3. “Why do older people get Atrial Fibrillation more than younger people?”
We know that those over 60 years old are in the higher risk group for developing A-Fib. This may be related to what is called “Interstitial Fibrosis” which is often part of the aging process.
The Pulmonary Vein openings (where most A-Fib signals originate) sometimes become fibrous as we age. The Pulmonary Vein openings are similar in structure and have similar smooth muscle tissue as the Sinus and AV Nodes which generate your normal heart beat signal. The Pulmonary Vein openings are electrically active in the heart like the Sinus and AV Nodes but usually beat in sync with them. When the Pulmonary Vein openings become fibrous, they tend to beat out of sync with the Sinus and AV Nodes which results in A-Fib.
Please be advised that the above statement is an observation, an attempt to explain, rather than a medical fact. Further research is necessary to confirm this observation.