My Love for Sgarbossa
ECG (or EKG) is the bane of many local medical students here. Some find it utterly incomprehensible. Others treat it with so little respect that it's simply not worth the effort and time. I, however, fell in love with it. Many thanks to Professor Chia Boon Lock and his book (Clinical Electrocardiography 3rd Edition).
I'm going to discuss the Sgarbossa's criteria and some new additions which Prof Chia did not include in his book, probably not wanting to swamp us medical students with his immense knowledge.
Sgarbossa's criteria is used to detect AMI in people in LBBB
So after doing a little self reading, this is what i have to share: as brief as i can get.
Btw while there is a normal LBBB pattern, LBBB itself is almost never seen in normal people. Its presence should indicate possible underlying pathologies of the heart: ischaemia, infarction, hypertension, cardiomyopathy, degenerative diseases of the conductive system.
So, if you have a patient presenting for the central chest pain, constricting in nature, radiating to L arm and neck, a/w vomiting and diaphoresis with 12L-ECG reading of a normal LBBB, you still request for cardiac markers to be done as the presence of LBBB itself isnt normal! especially so if you can't say for sure if the LBBB is new or old.
Sgarbossa criteria: to help detect an AMI in LBBB
A normal LBBB on 12L ECG:
- Monophasic QS or rS ventricular complexes usually seen in R sided praecordial (V1 esp)
- Slightly notched R wave or M shaped R wave in V5/V6
- Appropriately discordant T wave throughout
An LBBB with changes suggesting AMI:
(i) in Right praecordial leads
- ST elevation >5mm or, if S wave is huge, >1/4 of S wave's depth
- ST depression with discordant T waves
(ii) in Left praecordial leads
- concordant ST elevation >1mm and concordant T waves
Interestingly, a similar pattern is present in detecting AMI in RBBB.
Unlike in LBBB where we talk about the main deflection while discussing concordance or discordance of the T waves, in RBBB we're talking about the terminal deflection.
Normally in RBBB, the T waves are usually discordant to the terminal deflection in (?)all leads
However, should the T waves show inappropriate concordance to the terminal deflection of the QRS wave, then we should suspect AMI.
But like in all cases, the diagnosis of AMI requires 3 things:
1. clinical history (high, moderate, low likelihood)
2. 12 lead ECg
3. cardiac markers
all equally important (look out for atypical chest pain in 3 groups of people: the elderly, post-menopausal women and the diabetic)
Do visit the sites listed under sources. Excellent information, great instruction, sufficient depth. Professional.
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