"It felt weird but it felt good," Silva said of his session Monday.
Silva, who came out of his last start Aug. 1 after four batters, had a procedure known as radio frequency catheter ablation (RFCA) performed to prevent recurrence of his paroxysmal supraventricular tachycardia (PSVT). The procedure was done Aug. 9.
The right-hander will have another side session Wednesday and then the Cubs medical team will determine the next step. Silva said he felt relieved after Monday's session.
"Friday was the first time I threw [and played catch]," he said. "I told the trainer I don't know if it's mental or what, but I felt like I don't have to worry about it anymore. I felt loose, that nothing is going to happen. I know nothing bad is going to happen."
The experience was a little nerve wracking, Silva said.
"For my family, it was something big and they were worried, and my wife was so worried," he said. "When you're talking about your heart, it's something big. The good thing was before I had the procedure, a lot of people talked to me and said, 'My sister had this done,' or 'My brother had this done and everything will be fine.'"
Silva (10-5, 3.92 ERA) said the medical staff told him he'll feel the difference quickly.
"[The doctor] said, 'You won't be as tired any more and this will be better for you,'" Silva said.