hcm risk calculator

What this HCM risk calculator does

This calculator estimates the probability of sudden cardiac death over 5 years for adults with hypertrophic cardiomyopathy using the ESC HCM Risk-SCD approach. It combines age, cardiac imaging values, and key clinical history items into a single risk estimate.

The output is most useful when interpreted in context: symptoms, MRI findings, genotype, comorbidities, athlete status, and patient preferences all matter in real-world decision-making.

Inputs explained

1) Age

Age is entered in years. In this model, increasing age generally lowers calculated SCD risk, all else equal.

2) Maximum LV wall thickness

This is usually measured by echocardiography or cardiac MRI. Greater hypertrophy is associated with higher risk up to a point, and the model includes a squared term to handle non-linearity.

3) Left atrial diameter

Left atrial enlargement reflects chronic filling pressure burden and may correlate with overall disease severity.

4) LVOT gradient

Maximum left ventricular outflow tract gradient in mmHg contributes to risk. Use the maximum value documented in your workup.

5) Family history of SCD

A positive family history of sudden death attributed to HCM increases calculated risk.

6) NSVT

Non-sustained ventricular tachycardia on ambulatory monitoring is an important arrhythmic marker in HCM.

7) Unexplained syncope

History of unexplained fainting events may signal greater arrhythmic vulnerability in selected patients.

How to interpret results

• < 4% (Low risk): ICD generally not recommended based on this score alone.
• 4% to < 6% (Intermediate risk): ICD may be considered after shared decision-making.
• ≥ 6% (High risk): ICD should be considered in many patients.

These thresholds are commonly used in guideline-based discussions, but individual care plans may differ depending on additional risk markers and treatment goals.

Important limitations

• This model is not validated for every subgroup (for example, many pediatric scenarios).
• It does not replace specialist assessment, imaging review, or rhythm interpretation.
• Risk changes over time; repeated evaluation is often necessary.
• Clinical decisions should account for quality of life, competing risks, and patient values.

Practical next steps if risk is elevated

• Review findings with an HCM center or experienced cardiologist.
• Discuss ICD benefits, limitations, and device-related complications.
• Optimize HCM management (symptom control, blood pressure, rhythm surveillance).
• Consider family screening and genetic counseling where appropriate.

Bottom line

An HCM risk calculator is a useful framework for structured, data-driven conversations about sudden death prevention. Use it as one piece of evidence, then pair it with comprehensive specialist care and shared decision-making for the safest and most personalized plan.