CPT1B and atrial fibrillation: The gene expression of FABP3, which facilitates fatty acid uptake into the cell and intracellular fatty acid transport, was significantly increased in the AF group (Fig 2B), but there was no significant difference between the two groups in the atrial expression of CD36, which facilitates fatty acid uptake across the plasma membrane, and CPT1B, which is located on the outer mitochondrial membrane for fatty acid transport into the mitochondria (Fig 2A–2C).