Activation of the parasympathetic pathway leads to negative chronotropic, negative dromotropic, and negative inotropic changes in the heart. 11 The postganglionic neurons in the vagus nerve project to the sinoatrial (SA) and atrioventricular (AV) nodes, as well as to the atrial and ventricular musculature. In the adult, the right vagus nerve innervates predominantly the SA node, the atrial muscle and, to a much lesser degree, the AV node. On the other hand, the left vagus nerve innervates the SA node and atrial muscle to a lesser degree than it innervates the AV node. However, there can be significant overlap in the anatomical distribution.