A treatment method is provided, including identifying a subject as one who is selected to undergo an interventional medical procedure, and, in response to the identifying, reducing a likelihood of a potential adverse effect of the procedure by applying an electrical current to a parasympathetic site of the subject selected from the group consisting of: a vagus nerve of the subject, an epicardial fat pad of the subject, a pulmonary vein of the subject, a carotid artery of the subject, a carotid sinus of the subject, a coronary sinus of the subject, a vena cava vein of the subject, a jugular vein of the subject, a right ventricle of the subject, a parasympathetic ganglion of the subject, and a parasympathetic nerve of the subject.