Complicaciones y descargas inapropiadas tras el implante de un desfibrilador subcutáneo en pacientes pediátricos / Complications and inappropriate shocks in pediatric patients receiving a subcutaneous implantable cardioverter defibrilator

Introducción y objetivos: La experiencia con el desfibrilador automático implantable subcutáneo (DAI-SC) en pacientes pediátricos aún es reducida. El objetivo de este estudio es determinar la incidencia de complicaciones en pacientes pediátricos de nuestro centro en función del tipo de DAI y del tamaño del paciente.MétodosSe incluyó a pacientes menores de 18 años que recibieron un DAI-SC desde 2016 y pacientes contemporáneos (desde 2014) que recibieron un DAI transvenoso (DAI-TV). El evento principal fue el combinado de complicaciones y descargas inapropiadas.ResultadosSe implantó un DAI-SC a 26 pacientes (edad, 14 [intervalo, 5-17] años; índice de masa corporal [IMC], 20,2). De ellos, 23 (88%) fueron implantes intermusculares y el resto, en subserrato, 24 (92%) con 2 incisiones. Se programaron 2 zonas en todos los pacientes: condicional a 230 (220-230) lpm y de choque a 250 lpm. El grupo de DAI-TV incluyó a 19 pacientes (edad, 11 [5-16] años; IMC, 19,2; el 79% monocamerales). La supervivencia libre del evento principal a 5 años fue el 80% de los pacientes con DAI-SC y el 63% del grupo con DAI-TV (p=0,54); la de descargas inapropiadas fue similar (el 85 frente al 89%; p=0,86), mientras que la de complicaciones fue mayor en el grupo de DAI-SC (el 96 frente al 57%; cloglog p=0.016). En el grupo de DAI-SC no hubo fallo de la terapia ni mayores complicaciones con un IMC ≤ 20.ConclusionesCon las técnicas de implante y programación actuales, el DAI-SC es eficaz y seguro en pacientes pediátricos, con similares descargas inapropiadas y menos complicaciones a corto y medio plazo que el DAI-TV. (AU)

Introduction and objectives: There is limited evidence regarding the use of subcutaneous implantable cardioverter-defibrillators (S-ICD) in pediatric patients. The aim of this study was to determine the incidence of complications in these patients at our center, according to the type of ICD and patient size.MethodsWe included all patients aged<18 years who received an S-ICD since 2016 at our center. As a control group, we also included contemporary patients (since 2014) who received a transvenous ICD (TV-ICD). The primary endpoint was a composite of complications and inappropriate shocks.ResultsA total of 26 patients received an S-ICD (median age, 14 [5-17] years; body mass index [BMI], 20.2 kg/m2). Implantation was intermuscular in 23 patients (88%) and subserratus in the remainder. Two incisions were used in 24 patients (92%). In all patients, 2 zones were programmed: a conditional zone set at 230 (220-230) bpm, and a shock zone set at 250 bpm. Nineteen patients received a TV-ICD (median age, 11 [range, 5-16] years; BMI, 19.2 kg/m2, 79% single-chamber). Survival free from the primary endpoint at 5 years was 80% in the S-ICD group and 63% in the TV-ICD group (P=.54). Survival free from inappropriate shocks was similar (85% vs 89%, P=.86), while survival free from complications was higher in the S-ICD group (96% vs 57%, cloglogP=.016). There were no therapy failures in the S-ICD group, and no increased complication rates were observed in patients with BMI ≤ 20 kg/m2.ConclusionsWith contemporary implantation techniques and programming, S-ICD is a safe and effective therapy in pediatric patients. The number of inappropriate shocks is similar to TV-ICD, with fewer short- and mid-term complications. (AU)

Sudden cardiac death triggered by minimal alcohol consumption in the context of novel PPA2 mutations in 2 unrelated families.

