Effects of Cardiac Stem Cell on Postinfarction Arrhythmogenic Substrate.

Clinical data suggest that cardiosphere-derived cells (CDCs) could modify post-infarction scar and ventricular remodeling and reduce the incidence of ventricular tachycardia (VT). This paper assesses the effect of CDCs on VT substrate in a pig model of postinfarction monomorphic VT. We studied the effect of CDCs on the electrophysiological properties and histological structure of dense scar and heterogeneous tissue (HT). Optical mapping and histological evaluation were performed 16 weeks after the induction of a myocardial infarction by transient occlusion of the left anterior descending (LAD) artery in 21 pigs. Four weeks after LAD occlusion, pigs were randomized to receive intracoronary plus trans-myocardial CDCs (IC+TM group, n: 10) or to a control group. Optical mapping (OM) showed an action potential duration (APD) gradient between HT and normal tissue in both groups. CDCs increased conduction velocity (53 ± 5 vs. 45 ± 6 cm/s, p < 0.01), prolonged APD (280 ± 30 ms vs. 220 ± 40 ms, p < 0.01) and decreased APD dispersion in the HT. During OM, a VT was induced in one and seven of the IC+TM and control hearts (p = 0.03), respectively; five of these VTs had their critical isthmus located in intra-scar HT found adjacent to the coronary arteries. Histological evaluation of HT revealed less fibrosis (p < 0.01), lower density of myofibroblasts (p = 0.001), and higher density of connexin-43 in the IC+TM group. Scar and left ventricular volumes did not show differences between groups. Allogeneic CDCs early after myocardial infarction can modify the structure and electrophysiology of post-infarction scar. These findings pave the way for novel therapeutic properties of CDCs.

Outcomes of leadless pacemaker implantation in patients with mechanical heart valves.

INTRODUCTION: Device infections constitute a major complication of transvenous pacemakers. Mechanical heart valves (MHV) increase the risk of infective endocarditis (IE) and pacemaker infection, requiring lifelong vitamin K-antagonists (VKA), which may affect patient management. Leadless pacemakers (LP) are associated with low infection rates, posing an attractive option in MHV patients requiring permanent pacing. This study describes outcomes following LP implantation in patients with MHV. METHODS: This is a multicenter, observational, retrospective study including consecutive patients implanted with an LP at 5 centers between June 2015 and January 2020. Procedural outcomes, antithrombotic management, complications, performance during follow-up and episodes of bacteremia and IE were compared between patients with and without an MHV (MHV and non-MHV groups). RESULTS: Four hundred fifty-nine patients were included (74 in the MHV group, 16.1%, and 385 in the non-MHV group, 83.9%). Procedural outcomes and acute electrical performance were comparable between groups. Vascular complications and cardiac perforation occurred in 2.7 versus 2.3% (p = 1) and 0% versus 0.8% (p = 1) in the MHV group and non-MHV group. One case of IE occurred in the MHV group and 2 in the non-MHV group. In MHV patients, uninterrupted VKA was used in 83.8%, whereas 16.2% were heparin-bridged. Vascular complication or tamponade occurred in 1 (8.3%) MHV heparin-bridged patient versus 1 (1.6%) MHV uninterrupted VKA patient (p = .3). CONCLUSION: LP implantation outcomes in MHV patients are comparable to the general LP population. Device-related infections are rare following LP implantation, including in patients with MHV. In the MHV group, periprocedural anticoagulation management was not associated with significantly different rates of tamponade or vascular complication.

Predictors of adoption and impact of evidence-based programming on the incidence of implantable cardioverter-defibrillator therapies.

