The Effect of Low LEVel TrAgus STimulation on the Electrophysiological Substrate of Patients With Ischemic CardioMyopathy Substrate of Subjects With Ischemic CardioMyopathy

Patients with ischemic cardiomyopathy (left ventricular ejection fraction \<35%) and heart failure who already have an implantable device with an atrial lead (dual chamber defibrillator or biventricular defibrillator) will undergo sequentially 1. Sham low level tragus stimulation (LLTS) (5min), 2. Active LLTS at 5Hz (15min) and 20Hz (15min) and 3. Active LLTS group with atrial pacing at 100bpm at 5Hz (15min) and 20Hz (15min). The latter is required to examine the effect of LLTS on RA independent of heart rate. Repolarization alternans will be measured by analyzing a regular 12-lead ECG using a custom-made software.