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

Andrea Orosz, István Baczkó, Viktória Nagy, Henriette Gavallér, Miklós Csanády, Tamás Forster, Julius Gy Papp, András Varró, Csaba Lengyel, Róbert Sepp

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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.

Original languageEnglish
Pages (from-to)765-772
Number of pages8
JournalCanadian journal of physiology and pharmacology
Volume93
Issue number9
DOIs
Publication statusPublished - Apr 15 2015

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Keywords

  • Hypertrophic cardiomyopathy
  • Left ventricular hypertrophy
  • QT dispersion
  • QT prolongation
  • Repolarization
  • Short-term beat-to-beat variability of the QT interval
  • Sudden cardiac death
  • Tpeak–Tend interval

ASJC Scopus subject areas

  • Physiology
  • Pharmacology
  • Physiology (medical)

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