Normal Qt Interval By Age Chart

This chart provides the normal QT interval ranges in milliseconds for different ages, from newborn to adults.
Age Normal QT Interval (ms)
Newborn (1-2 days) 70-100 ms
1 week 90-110 ms
1 month 100-120 ms
3-6 months 110-140 ms
6-12 months 100-150 ms
1-4 years 90-140 ms
4-10 years 90-150 ms
10-16 years 90-160 ms
Adults (>16 years) 350-450 ms

The Normal QT Interval By Age Chart provides information about the normal QT interval duration in milliseconds (ms) for individuals in various age groups. The QT interval is a measure of the electrical activity of the heart, specifically the time it takes for the ventricles to contract and then relax during each heartbeat. This chart outlines the expected range for the QT interval at different ages, helping to identify any potential abnormalities or irregularities in heart functioning. The chart spans from newborns (1-2 days old) to adults over 16 years of age.


What is a normal QT interval?

The QT interval refers to the time duration of electrical activity in the heart's ventricles. The normal QT interval varies depending on age, sex, and heart rate. It is typically measured from the start of the QRS complex to the end of the T wave on an electrocardiogram (ECG).

How does the QT interval change with age?

The QT interval generally shortens with increasing age. In infants and children, the QT interval is typically longer compared to adolescents and adults. It gradually decreases during adolescence and reaches adult values by the age of 20.

What is the normal range of the QT interval for adults?

The normal range of the QT interval for adults is usually between 350 and 440 milliseconds (ms) in men, and 360 to 450 ms in women. However, it's important to consider heart rate correction formulas such as the Bazett's formula to accurately determine the QT interval.

Are there any factors that can influence the QT interval?

Yes, several factors can influence the QT interval, including medications (e.g., certain antibiotics, antidepressants), electrolyte imbalances (e.g., low potassium or magnesium levels), heart conditions, genetic factors (e.g., long QT syndrome), and physical activity.

Why is it important to know the normal QT interval?

Knowledge of the normal QT interval is crucial for assessing the risk of potentially life-threatening arrhythmias, such as torsades de pointes. Abnormal prolongation or shortening of the QT interval may indicate an increased risk of arrhythmias and may require further evaluation and treatment.

How we write our statistic reports:

We have not conducted any studies ourselves. Our article provides a summary of all the statistics and studies available at the time of writing. We are solely presenting a summary, not expressing our own opinion. We have collected all statistics within our internal database. In some cases, we use Artificial Intelligence for formulating the statistics. The articles are updated regularly.

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