Coffee helps atrial fibrillation with high blood pressure

I've been seeing a lot of studies that document beneficial effects from drinking coffee, but I never expected this paper that was recently published in the journal Nutrition, Metabolism & Cardiovascular Diseases. Atrial fibrillation is the most common arrhythmia (irregular heart rhythm). The authors set out to investigate...

"the influence of coffee and caffeine consumption on atrial fibrillation (AF) in hypertensive patients...with regard to spontaneous conversion of arrhythmia."

Spontaneous conversion is when the heart rhythm normalizes on its own. Along the way they made some interesting observations:

"Coffee consumption was higher in normotensive (normal blood pressure) patients. High coffee consumers were more frequent in normotensive patients compared with hypertensive patients. On the other hand, the intake of caffeine was similar in hypertensive and normotensive patients, owing to a higher intake in hypertensive patients from sources other than coffee. Within normotensive patients, we report that non-habitual and low coffee consumers showed the highest probability of spontaneous conversion, whereas, within hypertensive patients, moderate but not high coffee consumers had the lowest probability of spontaneous conversion."

Interestingly, their data show that if you have high blood pressure, more coffee is better for normalizing atrial fibrillation. Their conclusion:

"Coffee and caffeine consumption influence spontaneous conversion of atrial fibrillation. Normotensive non-habitual coffee consumers are more likely to convert arrhythmia within 48h from the onset of symptoms. Hypertensive patients showed a U-shaped relationship between coffee consumption and spontaneous conversion of AF, moderate coffee consumers were less likely to show spontaneous conversion of arrhythmia."