Exclusion Criteria: Patients with obstructive hypertrophic cardiomyopathy, pronounced hypovolemia, alcohol use in the last 8 hours, clinical intoxication, STEMI or presumed cardiac chest pain, inferior myocardial infarction with right ventricular involvement, raised intracranial pressure, cardiac tamponade and patients taking certain drugs for erectile dysfunction (phosphodiesterase inhibitors), pregnancy or with a known allergy to nitroglycerin will be excluded from the study. Patients unable to give consent will be excluded.