10 research outputs found
Pathophysiologic mechanisms underlying dobutamine- and exercise-induced wall motion abnormalities.
BACKGROUND: Dobutamine and exercise echocardiography are accepted as tests of comparable efficacy for the diagnosis of coronary artery disease. Although dobutamine has been classified as "exercise simulating," the mechanisms of ischemia with dobutamine and exercise have not been well studied. This study sought to compare the determinants of myocardial oxygen consumption. METHODS AND RESULTS: We studied 54 patients with coronary artery disease undergoing dobutamine and exercise stress. A subgroup of 13 patients with comparable degrees of wall motion abnormalities and ST-segment changes during both stresses were selected to compare the determinants of ischemia in comparable circumstances. Dobutamine was infused to a mean maximal dose of 32+/-8 microg/kg/min, and exercise was stopped at an average of 135+/-25 W. The mean regional wall motion score was not statistically different between the two protocols (p = 0.27). At the onset of wall motion abnormalities and peak stress, the heart rate increased significantly less during dobutamine than during exercise (106+/-23 vs 126+/-19 beats/min, p < 0.001). The same was true of systolic blood pressure (155+/-21 vs 205+/-24 mm Hg, p < 0.001) and the rate-pressure product (16.5+/-4.6 vs 25.9+/-5, p < 0.001). Cardiac volumes were similar during both tests. CONCLUSIONS: Ischemia occurs at a lower level of external cardiac work during dobutamine than during exercise stress. We suspect that additional mechanisms, such as the oxygen wasting effect of dobutamine, may be responsible for this observation
Abnormal synaptic morphology and neuronal Ca2+-homeostasis in migraine mutant mice
Assessing neuronal structure and intracellular Ca 2+ levels at baseline, during and after cortical spreading depression in transgenic mice for familial hemiplegic migrain
Abnormal synaptic Ca2+ homeostasis and morphology in cortical neurons of familial hemiplegic migraine type 1 mutant mice
Paroxysmal Cerebral Disorder
Abnormal Synaptic Morphology and Neuronal Ca2+-Homeostasis in Migraine Mutant Mice
Paroxysmal Cerebral Disorder