Mateo_1387 Posted June 5, 2009 Posted June 5, 2009 Another excellent case that illustrates the value of prehospital 12 lead ECGs for rhythm analysis. Wide complex tachycardia, rate of 150, with bifascicular morphology (RBBB/LAFB). Atrial complexes clearly visible in several leads (especially aVR, V1 and V2). The trained eye can identify 2:1 atrial flutter in lead III. Conclusion: 2:1 atrial flutter with bifascicular block (RBBB/LAFB). Treatment: Assuming the patient is hemodynamically stable, supportive care. Not to beat a dead horse, but this is another heart rhythm you wouldn't want to treat with antiarrhythmics, especially if the chief complaint was chest pain or syncope. Tom I agree with the RBBB and LAFB. Underlying rhythm I believe is sinus in origin. I see clear p-waves in lead V2. Because with bifascicular block, A-V conduction is limited to a single fascicle (in this case the left posterior fascicle of the left ventricle). If the chief complaint is syncope, you have to consider that the patient is probably having transient episodes of 3AVB. If the chief complaint is chest pain you have to worry about ischemia of the last remaining fascicle. Either way, you don't want to make the situation worse with an antiarrhythmic which could trigger 3AVB (and wipe out any ventricular escape rhythms). If the patient is stable, that's good! Why mess with a good thing? Tom You could always give a little bit of fluid to treat for dehydration...
FL_Medic Posted June 6, 2009 Author Posted June 6, 2009 Not that I need to do this, but... CLICK HERE FOR THE ANSWER PS... lets not forget the "Insert: SPOILER" option to hide your answers from those who don't want to read them yet.
fiznat Posted June 8, 2009 Posted June 8, 2009 (edited) Could we please have a discussion about bundle and fascicular blocks, the types, identification, and physiology? This is an area I feel I am weak on. Edited June 8, 2009 by fiznat
akroeze Posted June 8, 2009 Posted June 8, 2009 I second this. I'll admit that the extent of my ability to interpret BBBs is the turn signal cheating method. My ability to interpret fascicular blocks is 0. I'd really appreciate a lesson on it too!
Tom B. Posted June 8, 2009 Posted June 8, 2009 fiznat - Rules for RBBB: -Supraventricular rhythm -QRS duration = or > 120 ms (0.12 sec) -Terminal R wave in lead V1 -Terminal S wave in lead I Note that with RBBB the conduction delay is in the second part of the QRS complex (which represents delayed right ventricular depolarization) To identify bifascicular block RBBB/LAFB -Supraventricular rhythm -QRS duration = or > 120 ms (0.12 s) -Terminal R wave in lead V1 -Left axis deviation (upright QRS lead I, negative QRS leads II, III, aVF) Note that RBBB with Q waves from inferior MI can pull the axis left. How do you tell the difference between bifascicular block (RBBB/LAFB) and RBBB with Q waves from inferior MI? You don't. You just identify that it's a bifascicular morphology and move on. To identify bifasicular block RBBB/LPFB (less common) -Supraventricular rhythm -QRS duration = or > 120 ms (0.12 s) -Terminal R wave in lead V1 -Right axis deviation (negative QRS lead I, upright QRS leads III, aVF) Rules for LBBB -Supraventricular rhythm -QRS duration = or > 120 ms (0.12 s) -rS or QS complex in lead V1 -Monophasic R wave (usually notched) in lead I Note that I don't use lead V6 to confirm RBBB or LBBB. That's because lead placement is too variable, and also because LBBB can show an S wave in V6 with RVH (or can be a normal variant). However, LBBB should not have an S wave in lead I. Rules for nonspecific IVCD -Supraventricular rhythm -QRS duration = or > 120 ms (0.12 s) -LBBB in precordial leads and RBBB in limb leads (most common) -Any other morphology not explained by typical RBBB, LBBB, or bifascicular pattern -Suggests hyperkalemia or cardiomyopathy Note that wide complex rhythms not known with certainty to be supraventricular should not be called bundle branch blocks. It's better to say that it's a wide complex rhythm "with RBBB morphology" or "with LBBB morphology" or "with bifascicular morphology" to avoid confusion/mistakes. Tom
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