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Childhood hypertrophic cardiomyopathy; Outcomes; Phenotype Miocardiopatía hipertrófica infantil; Resultados; Fenotipo Miocardiopatia hipertròfica infantil; Resultats; Fenotip Background Up to one-half of childhood sarcomeric hypertrophic cardiomyopathy (HCM) presents before the age of 12 years, but this patient group has not been systematically characterized. Objectives The aim of this study was to describe the clinical presentation and natural history of patients presenting with nonsyndromic HCM before the age of 12 years. Methods Data from the International Paediatric Hypertrophic Cardiomyopathy Consortium on 639 children diagnosed with HCM younger than 12 years were collected and compared with those from 568 children diagnosed between 12 and 16 years. Results At baseline, 339 patients (53.6%) had family histories of HCM, 132 (20.9%) had heart failure symptoms, and 250 (39.2%) were prescribed cardiac medications. The median maximal left ventricular wall thickness z-score was 8.7 (IQR: 5.3-14.4), and 145 patients (27.2%) had left ventricular outflow tract obstruction. Over a median follow-up period of 5.6 years (IQR: 2.3-10.0 years), 42 patients (6.6%) died, 21 (3.3%) underwent cardiac transplantation, and 69 (10.8%) had life-threatening arrhythmic events. Compared with those presenting after 12 years, a higher proportion of younger patients underwent myectomy (10.5% vs 7.2%; P = 0.045), but fewer received primary prevention implantable cardioverter-defibrillators (18.9% vs 30.1%; P = 0.041). The incidence of mortality or life-threatening arrhythmic events did not differ, but events occurred at a younger age. Conclusions Early-onset childhood HCM is associated with a comparable symptom burden and cardiac phenotype as in patients presenting later in childhood. Long-term outcomes including mortality did not differ by age of presentation, but patients presenting at younger than 12 years experienced adverse events at younger ages. This work was supported by the British Heart Foundation (grant FS/16/72/32270) to Drs Norrish and Kaski. This work is (partly) funded by the National Institute for Health Research Great Ormond Street Hospital Biomedical Research Centre. Dr Norrish is supported by Great Ormond Street Hospital Children’s Charity. Drs Field and Kaski are supported by Max’s Foundation and Great Ormond Street Hospital Children’s Charity. Dr Kaski is supported by a Medical Research Council–National Institute for Health Research Clinical Academic Research Partnership award. This work was financially supported by the Foundation for Paediatric Research of Finland (Dr Ojala). Dr Fernandez has received speaker fees from Sanofi-Genzyme. Dr Kubus is supported by MH CZ – DRO, Motol University Hospital (00064203). All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Aims Sudden cardiac death (SCD) is the most common mode of death in childhood hypertrophic cardiomyopathy (HCM). The newly developed HCM Risk-Kids model provides clinicians with individualized estimates of risk. The aim of this study was to externally validate the model in a large independent, multi-centre patient cohort. Methods and results A retrospective, longitudinal cohort of 421 patients diagnosed with HCM aged 1–16 years independent of the HCM Risk-Kids development and internal validation cohort was studied. Data on HCM Risk-Kids predictor variables (unexplained syncope, non-sustained ventricular tachycardia, maximal left ventricular wall thickness, left atrial diameter, and left ventricular outflow tract gradient) were collected from the time of baseline clinical evaluation. The performance of the HCM Risk-Kids model in predicting risk at 5 years was assessed. Twenty-three patients (5.4%) met the SCD end-point within 5 years, with an overall incidence rate of 2.03 per 100 patient-years [95% confidence interval (CI) 1.48–2.78]. Model validation showed a Harrell’s C-index of 0.745 (95% CI 0.52–0.97) and Uno’s C-index 0.714 (95% 0.58–0.85) with a calibration slope of 1.15 (95% 0.51–1.80). A 5-year predicted risk threshold of ≥6% identified 17 (73.9%) SCD events with a corresponding C-statistic of 0.702 (95% CI 0.60–0.81). Conclusions This study reports the first external validation of the HCM Risk-Kids model in a large and geographically diverse patient population. A 5-year predicted risk of ≥6% identified over 70% of events, confirming that HCM Risk-Kids provides a method for individualized risk predictions and shared decision-making in children with HCM.

Background: Maximal left ventricular wall thickness (MLVWT) is a risk factor for sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM). In adults, the severity of left ventricular hypertrophy has a nonlinear relationship with SCD, but it is not known whether the same complex relationship is seen in childhood. The aim of this study was to describe the relationship between left ventricular hypertrophy and SCD risk in a large international pediatric HCM cohort. Methods: The study cohort comprised 1075 children (mean age, 10.2 years [±4.4]) diagnosed with HCM (1–16 years) from the International Paediatric Hypertrophic Cardiomyopathy Consortium. Anonymized, noninvasive clinical data were collected from baseline evaluation and follow-up, and 5-year estimated SCD risk was calculated (HCM Risk-Kids). Results: MLVWT Z score was Z scores were associated with heart failure symptoms, unexplained syncope, left ventricular outflow tract obstruction, left atrial dilatation, and nonsustained ventricular tachycardia. One hundred twenty-two patients (71.3%) with MLVWT Z score ≥20 had coexisting risk factors for SCD. Over a median follow-up of 4.9 years (interquartile range, 2.3–9.3), 115 (10.7%) had an SCD event. Freedom from SCD event at 5 years for those with MLVWT Z scores Z score, peaking at Z score +23. The presence of coexisting risk factors had a summative effect on risk. Conclusions: In children with HCM, an inverted U-shaped relationship exists between left ventricular hypertrophy and estimated SCD risk. The presence of additional risk factors has a summative effect on risk. While MLVWT is important for risk stratification, it should not be used either as a binary variable or in isolation to guide implantable cardioverter defibrillator implantation decisions in children with HCM.

