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Circadian rhythm of the autonomic nervous system in long QT syndrome
Author(s) -
KATO HITOSHI,
YANAGAWA YUKISHIGE
Publication year - 1994
Publication title -
pediatrics international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.49
H-Index - 63
eISSN - 1442-200X
pISSN - 1328-8067
DOI - 10.1111/j.1442-200x.1994.tb03157.x
Subject(s) - medicine , asymptomatic , circadian rhythm , autonomic nervous system , morning , qt interval , cardiology , long qt syndrome , rhythm , heart rate , syncope (phonology) , heart rate variability , sympathetic nervous system , electrocardiography , anesthesia , pediatrics , blood pressure
The circadian changes in the activity of the autonomic nervous system in a group showing long QT duration in electrocardiogram (ECG) were studied in order to differentiate symptomatic congenital long QT syndrome from asymptomatic. The asymptomatic group presented only long QT duration (QTc > 0.46). Seven girls and two boys, including two subjects experiencing syncope of non‐neurological origins, were examined by using heart rate (HR) power spectrum analysis. In three subjects, the peak of the high frequency band, indicating the parasympathetic activity, disappeared during night‐time (sleep), which means the possibility of a high risk of sudden cardiac death. In two of three subjects, moreover, the averaged sympathetic activity during daytime was significantly increased compared to that during night‐time, in addition to the abrupt increase of sympathetic activity in the morning. These two subjects, in which one boy had a family history of Romano‐Ward syndrome, were the same people experiencing the syncope attack. We succeeded in objectively elucidating that congenital long QT syndrome is adrenergic‐dependent, and suggest that HR power spectrum analysis may be of value in distinguishing symptomatic congenital long QT syndrome from asymptomatic showing only long QT duration.