right axis deviation

ECG axis between +90 to +180 Using only ECG lead I & ECG lead II, between +90 to +120 Etiology: 1) right ventricular hypertrophy (most common) - cor pulmonale - pulmonary embolism - atrial septal defect - pulmonic valvular stenosis 2) myocardial infarction (lateral or anterolateral wall) 3) accessory pathway (WPW, left free wall location) 4) left posterior fascicular block 5) uncommon causes a) tricyclic antidepressant (TCA) overdose b) left pneumothorax c) normal variant (young & tall, slender adults)

References

Practical ECG Interpretation, T Evans, Ring Mountain Press, 1998