Snapshot A 72-year-old man is admitted to the medicine floor for a chronic obstructive pulmonary disease exacerbation. On the second day, he reports feeling lightheaded and having some chest pain. His telemetry at that time reveals an irregular rhythm with a pulse of 120/min. Electrocardiogram reveals an irregularly irregular rhythm, tachycardia, discrete P waves before every QRS complex, and at least 3 different P wave morphologies. Introduction Clinical definition login to view 2 more bullets Associated conditions login to view 1 more bullet Epidemiology Risk factors login to view 1 more bullet Etiology Decompensated chronic lung disease login to view 1 more bullet Heart failure Structural heart damage Methylxanthine toxicity Pathogenesis login to view 1 more bullet Presentation Symptoms login to view 7 more bullets Physical exam login to view 2 more bullets Studies Electrocardiogram login to view 5 more bullets Making the diagnosis login to view 1 more bullet Differential Atrial fibrillation login to view 2 more bullets Atrial flutter login to view 2 more bullets Premature atrial contractions login to view 1 more bullet Treatment Management approach login to view 4 more bullets Medical login to view 10 more bullets Complications Emboli Myocardial infarction Prognosis Mortality is high but often due to multiple medical comorbidities in these patients rather than from MAT itself