see also: [[Atrial Flutter]], [[Atrial fibrillation]], [[Ventricular Tachycardia#Differentiation between VT and SVT|VT vs SVT]] | | AVNRT | Atrial flutter | | --------------- | ----------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------ | | pathophysiology | functional re-entrant circuit within AV node | re-entrant circuit in right atrium leading ot atrial rate of ~ 300 BPM and ↑ ventricular rate dependent on AV conduction | | ECG | - rate 140 - 240<br>- retrograde p waves, especially II, III, aVF | - regular atrial activity at 300 BPM<br>- vent rate often ~150<br>saw tooth pattern of inverted p waves, espec inferior | | Causes | - idiopathic<br>- stimulants, coffee, drugs | HTN, lung disease, obesity, PE, hyperthyroidism | | ED Tx | - vagal manoevres<br>- adenosine 6mg IV<br>- verapamil 5mg IV | IV beta blockers (eg metoprolol)<br>treat underlying cause |