Introduction Pediatric heart transplantation is commonly performed as a last resort treatment for severe heart dysfunction. We sought to analyze our 20 years’ experience with pediatric heart transplant: long-term outcome and fate at transition to adulthood. Methods Retrospective analysis of all children ( Results Forty-nine transplants were performed in 48 children at median age and weight of 8,3 years [2,9–13,5] and 20,5 kg [13,2–39,5]. 86% had cardiomyopathy (dilated in 57% of those), 8% congenital heart disease and 6% myocarditis. Median time on waiting list was 46 days [19–132] with a trend to increase with time. Global survival reached 88% at 1 year and 80% at 5 years post-transplantation. No death nor organ failure occurred for patients transplanted after January 2011. 9 patients (18%) died, 6(67%) for transplant failure, 2(22%) for septic shock, 1 for post-operative cerebral hypoxia. Graft rejections occurred 32 times in 17 patients (35%). 8 patients of them (47%) were symptomatic, a median of 16 months after transplant [6–30]. 1 patient underwent a second combined heart-kidney transplant, 1 had lymphoma. Median age of transition to adult care was 17,9 years [16,5–18,4] after a mean pediatric care of 6,9 years (0,4 to 19,2). Global median follow-up was 3,8 years [1,5–7,9]. At latest follow-up, 36 children (74%) had normal schooling, 7(14%) had some school adaptations, 1 was in a special institution and 1 did not attend school. Discussion Our retrospective analysis shows good survival, when compared to current reported data (ISHLT) with normal schooling in 75% of the children, compared to 94% in the normal French population. Quality of life and exercise capacity are currently being studied in our cohort.

Aims The aim of this article was to assess whether abnormal dobutamine stress echocardiography (DSE) can be due to a dobutamine-induced coronary spasm in patients with angiographically documented vasospastic coronary arteries. Methods and results Between January 2004 and April 2008, we prospectively evaluated all patients with known or suspected coronary artery disease (CAD) referred to the echocardiography laboratory for dobutamine stress tests (6061 examinations). Those with abnormal DSE underwent coronary angiogram with a systematic methylergometrine intracoronary injection in the case of absence of significant coronary stenosis or spontaneous occlusive coronary spasm. Patients who had spontaneous occlusive coronary spasm or positive methylergometrine test, but no significant stenoses, were ultimately included in this study. About 581 patients had abnormal DSE, among them only 20 (3.4%) fulfilled the inclusion criteria. There were 15 males and 5 females, and mean age was 64.35 years (range 52–85); 8 patients had a known history of CAD and all of them had at least two established cardiovascular risk factors. The culprit vessel was the left anterior descending artery in 10 cases (50%), right coronary artery in 8 cases (40%), and left circumflex in 2 cases (10%). There was a systematic correspondence between the culprit arteries and dobutamine-induced wall motion abnormality territories. No complications occurred during examination or during the provocation test. All the patients were discharged with a calcium channel blocker and were doing well after 13 months of mean follow-up. Conclusion Coronary artery spasm can be induced at DSE, but is a rare finding; it could, though, be clinically relevant as it may partly explain some erroneously labelled ‘false-positive’ examinations. Methylergometrine provocation test is a safe and advisable approach in such situations.

Aims To assess whether abnormal dobutamine stress echocardiography (DSE) can be a consequence of dobutamine-induced coronary spasm in patients with angiographically documented vasospastic coronary arteries. Methods Between January 2004 and April 2008, we prospectively evaluated all patients with known or suspected coronary artery disease (CAD) referred to the echocardiography laboratory for dobutamine stress tests (6061 examinations). Those with abnormal DSE underwent coronary angiogram with a systematic methylergometrine intracoronary injection in the case of absence of significant coronary stenosis or spontaneous occlusive coronary spasm. Patients who had spontaneous occlusive coronary spasm or positive methylergometrine test, but no significant stenoses, were ultimately included in this study. Results About 581 patients had abnormal DSE, among them only 20 (3.4%) fulfilled the inclusion criteria. There were 15 males and 5 females, and mean age was 64.35 years (range 52-85); 8 patients had a known history of CAD and all of them had at least two established cardiovascular risk factors. The culprit vessel was the left anterior descending artery in 10 cases (50%), right coronary artery in 8 cases (40%), and left circumflex in 2 cases (10%). There was a systematic correspondence between the culprit arteries and dobutamine-induced wall motion abnormality territories. No complications occurred during examination or during the provocation test. All the patients were discharged with a calcium channel blocker and were doing well after 13 months of mean follow-up. Conclusion Coronary artery spasm can be induced at DSE, but is a rare finding; it could, though, be clinically relevant as it may partly explain some erroneously labelled ‘false-positive’ examinations. Methylergometrine provocation test is a safe and advisable approach in such situations.