What is appropriate discordance?
What is appropriate discordance?
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.
What does discordant mean in ECG?
ST-elevation is “excessively discordant” when the ST-elevation (measured at the J-point) is > 0.25 or 25% the depth of the S-wave. ST-depression is “excessively discordant” when the ST-depression (measured at the J-point) is > 0.3 or 30% the height of the R-wave.
What is concordant and discordant in ECG?
3,4 By definition, the electrocardiographic pattern of concordant LBBB (cLBBB: T-wave orientation concordant with QRS complex) is characterized by a positive/diphasic T wave in leads I and V5 or V6 (at least in two of these three leads), whereas the electrocardiographic pattern of discordant LBBB (dLBBB: T-wave …
What is concordant and discordant ST elevation?
ST elevation ≥1 mm in a lead with a positive QRS complex (ie: concordance) – 5 points. concordant ST depression ≥1 mm in lead V1, V2, or V3 – 3 points. ST elevation ≥5 mm in a lead with a negative (discordant) QRS complex – 2 points.
What does EFW discordance mean?
Twin growth discordance is a term used in obstetric imaging to describe a significant size or weight difference between the two fetuses of a twin pregnancy. To be classified as a growth discordance, some consider that the estimated fetal weight (EFW) of the smaller twin should fall under the 10th centile.
What does discordant mean in genetics?
Discordance, in genetics typically means that a similar trait is not shared between twin members. Studies of twins have shown that genetic traits of monozygotic twins are fully concordant whereas in dizygotic twins, half of genetic traits are concordant, while the other half are discordant.
What is normal discordance in twins?
About 75% of twins exhibit < 15% discordance (concordant), 20% are 15-25% (mildly) discordant, and about 5% are more than 25% (severely) discordant. Higher frequencies and increased severity are seen among triplets.
What does discordant mean in medical terms?
Discordant: 1. Showing discordance, lack of agreement. A couple may be discordant for a sexually transmitted infection, with one partner having it and the other not. 2. In transplantation genetics, between different species.
What is discordance biology?
Discordance: 1. The presence of any given condition such as HIV in only one member of a couple. 2. In genetics, the presence of a phenotype such as asthma in only one members of a twin pair.
What’s the rule of appropriate discordance in ECG?
So these are significantly higher than the normal maximum (of V1-V4) ratio, which is about 0.10. Rule of appropriate discordance: ST segments in all leads should be discordant to the majority of the QRS. Smith rule: Discordance should be proportional to the QRS, with an ST/S or ST/R ratio no greater than 0.25.
What makes an ECG abnormal in the context of LBBB?
Other features on this ECG that are abnormal in the context of LBBB (but not considered “positive” Sgarbossa criteria) are the pathological Q wave in lead I and the concordant ST depression in the inferior leads III and aVF. This constellation of abnormalities suggests to the authors that the patient was having a high lateral infarction
When does an EKG show inappropriate concordance?
Now, when the EKG shows inappropriate concordance (J-point and ST-segment elevation in positive leads, and J-point and ST-segment depression in negative leads), there is a 90% likelihood that the patient is having a STEMI.
What is excessive discordance in the middle of a beat?
In the beat on the right, you’ll note inappropriate concordance in a lead with a negative QRS (Sgarbossa Criteria B). Inappropriate concordance of ≥ 1 mm is highly predictive of STEMI. The middle beat illustrates Sgarbossa Criteria C, ≥ 5 mm excessive discordance.