INTRODUCTION AND OBJECTIVES: The ADVANCE III trial showed that a delayed-detection strategy reduces implantable cardioverter-defibrillator (ICD) therapies. Here, we describe the adherence to and predictors of ADVANCE adoption and compare ICD therapy rates between patients with and without ADVANCE programming. METHODS: This observational retrospective study analyzed patients implanted with Medtronic ICDs included from 2005 to 2016 in a Spanish national multicenter registry (UMBRELLA database; ClinicalTrials.gov, NCT01561144). Changes in ADVANCE programming adoption were described in relation to a) publication of the ADVANCE trial, b) implementation of an "ADVANCE awareness" campaign, and c) publication of an expert consensus statement. Multivariate logistic regression identified predictors of adoption. Therapy incidence rates were compared between groups by estimating the adjusted incidence rate ratio (aIRR) using negative binomial regression. RESULTS: A total of 3528 patients were included. An ADVANCE strategy was used in 20% overall and in 44% at the end of the study. ADVANCE III adoption increased after trial publication, with less growth after an "ADVANCE awareness" campaign and after expert consensus statement publication. Predictors of ADVANCE adoption were as follows: ICD device with a nominal number of intervals to detect 30/40 (aOR, 4.4; 95%CI, 3.5-5.4), implantation by an electrophysiologist (aOR, 1.7; 95%CI, 1.4-2.2), and secondary prevention (aOR, 3.2; 95%CI, 2.6-3.9). Dual-chamber ICDs (aOR, 0.6; 95%CI, 0.5-0.8) and cardiac resynchronization-defibrillators (aOR, 0.5; 95%CI, 0.4-0.7) were associated with lower adoption. ADVANCE programming was associated with reduced total therapy burden (aIRR, 0.77; 95%CI, 0.69-0.86) and fewer inappropriate shocks (aIRR, 0.66; 95%CI, 0.52-0.85). CONCLUSIONS: ADVANCE adoption remains modest and can be improved through evidence-driven selection of nominal ICD settings. ADVANCE programming is associated with reduced therapy rates in real-world ICD recipients.

Radiofrequency treatment for electrical storm: evolution and monitoring. / Tratamiento con radiofrecuencia de la tormenta eléctrica: evolución y seguimiento.

Introducción y objetivos: La tormenta eléctrica (TE) se caracteriza por episodios repetidos de taquicardia ventricular o fibrilación ventricular relacionados con mal pronóstico a corto y largo plazos. El objetivo fue evaluar la prevalencia, resultados y supervivencia de los pacientes sometidos a tratamiento intervencionista por TE en un centro de referencia. Métodos: Estudio unicéntrico, observacional y retrospectivo. Se revisaron los procedimientos de ablación por TE y se evaluaron las características basales de los pacientes, tipo de procedimiento, mortalidad total, recurrencia de arritmia, mortalidad cardiovascular y necesidad de trasplante. Resultados: Desde enero de 2009 hasta diciembre de 2016 se realizaron 67 procedimientos (38% de complejos: 19% de ablación endoepicárdica, 7.5% de crioablación epicárdica quirúrgica, 3% de simpatectomía, 3% de inyección coronaria con alcohol; 6% de apoyo con oxigenación con membrana extracorpórea) en 41 pacientes (61% de causa isquémica) por TE. La mortalidad intraprocedimiento fue del 1.5%. La mediana de seguimiento fue de 23.5 meses (RIQ, 14.2-52.7). Tras el primer ingreso por TE (uno o varios procedimientos), la mortalidad a un año fue de 9.8%. La incidencia acumulada de trasplante cardiaco por TE fue de 2.4%. En el análisis multivariado, el riesgo de recurrencias arrítmicas o muerte por cualquier causa fue significativamente mayor en pacientes con arritmias clínicas inducibles (HR, 9.03; p = 0.017). Conclusiones: El tratamiento de pacientes con TE, instituido en un centro de referencia y con experiencia, se relacionó con una tasa baja de recurrencia y supervivencia elevada, con una tasa de trasplante cardiaco por TE muy baja. Ante una recurrencia temprana es recomendable practicar un nuevo procedimiento durante el ingreso. Introduction and objective: Electrical storm (ES) is characterized by repeated episodes of ventricular tachycardia or ventricular fibrillation, with poor short and long term prognosis. Our objective was to evaluate the prevalence, results of interventional treatment and survival of patients undergoing interventional treatment for ES in our center. Methods: Retrospective, unicentric and observational study. ES ablation procedures were revised and data regarding baseline characteristics of the patients, type of procedure, total mortality, recurrence of arrhythmia, cardiovascular mortality and the need for transplantation were evaluated. Results: From January 2009 to December 2016, 67 procedures (38% complex procedures: 19% epicardial ablation, 7.5% surgical epicardial crioablation, 3% simpatectomy, 3% coronary alcohol injection, 6% extracorporeal membrane oxygenation support) were performed in 41 patients (61% Ischemic etiology) due to ES. Intraprocedural mortality was 1.5%. The median follow-up was 23.5 months (IQR [14.2-52.7]). After the first admission for ES (one or several procedures), 1-year mortality was 9.8%. The cumulative incidence of cardiac transplantation was 2.4%. The risk of arrhythmic recurrences or death was significantly higher in patients with inducible clinical arrhythmias after ablation (HR: 9.03, p = 0.017). Conclusions: The treatment of patients with ES, performed in a reference center, allows obtaining good rates of recurrence and survival, with very low rates of cardiac transplantation for ES. In the presence of an early recurrence, it is advisable to perform a new procedure during admission.

