title: Changes in heart rate variability before and after surgery in patients with pheochromocytoma.
abstract: We assessed ambulatory blood pressure and heart rate variability in two female patients with pheochromocytoma. The ambulatory blood pressure and ECG R-R intervals were measured during a 24-h period with a portable recorder before and 3 weeks after surgery. A power-spectral analysis of R-R intervals was performed to obtain the low-frequency (LF) and high-frequency (HF) components. The percentage of differences between adjacent normal R-R intervals >50 ms (pNN50) was also calculated. In both patients, the plasma epinephrine and norepinephrine levels decreased markedly after surgery. The 24-h blood pressures also decreased after surgery. In both patients, the 24-h average LF component, HF component, and pNN50 decreased after surgery, while the 24-h average LF/HF ratio increased after surgery. These results suggest that high circulating catecholamines inhibit central sympathetic neural outflow and augment parasympathetic nerve activity in patients with pheochromocytoma.
authors.affiliation: Department of Hypertension and Cardiorenal Medicine, Dokkyo University School of Medicine, Mibu, Tochigi 321-0293, Japan. j-minami@dokkyomed.ac.jp
authors.forename: Junichi
authors.initials: J
authors.lastname: Minami
authors.forename: Masakatsu
authors.initials: M
authors.lastname: Todoroki
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Ishimitsu
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Matsuoka
mesh_terms: D000293:Adolescent; D000310:Adrenal Gland Neoplasms / Q000503:physiopathology* / Q000601:surgery*; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory; D005260:Female; D006339:Heart Rate; D006801:Humans; D008875:Middle Aged; D010275:Parasympathetic Nervous System / Q000502:physiology; D010673:Pheochromocytoma / Q000503:physiopathology* / Q000601:surgery*; D013564:Sympathetic Nervous System / Q000502:physiology