Biallelic variants in PPA2 gene cause a rare but lethal mitochondrial disorder. We describe the first four cases reported in Spain of PPA2 disease in two unrelated families. We have conducted a revision of the clinical history, necropsies, and postmortem genetic testing from probands, and clinical evaluation, genetic testing and blood transcript analysis in family members. All the cases harbored biallelic PPA2 variants in compound heterozygous status. Two brothers from family 1 suffered sudden death after a small first intake of alcohol in 2013 and 2022. The sister remains alive but affected with cardiomyopathy, extensive scar on cardiac imaging, and high sensitivity to alcohol intake. The three siblings carried PPA2 c.290A > G (p.Glu97Gly) novel missense variant and PPA2 c.513C > T (p.Cys171 = ) altering splicing site variant, both probably leading to mRNA degradation based on in-silico and transcript analyses. A teenager from family 2 suffered sudden death after a small intake of alcohol in 2018 and carried PPA2 c.683C > T (p.Pro228Leu) missense and PPA2 c.980_983del (p.Gln327fs) novel frameshift variant, both probably leading to abnormal protein structure. All cases were asymptomatic until adolescence. Furthermore, the sister in family 1 has survived as an asymptomatic adult. PPA2 disease can manifest as cardiac arrest in the young, especially after alcohol exposure. Our results show that PPA2 deficiency can be related to different pathogenicity mechanisms such as abnormal protein structure but also mRNA decay caused by synonymous or missense variants. Strict avoidance of alcohol consumption and early defibrillator implantation might prevent lethal arrhythmias in patients at risk.

Complications and inappropriate shocks in pediatric patients receiving a subcutaneous implantable cardioverter defibrilator.

INTRODUCTION AND OBJECTIVES: There is limited evidence regarding the use of subcutaneous implantable cardioverter-defibrillators (S-ICD) in pediatric patients. The aim of this study was to determine the incidence of complications in these patients at our center, according to the type of ICD and patient size. METHODS: We included all patients aged<18 years who received an S-ICD since 2016 at our center. As a control group, we also included contemporary patients (since 2014) who received a transvenous ICD (TV-ICD). The primary endpoint was a composite of complications and inappropriate shocks. RESULTS: A total of 26 patients received an S-ICD (median age, 14 [5-17] years; body mass index [BMI], 20.2 kg/m2). Implantation was intermuscular in 23 patients (88%) and subserratus in the remainder. Two incisions were used in 24 patients (92%). In all patients, 2 zones were programmed: a conditional zone set at 230 (220-230) bpm, and a shock zone set at 250 bpm. Nineteen patients received a TV-ICD (median age, 11 [range, 5-16] years; BMI, 19.2 kg/m2, 79% single-chamber). Survival free from the primary endpoint at 5 years was 80% in the S-ICD group and 63% in the TV-ICD group (P=.54). Survival free from inappropriate shocks was similar (85% vs 89%, P=.86), while survival free from complications was higher in the S-ICD group (96% vs 57%, cloglog P=.016). There were no therapy failures in the S-ICD group, and no increased complication rates were observed in patients with BMI ≤20 kg/m2. CONCLUSIONS: With contemporary implantation techniques and programming, S-ICD is a safe and effective therapy in pediatric patients. The number of inappropriate shocks is similar to TV-ICD, with fewer short- and mid-term complications.

The role of the electrocardiographic phenotype in risk stratification for sudden cardiac death in childhood hypertrophic cardiomyopathy.

AIMS: The 12-lead electrocardiogram (ECG) is routinely performed in children with hypertrophic cardiomyopathy (HCM). An ECG risk score has been suggested as a useful tool for risk stratification, but this has not been independently validated. This aim of this study was to describe the ECG phenotype of childhood HCM in a large, international, multi-centre cohort and investigate its role in risk prediction for arrhythmic events. METHODS AND RESULTS: Data from 356 childhood HCM patients with a mean age of 10.1 years (±4.5) were collected from a retrospective, multi-centre international cohort. Three hundred and forty-seven (97.5%) patients had ECG abnormalities at baseline, most commonly repolarization abnormalities (n = 277, 77.8%); left ventricular hypertrophy (n = 240, 67.7%); abnormal QRS axis (n = 126, 35.4%); or QT prolongation (n = 131, 36.8%). Over a median follow-up of 3.9 years (interquartile range 2.0-7.7), 25 (7%) had an arrhythmic event, with an overall annual event rate of 1.38 (95% CI 0.93-2.04). No ECG variables were associated with 5-year arrhythmic event on univariable or multivariable analysis. The ECG risk score threshold of >5 had modest discriminatory ability [C-index 0.60 (95% CI 0.484-0.715)], with corresponding negative and positive predictive values of 96.7% and 6.7. CONCLUSION: In a large, international, multi-centre cohort of childhood HCM, ECG abnormalities were common and varied. No ECG characteristic, either in isolation or combined in the previously described ECG risk score, was associated with 5-year sudden cardiac death risk. This suggests that the role of baseline ECG phenotype in improving risk stratification in childhood HCM is limited.

