Throughout my life I have never had the stamina of others. I'm 73 years old and recently had an ablation (after two cardioversions) for A-fib. After the ablation, the doctor told me I only have three veins going back into the heart instead of the normal four. I didn't think of my questions at the time as this caught me by surprise. I'm now wondering if the birth defect could contribute to my abnormal fatigue throughout my life. Any information would be helpful. Thank you.