Mike Bloomberg and Bernie Sanders. Photos: Joe Raedle/Getty Images; Brian Blanco/Getty Images

Mike Bloomberg released new information on his heart health Thursday and called on his rival Bernie Sanders to do so as well.

Why it matters: The development, first reported by CNN, continues a public feud between the two candidates, both of whom are 78 years old. The move appears to be an attempt by Bloomberg to make Sanders' health a central issue in the Democratic contest.

Flashback: The senator from Vermont underwent a medical procedure after suffering a heart attack last year.

Details: The former New York City mayor's annual health exam last July included cardiac stress testing and a stress echocardiogram, per a letter from Johns Hopkins University physician Stephen Sisson.

  • The results showed Bloomberg's left ventricular ejection fraction at 60–65%, his left ventricular cavity size and left ventricular function were described as "normal," and his exercise capacity was "excellent," according to Sisson.
  • Between the lines: Ejection fractions measure "how much blood the left ventricle pumps out with each contraction," per the American Heart Association. A normal ejection fraction is between 50 and 70.

What they're saying: "Releasing this single scientific number about heart health could start to put to rest any concerns about Senator Sanders' secrecy about his recent heart attack," Bloomberg campaign spokesperson Stu Loeser told Axios. "Mike Bloomberg's doctor shared Mike's number. Will Senator Sanders ask his doctor to do the same?"

  • A spokesperson for Sanders told CNN the campaign already released documents related to the candidate's overall health. Sanders publicly shared letters from his primary physician and two cardiologists last December.

Go deeper: Bernie Sanders and Democrats' age problem

Go deeper

Supreme Court rejects GOP push to cut absentee ballot deadline in N.C.

Photo: Robert Alexander/Getty Images

The Supreme Court on Wednesday rejected an attempt by conservatives to shorten North Carolina's deadline for mail-in ballots from nine to three days.

The big picture: This is the latest of a series of decisions over mail-in ballot deadlines in various states.

Hurricane Zeta makes landfall on Louisiana coast as Category 2 storm

A satellite image of Hurricane Zeta. Photo: National Hurricane Center/NOAA

Hurricane Zeta made landfall along the southeastern coast of Louisiana as a Category 2 storm on Wednesday, bringing with it "life-threatening storm surge and strong winds," per the National Hurricane Center.

What's happening: The hurricane was producing maximum sustained winds of nearly 110 mph and stronger gusts.

Updated 2 hours ago - Politics & Policy

Coronavirus dashboard

Illustration: Sarah Grillo/Axios

  1. Politics: Biden ahead in Wisconsin, Michigan as cases surge in the Midwest.
  2. Health: Surge "is real" and not just caused by more tests, Trump's testing czar saysMask mandates help control rise in hospitalizations Some coronavirus survivors have "autoantibodies."
  3. Business: Surge is sinking consumer confidence Testing is a windfall.
  4. World: Europe faces "stronger and deadlier" coronavirus wave France imposes lockdown as Macron warns of overwhelming second COVID wave Germany to close bars and restaurants for a month.
  5. Sports: Boston Marathon delayed as COVID-19 surges MLB to investigate Dodgers player who joined celebration after positive COVID test.