Document Detail

T wave alternans as a risk predictor in patients with cardiomyopathy and mild-to-moderate heart failure.
MedLine Citation:
PMID:  11025895     Owner:  NLM     Status:  MEDLINE    
The analysis of t wave alternans (TWA) was introduced to identify patients with an increased risk of ventricular tachyarrhythmias. The inducibility of ventricular tachyarrhythmias and the spontaneous arrhythmic events are correlated with a positive TWA in patients with a reduced left ventricular ejection fraction and survived myocardial infarction. In contrast, this study is the first to investigate the correlation of a survived sudden cardiac death and TWA in patients without coronary heart disease and only slightly decreased left ventricular function. Sixty patients were included in the study. The TWA analysis was performed using the Cambridge Heart system (CH2000). Patients were sitting on a bicycle ergometer and exercised with a gradual increase of workload to maintain a heart rate of at least 105 beats/min. The exercise test was stopped after recording 254 consecutive low noise level heart beats. The electrocardiographic signals were digitally processed using a spectral analysis method. The magnitude of TWA was measured at a frequency of 0.5 cycles/beat. A TWA was defined as positive if the ratio between TWA and noise level was > 3.0 and the amplitude of the TWA was > 1.8 microV. Twelve (20%) of the included 60 patients showed a positive TWA. The sensitivity concerning a previous arrhythmic event amounted to 65%, the specificity up to 98%, respectively. The alternans ratio was significantly higher in patients with a previous event (30.3 +/- 53.2 vs 2.9 +/- 5.9, P < 0.001) and cumulative alternans voltage (4.67 +/- 3.55 vs 1.75 +/- 1.88 microV, P < 0.001). In 19 patients, invasively investigated by an electrophysiological study, a significant correlation between inducibility of tachyarrhythmias and a positive TWA result was found (Spearman R = 0.51, P = 0.01). In conclusion, the TWA analysis seems to identify patients with nonischemic cardiomyopathy who are at an increased risk of ventricular tachyarrhythmias.
M G Hennersdorf; C Perings; V Niebch; E G Vester; B E Strauer
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Pacing and clinical electrophysiology : PACE     Volume:  23     ISSN:  0147-8389     ISO Abbreviation:  Pacing Clin Electrophysiol     Publication Date:  2000 Sep 
Date Detail:
Created Date:  2001-02-02     Completed Date:  2001-02-02     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  7803944     Medline TA:  Pacing Clin Electrophysiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1386-91     Citation Subset:  IM    
Department of Cardiology, Pneumology, and Angiology, Heinrich-Heine-University, Duesseldorf, Germany.
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MeSH Terms
Arrhythmias, Cardiac / diagnosis*
Cardiomyopathy, Dilated / diagnosis*
Electrocardiography, Ambulatory / statistics & numerical data
Exercise Test / instrumentation,  methods,  statistics & numerical data
Follow-Up Studies
Heart Failure / diagnosis*
Middle Aged
Risk Factors
Sensitivity and Specificity
Statistics, Nonparametric

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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