What is the normal QTc interval in males?

From the Guidelines

The normal QTc interval in males is approximately 0.45 seconds or 450 ms.

Normal QTc Interval Values

• The normal QTc interval values are as follows:
  • 0.45 seconds or 450 ms in men 1
  • 0.46 seconds or 410-420 ms in postpubertal males 1
  • 440 ms in children 1

QTc Interval Measurement

• The QT interval should be measured from the beginning of the QRS complex to the end of the T wave 1
• The most commonly used QT correction formula in clinical practice is the one introduced by Bazett, QTC = QT interval divided by the square root of the R-R interval measured in seconds 1

Clinical Significance

• A QTc value that exceeds the 99th percentile value for otherwise healthy individuals (470 ms in postpubertal males) may signal an individual at increased risk for QT-related ventricular arrhythmias 1
• Patients with a resting QTc of 500 ms or more have a considerably greater risk for both drug-induced torsades de pointes and sudden cardiac death 1

From the Research

Normal QTc Interval in Males

The normal QTc interval in males can vary depending on the study and the criteria used. Here are some findings from different studies:

• A study published in 2013 2 suggests that a QTc interval of 470-500 ms for males is considered prolonged.
• A study published in 2014 3 established criteria for prolonged QTc using formulas that minimize QTc bias at the upper normal limits. According to this study, the upper normal limit for QTc in males is:
  • 430 ms for men aged < 40 years
  • 440 ms for men aged 40 to 69 years
  • 455 ms for men aged ≥ 70 years
• A study published in 2019 4 used a patient-specific QT correcting algorithm (QTcA) and found that a QTc interval of > 450 ms for men is considered prolonged.
• A study published in 2023 5 used individualized QT interval (QTi) and found that a QTi of > 430 ms in males is considered abnormal.
• A study published in 2006 6 found that a QTc interval of > 440 ms in children and adolescents is considered prolonged, with no significant difference between males and females until the age of 8 years, after which girls had longer QTc than boys.

Key Findings

• The normal QTc interval in males can vary depending on age and the criteria used.
• Different studies have established different criteria for prolonged QTc in males, ranging from 430 ms to 470 ms.
• Individualized QT interval (QTi) may be a more accurate measure of QT interval prolongation than traditional QTc interval.