Tratamiento con radiofrecuencia de la tormenta eléctrica: evolución y seguimiento / Radiofrequency treatment for electrical storm: evolution and monitoring

Resumen Introducción y objetivos: La tormenta eléctrica (TE) se caracteriza por episodios repetidos de taquicardia ventricular o fibrilación ventricular relacionados con mal pronóstico a corto y largo plazos. El objetivo fue evaluar la prevalencia, resultados y supervivencia de los pacientes sometidos a tratamiento intervencionista por TE en un centro de referencia. Métodos: Estudio unicéntrico, observacional y retrospectivo. Se revisaron los procedimientos de ablación por TE y se evaluaron las características basales de los pacientes, tipo de procedimiento, mortalidad total, recurrencia de arritmia, mortalidad cardiovascular y necesidad de trasplante. Resultados: Desde enero de 2009 hasta diciembre de 2016 se realizaron 67 procedimientos (38% de complejos: 19% de ablación endoepicárdica, 7.5% de crioablación epicárdica quirúrgica, 3% de simpatectomía, 3% de inyección coronaria con alcohol; 6% de apoyo con oxigenación con membrana extracorpórea) en 41 pacientes (61% de causa isquémica) por TE. La mortalidad intraprocedimiento fue del 1.5%. La mediana de seguimiento fue de 23.5 meses (RIQ, 14.2-52.7). Tras el primer ingreso por TE (uno o varios procedimientos), la mortalidad a un año fue de 9.8%. La incidencia acumulada de trasplante cardiaco por TE fue de 2.4%. En el análisis multivariado, el riesgo de recurrencias arrítmicas o muerte por cualquier causa fue significativamente mayor en pacientes con arritmias clínicas inducibles (HR, 9.03; p = 0.017). Conclusiones: El tratamiento de pacientes con TE, instituido en un centro de referencia y con experiencia, se relacionó con una tasa baja de recurrencia y supervivencia elevada, con una tasa de trasplante cardiaco por TE muy baja. Ante una recurrencia temprana es recomendable practicar un nuevo procedimiento durante el ingreso.

