ECG manifestations of chamber enlargement:

1. P wave duration equal or more than 0.12 sec.
   
2. Notched, slurred P wave in lead I and II (P mitrale).
   
3. Biphasic P wave in lead V1 wit ha wide ,deep and negative terminal component.
   
4. Mean P wav axis shifted to the left ( between +45 to – 30 degree ).

1. P wave duration equal or less than 0.11 sec.
   
2. Tall, peaked T wave equal or more than 2.5 mm in amplitude in lead II,III or aVF (P pulmonale).
   
3. Mean P wave axis shifted to the right( more than +70 degree).

1. "Voltage criteria": 1-R or S wave in limb lead equal or more than 20mm 2-S wave in V1,V2 or V3 equal or more than 30mm 3-R wave in V4,V5 or V6 equal or more than 30mm.
   
2. Depressed ST segment with inverted T waves in lateral leads(strain pattern ;more reliable in the absence of digitalis therapy.
   
3. Left axis of -30 degree or more.
4. QRS duration equal or more than 0.09 sec.
5. Time of onset of the intrinsicoid deflection ( time from the beginning of the QRS to the peak of the R wave ) equal or more than 0.05 sec in lead V5 or V6.

1. Tall R waves over the right precordium and deep S waves over the left precordium ( R:S ratio in lead V1 > 1.0)
   
2. Normal QRS duration (if no bundle branch block)
   
3. Right axis deviation.
   
4. ST-T "strain" pattern over the right precordium.
   
5. Late intrinsicoid deflection in lead V1 or V2.

Category: Cardiology Notes