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Predictors of risk for sudden death in childhood hypertrophic cardiomyopathy : The importance of the ECG risk score

Östman-Smith, Ingegerd; Sjöberg, Gunnar; Rydberg, Annika; Larsson, Per and Fernlund, Eva LU (2017) In Open Heart 4(2).
Abstract

Objective To establish which risk factors are predictive for sudden death in hypertrophic cardiomyopathy (HCM) diagnosed in childhood. Methods A Swedish national cohort of patients with HCM diagnosed <19 years of age was collected between 1972 and 2014, consisting of 155 patients with available ECGs, with average follow-up of 10.9±(SD 9.0) years, out of whom 32 had suffered sudden death or cardiac arrest (SD/CA group). Previously proposed risk factors and clinical features, ECG and ultrasound measures were compared between SD/CA group and patients surviving >2 years (n=100), and features significantly more common in SD/CA group were further analysed with univariate and multivariate Cox hazard regression in the total cohort.... (More)

Objective To establish which risk factors are predictive for sudden death in hypertrophic cardiomyopathy (HCM) diagnosed in childhood. Methods A Swedish national cohort of patients with HCM diagnosed <19 years of age was collected between 1972 and 2014, consisting of 155 patients with available ECGs, with average follow-up of 10.9±(SD 9.0) years, out of whom 32 had suffered sudden death or cardiac arrest (SD/CA group). Previously proposed risk factors and clinical features, ECG and ultrasound measures were compared between SD/CA group and patients surviving >2 years (n=100), and features significantly more common in SD/CA group were further analysed with univariate and multivariate Cox hazard regression in the total cohort. Results Ranked according to relative risk (RR) the ECG risk score >5 points had an RR of 46.5 (95% CI 6.6 to 331), sensitivity of 97% (83% to 100%) and specificity of 80% (71% to 88%) (p<0.0001), and was the best ECG predictor, predicting a 5-year risk of SD/CA of 30.6%. The following are other features with importantly raised RR: Detroit wall thickness Z-score >4.5: 9.9 (3.1 to 31.2); septal thickness ≥190% of upper limit of normal for age (septum in % of 95th centile for age (SEPPER) ≥190%): 7.9 (3.2 to 19.4); ventricular tachycardia: 9.1 (3.6 to 22.8); ventricular ectopics on exercise testing: 7.4 (2.7 to 20.2); and left ventricular outflow gradient (left ventricular outflow tract obstruction (LVOTO)) >50 mm Hg: 6.6 (4.0 to 11.0). Family history was non-significant. Multivariate Cox hazard analysis gives the following as early predictors: limb-lead QRS amplitude sum (p=0.020), SEPPER ≥190% (p<0.001) and LVOTO at rest (p=0.054); and for late predictors: last ECG risk score (p=0.002) and last Detroit Z-score (p=0.001). Both early (p=0.028) and late (p=0.037) beta-blocker doses reduced risk in the models. Conclusions ECG phenotype as assessed by ECG risk score is important for risk of sudden death and should be considered for inclusion in risk stratification of paediatric patients with HCM.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
cardiomyopathy hypertrophic, electrocardiography, paediatric arrythmias, risk factors, sudden cardiac death
in
Open Heart
volume
4
issue
2
publisher
BMJ Publishing Group
external identifiers
  • scopus:85032335264
ISSN
2053-3624
DOI
10.1136/openhrt-2017-000658
language
English
LU publication?
yes
id
7425fdd0-dcda-4492-b611-e0512a0c1393
date added to LUP
2017-11-20 12:45:52
date last changed
2018-01-07 12:26:12
@article{7425fdd0-dcda-4492-b611-e0512a0c1393,
  abstract     = {<p>Objective To establish which risk factors are predictive for sudden death in hypertrophic cardiomyopathy (HCM) diagnosed in childhood. Methods A Swedish national cohort of patients with HCM diagnosed &lt;19 years of age was collected between 1972 and 2014, consisting of 155 patients with available ECGs, with average follow-up of 10.9±(SD 9.0) years, out of whom 32 had suffered sudden death or cardiac arrest (SD/CA group). Previously proposed risk factors and clinical features, ECG and ultrasound measures were compared between SD/CA group and patients surviving &gt;2 years (n=100), and features significantly more common in SD/CA group were further analysed with univariate and multivariate Cox hazard regression in the total cohort. Results Ranked according to relative risk (RR) the ECG risk score &gt;5 points had an RR of 46.5 (95% CI 6.6 to 331), sensitivity of 97% (83% to 100%) and specificity of 80% (71% to 88%) (p&lt;0.0001), and was the best ECG predictor, predicting a 5-year risk of SD/CA of 30.6%. The following are other features with importantly raised RR: Detroit wall thickness Z-score &gt;4.5: 9.9 (3.1 to 31.2); septal thickness ≥190% of upper limit of normal for age (septum in % of 95th centile for age (SEPPER) ≥190%): 7.9 (3.2 to 19.4); ventricular tachycardia: 9.1 (3.6 to 22.8); ventricular ectopics on exercise testing: 7.4 (2.7 to 20.2); and left ventricular outflow gradient (left ventricular outflow tract obstruction (LVOTO)) &gt;50 mm Hg: 6.6 (4.0 to 11.0). Family history was non-significant. Multivariate Cox hazard analysis gives the following as early predictors: limb-lead QRS amplitude sum (p=0.020), SEPPER ≥190% (p&lt;0.001) and LVOTO at rest (p=0.054); and for late predictors: last ECG risk score (p=0.002) and last Detroit Z-score (p=0.001). Both early (p=0.028) and late (p=0.037) beta-blocker doses reduced risk in the models. Conclusions ECG phenotype as assessed by ECG risk score is important for risk of sudden death and should be considered for inclusion in risk stratification of paediatric patients with HCM.</p>},
  articleno    = {e000658},
  author       = {Östman-Smith, Ingegerd and Sjöberg, Gunnar and Rydberg, Annika and Larsson, Per and Fernlund, Eva},
  issn         = {2053-3624},
  keyword      = {cardiomyopathy hypertrophic,electrocardiography,paediatric arrythmias,risk factors,sudden cardiac death},
  language     = {eng},
  month        = {10},
  number       = {2},
  publisher    = {BMJ Publishing Group},
  series       = {Open Heart},
  title        = {Predictors of risk for sudden death in childhood hypertrophic cardiomyopathy : The importance of the ECG risk score},
  url          = {http://dx.doi.org/10.1136/openhrt-2017-000658},
  volume       = {4},
  year         = {2017},
}