| HCM Risk-SCD Calculator | ||||||||||||||
| Age | Years | Age at evaluation | ||||||||||||
| Maximum LV wall thickness | mm |
Transthoracic Echocardiographic measurement
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| Left atrial size | mm |
Left atrial diameter determined by M-Mode or 2D echocardiography in the parasternal long axis plane at time of evaluation
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Max LVOT
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mmHg |
The maximum LV outflow gradient determined at rest and with Valsalva provocation (irrespective of concurrent medical treatment) using pulsed and continuous wave Doppler from the apical three and five chamber views. Peak outflow tract gradients should be determined using the modified Bernouilli equation: Gradient= 4V
2
, where V is the peak aortic outflow velocity
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| Family History of SCD |
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History of sudden cardiac death in 1 or more first degree relatives under 40 years of age or SCD in a first degree relative with confirmed HCM at any age (post or ante-mortem diagnosis).
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| Non-sustained VT |
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3 consecutive ventricular beats at a rate of 120 beats per minute and <30s in duration on Holter monitoring (minimum duration 24 hours) at or prior to evaluation.
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| Unexplained syncope |
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History of unexplained syncope at or prior to evaluation. | ||||||||||||
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O’Mahony C et al Eur Heart J (2014) 35 (30): 2010-2020
HCM Risk-SCD should not be used in:
- Paediatric patients ( <16 years)
- Elite/competitive athletes
- HCM associated with metabolic diseases (e.g. Anderson-Fabry disease), and syndromes (e.g. Noonan syndrome).
- Patients with a previous history of aborted SCD or sustained ventricular arrhythmia who should be treated with an ICD for secondary prevention.
Caution should be exercised when assessing the SCD in patients following invasive reduction in left ventricular outflow tract obstruction with myectomy or alcohol septal ablation.
Pending further studies, HCM-RISK should be used cautiously in patients with a maximum left ventricular wall thickness ≥35 mm.