I have had many people email me telling me of similar stories. A few doctors have indicated some support for the idea of a possible causative relationship. I still live with the fear of future rhythm problems. So what is causing all this - here is one possible theory based on what I have experienced. The heart is controlled by the autonomic nervous system which has two basic mechanisms.
Sympathetic nerves serve to stimulate or speed up the heart rate.
Parasympathetic nerves do the opposite, that is slow the heart rate. During the day most of us are in a continuous sympathetic tone. At night the parasympathetic response takes over. The Vagus nerve is a massive nerve that runs along the posterior part of the esophagus. I believe that chronic reflux has caused an irritation of this nerve which, especially when I swallow , delivers an inappropriate parasympathetic stimulus to the SA node.