Abstract Introduction and objective: Electrical storm (ES) is characterized by repeated episodes of ventricular tachycardia or ventricular fibrillation, with poor short and long term prognosis. Our objective was to evaluate the prevalence, results of interventional treatment and survival of patients undergoing interventional treatment for ES in our center. Methods: Retrospective, unicentric and observational study. ES ablation procedures were revised and data regarding baseline characteristics of the patients, type of procedure, total mortality, recurrence of arrhythmia, cardiovascular mortality and the need for transplantation were evaluated. Results: From January 2009 to December 2016, 67 procedures (38% complex procedures: 19% epicardial ablation, 7.5% surgical epicardial crioablation, 3% simpatectomy, 3% coronary alcohol injection, 6% extracorporeal membrane oxygenation support) were performed in 41 patients (61% Ischemic etiology) due to ES. Intraprocedural mortality was 1.5%. The median follow-up was 23.5 months (IQR [14.2-52.7]). After the first admission for ES (one or several procedures), 1-year mortality was 9.8%. The cumulative incidence of cardiac transplantation was 2.4%. The risk of arrhythmic recurrences or death was significantly higher in patients with inducible clinical arrhythmias after ablation (HR: 9.03, p = 0.017). Conclusions: The treatment of patients with ES, performed in a reference center, allows obtaining good rates of recurrence and survival, with very low rates of cardiac transplantation for ES. In the presence of an early recurrence, it is advisable to perform a new procedure during admission.

Predictors of pacemaker dependency in patients implanted with a pacemaker after Transaortic valve replacement.

INTRODUCTION AND OBJECTIVES: The development of complete AV block and the need for pacemaker implantation (PM) is the most frequent complication after Transaortic valve replacement (TAVR). In other PM clinical contexts, a higher percentage of ventricular stimulation has been associated with worse prognosis. The objective was to study the existence of predictors of PM dependence. METHODS: We identified 96 consecutive patients who had received a PM post-TAVR (all Core-Valve). We retrospectively analyzed this cohort with the aim of identifying predictors of a high and very high percentage of ventricular pacing (VP), PM dependency and survival. RESULTS: The mean age was 82.3 years, with a mean logistic EuroSCORE of 17.1, 53% were women and 12% of patients had LVEF < 50%. The indication was complete AV block in 40.5%, and LBBB in 59.5%. Mean survival was 62.7 months, IQR [54.4-71]. The only independent predictor of mortality was the pre-TAVR logistic Euro-SCORE (RR = 1,026, p = 0.033), but not LVEF < 50%, VP > 50%, VP > 85% or PM dependence. In 73 patients PM rhythm was documented at the end of follow-up. Of these, 14 (19.2%) were considered dependent, and 37 (50.7%) presented VP > 50%. The post-TAVR complete AV block recovery rate was 67.8%. In multivariate analysis, female sex (HR = 5.6, p = 0.005), and indication of complete AV block vs. LBBB (HR = 15.7, p = 0.017) were independently associated with PM dependency. CONCLUSIONS: Female sex and indication due to complete AV block were independent predictors of PM dependency during follow up. In our series of patients with mostly normal LVEF, a high percentage of stimulation does not influence prognosis.

Impact of routine right parasternal electrocardiographic screening in assessing eligibility for subcutaneous implantable cardioverter-defibrillator.

INTRODUCTION: Between 7% and 15% of patients with an indication for an implantable cardioverter-defibrillator (ICD) are not eligible for implantation of a subcutaneous implantable cardioverter-defibrillator (S-ICD) on the basis of the result of the conventional left parasternal electrocardiographic screening (LPES). Our objective was to determine the impact of systematically performing right parasternal electrocardiographic screening (RPES) in addition to conventional LPES, in terms of increasing both the total percentage of potentially eligible patients for S-ICD implantation and the number of suitable vectors per patient. METHODS AND RESULTS: Consecutive patients from the outpatient device clinic who already had an implanted ICD, and no requirement for pacing were enrolled. Conventional left parasternal electrode position and right parasternal electrode positions were used. The automatic screening tool was used to analyze the recordings. Screenings were performed in the supine and standing positions. Overall, 209 patients were included. The mean age was 63.4 ± 13 years, 59.8% had ischemic heart disease, mean QRS duration was 100 ± 31 ms, and 69.9% had a primary prevention ICD indication. Based on conventional isolated LPES, 12.9% of patients were not eligible for S-ICD compared with 11.5% based on RPES alone (P = .664). Considering LPES and RPES together, only 7.2% of patients were not eligible for S-ICD (P < .001). Moreover, the number of patients with more than one suitable vector increased from 66.5% with isolated LPES to 82.3% (23.7% absolute increase [P < .001]). CONCLUSION: Adding an automated RPES to the conventional automated LPES increased patient eligibility for the S-ICD significantly. Moreover, combined screening increased the number of suitable vectors per eligible patient.

