Impact of successful treatment of acromegaly on overnight heart rate variability and sleep apnea.
BACKGROUND
Successful treatment of acromegaly improves disease-related cardiovascular mortality and morbidity, but its effects on autonomic modulation of the heart rate are unknown.


OBJECTIVE
We documented treatment-induced changes in time-domain heart rate variability, taking into account the confounding effects of obstructive sleep apnea.


METHODS
Sixteen consecutive patients (12 males, aged 43 ± 12 y) with newly diagnosed acromegaly underwent overnight (12:00-7:00 am) cardiac Holter recordings coupled with polysomnography. Data were obtained before and 10 ± 6 months after successful treatment of acromegaly.


RESULTS
IGF-1 levels fell from 807 ± 333 to 207 ± 69 μg/L and normalized in all patients. Seven patients (44%) had obstructive sleep apnea (apnea-hypopnea index 33 ± 21/h) at baseline. Treatment had no significant effect on polysomnographic indices. After treatment, increases were noted in the normal-to-normal heart period (NN), SD-NN, the percentage of NN differing from the previous NN by greater than 50 msec, and the root mean square of successive differences in NN (each P < .05). These heart rate variability results were not influenced by the type of treatment, and there was no relationship between changes in NN and changes in the apnea-hypopnea index (P = .58).


CONCLUSIONS
Early after successful treatment of acromegaly, we observed increased parasympathetic modulation/decreased sympathetic modulation of the nighttime heart rate, an effect that seems unrelated to changes in sleep apnea status. Treatments aimed at normalizing IGF-1 may improve cardiovascular homeostasis through improved cardiac autonomic nervous system modulation.
Assistance Publique-Hôpitaux de Paris (D.C., P.A.), Hôpitaux Universitaires Paris-Sud, Hôpital de Bicêtre, Service de Physiologie, Assistance Publique-Hôpitaux de Paris (L.M., S.S., P.K., P.C.), Hôpitaux Universitaires Paris-Sud, Hôpital de Bicêtre, Centre de Référence des Maladies Endocriniennes Rares de la Croissance, Service d'Endocrinologie et des Maladies de la Reproduction, Assistance Publique-Hôpitaux de Paris (P.A., S.B.), Hôpitaux Universitaires Paris-Sud, Hôpital de Bicêtre, Service d'Oto-Rhino-Laryngologie, and Université Paris-Sud 11 (D.C., P.A.) EA4533-Faculté de Médecine Paris Sud, Le Kremlin Bicêtre, F-94275, France; Centre de Pneumologie (A.-S.V., G.M., D.B.), F-94550 Chevilly Larue, France; and Université Paris-Sud 11 (P.K., P.C.), INSERM Unité Mixte de Recherche S693, Faculté de Médecine Paris-Sud, and Université Paris-Sud 11 (S.B.) Faculté de Médecine Paris-Sud, Le Kremlin-Bicêtre, F-94276, France.
Denis
D
Chemla
Pierre
P
Attal
Luigi
L
Maione
Anne-Sophie
AS
Veyer
Ghassan
G
Mroue
Dany
D
Baud
Sylvie
S
Salenave
Peter
P
Kamenicky
Serge
S
Bobin
Philippe
P
Chanson
D000172:Acromegaly / Q000150:complications / Q000188:drug therapy*; D000328:Adult; D001341:Autonomic Nervous System / Q000503:physiopathology; D002940:Circadian Rhythm; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012074:Remission Induction; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000503:physiopathology*; D016896:Treatment Outcome