ECG

Normal Axis

QRS up in I and aVF

Left Axis

QRS up in I, down in aVF

Right Axis

QRS down in I, up in aVF

Right atrial enlargement

P wave in II, III and aVF larger than 2.5mm

left atrial enlargement

V1 terminal p wave drops more than 1mm and is 0.04 sec

biatrial enlargement

in II, III and aVF p wave larger than 2.5mm and 0.12 in duration. In V1, terminal drop of 1mm or more.

Right ventricular enlargement

right axis deviation (down in I, up in aVF), abnormal r wave progression, V1 r wave greater than 7mm or R>S

left ventricular hypertrophy

R wave in AVL + S wave in V3 > 20mm in females or 28mm in males

R wave in aVL is >11mm

S wave in V1 + R in V5 or V6 > 35mm

LVH with strain pattern

ST depression or T wave inversion in lateral leads (I, aVL, V5 and V6)

indicates/treat as AMI if no previous EKG

normal sinus rhythm

p wave before each QRS, regular R-R interval

Sinus tachy

sinus rhythm but >100bpm

Sinus brady

sinus rhythm but <60bpm

Sinus arrythmia

p before each QRS but irregular R-R interval

Junctional rhythm

regular R-R interval but absence of P waves

sinus arrest

one or more missed beats

SVT

abnormal rhythm from above the ventricles

PAC’s

premature atrial contraction, early P wave followed by different QRS, irregular rhythm

PJCs

premature junctional contraction, no or inverted P wave, regular rhythm

PSVT

regular rhythm, very fast 150-250bpm, very common (treated with carotid massage or adenosine)

A flutter

sawtooth pattern, regular atrial rate of 250-300bpm

A fib

irregularly irregular pattern, no p waves, usually tachy and increases stroke risk

MAT

irregular, rate 100-140bpm, different p wave morphologies

PAT

regular rhythm, 100-200 bpm, normal hearts and cannot distinguish from PSVT on ECG but carotid massage doesn’t work.