Effectiveness of Atropine as a Chronotropic Adjunct in Cardiac Transplant Recipients Undergoing Dobutamine Stress Echocardiography

Annual dobutamine stress echocardiography (DSE) is used to detect cardiac allograft vasculopathy in heart transplant (HTX) recipients. Atropine is commonly used in non-transplant patients to increase the sensitivity of DSE by achieving the target heart rate (THR=85% of 220 – patient’s age). Orthotopic HTX completely denervates the donor’s heart, with little evidence to suggest parasympathetic reinnervation. As such, the efficacy of atropine as a chronotropic agent in HTX patients undergoing DSE is unknown. A retrospective review from August 2008 to February 2011 yielded 173 consecutive, individual HTX patients (56.5± 13 years; time since HTX 9.5± 5 years) after excluding seven patients on negatively chronotropic medication within 48 hours prior to DSE. Standard protocol dobutamine was commenced at 5mcg/kg/min. If THR was not attained at 50mcg/kg/min, a bolus of maximal 1200mcg atropine was given. 123 p p 6 i v y y p