Sgarbossa's Criteria

[firefighter523]

Bringing in a Pt with chest pain, SOB, NV, pale, cool, diaphoretic skin with a rhythm with a LBBB is very scary, we all know that you must treat for the worst. Has anyone ever given a report to a facility with this scenerio, differentiating it with the use of scarbossa's criteria.

- st elevation of 1mm or more in concordant st segs QRS's,

- st elevation of 5mm or more in discordant st segs QRS's

- st depression in V1,V2,orV3

My second question for the docs, is if you have ever taken a report over the radio consisting of this, and how noteworthy is it?

I find it very interesting......

[AZCEP]

As with any ECG data that is gathered, too many patients are not going to show any outward sign that you will be able to use. For those without a LBBB pattern, you have a less than 50% chance the ECG will have the trademark ST deviations. With a LBBB, it is in the same neighborhood.

Diagnosing acute myocardial infarction in the setting of left bundle branch block: prevalence and observer variability from a large community study.Gula LJ, Dick A, Massel D.

Department of Medicine, University of Western Ontario, London, Canada.

BACKGROUND: Despite the known benefit of thrombolysis it remains under-utilized among eligible patients with acute myocardial infarction (AMI) and left bundle branch block (LBBB). We sought to determine the test characteristics and observer reliability of well-known criteria for the diagnosis of AMI when LBBB is present on the electrocardiogram (ECG). METHODS: Four hundred and fourteen ECGs with LBBB from a large cohort of AMI patients (7.4% of the total) and 85 ECGs with LBBB not in the setting of acute coronary syndromes were interpreted for the presence of the Sgarbossa criteria. RESULTS: Agreement for the various Sgarbossa criteria ranged from only fair to moderate. The three-way comparison kappa values were significantly better for ST depression than for both discordant (P<0.001) and concordant (P=0.001) ST-segment elevation. Concordant ST-segment elevation [6.3%, 95% confidence interval (CI) 4.3-9.1%] and depression (3.1%, 95% CI 1.8-5.4%) were infrequently seen in the setting of AMI and rarely seen otherwise. Discordant ST-segment elevation was seen more frequently (19.0%, 95% CI 15.5-23.1%). Concordant ST elevation and ST depression in V1-V3 were highly specific, but insensitive, for the diagnosis of AMI. The presence of discordant ST elevation was neither sensitive nor specific. CONCLUSION: The low prevalence, poor sensitivity and marked observer variability make the Sgarbossa criteria for AMI in the setting of LBBB less than adequate. Although use of these criteria would be an advance over contemporary practice, it would still fall short among this high-risk subset.

PMID: 12878904 [PubMed - indexed for MEDLINE]

Titre du document / Document title

Electrocardiographic diagnosis of myocardial infarction in patients with left bundle branch block

Auteur(s) / Author(s)

SIU FAI LI (1) ; WALDEN Philip L. (1) ; MARCILLA Oscar (2) ; GALLAGHER E. John (3) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) Department of Emergency Medicine, Albert Einstein College of Medicine, Jacobi Medical Center, ETATS-UNIS

(2) Department of Emergency Medicine, New York-Presbyterian Hospital, New York, NY, ETATS-UNIS

(3) Montefiore Medical Center, ETATS-UNIS

Résumé / Abstract

Study objective: To validate ECG criteria previously proposed by Sgarbossa et al for the detection of myocardial infarction (MI) in patients with left bundle branch block (LBBB) and suspected ischemia. Methods: A retrospective cohort study was performed at an urban teaching hospital. All patients admitted with suspected ischemia and LBBB were eligible. Ml was defined as an elevated creatine kinase (CK) isoenzyme MB (>14 IU/L) that was at least 5% of total CK level. ECGs were interpreted by 2 physicians blinded to patient outcome. Interpreters were asked to rate ECGs for the presence of each of the 3 criteria proposed by Sgarbossa et al: (1) ST-segment elevation greater than or equal to 1 mm concordant with the QRS complex; (2) ST-segment elevation greater than or equal to 5 mm discordant with the QRS complex; and (3) ST-segment depression in leads V[1] through V[3]. Interobserver agreement was assessed. Results: Of 190 eligible patients, 25 (13%) had Ml. Sensitivities of the 3 criteria varied from 0 to 16%, with specificities of 93% to 100%. Only the first criterion demonstrated a clinically useful likelihood ratio (positive likelihood ratio=16 [95% confidence interval 4 to >100]). Patients with new LBBB were more likely to have Ml (relative risk=5.1 [95% confidence interval 2.6 to 10]). Interobserver agreement among ECG interpreters ranged from 93% to 98%. Conclusion: The criteria of Sgarbossa et al cannot be used to exclude Ml in patients with LBBB because of low sensitivities and poor negative likelihood ratios. ST-segment elevation concordant with the QRS complex had a high positive likelihood ratio for identification of Ml. Patients with new LBBB and suspected ischemia are 5 times more likely to have Ml than patients with LBBB of chronic or unknown duration.

Revue / Journal Title

Annals of emergency medicine (Ann. emerg. med.) ISSN 0196-0644 CODEN AEMED3

Source / Source

2000, vol. 36, no6, pp. 561-565 (20 ref.)

This group of criteria haven't adequately demonstrated they will be any more useful than clinical judgement, yet.

[fiznat]

Info on Sgarbossa. I admit I had to look it up too.

