Gap junction uncoupling can alter conduction pathways and promote cardiac re-entry mechanisms that potentiate many supraventricular arrhythmias, such as atrial fibrillation (AF) and atrial flutter (AFL). GAP-134 (Danegaptide), a small modified dipeptide, has been identified as a potent and selective second generation gap junction modifier with oral bioavailability. Gap junction modifier GAP-134, showed consistent efficacy on measures of conduction and AF/AFL inducibility in the canine sterile pericarditis model. GAP-134 is a pharmalogical agent with a favorable clinical safety profile and potential antiarrhythmic efficacy, as already confirmed in phase I clinical trials.