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Dynamic Changes of Cardiac Repolarization Instability during Exercise Testing.

Wolfgang Hamm^1,2, Lukas VON Stülpnagel^1,2, Konstantinos D Rizas^1,2

¹Department of Medicine I, University Hospital, Ludwig-Maximilians-Universität München, Munich, GERMANY.

Medicine and Science in Sports and Exercise

|January 22, 2019

Summary

This summary is machine-generated.

Repolarization instability, measured by a novel vector-based method, exhibits a distinct pattern during exercise that accurately estimates the anaerobic threshold (AT). This noninvasive technique offers a new way to assess exercise physiology.

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Published on: October 17, 2018

Area of Science:

Cardiology
Exercise Physiology
Biomedical Engineering

Background:

Physical exercise activates the cardiac sympathetic nervous system.
Cardiac repolarization dynamics can change during exercise.
Identifying the anaerobic threshold (AT) is crucial for exercise assessment.

Purpose of the Study:

To investigate beat-to-beat changes in cardiac repolarization during exercise.
To determine if these changes correlate with the anaerobic threshold (AT).
To explore a novel noninvasive method for AT estimation.

Main Methods:

20 healthy adults underwent a standardized incremental exercise test.
High-resolution ECG monitoring was used.
Three-dimensional beat-to-beat repolarization instability (dT°) was assessed using a novel vector-based method.
Lactate threshold (LT) was determined using established methods (Dickhuth and Mader).

Main Results:

Repolarization instability (dT°) increased with heart rate during exercise.
A transient drop in dT° was observed at the AT, indicating discordant behavior between dT° and heart rate.
The maximal discordance (ATdT°) strongly correlated with lactate-derived AT (r = 0.841, P < 0.001).
This pattern was specific to exercise and not observed during atrial pacing.

Conclusions:

Repolarization instability exhibits a characteristic pattern during standardized exercise.
This pattern allows for noninvasive estimation of the anaerobic threshold (AT).
The novel vector-based method provides a promising tool for assessing exercise physiology.