A left posterior-inferior hemiblock can be identified based on changes in the electrocardiogram.


Right axis deviation in frontal plane: often > 110° (others use > 90°)


QRS interval: <= 100 msec (may be greater if right bundle branch block present)


Lead aVL: small initial r wave and large S wave


Lead aVF: small q wave and large R wave, late intrinsicoid deflection


Lead I: small r wave and large S wave


Leads II and III: small q wave and large R wave


Exclusions (can produce similar changes in the ECG):

(1) chronic lung disease

(2) right ventricular hypertrophy

(3) large left lateral wall myocardial infarct

(4) asthenic body habitus


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