Some media stories have indicated that caffeine can cause a specific, unusual heartbeat pattern (i.e., an arrhythmia), atrial fibrillation (AF). AF is a type of arrhythmia that can cause chest pain, dizziness, and fatigue. However, these media stories have been based on anecdotal case studies of individual people. When examining the data from observational research and large cohort studies, the current evidence shows that neither caffeine nor coffee is likely to increase the risk of atrial fibrillation.[1][2][3][4] However, people with heart problems should seek advice from their doctor concerning caffeine intake.