Journal Feed Weekly Wrap-Up
- Aug 7th, 2021
- Clay Smith
This is a review of the emergency diagnosis and management of myocarditis, which is inflammation of the myocardium leading to cardiac dysfunction.
Why does this matter?
Myocarditis is associated with significant morbidity and mortality, but it can be tricky to diagnose if you don’t suspect it. We cover the AHA statement on pediatric myocarditis tomorrow.
What a heartache you turned out to be…
Myocarditis can be infectious, toxic, or autoimmune. Viral causes are most common in Europe and North America, and Chagas disease is more common in South/Central America. Complications include heart failure, dysrhythmias, fulminant myocarditis (prior JF post here), and dilated cardiomyopathy.
Presentation: Many patients have a preceding viral prodrome. The most common signs/symptoms are tachypnea, tachycardia, and chest pain in pediatric patients and dyspnea in adults. Suspect this diagnosis in patients with suspected ACS or heart failure without typical risk factors or in those with recent infection or suspected sepsis who worsen with IV fluids.
Workup: ED workup includes ECG, laboratory tests (elevated ESR, CRP, troponin, BNP), and CXR. Point-of-care ultrasound is most useful to identify cardiac dysfunction in the ED. Cardiac MRI, catherization, and endomyocardial biopsy usually occur after admission.
Management: These patients require admission. 50% of patients will fully recover, 30% will decompensate, and 20% will require transplant. ED treatment focuses on management of acute heart failure. NSAIDs should be avoided, as they may worsen mortality. Specific therapies vary based on etiology; IVIG is controversial, and immunosuppressants and steroids can be used for giant cell or eosinophilic myocarditis. Mechanical circulatory support may be indicated for severe cases and requires transfer to transplant center.
Diagnosis and Management of Myocarditis: An Evidence-Based Review for the Emergency Medicine Clinician. J Emerg Med. 2021 Jun 6:S0736-4679(21)00312-7. doi: 10.1016/j.jemermed.2021.03.029. Epub ahead of print.
The modified Sgarbossa criteria were significantly more sensitive (81% vs 56%) and just as specific (96% vs 97%) compared to the original Sgarbossa criteria for diagnosis of occlusion myocardial infarction in the presence of ventricular paced rhythms.
Why does this matter?
Diagnosis of myocardial infarction for patients with ventricular paced rhythms is challenging. The usual STEMI criteria on ECG cannot be applied in these scenarios, and recent guidelines have suggested utilizing the original Sgarbossa criteria. Unfortunately, the original Sgarbossa criteria have high specificity but low sensitivity for OMI.
In 2012, Smith et al derived a modified Sgarbossa criteria (MSC) defining excessively discordant ST-elevation relative to the amplitude of the preceding S-wave, which appeared to have higher sensitivity than the original Sgarbossa criteria (OSC). See Figure 1 from the article below which describes the original (unweighted) and modified Sgarbossa criteria. Please note that the concordant ST-depression criterion for the MSC below was expanded to include leads V4-V6 because a dominant QS pattern is frequently seen throughout the precordial leads in paced rhythms. So, how does the MSC actually stack up for patients with ventricular paced rhythms?
Keep up the pace, modified Sgarbossa wins the race!
This was a multicenter, international, observational case-control study from January 2008 to January 2018 for adult patients with ventricular paced rhythms who presented with symptoms concerning for acute coronary syndrome (ACS).
There were 3 main groups in the study. The OMI group was defined angiographically as TIMI grade 0 to 1 flow or angiographic evidence of coronary thrombosis and peak cardiac troponin I ≥10.0 ng/mL or troponin T ≥1.0 ng/mL. There were 2 control groups: the “non-occlusion MI-angio” group consisted of patients who underwent coronary angiography for presumed type I MI but did not meet the definition of OMI, and the “no occlusion MI” control group consisted of randomly selected ED patients without OMI. In total, there were 59 patients in the OMI group, 90 patients in the non-occlusion MI-angio group, and 102 patients in the no occlusion MI group.
Sensitivity for OMI was 81% for the MSC compared to 56% for the OSC. When utilizing the expanded ST-depression criterion to include leads V4-V6, the sensitivity of MSC for OMI improved to 86%. The sensitivity of the original “weighted” Sgarbossa criteria for OMI was even lower at 53%. The MSC criterion of proportionally excessive discordance helped identify 17 (29%) additional OMI patients. Overall, both rules had high specificity for no OMI (96% for MSC vs 97% for OSC). Specificity for the non-occlusion MI-angio group was slightly lower for both groups (84% for the MSC vs 90% for the OSC).
There were several limitations of this study, including the case-control design and variations between study sites. However, the authors noted that any bias should equally affect the MSC and OSC, so the primary results of the study appear to be valid. Based on this data, the modified Sgarbossa criteria seem to more accurately diagnose OMI and appear to be the best electrocardiographic tool for evaluating patients with ventricular paced rhythms and symptoms concerning for ACS.
Electrocardiographic Diagnosis of Acute Coronary Occlusion Myocardial Infarction in Ventricular Paced Rhythm Using the Modified Sgarbossa Criteria. Ann Emerg Med. 2021 Jun 22;S0196-0644(21)00249-3. doi: 10.1016/j.annemergmed.2021.03.036. Online ahead of print.
GRACE-1 offers eight evidence based guidelines to determine which adult patients with recurrent chest pain are low risk and can be safely sent home from the ED.
Why does this matter?
Up to 40% of patients return to the ED with recurrent chest pain, and it’s hard to know what to do. We don’t want to blow them off and miss an MI, but we also don’t want to keep doing expensive tests with high-dose radiation exposure. It would be nice if we could all agree on what constitutes low risk so we could send more patients home. This is a first stab at that. By the way, low risk in this guideline is defined as a HEART score <4 or low risk determination by other validated score, such as the HEART pathway.
Give some GRACE
The authors made eight evidence based recommendations to determine low risk status for patients who have recurrent ED visits for chest pain. For each, I will quote the guideline and add a comment.
“Recommendation 1: In adult patients with recurrent, low-risk chest pain, for >3 h duration we suggest a single, high-sensitivity troponin below a validated threshold to reasonably exclude ACS within 30 days. (Conditional, For) [Low level of evidence].”
Comment: I am looking forward to getting hs-Tn where I work. This is a quick way to rule out ACS if you have it.
“Recommendation 2: In adult patients with recurrent, low-risk chest pain, and a normal stress test within the previous 12 months, we do not recommend repeat routine stress testing as a means to decrease rates of MACE at 30 days. (Conditional, Against) [Low level of evidence].”
Comment: If the patient is already low risk, we really shouldn’t feel pressed to do a stress test anyway, right?
“Recommendation 3: In adult patients with recurrent, low-risk chest pain, there is insufficient evidence to recommend hospitalization (either standard inpatient admission or observation stay) versus discharge as a strategy to mitigate major adverse cardiac events within 30 days. [No evidence].”
Comment: This is an evidence free zone. If a patient repeatedly returns to the ED with chest pain, and there has been no prior stress test or CCTA, it is reasonable to consider admission in my opinion.
“Recommendation 4: In adult patients with recurrent, low-risk chest pain and non-obstructive (<50% stenosis) CAD on prior angiography within 5 years, we suggest referral for expedited outpatient testing as warranted rather than admission for inpatient evaluation. (Conditional, For) [Low level of evidence].”
Comment: This helps clarify a common question about what to do with a prior cath with minor abnormalities.
“Recommendation 5: In adult patients with recurrent, low-risk chest pain and no occlusive CAD (0% stenosis) on prior angiography within 5 years, we recommend referral for expedited outpatient testing as warranted rather than admission for inpatient evaluation. (Conditional, For) [Low level of evidence].”
Comment: This clarifies another perennial question – what is the warranty period after a clean cath?
“Recommendation 6: In adult patients with recurrent, low-risk chest pain and prior CCTA within the past 2 years with no coronary stenosis, we suggest no further diagnostic testing other than a single, high-sensitivity troponin below a validated threshold to exclude ACS within that 2-year time frame. (Conditional, For) [Moderate level of evidence].”
Comment: A recent clean CCTA is helpful – hs-Tn and done.
“Recommendation 7: In adult patients with recurrent, low-risk chest pain, we suggest the use of depression and anxiety screening tools as these might have an effect on healthcare use and return ED visits. (Conditional, Either) [Very low level of evidence].”
Comment: Careful with this. This assumes you have already taken the chest pain seriously and worked it up. Don’t assume anxiety prior to doing your due diligence. That said, chest pain is a common way for anxiety to manifest physically. Just be careful.
“Recommendation 8: In adult patients with recurrent, low-risk chest pain, we suggest referral for anxiety or depression management, as this might have an impact on healthcare use and return ED visits. (Conditional/Either) [Low level of evidence].”
Comment: Well, there you go. If your patient screens positive for depression/anxiety, referral can help them.
Guidelines for reasonable and appropriate care in the emergency department (GRACE): Recurrent, low-risk chest pain in the emergency department. Acad Emerg Med. 2021 Jul 6. doi: 10.1111/acem.14296. Online ahead of print.