Annals of noninvasive electrocardiology : the official journal of the International Society for Holter and Noninvasive Electrocardiology, Inc
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Ann Noninvasive Electrocardiol · Jan 2009
Comparative StudyZ-score for benchmarking reader competence in a central ECG laboratory.
ECGs from thorough QT studies must be read in a central laboratory by trained experts. Standards of expertise are not presently defined. We, therefore, studied the use of Z-scores to define reader competence. ⋯ Mean absolute Z-score is useful to assess competence for measuring the QT interval on ECGs. Analysis of histograms can pinpoint problems in QT measurements.
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Ann Noninvasive Electrocardiol · Jul 2008
Case ReportsQRS alternans with 2:1 atrioventricular conduction block: what is the mechanism?
An 81-year-old woman was admitted for symptomatic bradycardia. On admission, the ECG exhibited QRS alternans, narrow QRS complex and left bundle branch block with 2:1 AV block. ⋯ An appropriate mechanism for explaining those ECG findings might be 4:1 conduction over the left bundle branch and 2:1 conduction over the right bundle branch. An ECG pattern exhibiting QRS alternans with a narrow QRS complex and bundle branch block with 2:1 AV block may suggest the coexistence of both bundle branch blocks and a high risk of complete AV block.
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Ann Noninvasive Electrocardiol · Jul 2008
Beat-to-beat QT interval variability is primarily affected by the autonomic nervous system.
Beat-to-beat QT interval variability is associated with life-threatening arrhythmias and sudden death, however, its precious mechanism and the autonomic modulation on it remains unclear. The purpose of this study was to determine the effect of drugs that modulate the autonomic nervous system on beat-to-beat QT interval. ⋯ Beat-to-beat QT interval variability is affected by drugs that modulate the autonomic nervous system.