The PRecIsion Medicine for CardiomyopathY (PRIMaCY) study is an international multicenter observational cohort study. This study has developed a tool that uses patient variables to predict the sudden cardiac death (SCD) risk in pediatric patients with hypertrophic cardiomyopathy (HCM).

Eligible patients

  • Phenotype-positive patients* with primary HCM
  • <18 years old at diagnosis

* Phenotype-positive = maximal LV wall thickness z-score >2 in an at-risk patient.

Ineligible patients

  • Phenotype-negative patients
  • >18 years old at diagnosis
  • Patients with secondary HCM**

**RASopathies (such as Noonan Syndrome), Metabolic, Neuromuscular or other secondary causes

Information to review before using the prediction tool

  1. The model predicts 5-year sudden cardiac death (SCD) risk from the first evaluation i.e. the time a patient first became phenotype-positive, and has not been currently validated for serial use. If using the model for later time points, please ensure that all information including age is changed to the later time point.
  2. Echocardiographic z-scores were calculated using the Boston z-score calculator.
  3. Learn how to to measure left atrial diameter using this downloadable document (PDF).
  4. Inclusion of genotype status* is optional. The model can calculate risk in the absence of a genetic diagnosis.
  5. Tool performance may be affected in those at the extremes of the parameter range. For instance, the tool may under-perform in patients between 16-18 years old due to under-representation of this age group in the original PRIMaCY cohort.
  6. The tool does not include potentially important risk factors like CMR findings of significant fibrosis, LV dysfunction, LV aneurysm, and family h/o SCD. These results, if available, should be taken into consideration separately from the tool risk score.
  7. The tool should not be used in secondary HCM e.g. RASopathies
  8. Please note that the output from this tool provides an estimate of individualized 5-year SCD risk in eligible patients, rather than treatment recommendations. Treatment decisions based on this risk assessment should be guided by physician and patient shared decision making.

*Genotype definitions
Genotype-positive = Pathogenic/likely pathogenic (P/LP) variant on genetic testing deemed to be causal.
Genotype-negative: No P/LP variant on genetic testing.
VUS = Variant of uncertain significance on genetic testing (genotype-inconclusive).

Open the PRIMaCY SCD Risk Prediction Tool

Dr. Seema Mital (PI)

Dr. Seema Mital, MD, is a Staff Cardiologist and Senior scientist and Professor of Pediatrics at the Hospital for Sick Children, University of Toronto in Ontario, Canada. Dr. Mital’s research focuses on cardiac precision medicine for childhood onset heart disease. The full list of publications and her contact information is available here:


We thank Chun-Po Steve Fan, Emily Somerset and Myriam Lafreniere-Roula (Ted Rogers Computational Program, Ted Rogers Centre for Heart Research, The Hospital for Sick Children, University Health Network) for their collaboration in the analysis, development and implementation of the risk calculator.

Relevant publication

Miron A et al. A validated model for sudden cardiac death risk prediction in pediatric hypertrophic cardiomyopathy. Circulation 2020; 142(3): 217-229.

Read the full publication