Is a QRS (electrocardiogram interval) axis of -25 degrees considered normal?

QRS Axis of -25 Degrees: Mild Left Axis Deviation (Borderline Normal)

A QRS axis of -25 degrees represents mild left axis deviation that falls just outside the strict normal range but is commonly seen in healthy adults, particularly with increasing age, and typically does not indicate significant cardiac pathology in isolation. 1, 2

Definition and Classification

• The normal QRS axis in adults is defined as between +30° and +90° by the American College of Cardiology 1, 2
• Left axis deviation begins at any value less than +30°, making -25° technically abnormal 1, 2
• Your axis of -25° falls into the mild left axis deviation category, which ranges from 0° to -30° 2
• This is distinct from moderate left axis deviation (-30° to -45°) and marked left axis deviation (-45° to -90°, often associated with left anterior fascicular block) 1, 2

Clinical Significance of -25 Degrees

This degree of axis deviation is frequently a normal variant, especially with aging, and has limited diagnostic value when isolated. 2

• Research shows that in patients aged 50 or older without cardiopulmonary disease, 99% had QRS axes between -45° and +75°, indicating that -25° falls well within commonly observed ranges 3
• The American College of Cardiology emphasizes that left axis deviation may be associated with various cardiac conditions but can also be a normal variant 2
• A study of middle-aged and elderly patients demonstrated progressive leftward shift of the QRS axis with age, with median values around +55° in younger adults but extending to -30° in older populations 3

What to Evaluate Next

Rather than focusing on the axis alone, you should assess for:

• Other ECG abnormalities that might indicate underlying pathology, such as Q waves, ST-segment changes, or T-wave inversions 2
• Criteria for left anterior fascicular block: qR pattern in lead aVL, R-peak time in aVL ≥45 ms, and QRS duration <120 ms 1, 2
• Signs of left ventricular hypertrophy, which is a common cause of left axis deviation 2
• Clinical context: symptoms, age, comorbidities, and other cardiac risk factors 2, 4

Common Pitfalls to Avoid

• Overdiagnosing left axis deviation as a primary diagnosis rather than recognizing it as a finding requiring clinical correlation 2
• Failing to consider age-related changes in QRS axis, which naturally shifts leftward with aging 2, 5
• Ignoring the clinical context: an abnormal axis in isolation occurs in a small number of normal individuals and should prompt thorough ECG evaluation rather than immediate concern 4

Bottom Line

At -25 degrees, your QRS axis is only 5 degrees outside the strict normal range and represents a borderline finding that is commonly seen in healthy adults. 1, 2 Unless accompanied by other ECG abnormalities or clinical symptoms, this mild deviation does not warrant concern or further cardiac workup. 2, 4