title: The prevalence and the prognostic value of microvolt T-wave alternans in patients with hypertrophic cardiomyopathy.
abstract: BACKGROUND
  Nonsustained ventricular tachycardia (nVT) may have ominous implications for patients with hypertrophic cardiomyopathy (HCM). The microvolt T-wave alternans (TWA) has been proposed as a noninvasive tool-identifying patients at risk of sudden cardiac death and ventricular tachycardia/fibrillation (VT/VF). The aim of the study was to determine the significance of TWA in predicting nVT episodes and compare how other electrocardiographic parameters can predict the occurrence of nVT.
  
  
  METHODS
  The study group consisted of 88 patients with HCM. TWA was assessed during exercise test using the CH2000 system. All patients underwent Holter monitoring (HM) within 2-4 weeks before TWA test (preexercise HM1) and immediately after (postexercise HM2). During HM, we analyzed: arrhythmias, QT intervals, the presence of late ventricular potentials (LP), heart rate variability, heart rate turbulence.
  
  
  RESULTS
  Depending on TWA results, the patients were divided into two groups: TWA+; 46 patients (52.3%) with positive/indeterminate results, and TWA-; 42 patients (47.7%) with negative results. The nVT episodes were more frequent among TWA(+) both in HM1 and HM2. The presence of TWA increases the risk of postexercise nVT over twenty times (OR = 21.03). Moreover, in HM1, QTc and LP, and in HM2, again QTc and N-terminal precursor of brain natriuretic peptide proved to be significant predictors of nVT. The addition of TWA to the models did not improve the arrhythmia risk assessment.
  
  
  CONCLUSIONS
  Repolarization abnormality plays an important role in generating nVT in patients with HCM, but TWA does not specifically predict the risk of arrhythmic end point.
authors.affiliation: Department of Cardiology, Biegański Hospital, Medical University of Lodz, Lodz, Poland. ewa_trzos@op.pl
authors.forename: Ewa
authors.initials: E
authors.lastname: Trzos
authors.forename: Jarosław D
authors.initials: JD
authors.lastname: Kasprzak
authors.forename: Maria
authors.initials: M
authors.lastname: Krzemińska-Pakuła
authors.forename: Tomasz
authors.initials: T
authors.lastname: Rechciński
authors.forename: Karina
authors.initials: K
authors.lastname: Wierzbowska-Drabik
authors.forename: Barbara
authors.initials: B
authors.lastname: Uznańska
authors.forename: Adam
authors.initials: A
authors.lastname: Śmiałowski
authors.forename: Tomasz
authors.initials: T
authors.lastname: Rudziński
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Kurpesa
mesh_terms: D000465:Algorithms; D015415:Biomarkers / Q000097:blood; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging / Q000503:physiopathology*; D016009:Chi-Square Distribution; D015150:Echocardiography, Doppler; D015716:Electrocardiography, Ambulatory; D005080:Exercise Test; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood; D010446:Peptide Fragments / Q000097:blood; D015995:Prevalence; D011379:Prognosis; D012372:ROC Curve; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric
chemical_list: D015415:Biomarkers; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain