Atrial fibrillation (AF) may be underdiagnosed, and there is much that remains unknown about this prevalent and potentially life-threatening arrhythmia. AF epidemiology has been thwarted in part by the fact that about a third of patients with AF have no symptoms, those with symptoms may experience them intermittently or have vague symptoms, and it can be challenging to capture an episode on a 12-lead ECG, which is required for diagnosis. There are many significant knowledge gaps in our understanding of AF etiology and progression. A new user-friendly device that allows for frequent self-monitoring of the heart rhythm has been introduced. With the thumb ECG, patients can record a tracing multiple times a day. A smartphone app will soon allow them to interact with their healthcare providers about these ECG recordings. An ECG parser will allow for an algorithm-directed, rapid, automatic interpretation of these recordings with high specificity and sensitivity. This may help researchers learn more about the so-called silent AF, AF progression (and possible remission), and risk factors for AF. This technology holds great promise for patient care as well as for research into AF.