BACKGROUND: Abnormal dynamicity of repolarization is considered to be a marker of myocardial vulnerability contributing to increased risk of arrhythmic events and sudden death. However, little is known about QT dynamics in hypertrophic cardiomyopathy (HCM). In this study, we aimed to evaluate ventricular repolarization by QT dynamicity in patients with HCM, focusing on its value to define if it is able to differentiate among low- and high-risk HCM patients. METHODS: The linear regression slopes of the QT interval, measured to the apex and to the end of the T wave plotted against RR intervals (QTapex/RR and QTend/RR slopes, respectively) were calculated from 24-hour Holter recordings using a standard algorithm in 36 HCM patients and 64 control subjects. RESULTS: QTapex/RR and QTend/RR slopes were significantly steeper in the HCM patients in contrary to healthy control subjects (QTapex/RR = 0.22 + 0.08 vs 0.20 + 0.05, P = 0.0367; QTend/RR = 0.25 + 0.10 vs 0.20 + 0.06, P = 0.023). Moreover, the slopes of QTend/RR and QTapex/RR of high-risk patients were significantly steeper than those of control subjects while no significant differences were found among low-risk HCM patients and control subjects and only QTe/RR of high-risk patients was significantly different between low- and high-risk HCM patients. CONCLUSIONS: Our study results suggest that QT dynamicity is impaired in patients with HCM and may help to differentiate among low- and high-risk patients. Further studies are needed to elucidate the prognostic significance and clinical implications of impaired ventricular repolarization in patients with HCM.
BACKGROUND: Abnormal dynamicity of repolarization is considered to be a marker of myocardial vulnerability contributing to increased risk of arrhythmic events and sudden death. However, little is known about QT dynamics in hypertrophic cardiomyopathy (HCM). In this study, we aimed to evaluate ventricular repolarization by QT dynamicity in patients with HCM, focusing on its value to define if it is able to differentiate among low- and high-risk HCM patients. METHODS: The linear regression slopes of the QT interval, measured to the apex and to the end of the T wave plotted against RR intervals (QTapex/RR and QTend/RR slopes, respectively) were calculated from 24-hour Holter recordings using a standard algorithm in 36 HCM patients and 64 control subjects. RESULTS: QTapex/RR and QTend/RR slopes were significantly steeper in the HCM patients in contrary to healthy control subjects (QTapex/RR = 0.22 + 0.08 vs 0.20 + 0.05, P = 0.0367; QTend/RR = 0.25 + 0.10 vs 0.20 + 0.06, P = 0.023). Moreover, the slopes of QTend/RR and QTapex/RR of high-risk patients were significantly steeper than those of control subjects while no significant differences were found among low-risk HCM patients and control subjects and only QTe/RR of high-risk patients was significantly different between low- and high-risk HCM patients. CONCLUSIONS: Our study results suggest that QT dynamicity is impaired in patients with HCM and may help to differentiate among low- and high-risk patients. Further studies are needed to elucidate the prognostic significance and clinical implications of impaired ventricular repolarization in patients with HCM.
Authors: Josef Halamek; Jean-Philippe Couderc; Pavel Jurak; Vlastimil Vondra; Wojciech Zareba; Ivo Viscor; Pavel Leinveber Journal: Ann Noninvasive Electrocardiol Date: 2012-08-13 Impact factor: 1.468
Authors: Iwona Cygankiewicz; Wojciech Zareba; Rafael Vazquez; Jesus Almendral; Antoni Bayes-Genis; Miquel Fiol; Mariano Valdes; Carlos Macaya; Jose R Gonzalez-Juanatey; Juan Cinca; Antoni Bayes de Luna Journal: J Cardiovasc Electrophysiol Date: 2008-06-28
Authors: Mikko Jalanko; Heikki Väänänen; Mika Tarkiainen; Petri Sipola; Pertti Jääskeläinen; Kirsi Lauerma; Tiina Laitinen; Tomi Laitinen; Mika Laine; Tiina Heliö; Johanna Kuusisto; Matti Viitasalo Journal: Ann Noninvasive Electrocardiol Date: 2018-07-04 Impact factor: 1.468
Authors: Alan Sugrue; Ammar M Killu; Christopher V DeSimone; Anwar A Chahal; Josh C Vogt; Vaclav Kremen; JoJo Hai; David O Hodge; Nancy G Acker; Jeffrey B Geske; Michael J Ackerman; Steve R Ommen; Grace Lin; Peter A Noseworthy; Peter A Brady Journal: Open Heart Date: 2017-02-23