![]() ![]() Set Re-ECG tracings: on slowing the ventricular rate, one should make an effort to visualize atrial flutter with more clarity.Slow the ventricular rate by carotid massage / adenosine whenever needed.Is there any transient short spell of atrial flutter visible anywhere on ECG? Scrutinize every lead of 12 surface ECG to find out the points in favor of ‘Bix rule’, is already mentioned.Suspect any supraventricular tachycardia around 150/min to be atrial flutter / atrial tachycardia with 2:1 AV conduction, unless and until disapproved. ![]() SVT with 2:1 AV conduction, the first P’ may be visible midway between two ventricular complexes while the next one is probably lurking within the next QRS complex.Ī methodical approach to Bix rule: My mnemonic – Six ‘S’.Waves of atrial tachycardia with higher rate might also be conducted with 2:1.These flutter waves, especially of newer onset are conducted with 2:1 through AV node resulting in ventricular rate 125-175/min, on average around 150. Atrial flutter waves occur at about 250-350/min usually around 300.Thus, with 2:1 AV conduction one atrial beat is allowed to pass through AV node in a sequential way P-QRS-T, but the next activated non-passed atrial beat is just coincidentally coming at a time of QRS so it is hidden within.īix rule – know the breaking point of rhythm pattern on ECG The decremental conduction across AV Node does not usually tolerate supraventricular increment beyond a limit if directly imposed upon it – the comfortable ventricular zone is 150 bpm, so is due to 2:1 AV conduction. Saw-tooth appearance without intervening isoelectric lineĪtrial tachycardia: Enhanced Automaticity (others- triggered or micro entry).This rule is mainly helpful in identifying atrial flutter with 2:1 AV conduction but also helpful in atrial tachycardia with 2:1 conductionĪ basic concept of atrial flutter and atrial tachycardia The appreciation of ‘Bix rule’ opens a door while interpreting SVT.īix rule – If one is dealing with supraventricular tachycardia in which visible P’ wave is situated midway between two ventricular complexes, there will be a probability that there is a P’ wave lurking within the next QRS complex. And one starts to feel that regular practicing is the starting point of the practical implication of whatever knowledge one possesses. If one thinks over and over almost every time while encountering a rhythm of SVT and adopts ‘Bix rule’ as a habit to pickup the P’ wave situated midway between two ventricular complexes – one may become a Rockstar picking up an atrial flutter / atrial tachycardia with 2:1 conduction, otherwise this is being missed.(V1 is the most useful lead in view of uncertainty, also excellent lead for characterizing atrial activity).Yash Lokhanwala, eminent cardiologist: Atrial tachycardia with IVCD of LBB type. Narendra Kumar, eminent cardiologist – Atrial tachycardia (long RP interval) Heart rate = 150/min, midway P’ obvious over V1 with long RP interval (other findings – low voltage in limb leads, interpolated ventricular premature beat occasional and single over precordial leads).
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