Risk factors for sudden cardiac death in childhood hypertrophic cardiomyopathy: A systematic review and meta-analysis

Abstract

Results: Twenty five studies (3394 patients) met inclusion criteria. We identified four conventional major risk factors which were evaluated in at least 4 studies and found to be statistically associated with an increased risk of death in at least 2 studies: previous adverse cardiac event (pooled hazard ratio 5.4 (95% CI 3.67-7.95), p <0.001 ); non-sustained ventricular tachycardia (pooled hazard ratio 2.13 (95% CI 1.21-3.74), p=0.009); unexplained syncope (pooled hazard ratio 1.89 (95% CI 0.69-5.16), p=0.22);and extreme left ventricular hypertrophy (pooled hazard ratio 1.80 (95% CI 0.75-4.32), p=0.19). Left atrial diameter did not meet the major risk factor criteria, however is likely to be an additional significant risk factor. 'Minor' risk factors included a family history of sudden cardiac death, gender, age, symptoms, ECG changes, abnormal blood pressure response to exercise and left ventricular outflow tract obstruction. Conclusions:A lack of well-designed, large population based studies in childhood hypertrophic cardiomyopathy means the evidence-base for individual risk factors is not robust. We have identified four clinical parameters which are likely to be associated with increased risk of SCD, SCD-equivalent event or CVD. Multi-centre prospective studies are needed to further determine their relevance in predicting SCD in childhood HCM and to identify novel risk markers. Condensed abstract:3 A systematic review and meta-analysis of clinical risk factors predicting sudden cardiac death (SCD) in childhood hypertrophic cardiomyopathy (HCM) was performed identifying four 'major' factors: previous adverse cardiac event; non-sustained ventricular tachycardia; syncope and extreme left ventricular hypertrophy. Well-designed multi-centre studies are required in the future to confirm these findings.4

Long-term Outcomes of Pediatric-Onset Hypertrophic Cardiomyopathy and Age-Specific Risk Factors for Lethal Arrhythmic Events

“…Heart failure-related events were uncommon, consistent with previous studies. [1][2][3][4][5][6][7] Notably, only 42.0% of deaths actually occurred while patients were in the pediatric age range, and the event rate remained constantly high during the follow-up period, which ran well into adulthood. In total, about one-quarter of the events occurred when patients were older than 30 years.…”

Sex-related differences in exercise performance and outcome of patients with hypertrophic cardiomyopathy

“…Despite an equal expected prevalence by sex, women are less represented than men in HCM cohorts, ranging from 45% to 22% [5][6][7][8] . Regardless of ethnicity, females are generally older, with more advanced disease at diagnosis and greater likelihood of heart failure progression compared to males 5,6,[8][9][10] ; furthermore, female sex could be a minor risk factor for cardiovascular death in childhood HCM 11 . Reasons for such discrepancies are still unknown, and may reflect sex-related differences in the pathophysiology of HCM, ultimately relevant to risk stratification and management 12 .…”

Sudden Cardiac Death in Children Affected by Cardiomyopathies: An Update on Risk Factors and Indications at Transvenous or Subcutaneous Implantable Defibrillators

“…In 2017 a systematic meta-analysis was conducted by Norrish et al (28) on 3,394 patients below 18 years from 25 studies, and four major risk factors have been identified including previous adverse cardiac event, non-sustained ventricular tachycardia, unexplained syncope and extreme left ventricular hypertrophy. Along with these major criteria, left atrial diameter has been pointed out as an additional important risk factor (28). More recently, Norrish et al (45) developed a novel risk prediction model for sudden cardiac death in HCM children through a retrospective, multicenter, longitudinal cohort study on 1,024 patients below 16 years and the most predictive variables included in the model were unexplained syncope, degree of hypertrophy, LA diameter and NSVT, while the maximal LVOT gradient appeared to be inversely related with SCD risk, a data that clearly needs further investigation.…”