An Oregon middle school student died Friday after collapsing during baseball practice, just months after he suffered a heart attack during basketball practice and later underwent surgery to correct a heart defect.

According to ABC affiliate KATU-TV in Portland, witnesses said 12-year-old Isaac Arzate started coughing up blood during Friday evening's practice and collapsed.

Back in January, doctors told Arzate's family that his heart attack occurred as a result of a defect characterized by an artery not originating in the proper place in the heart, reported The Oregonian.

After surgery to repair the defect, doctors said the sixth grader would have to wait six to eight weeks before participating in sports again.

Officials said there will not be an autopsy since Arzate died of natural causes.

Dr. Paolo Rusconi, associate professor of pediatrics at the University of Miami's Miller School of Medicine said without knowing more details, he can only speculate that Arzate suffered from a coronary artery defect.  Even after surgery, this type of anomaly can still carry risks.

"The coronary arteries are so small that when you do surgery on them, there is always the possibility that after surgery, because of kinking or clot formation in the coronary arteries, a child may suffer a heart attack," he said.

Sudden death in children is very uncommon, Rusconi explained, and there are a number of conditions that can cause it.

"Among the cardiac causes of sudden death particularly in athletes is hypertrophic cardiomyopathy (HCM) a condition characterized by the thickening of the heart muscle," he said.

An irregular heart beat can also cause sudden death, since the heart may suddenly stop beating or may beat so fast that it can't effectively pump blood, he added.

There are also congenital defects, such as coronary artery defects and aortic stenosis that can lead to sudden death, Rusconi added.