Dynamic Changes of Cardiac Repolarization Instability during Exercise Testing

Hamm, Wolfgang; Stuelpnagel, Lukas von; Rizas, Konstantinos D.; Vdovin, Nikolay; Klemm, Mathias; Bauer, Axel und Brunner, Stefan (2019): Dynamic Changes of Cardiac Repolarization Instability during Exercise Testing. In: Medicine and Science in Sports and Exercise, Bd. 51, Nr. 7: S. 1517-1522

Abstract

Introduction Physical exercise triggers efferent cardiac sympathetic activation. Here, we tracked the spatiotemporal properties of cardiac repolarization on a beat-to-beat basis throughout a standardized exercise test and hypothesized a detectable change at the point of the anaerobic threshold (AT). Methods The study included 20 healthy adults (age 35.3 +/- 6.7 yr) undergoing a standardized incremental exercise test on a cycle ergometer. During exercise testing, high-resolution (2000 Hz) ECG monitoring in Frank lead configuration was performed. Three-dimensional beat-to-beat repolarization instability (dT degrees) was assessed by a novel vector-based method according to a previously published technology. In parallel, the lactate threshold (LT) was detected according to Dickhuth and Mader. Results We could identify a characteristic pattern of dT degrees signal during exercise testing. With increasing physical activity, dT degrees increased concordantly to heart rate. At an average of 164 +/- 38 W, dT degrees and heart rate abruptly showed a discordant behavior, characterized by a transient drop of dT degrees. The maximal discordance between dT degrees and heart rate was defined as AT(dT degrees) and highly significantly correlated with LTDickhuth (r = 0.841, P < 0.001) and LTMader (r = 0.819, P < 0.001), which were at 156 +/- 39 and 172 +/- 46 W, respectively. The characteristic of dT degrees could not be provoked by fast atrial pacing in the absence of exercise. Conclusions Repolarization instability shows a characteristic pattern during standardized exercise in healthy individuals that allows for a noninvasive estimation of AT.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Medizin
• Themengebiete: 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit
• ISSN: 0195-9131
• Sprache: Englisch