A system for treating atrial dysfunction, including heart failure and/or atrial fibrillation, that includes one or more pressurizing elements and control circuitry. The one or more pressurizing elements can comprise one or more balloons and can be configured to be positioned in the left atrium, and optionally the pulmonary artery, of a patient's heart. The one or more pressurizing elements can be coupled to one or more positioning structures that can be configured to position the one or more pressurizing elements in the left atrium, and optionally the pulmonary artery. The control circuitry can be configured to operate the one or more pressurizing elements to decrease or increase pressure and/or volume in the left atrium, and optionally the pulmonary artery, in accordance with different phases of the cardiac cycle. The control circuitry can be further configured to operate the one or more pressurizing elements to generate coordinated pressure modifications in the left atrium, and optionally the pulmonary artery.
