QRS Complex Duration of 98 ms is Normal
A QRS duration of 98 milliseconds is completely normal in adults. This falls well within the accepted normal range and does not indicate any conduction abnormality.
Normal QRS Duration Thresholds
According to the AHA/ACCF/HRS guidelines 1, the key thresholds for defining abnormal intraventricular conduction in adults are:
- Normal QRS duration: Less than 110 ms
- Nonspecific intraventricular conduction disturbance: Greater than 110 ms
- Incomplete bundle branch block: 110-119 ms
- Complete bundle branch block: ≥120 ms
Your QRS duration of 98 ms is 12 milliseconds below the threshold for any conduction abnormality.
Context and Interpretation
The normal physiologic range of QRS duration spans between 80-125 ms 2. Research examining large populations shows:
- Mean QRS duration in healthy adults is approximately 97 ± 13 ms 3
- The 10th percentile (lower limit of normal) is around 84-85 ms 3
- QRS durations in the 90s are extremely common in healthy individuals
Your value of 98 ms sits right at the population mean for healthy adults, making it entirely unremarkable.
Important Caveats
While 98 ms is normal, remember that:
- QRS duration varies with heart rate - faster heart rates slightly shorten QRS duration 4
- Sex differences exist - females typically have slightly shorter QRS durations than males (though both sexes have normal ranges well above and below 98 ms) 2
- The complete ECG matters more than one measurement - QRS duration alone doesn't define cardiac health; the morphology, axis, and other ECG features are equally important
Clinical Bottom Line
No action is needed for a QRS duration of 98 ms. This represents normal intraventricular conduction with no evidence of bundle branch block, fascicular block, or any other conduction disturbance 1.