title: Wavelet transform analysis of heart rate variability to assess the autonomic changes associated with spontaneous coronary spasm of variant angina.
abstract: We used Wavelet transform (WT) to investigate whether variation in autonomic tone was associated with spontaneous coronary spasm in patients with variant angina by analysis of heart rate variability (HRV). Twenty-one episodes preceding ST-segment elevation were selected under Holter monitoring in 12 men and 3 women with variant angina. HRV indices were calculated at 10 second intervals with the continuous WT, and analyzed within 30 minutes preceding ST-segment elevation. High frequency (HF; 0.15 approximately 2.00 Hz) increased significantly during the 4 minutes prior to ST-segment elevation, low frequency (LF; 0.04 approximately 0.15 Hz) decreased significantly during the period from 10 to 5 minutes and increased significantly during the 2 minutes prior to ST-segment elevation, the LF/HF ratio decreased significantly during the period from 10 to 3 minutes and increased significantly during the 2 minutes prior to ST-segment elevation. The RR interval decreased significantly during the 2 minutes prior to ST-segment elevation. These results suggest that the acute variation in autonomic tone was associated with spontaneous coronary spasm in patients with variant angina. A reduction in sympathetic activity, then enhancement of vagal activity may play a key role in triggering the spontaneous coronary spasm, and the secondary activation of sympathetic activity may worsen the coronary spasm resulting in the attack.
authors.affiliation: Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan. bihuatan@hyo-med.ac.jp
authors.forename: Bi-Hua
authors.initials: BH
authors.lastname: Tan
authors.forename: Hiroki
authors.initials: H
authors.lastname: Shimizu
authors.forename: Kenji
authors.initials: K
authors.lastname: Hiromoto
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Furukawa
authors.forename: Mitsumasa
authors.initials: M
authors.lastname: Ohyanagi
authors.forename: Tadaaki
authors.initials: T
authors.lastname: Iwasaki
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D000788:Angina Pectoris, Variant / Q000150:complications / Q000503:physiopathology*; D001341:Autonomic Nervous System / Q000503:physiopathology*; D003329:Coronary Vasospasm / Q000150:complications / Q000503:physiopathology*; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged