The Sgarbossa criteria are a set of electrocardiographic (ECG) data used to identify acute myocardial infarction (MI) in patients with left bundle branch block (LBBB) or ventricular paced beats. These factors are important for identifying patterns of acute coronary occlusion (ACO) that might be overlooked due to existing heart flow problems.
Dr. Elena Sgarbossa first introduced these recommendations in 1996. They have been improved over time and are now widely used in emergency medicine and heart care. It is important to quickly and accurately spot heart attacks in these people to provide fast care and improve their health outcomes.
Why the Sgarbossa Criteria Are Important?
ST-segment elevation in certain regions on an ECG diagnoses ST-elevation myocardial infarction. LBBB and pacemaker patients may have incorrect STEMI ECGs. Having LBBB changes the normal QRS complex and impacts how the heart recovers after beating. This can hide the typical signs of heart problems, like ST-segment elevation or sadness. Doctors may find it difficult to tell the difference between a normal LBBB rhythm and a real heart attack.
Not identifying and diagnosing acute coronary syndromes (ACS) soon can lead to inadequate treatment and poorer health. Detecting STEMI patients might be difficult without precise criteria, preventing them from receiving prompt treatment. The Sgarbossa recommendations are beneficial because they give a clear and evidence-based technique to identify heart attacks in LBBB or pacemaker patients.
This lets doctors make faster judgments and administer reperfusion therapy.
Parts of the Original Sgarbossa Criteria
The Sgarbossa criteria use three specific ECG signs, each given points, to help identify the chance of a heart attack in patients with left bundle branch block (LBBB) or those with a ventricular-paced heartbeat. Dr. Sgarbossa’s original standards highlight three important findings:
Concordant ST Elevation
This is the most detailed criterion in the Sgarbossa scoring method. This happens when the ST section is raised by 1 mm or more in a lead that matches the direction of the QRS complex. A concordant QRS complex shows that both the depolarisation and repolarisation processes in that lead are aligned, making it a strong sign of transmural ischaemia.
If there’s an ST rise of 1 mm or more in the lead, it likely means there is a sudden heart attack, which gives a score of 5 points. This is the most dependable result in the Sgarbossa criteria, especially when compared to other criteria in the system.
Concordant ST Depression in V1-V3
If there is a decline in the ST segment of 1 mm or more in leads V1 to V3, it suggests a possible heart injury in the back part of the heart. This can sometimes be hidden if there is a left bundle branch block (LBBB). In the case of posterior MI, ischaemia in the posterior wall of the heart leads to reciprocal changes that are best represented in leads V1-V3.
If there is an ST dip of 1 mm or more in these leads, you get 3 points. This finding shows the presence of a posterior MI that may not be visible in other ECG leads due to the LBBB pattern.
Excessively Discordant ST Elevation
This means there is an ST-segment elevation of 5 mm or more in a lead where the QRS complex is negative. This result is called discordant ST elevation, and it is seen as odd if it goes over 5 mm. This kind of mismatch is rare in normal left bundle branch block and could suggest a heart attack.
The greater the difference between ST elevation and the QRS complex, the more likely there is ischaemia. This finding is worth 2 points in the score system.
Modified Sgarbossa Criteria
In 2012, Dr. Stephen Smith presented changes to the original Sgarbossa criteria to address the limits of the original scoring system, especially its moderate sensitivity. The changes were made to make it easier to identify heart attacks without losing the original level of accuracy.
The new criteria created an ST/S Ratio for inconsistent ST elevation, changing the previous standard of needing a measurement of at least 5 mm to a system based on ratios.
Concordant ST Elevation: The rule for concordant ST elevation hasn’t changed. If there is an ST elevation of 1 mm or more, it still gives 5 points, in the same way as the QRS complex.
Concordant ST depression in V1-V3: This means there is a drop of 1 mm or more in these leads. This rule hasn’t changed, and it still gives 3 points.
ST/S Ratio for Discordant ST Elevation: For Discordant ST Elevation, instead of needing an ST-segment elevation of 5 mm or more, the new rules look at the ST/S ratio. The new criteria say that ST rise is important if it is 25% or more of the depth of the S wave in the lead with a different QRS complex. This change improves the criteria by identifying smaller but important heart damage that the original criteria might have overlooked.
How the Sgarbossa Criteria are Used in Medicine
Emergency departments and heart care practices employ the Sgarbossa criterion to diagnose heart attacks in persons with left bundle branch block (LBBB) or a device-paced heart. Medical applications include:
Early Detection of Myocardial Infarction in LBBB
Left bundle branch block (LBBB) makes heart attack detection difficult. LBBB can mask heart attack ECG signals, making diagnosis tougher. The Sgarbossa criteria help clinicians diagnose and treat left bundle branch block (LBBB) heart attacks faster. Early therapy, such as thrombolysis or PCI, improves patient outcomes.
Benign vs. Pathologic ECG Changes
Not all LBBB ST-segment abnormalities imply myocardial infarction. The Sgarbossa factors help tell the difference between harmless changes in the heart’s electrical activity (often seen in the left bundle branch block) and real signs of heart problems. This reduces the chances of unnecessary treatments or wrong diagnoses.
Helping with Treatment Choices
If a patient gets a score of 3 or more on the Sgarbossa scale, it indicates a heart attack. This means that quick actions like coronary angiography or clot-busting treatment should be taken; this ensures timely care.
Risk stratification for Ventricular-paced rhythms: ECG alterations can mimic LBBB. In pacemaker users, the Sgarbossa criterion can help diagnose cardiac attacks and provide appropriate treatment. This tool is crucial for high-risk ischaemic individuals.
Drawbacks of the Sgarbossa Criteria
The Sgarbossa parameters work well, but they have some limitations:
- Low Sensitivity in Some Cases: The original Sgarbossa criteria may overlook some heart attack cases, resulting in false positives, particularly for smaller heart attacks.
- Reliance on a High Threshold: Relying on a high cutoff of 5 mm for ST elevation might miss smaller but important heart attacks. The new standards try to fix this issue by using a ratio method, but the problem still happens in some cases.
- Subjectivity in Measurement: Measuring ST-segment elevation and QRS discordance can be subjective, meaning that different doctors might read the same ECG differently. This variation can cause differences in how the standards are applied.
Summary
The Sgarbossa factors help doctors find out if a person has a heart attack, especially in those with specific heart rhythm issues like left bundle branch block or artificial heart pacing. Like any diagnostic tool, the Sgarbossa criteria should be used along with professional judgment, patient history, and further tests to ensure an accurate evaluation and the best care for patients.
FAQs
Q1: Why are Sgarbossa criteria used?
Ans: With LBBB or ventricular paced beat, Sgarbossa’s criteria identify myocardial infarction, sometimes referred to as a “heart attack”.
Q2: How accurate are Sgarbossa criteria?
Ans: The original unweighted Sgarbossa criteria have 26.7/86.2% sensitivity/specificity, MSC 60.0/86.0%, Barcelona 53.3/82.2%, and Selvester 46.7/88.3%.
Q3: Is Sgarbossa applicable to RBBB?
Ans: Bundle branch block patterns complicate identification. The right bundle branch block (RBBB) can detect ST elevation, whereas the left bundle branch block (LBBB) requires Sgarbossa and Barcelona criteria.
Reference:
https://www.mdcalc.com/calc/1732/sgarbossas-criteria-mi-left-bundle-branch-block
https://litfl.com/sgarbossa-criteria-ecg-library/
https://www.powerfulmedical.com/blog/sgarbossa-criteria/
https://www.healio.com/cardiology/learn-the-heart/cardiology-review/topic-reviews/sgarbossa-criteria
