Can This Formula Predict AFib in HCM Patients?

HCM specialists at Tufts Medical Center and Toronto General Hospital have devised a formula which they hope will help predict which HCM patients may go on to develop atrial fibrillation (“AFib”) over time. This tool can assist doctors in determining which patients are at highest risk so that these patients can be closely monitored and treated appropriately. AFib can be extremely dangerous for HCM patients since it can precipitate a stroke if not appropriately treated.   

Because existing tools to predict atrial fibrillation have not proven to be accurate for HCM patients, the researchers studied 1900 HCM patients with the goal of devising a new tool to help HCM patients and their physicians learn their personal risk for AFib over a 2 and 5 year period.


The formula works as follows:  Find your left atrial diameter on your most recent echocardiogram report.  On the chart below, find the number of points (listed in the 2nd column) that corresponds with your left atrial measurement (measured in millimeters). Then, find the number in the 2nd column that corresponds to your current age range.  Add these two numbers together. From that sum, subtract the number listed in the 2nd column that correlates with your age range when you were first diagnosed with HCM.  Lastly, if you have heart failure symptoms, add in 3 points.  The total is your score.

You can calculate using the table below, or you can use this online calculator which gives you your 2 and 5 year risk.



Low Risk scores are between 8 – 17

Intermediate Risk scores are between 18 – 21

High Risk scores are between 22 – 31

As always, discuss with your doctor. Everyone has individual factors which will influence their degree of risk. This tool is intended as a general guideline to facilitate discussion with your physician.

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