A system, device, and method for the treatment of cardiac arrhythmia by, specifically, cryolipolysis of non-myocardial tissue and cryoablation of myocardial tissue. A system for treating cardiac arrhythmia may include a first thermal treatment device configured for placement within a heart in contact with myocardial tissue, a second thermal treatment device configured for placement in contact with pericardial tissue, an ablation energy source in communication with the first thermal treatment device, and a cooling energy source in communication with the second thermal treatment device, the cooling energy source causing the second thermal treatment device to reach a temperature insufficient for myocardial ablation when the second thermal treatment device is activated. A method of treating cardiac arrhythmia may include introducing a cooling element into a pericardial space proximate pericardial adipose tissue, and activating the cooling element to reduce the temperature of adjacent pericardial adipose tissue to approximately 0° C.
