F-18 FDG uptake in transplanted heart.

Cladellas et al. concern patients who failed to achieve an adequate heart rate response; it is not clear whether heart rate decrease occurred in any patient. As we reported, only 1 of 14 patients with paradoxical sinus deceleration was taking beta-blockers. We mentioned in our report that all our patients fasted for at least 3 h before dobutamine stress echocardiography; mild hypovolemia may have facilitated the occurrence of the vasodepressor response. In our conclusions, we reported that paradoxical sinus deceleration was most often seen in patients with coronary artery disease, but in 14% of our patients with heart rate decrease, there were no angiographic, echocardiographic, electrocardiographic or clinical signs of coronary artery disease. Sinus deceleration was often accompanied by a decrease in blood pressure, nausea and chest pain. We believe that sinus deceleration during dobutamine stress echocardiography is typically mediated by the Bezold-Jarisch reflex and is most commonly seen in the presence of ischemia but may occur in its absence. The echocardiographic signs of myocardial ischemia may be subtle if heart rate is not increased and can be best appreciated by continuous echocardiographic surveillance. Atropine is effective in increasing heart rate in patients with paradoxical bradycardia and is recommended in those with no manifestations of ischemia.