A top cardiologist says Democratic presidential frontrunner Bernie Sanders could allay concerns about his health by releasing a standard measure that would indicate if his heart is healthy following his October heart attack, a new report said Monday.

Richard Kovacs, the president of the American College of Cardiology, told NBC News that letters about Sanders’ health released by the campaign left out “the left ventricular ejection fraction.”

Kovacs said the number measures how much blood volume the heart pushes out with each heartbeat, and that it gives a good indication of how likely another heart attack was.

“Normally the heart will push out 60 percent,” Kovacs told NBC.

“If you go down to 40 or 50 percent, we regard that as mild impairment of the left ventricle. Thirty to 40 percent would be moderate. If you get to 30 percent, that would be severe.”

Sanders and his camp would not say what the figure was when he suffered the attack or what it was now, the network reported.

The 78-year-old Vermont senator has been reluctant to provide more details about his health, saying they’re released as much information about his health as any candidate has done.

Sanders is not Kovac’s patient and the doctor would not comment on his condition.