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ECG QRS complex
ECG deflection resulting from depolarization of ventricles.
Clinical significance:
Normal width: 60-100 msec
Increased width (> 120 msec)
1) ventricular dysrhythmia
2) bundle branch block
Decreased amplitude (< 5 mm limb leads)
1) cardiac failure
2) pericardial effusion
3) coronary artery disease
4) amyloidosis
5) myxedema
triphasic complex, rsR' (bifid QRS)
- right bundle branch block
QRS + in lead QRS axis (degrees)
I -90 to +90
II -30 to +150
III +30 to -150
aVF 0 to +180
aVL +60 to -120
aVR +120 to -60
thus lead II negative in left axis deviation &
lead I negative or small in right axis deviation
normal QRS axis: -30 to +100
Related
electrocardiogram (ECG, EKG)
General
electrocardiogram feature
References
- Current Pocket Reference 1992 Pharmacopoeia & Medical
Notes, Shepherd/Whalen, Specialty Cards, Norman OK 1997
- Harrison's Principles of Internal Medicine, 14th ed.
Fauci et al (eds), McGraw-Hill Inc. NY, 1998
- Harrison's Principles of Internal Medicine, 13th ed.
Isselbacher et al (eds), McGraw-Hill Inc. NY, 1994, pg 961