Age-Related Features and Variability of the QTC Interval Among Apparently Healthy Men Based on 24-Hour Holter Monitoring

Q: What are the key findings of this study?

In apparently healthy men, 24-hour mean QTc remained stable with age (413.2 ± 16.5 ms; r = -0.021), while daily QTc variability (ΔQTc) significantly increased to 205.1 ± 57.3 ms at ages 76–82 (p<0.05).

Q: What is the clinical evidence from this study?

Study design: Cross-Sectional. Population: Apparently healthy adult men undergoing 24-hour Holter ECG monitoring (n=87). Intervention: Age stratification (18–43, 46–59, 60–74, and 76–82 years) during 24-hour Holter ECG monitoring vs. Younger adult age groups (18–43 and 46–59 years). Primary outcome: Mean QTc interval (mQTc) and daily QTc variability (ΔQTc) corrected by Bazett's formula over 24 hours (r = -0.021 for mQTc with age, p=<0.05).

Q: What does this research mean for the field?

In apparently healthy men, 24-hour mean QTc remains stable across adulthood, whereas daily ventricular repolarization variability (ΔQTc) significantly increases with advancing age. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

Q: What question did this study set out to answer?

To establish age-specific reference values and assess the 24-hour variability of the QTc interval among apparently healthy men using ambulatory ECG monitoring.

Дмитро Сергійович Дуванов; Юлія Сергіївна Вакал

doi:10.17721/1728.2748.2026.106.15-21

October 27, 2026Bulletin of Taras Shevchenko National University of Kyiv Series “Psychology”Open Access

Age-Related Features and Variability of the QTC Interval Among Apparently Healthy Men Based on 24-Hour Holter Monitoring

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Key result

Aging links to greater daily QTc variability in healthy men despite stable mean QTc.

r = -0.021 for mQTc with age
P<0.05
n=87

Why the study?

Data on age-related features and reference values of QTc parameters from 24-hour Holter monitoring in apparently healthy men, particularly in the Ukrainian population, were limited. Reliable reference values are needed to differentiate between physiological age-related changes and pathological conditions during ambulatory ECG interpretation.

How do 24-hour Holter-derived QTc interval parameters and daily QTc variability change across different age groups in apparently healthy men?

Key Points

To establish age-specific reference values and assess the 24-hour variability of the QTc interval among apparently healthy men using ambulatory ECG monitoring.
Analyzed 87 24-hour Holter ECG recordings from apparently healthy men aged 18–82 years (mean age 58.7 ± 16.6 years), stratified into four age groups: 18–43 (n=17), 46–59 (n=20), 60–74 (n=32), and 76–82 years (n=18).
Calculated mean QTc (mQTc), maximum QTc (QTcmax), minimum QTc (QTcmin), and daily variability (ΔQTc) using Bazett's formula, alongside evaluations of body mass index (BMI).
Mean mQTc across the entire cohort was 413.2 ± 16.5 ms (median 413 ms), peaking at 425.1 ± 14.2 ms in the 46–59 group, with no significant correlation observed between mQTc and age (r = –0.021).
Older age groups (60–82 years) exhibited significant increases in daily repolarization variability (ΔQTc up to 205.1 ± 64.7 ms) and QTcmax (up to 539.8 ± 31.6 ms).
The 95th percentile for mQTc was 445 ms (values exceeding 450 ms occurred in 2.3% of men), while mean BMI (28.83 ± 4.51 kg/m²) showed no significant correlation with any QTc parameter.

Study Design

Type

Cross-Sectional (n=87)

Multicenter

No

Structured PICO

How do 24-hour Holter-derived QTc interval parameters and daily QTc variability change across different age groups in apparently healthy men?

P

Population

87 apparently healthy Ukrainian men aged 18–82 years (mean age 58.7 ± 16.6 years, 0% female) free of cardiovascular disease and QT-prolonging medications evaluated over 24 hours of ambulatory Holter ECG monitoring.

E

Exposure

24-hour ambulatory Holter ECG monitoring using the 'CardioSens CS' system with QT interval correction via Bazett's formula.

C

Comparator

Comparison across four age strata: Group 1 (18–43 years), Group 2 (46–59 years), Group 3 (60–74 years), and Group 4 (76–82 years).

O

Outcome

Age-related features and reference values of QTc parameters over 24 hours, including mean QTc (mQTc), maximum QTc (QTcmax), minimum QTc (QTcmin), and daily QTc variability (ΔQTc).surrogate

Main Result

Effect estimate: r = -0.021 for mQTc with age

Absolute Event Rate: 205.1% vs 136.5%

p-value: p=<0.05

In apparently healthy men undergoing 24-hour Holter monitoring, mean QTc remains stable across adult life with a proposed upper limit of normal of 445 ms, while daily QTc variability and peak QTc values increase significantly after age 60.

