Is A Resting Heart Rate Of 50-53 Bpm Normal After Recently Quit Smoking?

I quit smoking 6 days ago. Since then, my resting heart rate has dropped from 62-65bpm down to 50-53bpm. I ve been checked recently by a cardiologist and had a echocardiogram and stress test performed and was told everything looked fine. I just find it hard to believe that my new normal resting heart rate is in bradycardia for a 6 , 289lbs, 39 year old male that is not athletic.