I jog 30km a week. 6 months after running, i started experiencing pvcs. only felt a few in my life prior. two cardiologists have cleared me ok with monitoring and lab work. did i harm or scar my heart from running too much too quickly from the start?

Like any muscle, the heart responds best to slow increases in exercise. The PVC's may have been a response to increasing your workouts to quickly, but like sore muscles, over time, the heart will adapt to your new workout regimen. There should be no scarring or harm.

Not likely that gradual exercise will harm your heart. Make sure you hydrate well and reduce caffeine containing drinks, if applicable.