(WYTV) – The Cleveland Clinic has been testing a drug that’s showing a lot of promise when it comes to treating a heart condition that affects around 20 million people worldwide: heart muscles that grow thick.

 You might think a thickened muscle is a stronger muscle and your heart’s in better shape. Just the opposite. Abnormal thickening is a serious heart condition.

“Common symptoms are shortness of breath, dizziness with exertion, lightheadedness. Occasionally they may have chest pain and passing out with, commonly with, exertion or due to arrhythmias,” says Dr. Milind Desai of the Cleveland Clinic.

The condition is called hypertrophic cardiomyopathy or HCM for short.

The drug the Clinic’s been testing is Mavacamtem and it appears to be an effective treatment as good as or better than something invasive.

Now the Clinic is waiting for the Food and Drug Administration to approve it.