Cardiac phenotype in ATP1A3-related syndromes: A multicenter cohort study.

OBJECTIVE: To define the risks and consequences of cardiac abnormalities in ATP1A3-related syndromes. METHODS: Patients meeting clinical diagnostic criteria for rapid-onset dystonia-parkinsonism (RDP), alternating hemiplegia of childhood (AHC), and cerebellar ataxia, areflexia, pes cavus, optic atrophy, and sensorineural hearing loss (CAPOS) with ATP1A3 genetic analysis and at least 1 cardiac assessment were included. We evaluated the cardiac phenotype in an Atp1a3 knock-in mouse (Mashl+/-) to determine the sequence of events in seizure-related cardiac death. RESULTS: Ninety-eight patients with AHC, 9 with RDP, and 3 with CAPOS (63 female, mean age 17 years) were included. Resting ECG abnormalities were found in 52 of 87 (60%) with AHC, 2 of 3 (67%) with CAPOS, and 6 of 9 (67%) with RDP. Serial ECGs showed dynamic changes in 10 of 18 patients with AHC. The first Holter ECG was abnormal in 24 of 65 (37%) cases with AHC and RDP with either repolarization or conduction abnormalities. Echocardiography was normal. Cardiac intervention was required in 3 of 98 (≈3%) patients with AHC. In the mouse model, resting ECGs showed intracardiac conduction delay; during induced seizures, heart block or complete sinus arrest led to death. CONCLUSIONS: We found increased prevalence of ECG dynamic abnormalities in all ATP1A3-related syndromes, with a risk of life-threatening cardiac rhythm abnormalities equivalent to that in established cardiac channelopathies (≈3%). Sudden cardiac death due to conduction abnormality emerged as a seizure-related outcome in murine Atp1a3-related disease. ATP1A3-related syndromes are cardiac diseases and neurologic diseases. We provide guidance to identify patients potentially at higher risk of sudden cardiac death who may benefit from insertion of a pacemaker or implantable cardioverter-defibrillator.

Respuesta al ECG de febrero de 2016 / Response to ECG, February 2016

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End-stage ischemic heart failure and Williams-Beuren syndrome: A unique scenario for pediatric heart transplantation.

WBS is a rare disorder caused by mutations in the chromosomal sub-band 7q11.23 involving the elastin gene. The clinical features (craniofacial, developmental, and cardiovascular abnormalities) are variable. The association with cardiac anomalies is a well-recognized feature, and SVAS is the most common cardiac defect found. End-stage ischemic heart disease is unusual in this setting but when it occurs, OHT remains the final therapeutic option. This decision can be difficult to determine, and it must be tailored to the individual patient based on the clinical status and concomitant cardiovascular and multisystem lesions. To date, no cases of OHT in patients with WBS have been described. We present a 14-month-old patient with WBS who developed severe LV dysfunction secondary to ischemia following a complex staged surgery for SVAS repair. He underwent successful OHT with no post-operative complications, and at three-month follow-up, he remains asymptomatic on standard immunosuppressive therapy. This case constitutes the first demonstration that OHT may be indicated for extended survival in selected children with WBS and we discuss the basic principles for extending the indication for OHT to this scenario as well as the particularities for post-transplant care.

ECG de febrero de 2016 / ECG, February 2016

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