Cardiac Reserve in the Transplanted Heart: Effect of a Graft Polymorphism in the β1-adrenoceptor

Heart transplant patients with the β1-AR Gly49 variants had a lower heart rate, and better stress endurance and diastolic function compared with patients homozygous for Ser49. They also showed a trend toward better chronotropic reserve. These results provide a possible explanation for differences in cardiac reserve among patients with heart transplants.