title: Short-term beat-to-beat variability of the QT interval is increased and correlates with parameters of left ventricular hypertrophy in patients with hypertrophic cardiomyopathy.
abstract: Stratification models for the prediction of sudden cardiac death (SCD) are inappropriate in patients with hypertrophic cardiomyopathy (HCM). We investigated conventional electrocardiogram (ECG) repolarization parameters and the beat-to-beat short-term QT interval variability (QT-STV), a new parameter of proarrhythmic risk, in 37 patients with HCM (21 males, average age 48 ± 15 years). Resting ECGs were recorded for 5 min and the frequency corrected QT interval (QTc), QT dispersion (QTd), beat-to-beat short-term variability of QT interval (QT-STV), and the duration of terminal part of T waves (Tpeak-Tend) were calculated. While all repolarization parameters were significantly increased in patients with HCM compared with the controls (QTc, 488 ± 61 vs. 434 ± 23 ms, p < 0.0001; QT-STV, 4.5 ± 2 vs. 3.2 ± 1 ms, p = 0.0002; Tpeak-Tend duration, 107 ± 27 vs. 91 ± 10 ms, p = 0.0015; QTd, 47 ± 17 vs. 34 ± 9 ms, p = 0.0002), QT-STV had the highest relative increase (+41%). QT-STV also showed the best correlation with indices of left ventricular (LV) hypertrophy, i.e., maximal LV wall thickness normalized for body surface area (BSA; r = 0.461, p = 0.004) or LV mass (determined by cardiac magnetic resonance imaging) normalized for BSA (r = 0.455, p = 0.015). In summary, beat-to-beat QT-STV showed the most marked increase in patients with HCM and may represent a novel marker that merits further testing for increased SCD risk in HCM.
authors: a Department of Pharmacology and Pharmacotherapy, University of Szeged, Hungary.
authors: Andrea
authors: A
authors: Orosz
authors: a Department of Pharmacology and Pharmacotherapy, University of Szeged, Hungary.
authors: István
authors: I
authors: Baczkó
authors: b Second Department of Internal Medicine and Cardiology Centre, Faculty of Medicine, University of Szeged, Korányi fasor 6, 6720 Szeged, Hungary.
authors: Viktória
authors: V
authors: Nagy
authors: b Second Department of Internal Medicine and Cardiology Centre, Faculty of Medicine, University of Szeged, Korányi fasor 6, 6720 Szeged, Hungary.|c Diagnoscan Hungary Ltd., Semmelweis utca 6, 6725 Szeged, Hungary.
authors: Henriette
authors: H
authors: Gavallér
authors: b Second Department of Internal Medicine and Cardiology Centre, Faculty of Medicine, University of Szeged, Korányi fasor 6, 6720 Szeged, Hungary.
authors: Miklós
authors: M
authors: Csanády
authors: b Second Department of Internal Medicine and Cardiology Centre, Faculty of Medicine, University of Szeged, Korányi fasor 6, 6720 Szeged, Hungary.
authors: Tamás
authors: T
authors: Forster
authors: a Department of Pharmacology and Pharmacotherapy, University of Szeged, Hungary.|d MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary.
authors: Julius Gy
authors: JG
authors: Papp
authors: a Department of Pharmacology and Pharmacotherapy, University of Szeged, Hungary.|d MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary.
authors: András
authors: A
authors: Varró
authors: e First Department of Internal Medicine, University of Szeged, Hungary.
authors: Csaba
authors: C
authors: Lengyel
authors: b Second Department of Internal Medicine and Cardiology Centre, Faculty of Medicine, University of Szeged, Korányi fasor 6, 6720 Szeged, Hungary.
authors: Róbert
authors: R
authors: Sepp
mesh_terms: D000328:Adult; D001145:Arrhythmias, Cardiac / Q000150:complications / Q000503:physiopathology*; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications / Q000503:physiopathology*; D016022:Case-Control Studies; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000150:complications / Q000473:pathology / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged
keywords: QT dispersion; QT prolongation; Tpeak–Tend interval; cardiomyopathie hypertrophique; dispersion de l’intervalle QT; hypertrophic cardiomyopathy; hypertrophie ventriculaire gauche; intervalle entre le pic et la fin de l’onde T; left ventricular hypertrophy; mort subite d’origine cardiaque; prolongation de l’intervalle QT; repolarisation; repolarization; short-term beat-to-beat variability of the QT interval; sudden cardiac death; variabilité à court terme de l’intervalle QT