Circadian modulation on T-wave alternans activity in chronic heart failure patients

Abstract

Average TWA activity has been shown to be an independent predictor of sudden cardiac death (SCD) respectively). In conclusion, time of the day should be considered for SCD risk prediction.

Circadian Modulation of Electrocardiographic Alternans in Kidney Failure Patients on Dialysis

“…Here, we decided to divide the 24-h day into two equal periods that would likely correspond to the periods of higher patient's activity (7:00 am-7:00 pm) and rest (7:00 pm-7:00 am). In these periods, time at which 4) 13( 6) 16( 5) 17( 9) 17(7) LM 10(4) 13( 5) 12( 5) 16( 6) 18 (6) 22(8) EA 8(5) 13*(8) 11( 6) 15( 7) 16 (7) maximum/minimum ECGA values were mostly registered (i.e., t1 and t2) are concordant with observations from other studies [3,4]. Dialysis interrupted the circadian periodicity of ECGA, causing a decrement of PWA/QRSA/TWA (lead average, 8/12/17 µV) in daytime.…”

“…Hashimoto et al studied TWA circadian modulation in a healthy population for a period of 24 h, and observed maximum TWA between 12:00 pm and 6:00 pm, and minimum TWA between 12:00 am and 6:00 am [3]. Analogous trends were found out by Martín-Yebra et al analyzing chronic heart failure patients and by Kanazawa et al analyzing patients with implanted cardioverter defibrillator [4,5].…”

Index of T:wave Variation as a Predictor of Sudden Cardiac Death in Chronic Heart Failure Patients with Atrial Fibrillation

“…3) In order to make a robust estimation, as this variation of the ventricular activity could be within the range of non-visible microvolt sometimes comparable to the noise level, we replicate the analysis already presented in [11] in the context of TWA analysis, where all TWA waveforms were averaged after being aligned in phase.…”

“…where w 1 corresponds to the first eigenvector associated to the greatest eigenvalue λ 1 of the spatial correlation matrix R ∆T k of all ∆T k,i , (see [11] for more details). 4) Finally, the T-wave variation waveform associated to the k th bin, i.e.…”