Limitations

Relatively small sample size in the extreme age groups (18–43 and 76–82 years)
Use of only a single QT correction formula (Bazett), which has known limitations at extreme heart rates
Lack of detailed quantitative analysis of lifestyle factors, physical activity level, heart rate variability, hormonal profile, and genetic features
Included only apparently healthy men, limiting direct generalizability to patients with comorbidities
Lack of comparative analysis between daytime and nighttime QTc values due to Holter software limitations
Use of only one QT correction formula (Bazett), which has known limitations at extreme heart rates
Lack of detailed quantitative analysis of additional factors such as physical activity level, heart rate variability, hormonal profile, and genetic features
Study included only apparently healthy men, so results cannot be directly extrapolated to patients with comorbidities
Lack of comparative analysis of daytime and nighttime QTc values due to software limitations

Implication

Establishes age-specific QTc norms from Holter in Ukrainian men; leaves open generalizability pending larger prospective validation.

Abstract

Background. The QTc interval is an important electrophysiological marker of ventricular repolarization. Its prolongation is associated with an increased risk of life-threatening ventricular arrhythmias and sudden cardiac death. Despite numerous studies, data on age-related features and reference values of QTc parameters obtained from 24-hour Holter monitoring in apparently healthy men, particularly in the Ukrainian population, remain limited. The relevance of this study is determined by the need to establish reliable reference values for accurate interpretation of ambulatory ECG monitoring results and differentiation between physiological age-related changes and pathological conditions. Methods. Eighty-seven 24-hour Holter ECG recordings of apparently healthy men aged 18–82 years (mean age 58.7 ± 16.6 years) were analyzed. Participants were divided into four age groups: 18–43, 46–59, 60–74, and 76–82 years. QT interval correction was performed using Bazett's formula. The following parameters were analyzed: mQTc (mean QTc), QTcmax, QTcmin, and ΔQTc (daily variability). Body mass index (BMI) was calculated and its influence on QTc parameters was assessed. Statistical analysis was performed using IBM SPSS Statistics 25 software. Results. The mean mQTc in the entire cohort was 413.2 ± 16.5 ms (median 413 ms). The highest mean mQTc was observed in the 46–59 years group (425.1 ± 14.2 ms). In older age groups (60–82 years), mean mQTc remained relatively stable, while daily variability (ΔQTc) and QTcmax significantly increased (up to 205.1 ± 64.7 ms and 539.8 ± 31.6 ms, respectively). There was no significant correlation between mQTc and age (r = –0.021). The 95th percentile of mQTc was 445 ms. mQTc values exceeding 450 ms were recorded in only 2.3% of men. Mean BMI was 28.83 ± 4.51 kg/m² and showed no significant correlation with any QTc parameters. Conclusions. In apparently healthy men, mean mQTc remains relatively stable throughout adult life, whereas repolarization variability (ΔQTc) significantly increases with age. The upper limit of normal mQTc is proposed to be 445 ms (95th percentile). The obtained results clarify age-specific reference values of QTc in Ukrainian men, highlight the diagnostic value of 24-hour Holter monitoring, and can be used in clinical practice to improve the accuracy of ambulatory ECG interpretation.

Discussion

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Cite This Study

Дуванов et al. (2026) conducted a cross-sectional in Apparently healthy adult men undergoing 24-hour Holter ECG monitoring (n=87). Age stratification (18–43, 46–59, 60–74, and 76–82 years) during 24-hour Holter ECG monitoring vs. Younger adult age groups (18–43 and 46–59 years) was evaluated on Mean QTc interval (mQTc) and daily QTc variability (ΔQTc) corrected by Bazett's formula over 24 hours (r = -0.021 for mQTc with age, p=<0.05). In apparently healthy men, 24-hour mean QTc remained stable with age (413.2 ± 16.5 ms; r = -0.021), while daily QTc variability (ΔQTc) significantly increased to 205.1 ± 57.3 ms at ages 76–82 (p<0.05).

synapsesocial.com/papers/6ae433fcd9418cd7c8f47554 https://doi.org/10.17721/1728.2748.2026.106.15-21

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Age-Related Features and Variability of the QTC Interval Among Apparently Healthy Men Based on 24-Hour Holter Monitoring

Key Points

Study Design

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

Age-Related Features and Variability of the QTC Interval Among Apparently Healthy Men Based on 24-Hour Holter Monitoring

Key Points

Study Design

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

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