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Titolo:
T-WAVE SPECTRAL VARIANCE - A NEW METHOD TO DETERMINE INHOMOGENEOUS REPOLARIZATION BY T-WAVE BEAT-TO-BEAT VARIABILITY IN PATIENTS PRONE TO VENTRICULAR ARRHYTHMIAS
Autore:
STEINBIGLER P; HABERL R; NESPITHAL K; SPIEGL A; SCHMUCKING I; STEINBECK G;
Indirizzi:
UNIV MUNICH,MED HOSP 1,MARCHIONINISTR 15 D-81366 MUNICH GERMANY
Titolo Testata:
Journal of electrocardiology
, volume: 30, anno: 1997, supplemento:, S
pagine: 137 - 144
SICI:
0022-0736(1997)30:<137:TSV-AN>2.0.ZU;2-P
Fonte:
ISI
Lingua:
ENG
Soggetto:
CORONARY-ARTERY DISEASE; INTERVAL PROLONGATION; MYOCARDIAL-INFARCTION; QT INTERVAL; RISK; TACHYCARDIA; RECORDINGS; ECG;
Keywords:
VENTRICULAR ARRHYTHMIAS; T WAVE SPECTRAL VARIANCE; REPOLARIZATION; BEAT-TO-BEAT VARIABILITY; HOLTER MONITORING;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
14
Recensione:
Indirizzi per estratti:
Citazione:
P. Steinbigler et al., "T-WAVE SPECTRAL VARIANCE - A NEW METHOD TO DETERMINE INHOMOGENEOUS REPOLARIZATION BY T-WAVE BEAT-TO-BEAT VARIABILITY IN PATIENTS PRONE TO VENTRICULAR ARRHYTHMIAS", Journal of electrocardiology, 30, 1997, pp. 137-144

Abstract

Inhomogeneous repolarization is considered to be associated with increased risk of ventricular arrhythmias, but exact determination of the end of the T wave is difficult, and a single measurement of the QTc interval may be insufficient for risk stratification. A new algorithm was therefore developed to determine the beat-to-beat variability of theT wave in Holter electrocardiographic recordings. This algorithm, termed T Wave Spectral Variance (TWSV) uses the two-dimensional fast Fourier transform to determine the beat-to-beat variability of the T wave in Holter ECG recordings. The two-dimensional East Fourier transform was calculated by use of a data matrix with 1,024 consecutive single beats (first dimension) and a 200-ms segment centered on the T wave (second dimension). The power spectra of the 2D-FFT revealed the frequencycontent of the T wave in the first dimension and the periodicity of these frequencies in cycles per beat in the second dimension. A TWSV index of periodicity was calculated by dividing total spectral energy byspectral energy at 0 cycles per beat. A TWSV index of 0 means a constant T wave from beat to beat; a TWSV index of 1 means a completely irregular T wave. Of the 200 patients investigated, all of whom had had myocardial infarctions, 50 had documented sustained ventricular tachycardia (VT)(<230 beats/min) (group 1), 50 had ventricular fibrillation (VF) (group 2), and 100 were without VT or VF (group 3); 10 normal subjects were also investigated. The visually determined QTc was 442 +/- 62 ms in group 1,402 +/- 13 ms in group 2, 411 +/- 26 ms in group 3, and 398 +/- 43 ms in normal subjects (differences not significant). The TWSV index was 0.95 +/- 0.14 in group 1, 0.90 +/- 0.16 in group 2, and0.64 +/- 0.24 in,group 3; it showed a highly constant T wave in normal subjects (0.52 +/- 0.23). Differences between patients with VT and VF as against patients without VT or VF were significant (P < .05), whereas no statistical differences between patients with VT and VF could be found. Thus, TWSV a new method to assess beat-to-beat variability of the T wave, revealed increased heterogeneity of repolarization in patients prone to both VT and VF after myocardial infarction. whereas a single QTc interval measurement showed no significant differences.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 18/09/20 alle ore 11:10:40