Atrial fibrillation and chronic heart failure often coexist. Asymptomatic atrial fibrillation is common in patients with known atrial fibrillation but also in patients with no history of previous atrial fibrillation. The enhanced diagnostic capabilities of modern implantable devices for cardiac resynchronization therapy allow collecting of data on the clinical status of the patient in addition to information on device performance and cardiac rhythm. We present a paradigmatic case of newly diagnosed atrial fibrillation with hemodynamic consequences detected by the diagnostics of a biventricular implantable cardioverter-defibrillator. We discuss the clinical utility of device-based monitoring and the potential advantages of wireless remote-control systems of implantable devices in the management of heart failure patients.