Electrocardiographic changes and long-term prognosis of children diagnosed with hypertrophic cardiomyopathy by the school screening program for heart disease in Japan

Abstract

Background: In Japan, the school screening program for heart disease (SS) has been performed since 1973. However, little has been reported on the electrocardiogram (ECG) changes and long-term prognosis in patients with hypertrophic cardiomyopathy (HCM) detected by the SS. Methods: All 44 consecutive pediatric HCM patients (10.1 AE 3.0 years old), who had been originally consulted by the SS before the diagnosis of HCM from April 1981 to April 2017, were reviewed retrospectively. Results: At the SS, all patients showed mild or no symptoms. All patients showed ECG abnormalities, and 75 % had a high proposed ECG risk score (36). However, 30 % of them had no echocardiogram finding of myocardial hypertrophy. During the follow-up period (14.8 AE 10.0 years), life-threatening events (LTE) occurred in 11 (25 %) patients, and the first LTE occurred during exercise in 8 (18 %). The estimated LTE and heart failure death-free survival rate at 10 years was 64.9 %. The LTE-free survival rate was lower in patients without than in those with myocardial hypertrophy at the SS. Conclusions: The SS was useful in detecting patients with HCM with mild or no symptoms at the early stage. However, our study indicated that early detection of HCM is not associated with improvement in the prognosis of the patients. Further studies are needed.

Sudden cardiac death in childhood hypertrophic cardiomyopathy is best predicted by a combination of electrocardiogram risk‐score and HCMRisk‐Kids score

“…That ECG Risk-score ≥6 points has high sensitivity for SCD/CA in paediatric patients has now been independently confirmed in a Japanese study of childhood HCM diagnosed by school ECG-screening, where sensitivity was also 100% for 'life-threatening events'. 28 However, that study also had a high rate of false positives amongst patients without events, who all had been diagnosed specifically because of ECG abnormalities. They constituted a high-risk group, confirmed by the high event-rate: 25% had events with a median interval of 3.7 years from diagnosis.…”

What Aspects of Phenotype Determine Risk for Sudden Cardiac Death in Pediatric Hypertrophic Cardiomyopathy?

“…In clinically diagnosed cases this ranges from 58–62% in geographical cohorts to 60–69% in tertiary centre studies [ 12 , 18 , 19 , 24 , 26 , 28 ]. Even in childhood-HCM detected by school screening, there is a 55% male preponderance [ 34 ]. The sex distribution of cases of SCD occurring in childhood-HCM very closely reflects the sex distribution in the case group in all the abovementioned studies.…”

Incidence, characteristics, and outcomes of pediatric out-of-hospital cardiac arrest in nursery schools and kindergartens in Japan

“…An article from Australia and New Zealand reported that approximately three-quarters of sudden cardiac deaths were classified as unexplained sudden cardiac death among autopsied children aged 1-5 years [28]. In addition, the effects on mortality reduction of the tests for identification of individuals at risk of cardiac arrest, such as heart disease screening in schools [29] and genetic testing [30], would currently be controversial. Therefore, as for this age group, further promotion of public-access defibrillation programs in certified nursery schools and kindergartens is necessary.…”