Atrial flutter
A characteristic 'sawtooth' or 'picket-fence' waveform of an intra-atrial re-entry circuit usually at about 300 bpm.

Atrial fibrillation with rapid ventricular response

Irregularly irregular ventricular rhythm.
Sometimes on first look the rhythm may appear regular but on closer inspection it is clearly irregular.

Ventricular fibrillation

bizarre, irregular, random waveform
no clearly identifiable QRS complexes or P waves
wandering baseline
A 12 lead of Ventricular fibrillation should not usually be taken ... for obvious reasons. Instead of continuing to record the ECG you should check the patient's pulse and reach for the defibrillator!



Ventricular tachycardia

A wide QRS tachycardia is VT until proven otherwise (1). Features suggesting VT include:-
evidence of AV dissociation
independent P waves
capture or fusion beats
beat to beat variability of the QRS morphology
very wide complexes (> 140 ms)


the same morphology in tachycardia as in ventricular ectopics
history of ischaemic heart disease
absence of any rS, RS or Rs complexes in the chest leads (2)
concordance (chest leads all positive or negative)

Sinus tachycardia


P wave rate greater than 100 bpm