We conducted patient-oriented research in clinical neurocardiology. Studies focused on etiology, diagnosis, pathophysiology, and treatment of diseases and disorders involving the catecholamines norepinephrine (NE), adrenaline (ADR), or dopamine (DA). Patient groups had primary chronic autonomic failure (Parkinson disease (PD), pure autonomic failure, or multiple system atrophy); chronic orthostatic intolerance (postural tachycardia syndrome or neurocardiogenic syncope), or pheochromocytoma, a clinically important tumor that produces catecholamines. Patients with familial PD from mutation of the gene encoding alpha-synuclein or from excessive expression of the normal gene had a loss of cardiac sympathetic nerves, indicating that in PD dysautonomia can reflect alpha-synucleinopathy. Patients with PD and orthostatic hypotension (OH) had poor baroreflexive regulation of the sympathetic nervous system and loss of sympathetic nerves in the heart, confirming PD+OH as not only a movement disorder but also a form of dysautonomia. Treatment with L-dihydroxphenylserine improved OH in patients with chronic autonomic failure; the improvement probably resulted from conversion of the drug to NE in neuronal and non-neuronal cells outside the brain. Results of a cardiac catheterization study supported the concept of cardiac sympathetic hyperactivity in postural tachycardia syndrome. In a new protocol the efficacy of non-selective beta-adrenoceptor blockade is being assessed in preventing tilt-induced neurocardiogenic syncope. Plasma levels of metanephrines, metabolites of NE and ADR, continue to provide a virtually perfectly sensitive screening test for pheochromocytoma. A large prospective study confirmed the validity of 6-[18F]fluorodopamine positron-emission tomographic scanning for diagnostic localization of pheochromocytoma. Microarray studies have indicated several gene expression changes that help explain the different clinical and neurochemical phenotypes of inherited pheochromocytomas.
Showing the most recent 10 out of 125 publications