Left bundle branch block and pacing can interfere with the electrocardiographic diagnosis of acute myocadial infarction. The GUSTO investigators Sgarbossa et al. developed a set of criteria for identifying acute myocardial infarction in the presence of left bundle branch block and paced rhythm. They include concordant ST segment elevation > 1 mm (0.1 mV), discordant ST segment elevation > 5 mm (0.5 mV), and concordant ST segment depression in the left precordial leads.[56] The presence of reciprocal changes on the 12 lead ECG may help distinguish true acute myocardial infarction from the mimics of acute myocardial infarction. The contour of the ST segment may also be helpful, with a straight or upwardly convex (non-concave) ST segment favoring the diagnosis of acute myocardial infarction.[57]

The constellation of leads with ST segment elevation enables the clinician to identify what area of the heart is injured, which in turn helps predict the so-called culprit artery.

It seems a little too academic to be useful for our purposes. Information like this is nice and all, but I think that in the ED very few docs are truly going to care THAT much about the exact "constellation of ST elevations" and extremely detailed evaluations of morphology when other, more direct assessments are available. Especially in the light of research like what AZCEP posted.

Nothing against you specifically at all, but I feel like a lot of people who use stuff like this are more trying to show off rather than do good for their patient.

[Ridryder 911]

I agree some of this criteria is for academia gloating. It is irrelevant on some of the specifics, when the main point is to treat the suspected AMI and ischemia. There is a time and place for details, usually emergency medicine is not one of those places, rather to see the forest not identify the types of leaves.

Most authors agree that BBB precludes and alters most ST identification of ECG's. Rather the identification of a new LBB and suspected AMI should be the goal. Treatment will be broad based upon clinical findings.

R/r 911

[firefighter523]

Fiz, and Rid, I think you are missing my point. I was trying to get info on whether this information is noteworthy to get a pt with a LBBB, that is hiding an AMI sent strait to the cath lab. That is why I asked a physician to help out with this.

[Doczilla]

Not really. First off, knowing what Sgarbossa's criteria are is one thing, correctly identifying them quite another. As AZCEP and Rid pointed out, the rule is also not that reliable. I would likely feel some amount of disbelief if a medic wanted to activate the cath lab on that alone. I would not make that call on the basis of a radio report from a medic unless it's someone that I have worked closely with and trust implicitly, and even then, I'd probably hold off until I could see the EKG myself.

Cardiology would be unimpressed as well. Until we can show a previous EKG and definite change in the current EKG over baseline or presence of positive cardiac markers in the blood, activation of the cath lab would depend quite a bit on their schedule, time of day, etc.

The bottom line is that reliable identification of acute MI on EKG in the presence of LBBB almost always requires comparison with previous EKG.

'zilla

[emstrainer]

Why do we keep trying to Dumb Down EMS .... If a Paramedic wants to better understand ECG Changes that occur in the setting of LBBB that will better predict STEMI why would we want to discourage this ? Concordant ST Elevation in the setting of LBBB is highly predictive of STEMI and should be an indicator of a patient who will need to be taken to the Cath Lab emergently. If your system has STEMI Alert Protocols for EMS this is definitely a Patient who is both High Risk and would benefit greatly from the EMS Activation of the Cath Lab. Far too often I have seen ED Physicians shrug off a LBBB Patient and defer to Cardiology ....The delay has proven Deadly in at least 2 patients I have seen. Had the Paramedic recognized any of the Sgarbossa's criteria the patients may have had a better outcome.

I applaud you for asking the question...and trying to better understand those ECG Findings that may indicate STEMI in this patient population.

Jason Kinley

Xenia, Ohio

[AZCEP]

Re-read the previous posts. Sgarbossa's criteria are not particularly useful in ruling in, or out, an acute MI in the presence of LBBB.

The question was would this information be useful when given in a report, and said nothing of "dumbing down" anything. The responses already given indicate that those that receive this information from the paramedic will not use it.

[emstrainer]

I'm not sure you are interpreting the study properly .....

Concordant ST Elevation in V1-V3 is very Specific ....... in the setting of LBBB. Just because it is not as sensitive does not make it a benign finding. If they have it ... it's an AMI ... The second study posted describes the low number of LBBB Pt's who properly get their PCI or Intervention ....leading to high Mortality. More reason to try to identify these patients early and get them the proper intervention. To say that ED Docs would just ignore this seems like No Faith in the EMS Provider .... Thats why it seems like we want to dumb down the EMT ... If the Docs dont have faith in the skills of the EMS folks they should invest in helping to educate them. It will equal better patient care .... Not trying to argue with you ...but in systems with AMI Alert Protocols ....These patients should get the benefit of an Alert ...

Jason Kinley

Xenia,Ohio

[Doczilla]

Having worked with Kinley, if he says it's positive, then I'm calling the cath lab.

That said, most providers in our area do not have his level of skill. If I pull the trigger prematurely on activating the cath lab and the cardiologist does not agree with the findings, this may adversely impact our ability to do cardiac alerts in the future. The cardiac alert system works because the cardiologists have faith in the ER docs, and when we say it's the real deal, they move their butts. When a medic calls it in and I make that phone call to activate prior to arrival in the ED, I am showing a certain amount of faith in the medic as well, and sticking my neck out if the medic is wrong. I don't mind doing this for STEMI (and I've been burned several times already), but feel far less comfortable doing it for interpretation by field providers with criteria that are not completely reliable and on EKGs that they are not that practiced reading.

'zilla