Inclusion Criteria:  Patients with heart disease requiring surgery Above 18 years Patients suitable for study participation without safety concerns based on the Investigator's evaluation of medical history and physical examination. The patient must be able to understand the aims and objectives of the trial, willing and able to comply with all study related procedures The patient must be willing and able to provide written informed consent prior to participation in the clinical investigation The patient agrees to abstain from enrollment in any other clinical investigation for the duration of the study  Exclusion Criteria:  Esophageal disease Atrial fibrillation Pregnancy