title: The utility of T-wave alternans during the morning in the summer for the risk stratification of patients with Brugada syndrome.
abstract: The prognostic value of the seasonal variations of T-wave alternans (TWA) and heart rate variability (HRV), and the seasonal distribution of ventricular fibrillation (VF) in Brugada syndrome (Br-S) is unknown. We assessed the utility of seasonal variations in TWA and HRV for risk stratification in Br-S using a 24-h multichannel Holter electrocardiogram (24-M-ECG). We enrolled 81 patients with Br-S (grouped according to their history of VF, n = 12; syncope, n = 8; no symptoms, n = 61) who underwent 24-M-ECG in all four seasons. Precordial electrodes were attached to the third (3L-V2) and fourth (4L-V2, 4L-V5) intercostal spaces. We determined the maximum TWA (max-TWA) values and calculated HRV during night and morning time periods for all seasons. During a follow-up period of 5.8 ± 2.8 years, 11 patients experienced new VF episodes and there was a peak in new VF episodes in the summer. The VF group had the greatest 3L-V2 max-TWA value during morning time in the summer among the three groups and showed higher 3L-V2 max-TWA value than in the other seasons. The cutoff value for the 3L-V2 max-TWA during morning time in the summer was determined to be 42 µV using ROC analysis (82 % sensitivity, 74 % specificity; p = 0.0006). Multivariate analysis revealed that a 3L-V2 max-TWA value ≥42 µV during morning time in the summer and previous VF episodes were predictors of future VF episodes. The 3L-V2 max-TWA value during morning time in the summer may be a useful predictor of future VF episodes in Br-S.
authors.affiliation: Department of Cardiovascular Medicine, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka, 545-8585, Japan.
authors.forename: Shogo
authors.initials: S
authors.lastname: Sakamoto
authors.affiliation: Department of Cardiovascular Medicine, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka, 545-8585, Japan. m7424580@msic.med.osaka-cu.ac.jp.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Takagi
authors.affiliation: Department of Cardiovascular Medicine, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka, 545-8585, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Kakihara
authors.affiliation: Department of Cardiovascular Medicine, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka, 545-8585, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Hayashi
authors.affiliation: Department of Cardiovascular Medicine, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka, 545-8585, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Doi
authors.affiliation: Department of Cardiovascular Medicine, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka, 545-8585, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Sugioka
authors.affiliation: Department of Cardiovascular Medicine, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka, 545-8585, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Yoshiyama
mesh_terms: D000328:Adult; D000368:Aged; D053840:Brugada Syndrome / Q000150:complications*; D017147:Defibrillators, Implantable; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate; D006801:Humans; D007564:Japan; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012372:ROC Curve; D018570:Risk Assessment; D012621:Seasons; D012680:Sensitivity and Specificity; D013575:Syncope / Q000209:etiology / Q000601:surgery*; D014693:Ventricular Fibrillation / Q000175:diagnosis* / Q000601:surgery*
keywords: 24-h multichannel Holter electrocardiogram; Brugada syndrome; Heart rate variability; Seasonal variation; T-wave alternans