Age-dependent influence of T wave amplitude on short period temporal dispersion in healthy subjects

Background: T wave amplitude and repolarization variability in ECG showed inverse correlations. Sympathetic activation, induced by head-up tilt, is associated to a reduced T wave amplitude. Methods: Noninvasive hemodynamic and ECG data from three healthy subjects' groups (Group 1: 10–19 years-old; Group 2: 40–49 years-old; Group 3: 80–89 years-old) were analyzed. Measurements were taken during controlled-breathing rest, and during head-up tilt. The mean and standard deviation (SD) were calculated for these ECG intervals: QT, STp (from S to Tpeak) and Te (from Tpeak to Tend). Results: During tilt, a significant decrease in T wave amplitude was observed in the younger groups (p < 0.001), but not in Group 3. At rest, Group 1 exhibited higher voltage compared to Group 2 (p < 0.05) and 3 (p < 0.001), as Group 2 compared to Group 3 (p < 0.05). A negative correlation was confirmed between T wave amplitude and QTSD, STpSD and TeSD (p < 0.001). Low-frequency normalized units (p < 0.05) and high-frequency normalized units (p < 0.001) were inversely related to T-wave amplitude. Conclusion: The findings suggest an age-dependent decline in T wave amplitude during tilt and elucidates the relationship between systolic function and T wave amplitude among healthy subjects. These insights warrant further investigations in clinical and research settings for cardiovascular diseases.