Methods and systems are provided for determining an increased likelihood of the occurrence of a cardiac arrhythmia, myocardial ischemia, congestive heart failure and other diseased conditions of the heart associated with elevated sympathetic neural discharges in a patient. The methods and systems comprise monitoring the sympathetic neural discharges of a patient from the stellate ganglia, the thoracic ganglia, or both, and detecting increases in the sympathetic neural discharges. The methods and systems may further comprise delivering therapy to the patient in response to a detected increase in the sympathetic neural discharge, such as delivering one or more pharmacological agents; stimulating myocardial hyperinnervation in the sinus node and right ventricle of the heart of the patient; and applying cardiac pacing, cardioversion or defibrillation shocks. Pharmacologic agents which may be used in connection with the delivery of include those which are known to exert anti-arrhythmic effect and anti-convulsant agents, such as phenytoin, carbamazepine, valproate, and phenobarbitone. Other pharmacologic agents may be used to treat impending myocardial ischemia and other diseased conditions of the heart associated with elevated sympathetic neural discharges.