What part of ans would be affected if one gets tachycardia after eating and drinking alcoholic beverages (wine coolers)? is that a sign of dysfunction?

May be normal: To some degree, it is normal to get some increase in heart rate after eating & drinking (esp high sugar foods like alcohol) as digestion naturally increases the work of the heart/Increased blood flows to the stomach to aid digestion. The vagus nerve interfaces with the autonomic, parasympathetic control of heart rate, and may impact this response. If this is only/main symptom, not dysfunction.