#Lbbb vs ivcd serial#

You should be very worried about STEMI here and, if you are reluctant to activate the cath lab, you should at the very least contact your cardiologist for an emergent formal ECHO, and obtain serial ECGs at least every 10-15 minutes to look for evolution. Since the S-wave is only 3 mm, this is proportionally excessively discordant ST elevation. There are about 2 mm of discordant STE in lead III. There is subtle concordant STE in lead aVF, almost 1 mm. Let’s go back to the case we started above. This turned out to not be MI or acute coronary syndrome, as predicted by the rule. Thus, by the unweighted Sgarbossa criteria, it is anterior STEMI, but by the ratio rule, it is non-ischemic. There is 5 mm of discordant STE in lead V2, but the S-wave is 40 mm, for a ratio of 5/40, or 0.125, which is a normal ratio. See figure 2 for an ECG with only sinus tachycardia and LBBB there is no evidence of coronary occlusion, as all ST-T complexes are discordant and appropriately proportional. Sgarbossa herself apparently likes this modification, as she and Cai incorporated it into their very nice algorithm. ≥ 1 lead anywhere with ≥ 1 mm STE and proportionally excessive discordant STE, as defined by ≥ 25% of the depth of the preceding S-wave. ≥ 1 lead of V1-V3 with ≥ 1 mm of concordant ST depression ≥ 1 lead with ≥1 mm of concordant ST elevation So how can you diagnose anterior STEMI in LBBB (unless there is proximal LAD occlusion producing a lateral MI with concordant STE)? Only if that STE is out of proportion. *īecause in LBBB, in leads V1-V3, the QRS is always predominantly negative (deep S-wave), the normal state of a patient with LBBB is ST Elevation in these right precordial leads. Finally, where Sgarbossa found 5 mm of discordant STE to be fairly specific for MI,* we found that an ST segment that is discordantly elevated out of proportion (≥ 25%) to the preceding S-wave was much more sensitive and accurate than a 5 mm absolute cutoff. In LBBB, V1-V3 always have a predominant S-wave (QRS is predominantly negative) and therefore ST depression (STD) in V1-V3 is always concordant ≥ 1 mm of STD in just one of these leads is diagnostic of STEMI (posterior STEMI, in fact). For instance, in lateral leads there is always an upright R-wave and so, if the ST segment is elevated, as it may be in lateral STEMI, it is diagnostic of STEMI if there is just one lead with ≥ 1 mm of concordant STE. Sgarbossa and others have found high specificity of an ST segment that is concordant to the QRS. “Concordance” (ST segment in the same direction as the QRS) is abnormal and indicates STEMI. The diagnosis of STEMI in LBBB is dependent on the “Rule of Appropriate Discordance,” which means that, in normal LBBB (without MI), the ST segment (and usually T-wave) are in the opposite direction (discordant to) the majority of the QRS. There are many reasons for the mistaken idea that MI cannot be diagnosed in the presence of LBBB and they go way back in history, but are beyond the scope of this article. In fact, in normal conduction, ST elevation on the ECG is only about 70% sensitive for the diagnosis of coronary occlusion in LBBB, the modified Sgarbossa criteria likely have a similar sensitivity. There are many physicians, including cardiologists and interventionalists, who still believe that you cannot diagnose STEMI in the setting of left bundle branch block and who are unaware of the Sgarbossa criteria, as well as of the Smith-modified Sgarbossa criteria. Thus, the 2013 guidelines abandoned this recommendation, with a nod toward use of the Sgarbossa criteria, which are well known to be specific, but not sensitive. This was a nearly useless recommendation, as it turns out that only approximately 2-4% of patients who present to the ED with chest pain and new LBBB have acute coronary occlusion, and this is no different than patients who present with old LBBB. Until recently, the guidelines for management of Acute MI recommended cath lab activation for patients with chest pain and new LBBB. The diagnosis of STEMI in the presence of left bundle branch block has been problematic for years. As with all LBBB, there is a small r-wave in V1-V3 and a deep S-wave. There is sinus rhythm with left bundle branch block (LBBB).