ECG
CBC
Chem 7
Magnesium level
Troponin if patient has chest pain
Cardiac Echo - if signs of new/worsening heart failure
Narrow complex tachycardia
Usually regular unless variable AV conduction present
Atrial rate near 300<unk>  waves (sawtooth pattern) in inferior leads
Hallmark is discordance in<unk>  wave direction between inferior leads and V1
AV nodal conduction
1:1 conduction can be unstable
Suggests pre-excitation, sympathetic excess, parasympathetic withdrawal, Class 1C anti-arrhythmic use
2:1 conduction is most common
Suspect<unk>  whenever ventricular rate is 150
conduction >2:1
More commonly even ratio
Suggests AV nodal blocking agents or AV node disease
Variable block
Difficult to distinguish from atrial fibrillation
Look for: R-R interval that is multiple of P-P interval and mathematical relationship between R-R intervals
A-fib is completely irregular with no relationship between intervals
Amal Mattu recommends flipping ECG 180 to easily see inverted P waves or speed machine up to 50 mm/s to stretch out ECG
Usually regular unless variable AV conduction present
Hallmark is discordance in<unk>  wave direction between inferior leads and V1
1:1 conduction can be unstable
Suggests pre-excitation, sympathetic excess, parasympathetic withdrawal, Class 1C anti-arrhythmic use
2:1 conduction is most common
Suspect<unk>  whenever ventricular rate is 150
conduction >2:1
More commonly even ratio
Suggests AV nodal blocking agents or AV node disease
Variable block
Difficult to distinguish from atrial fibrillation
Look for: R-R interval that is multiple of P-P interval and mathematical relationship between R-R intervals
A-fib is completely irregular with no relationship between intervals
Suggests pre-excitation, sympathetic excess, parasympathetic withdrawal, Class 1C anti-arrhythmic use
Suspect<unk>  whenever ventricular rate is 150
More commonly even ratio
Suggests AV nodal blocking agents or AV node disease
Difficult to distinguish from atrial fibrillation
Look for: R-R interval that is multiple of P-P interval and mathematical relationship between R-R intervals
A-fib is completely irregular with no relationship between intervals
Type 1 (Typical<unk> 
Re-entry circuit of right atrium (IVC and tricuspid valve)
Anticlockwise circuit- 90% of cases
Inverted<unk>  waves in inferior leads
Positive<unk>  waves in V1
Clockwise circuit
Positive<unk>  waves in inferior leads
Inverted<unk>  waves in V1
Type 2 (Atypical<unk> 
Does not meet criteria for typical<unk> 
Less amenable to treatment
Re-entry circuit of right atrium (IVC and tricuspid valve)
Anticlockwise circuit- 90% of cases
Inverted<unk>  waves in inferior leads
Positive<unk>  waves in V1
Clockwise circuit
Positive<unk>  waves in inferior leads
Inverted<unk>  waves in V1
Anticlockwise circuit- 90% of cases
Inverted<unk>  waves in inferior leads
Positive<unk>  waves in V1
Clockwise circuit
Positive<unk>  waves in inferior leads
Inverted<unk>  waves in V1
Inverted<unk>  waves in inferior leads
Positive<unk>  waves in V1
Positive<unk>  waves in inferior leads
Inverted<unk>  waves in V1
Does not meet criteria for typical<unk> 
Less amenable to treatment
Atrial flutter
Can be difficult to distinguish from atrial fibrillation
Wide-complex tachycardia
Regular
Narrow-complex tachycardia
AV Node Independent
Atrial fibrillation 
Sinus tachycardia