Pediatric Catheter Ablation: Characteristics and Results of a Series in a Tertiary Referral Hospital.

INTRODUCTION AND OBJECTIVES: Catheter ablation has become the treatment of choice in an increasing number of arrhythmias in children and adolescents. There is still limited evidence of its use at a national level in Spain. The aim was to describe the characteristics and results of a modern monocentric series form a referral tertiary care centre. METHODS: Retrospective register of invasive procedures between 2004 and 2016 performed in patients under 17 years and recorded clinical characteristic, ablation methodology and acute and chronic results of the procedure. RESULTS: A total of 291 procedures in 224 patients were included. Median age was 12.2 years, 60% male. Overall, 46% patients were referred from other autonomous communities. The most frequent substrates were accessory pathways (AP) (70.2%,>50% septal AP localization) and atrioventricular nodal reentrant tachycardia (AVNRT) (15.8%). Congenital and acquired heart disease was frequent (16.8%). Cryoablation was used in 35.5% of the cases. Overall acute success of the primary procedure was 93.5% (AP 93.8%; AVNRT 100%). Redo procedures after recurrence were performed in 18.9% of all substrates, with a long-term cumulative efficacy of 98.4% (AP 99.3%; AVNRT 100%). One (0.37%) serious complication occurred, a case of complete atrioventricular block. CONCLUSIONS: Our study replicated previous international reports of high success rates with scarce complications in a high complexity series, confirming the safety and efficacy of pediatric catheter ablation in our environment performed at highly experienced referral centers.

Safety and efficacy of cryoablation vs. radiofrequency ablation of septal accessory pathways: systematic review of the literature and meta-analyses.

Aims: Radiofrequency ablation (RFA) of septal accessory pathways (APs) is associated with a significant rate of first procedure failures and complications. Cryoablation is an alternative energy source but there are no studies comparing both ablation techniques. We aimed to systematically review the literature and compare the efficacy and safety of cryoablation vs. RFA of septal APs. Methods and results: We conducted two separate meta-analysis of cryoablation and RFA of septal APs and calculated the global estimates of the efficacy and safety. Sixty-four articles were included: 38 articles reporting RFA and 27 articles reporting cryoablation procedures. Additionally, we included the previously non-published cryoablation registry of septal APs performed at our institution. Overall, 4244 septal APs constitute our study population, 3495 in the RFA cohort and 749 in the cryoablation cohort. Acute procedural success rate of cryoablation was 86.0% (95% CI 81.6-89.4%) and RFA 89.0% (95% CI 86.8-91.0%). Recurrence rate of cryoablation was 18.1% (95% CI 14.8-21.8%) and RFA 9.9% (95% CI 8.2-12.0%). Long-term success rate after multiple ablation procedures of cryoablation was 75.9% (95% CI 68.2-82.3%) and RFA 88.4% (95% CI 84.7-91.3%). There were no reported cases of persistent atrioventricular block (AVB) with cryoablation and 2.7% (95% CI 2.2-3.4%) with RFA. Conclusion: Studies of RFA for treatment of septal APs report higher efficacy rates than do studies using cryoablation, but a significantly higher rate of AVB.

Association of cardiac resynchronization therapy with the incidence of appropriate implantable cardiac defibrillator therapies in ischaemic and non-ischaemic cardiomyopathy.

