ABSTRACT BACKGROUND Changes in mitochondria have been implicated in atrial fibrillation (AF), but their manifestations and significance are poorly understood. Here, we studied changes in mitochondrial morphology and function during AF and assessed the effect of a mitochondrial-targeted intervention in a large animal model. METHODS AND RESULTS Atrial cardiomyocytes (ACMs) were isolated from dogs in electrically-driven AF for periods of 24 hours to 3 weeks and from humans with/without longstanding persistent AF. Mit…

Abstract Aims To better characterize functional consequences of the presence of COPD on cardiorespiratory fitness in patients with HF. Methods and results Patients with any clinical indication for cardiopulmonary exercise testing (CPET) were included in the international FRIEND registry. Diagnosis of COPD was confirmed by a ratio of forced expiratory volume in 1 s and forced vital capacity (FEV1/FVC) < 0.70. HF was diagnosed in the presence of symptoms and signs of HF. A total of 10 957 patients were divide…