; 95% confidence interval: 2.6 to 10.2; p < 0. 001) received a pacemaker. CONCLUSIONS: Flecainide has a higher diagnostic yield than does procainamide in patients with BBB, syncope, and negative baseline EPS due to a greater increase of the His-ventricular interval. Additionally, there is a lesser need for pacemaker implantation in patients in whom the class I drug test using flecainide was negative.