BACKGROUND: QRS/T angle and the cosine of the angle between QRS and T-wave vectors (TCRT), measured from standard 12-lead electrocardiogram (ECG), have been used in risk stratification of patients. This study assessed the possible rate dependence of these variables during exercise ECG in healthy subjects. METHODS: Forty healthy volunteers, 20 men and 20 women, aged 34.6 +/- 3.4, underwent an exercise ECG testing. Twelve-lead ECG was recorded from each test subject and the spatial QRS/T angle and TCRT were automatically analyzed in a beat-to-beat manner with custom-made software. The individual TCRT/RR and QRST/RR patterns were fitted with seven different regression models, including a linear model and six nonlinear models. RESULTS: TCRT and QRS/T angle showed a significant rate dependence, with decreased values at higher heart rates (HR). In individual subjects, the second-degree polynomic model was the best regression model for TCRT/RR and QRST/RR slopes. It provided the best fit for both exercise and recovery. The overall TCRT/RR and QRST/RR slopes were similar between men and women during exercise and recovery. However, women had predominantly higher TCRT and QRS/T values. With respect to time, the dynamics of TCRT differed significantly between men and women; with a steeper exercise slope in women (women, -0.04/min vs -0.02/min in men, P < 0.0001). In addition, evident hysteresis was observed in the TCRT/RR slopes; with higher TCRT values during exercise. CONCLUSIONS: The individual patterns of TCRT and QRS/T angle are affected by HR and gender. Delayed rate adaptation creates hysteresis in the TCRT/RR slopes.
BACKGROUND: QRS/T angle and the cosine of the angle between QRS and T-wave vectors (TCRT), measured from standard 12-lead electrocardiogram (ECG), have been used in risk stratification of patients. This study assessed the possible rate dependence of these variables during exercise ECG in healthy subjects. METHODS: Forty healthy volunteers, 20 men and 20 women, aged 34.6 +/- 3.4, underwent an exercise ECG testing. Twelve-lead ECG was recorded from each test subject and the spatial QRS/T angle and TCRT were automatically analyzed in a beat-to-beat manner with custom-made software. The individual TCRT/RR and QRST/RR patterns were fitted with seven different regression models, including a linear model and six nonlinear models. RESULTS: TCRT and QRS/T angle showed a significant rate dependence, with decreased values at higher heart rates (HR). In individual subjects, the second-degree polynomic model was the best regression model for TCRT/RR and QRST/RR slopes. It provided the best fit for both exercise and recovery. The overall TCRT/RR and QRST/RR slopes were similar between men and women during exercise and recovery. However, women had predominantly higher TCRT and QRS/T values. With respect to time, the dynamics of TCRT differed significantly between men and women; with a steeper exercise slope in women (women, -0.04/min vs -0.02/min in men, P < 0.0001). In addition, evident hysteresis was observed in the TCRT/RR slopes; with higher TCRT values during exercise. CONCLUSIONS: The individual patterns of TCRT and QRS/T angle are affected by HR and gender. Delayed rate adaptation creates hysteresis in the TCRT/RR slopes.
Authors: V Batchvarov; P Dilaveris; P Färbom; A Ghuran; B Acar; K Hnatkova; A J Camm; M Malik Journal: Pacing Clin Electrophysiol Date: 2000-11 Impact factor: 1.976
Authors: Juha S Perkiömäki; Miia Hyytinen-Oinas; Mari Karsikas; Tapio Seppänen; Katerina Hnatkova; Marek Malik; Heikki V Huikuri Journal: Am J Cardiol Date: 2006-02-01 Impact factor: 2.778
Authors: Peter Smetana; Velislav N Batchvarov; Katerina Hnatkova; A John Camm; Marek Malik Journal: Am J Physiol Heart Circ Physiol Date: 2003-08-28 Impact factor: 4.733
Authors: Heidi Hintsala; Tuomas V Kenttä; Mikko Tulppo; Antti Kiviniemi; Heikki V Huikuri; Matti Mäntysaari; Sirkka Keinänen-Kiukaannemi; Risto Bloigu; Karl-Heinz Herzig; Riitta Antikainen; Hannu Rintamäki; Jouni J K Jaakkola; Tiina M Ikäheimo Journal: PLoS One Date: 2014-07-01 Impact factor: 3.240