Devices, systems, and methods for treating cardiac arrhythmias are disclosed. An exemplary device includes a support member having a first end and a second. At least a first pacing electrode is located proximate the first end of the support member and at least a second pacing electrode is located proximate the second end of the support member. A defibrillating electrode is located between the first pacing electrode and the second pacing electrode. An exemplary method of treating a patient comprises a device for treating cardiac arrhythmias and placing the device adjacent a heart of the patient.