AIMS: Cardiac resynchronization therapy (CRT) reduces the incidence of sudden cardiac death and the use of appropriate implantable cardioverter-defibrillator (ICD) therapies (AICDTs); however, this antiarrhythmic effect is only observed in certain groups of patients. To gain insight into the effects of CRT on ventricular arrhythmia (VA) burden, we compared the incidence of AICDT use in four groups of patients: patients with ischaemic cardiomyopathy vs. non-ischaemic dilated cardiomyopathy (NIDC) and patients implanted with an ICD vs. CRT-ICD. METHODS AND RESULTS: We analysed 689 consecutive patients (mean follow-up 37 ± 16 months) included in the Umbrella registry, a multicentre prospective registry including patients implanted with ICD or CRT-ICD devices with remote monitoring capabilities in 48 Spanish Hospitals. The primary outcome was the time to first AICDT. Despite a worse clinical risk profile, NIDC patients receiving a CRT-ICD had a lower cumulative probability of first AICDT use at 2 years compared with patients implanted with an ICD [24.7 vs. 41.6%, hazard ratio (HR): 0.49, P = 0.003]; on the other hand, there were no significant differences in the incidence of first AICDT use at 2 years in ischaemic patients (22.6 vs. 21.9%, P = NS). Multivariate analysis confirmed the association of CRT with lower AICDT rates amongst NIDC patients (Adjusted HR: 0.55, CI 95% 0.35-0.87). CONCLUSIONS: These data suggest that CRT is associated with significantly lower rates of first AICDT use in NIDC patients, but not in ischaemic patients. This study suggests that ICD patients with NIDC and left bundle branch block experiencing VAs may benefit from an upgrade to CRT-ICD despite being in a good functional class.

Immediate post-procedure bridging with unfractioned heparin versus low molecular weight heparin in patients undergoing radiofrequency ablation for atrial fibrillation with an interrupted oral anticoagulation strategy.

PURPOSE: Many centers perform catheter ablation for atrial fibrillation (AF) with periprocedural interruption of oral vitamin K antagonists. In this scenario, the optimal post-procedural anticoagulation strategy is still under debate. We sought to compare the incidence of major complications associated with post-procedural use of low molecular weight heparin (LMWH) versus unfractioned heparin (UFH) as a bridge to reinitiation of oral anticoagulation after an AF ablation procedure. METHODS: We retrospectively reviewed medical history data of all patients undergoing catheter ablation for AF at three Spanish referral centers between January 2009 and January 2014. A total of 702 patients were included in the analysis. We compared the incidence of major complications (a combination of major bleeding and thromboembolic events) between patients receiving UFH (291) and those receiving LMWH (411) after the procedure. RESULTS: The overall incidence of major complications was 4.1%, including five thromboembolic events (0.7%) and 24 major bleeding events (3.4%), with no significant differences in patients treated with LMWH vs. UFH (2.9 vs. 4.1%; P = NS). The presence of peripheral vascular disease emerged as the only independent predictor of major complications (adjusted odds ratio (OR) 9.1; confidence interval (CI) 95% 1.7-49.3; P < 0.01). CONCLUSIONS: Immediate post-procedural bridging with UFH or with LMWH are equally safe strategies in patients undergoing catheter ablation for AF in whom oral anticoagulation is interrupted for the procedure. Due to its greater simplicity of use, LMWH may be the preferred option. The presence of peripheral vascular disease is a potent predictor of major post-procedural complications.

Coronary physiology assessment in the catheterization laboratory.

Physicians cannot rely solely on the angiographic appearance of epicardial coronary artery stenosis when evaluating patients with myocardial ischemia. Instead, sound knowledge of coronary vascular physiology and of the methods currently available for its characterization can improve the diagnostic and prognostic accuracy of invasive assessment of the coronary circulation, and help improve clinical decision-making. In this article we summarize the current methods available for a thorough assessment of coronary physiology.

Self-Healing Extranodal Cutaneous Rosai-Dorfman in a Child.

Sinus histiocytosis with massive lymphadenopathy, or Rosai-Dorfman disease (RDD), is commonly characterized by painless cervical lymphadenopathy. Exclusively cutaneous Rosai-Dorfman disease is rare. In the absence of massive lymphadenopathy, the nonspecific skin lesions may complicate the diagnosis. To our knowledge, the case reported herein is the youngest case of extranodal cutaneous RDD.