Rate: Normal 60-100. Bradycardia <60. Tachycardia >10.
Rhythm: Sinus rhythm is P before every QRS, normal P wave morpology (upright Leads I and II)
Axis: Normal -30 to 90, LAD >90, RAD <-30

RAE: 
-P wave > 2.5mm in height (Lead II)
-Positive first part of P-wave in V1 > 1.5mm

LAE:
-Negative part of P-wave in V1 duration (ms) x depth (mm) larger than 40ms
-P-wave Duration ≥ 120ms (leads I, II, III) + negativity in V1 > 40ms
-P-wave Duration >120ms, and widely notched P-wave (>40ms)

RBBB
1. QRS > 120 ms in adults (>100 ms in children 4-16yo, and > 90 ms <4yo
2. Leads V1 or V2:
a. rsr’ , rsR’ , or rSR’ pattern
b. The R or r deflection is usually wider than the initial R wave.
c. A wide and notched R wave pattern may be seen in lead V1 and/or V2.
3. Leads 1 and V6: S > R in duration OR >40 ms in leads I and V6 in adults.
4. R-wave Peak Time (When a pure dominant R wave with or without a notch is present in V1)
a. Normal in V5/6, but >50 ms in V1

LBBB
1. QRS ≥ 120ms in adults (>100ms children 4-16, >90ms children <4yo)
2. Lateral Leads (I, aVL, V5, V6)
Broad notched/slurred R-wave in LATERAL leads (I, aVL, V5, V6) (Sometimes V5-6 can have RS pattern, due to displaced transition of QRS) Absent q-waves in LATERAL LEADS (I, V5, V6) (aVL may have q) R-wave peak-time WIDE in LATERAL > 60ms in V5-6 (Normal in V1-3) ST and T-waves usually opposite direction of QRS Positive concordance can be normal (Positive T-wave in leads with upright QRS) NOTE: Negative concordance is abnormal. (Depressed ST or T-waves in leads with negative QRS) Axis Deviation can be RIGHT, LEFT, or SUPERIOR