Jenneh Rishe could easily run six miles in under 45 minutes — until suddenly she couldn’t. In the spring of 2019, Mrs. Rishe, now 35, began finding her daily jogs a struggle. Years earlier, she had been diagnosed with two congenital heart conditions that, she said, doctors told her would not affect her daily functioning. Yet she was getting worse: Intense chest pains woke her up at night, and she started using a wheelchair after passing out too many times.