MIA 2012: Smith SW et al. Diagnosis of ST-Elevation Myocardial Infarction in the Presence of Left Bundle Branch Block With the ST-Elevation to S-Wave Ratio in a Modified Sgarbossa Rule. Ann Emerg Med. 2012 Dec;60(6):766-76

Bottom Line

Why It’s Important for Emergency Medicine

• We’ve been told that you just can’t accurately read cardiac ischemia on an EKG in the setting of a LBBB - even when you apply the Sgarbossa criteria. Its specificity is great (~98%), but with a sensitivity of around 20%, you’re missing a whole lot of acute MI’s. 
• Part of the problem is that LBBBs normally produce an ST-elevation in V1-V4, obscuring your ability to identify anterior MI’s. The original Sgarbossa criteria tries to solve this with its 3rd component: an ST-elevation in excess of 5 mm identifies an acute MI. Well, you can imagine that if the entire EKG suffers from low-voltage, the ST-elevation may not reach 5 mm, and you’d still miss acute MI’s. 
• As with everything in life, proportions should matter more than absolute size! This universal rule applies to the ST-elevations in LBBBs as well. Using a ratio of ST-elevation / S-wave < -0.25 will identify almost twice as many acute MI’s as using an absolute cutoff. 

Major Points

• 33 Study EKGs versus 129 matched controls

	Sens	Spec	+ LR	- LR
Modified Rule	91	90	9.0	0.1
Original weighted	52	98	22	0.5
Original unweighted	67	90	6.6	0.4

Limitations

As you can see, this study is small. And as if the original Sgarbossa wasn’t hard enough to remember, this modified version is not very “user friendly”...

Reviewed by V. Nguyen

Reference
Smith SW, Dodd KW, Henry TD, Dvorak DM, Pearce LA. Diagnosis of ST-Elevation Myocardial Infarction in the Presence of Left Bundle Branch Block With the ST-Elevation to S-Wave Ratio in a Modified Sgarbossa Rule. Ann Emerg Med. 2012 Dec;60(6):766-76. Pubmed

MIA 2012 = Most Interesting Articles series of 2012

MIA 2012: Levy P et al. Subclinical hypertensive heart disease in black patients with elevated blood pressure in an inner-city emergency department. Ann Emerg Med. 2012 Oct;60(4):467-74.e1.

Bottom Line

In asymptomatic black patients who presented to the ED with elevated blood pressure, subclinical hypertensive heart disease was detected in 9 of every 10 patients.

Why It’s Important for Emergency Medicine

Hypertension contributes more than any other factor to racial differences in cardiovascular disease survival. Hypertension is extremely common in blacks- especially poorly controlled hypertension. For many, their underlying hypertensive heart disease won’t be detected until it is at a very advanced stage. Uncontrolled blood pressure means an increased risk for MI’s, CHF, CKD, stroke, blindness, etc. So knowing that up to 90% of asymptomatic hypertensive individuals are at increased risk over time for death or other adverse events means that we need to be more proactive in up-titrating BP meds in the ED, ensuring outpatient follow-up, and empowering patients by educating them on diet, exercise, smoking cessation, and medication compliance.

Major Points

The majority of patients with subclinical hypertensive heart disease had diastolic dysfunction (89.7%). LVH was also common (61%). Evidence of systolic dysfunction with an EF<50 15.5="15.5" in="in" o:p="o:p" of="of" patients.="patients." seen="seen" was="was">

Design

• Prospective cross-sectional study. 
• Included patients who presented to the ED with BP ≥ 140/90 mm Hg on 2 measurements, 35 years or older, no history of cardiac or renal disease, and were asymptomatic from a cardiovascular perspective (ie, no dyspnea or chest pain). 
• Study cohort was a convenience sample of ED patients obtained Mon-Fri 9 am-4 pm. 
• 200 consented to participate in study; 20 failed to return for echo; 19 had prior documented heart disease; 161 included in final study cohort. 
• Hypertensive heart disease was defined as: LVH, systolic or diastolic dysfunction on echo

Criticisms

This study did not include a control group of normotensive individuals so we don’t know how much of the structural heart disease is due to racial differences alone and how much is due to the effects of uncontrolled hypertension. The specific group studied makes the results unable to be generalized to other populations.

Reviewed by A. Odunmbaku

Reference
Levy P, Ye H, Compton S, Zalenski R, Byrnes T, Flack JM, Welch R. Subclinical hypertensive heart disease in black patients with elevated blood pressure in an inner-city emergency department. Ann Emerg Med. 2012 Oct;60(4):467-74.e1. Pubmed

MIA 2012 = Most Interesting Articles series of 2012

MIA 2012: Canto JG et al. Association of age and sex with myocardial infarction symptom presentation and in-hospital mortality. JAMA. 2012 Feb 22;307(8):813-22.

Bottom Line

Chest pain free MI is a very real phenomenon and it is associated with higher mortality - especially in younger women (NRMI study).

Why It's Important for Emergency Medicine

How many times have you seen a relatively normal looking EKG in a young person non-specific symptoms, decided to send off troponins, only for them to come back positive; then the cardiology consult invariably would come down and underplay the severity of the patient because of the absence of chest pain?  

In spite of multiple studies demonstrating that our previously held understanding of the patient characteristics MI is actually not accurate, we still seem to under-treat "atypical" presentations of MI.  This is an observational study pulling from a very large industry sponsored database (the National Registry of Myocardial Infarction) in 1977 hospitals from 1994 to 2006. The characteristics of 2,160,671 patients were analyzed:

• 481,581 women and 661,932 men
• Almost half (42%) of women with MI present to the ED without chest pain vs 30.7% for males, with younger women experiencing higher numbers of chest pain free MI. 
• In addition, younger women who present without chest pain are at an increased risk for death while in the hospital.

 Major points

• The final study population included 1,143,513 MI (with 481,581 or 42.1% women) patients.
• Age, sex, and presence of chest pain were dichotomized at 65 years
• In both men and women in both age groups, mortality rates were higher in the chest pain free group vs the chest pain group.
• MI patients without chest pain were more likely to have diabetes and delay presentation to the hospital, regardless of sex or age, while MI patients with chest pain were more likely to present with STEMI irrespective of age and sex.
• MI patients without chest pain were less likely to receive any acute reperfusion therapies, or medical management such as aspirin, beta blockers and heparin.
• The in-hospital mortality rate was 14.6% for women and 10.3% for men. Younger women without chest pain had a higher mortality rate than men. The authors' adjustments for morbidity and clinical characteristics at presentation seem to account for the majority of the difference in mortality between the sexes in the younger age cohort. Adjustments based on intervention (reperfusion etc.) seem to only account for a modest difference in mortality between sexes, more pronounced in younger women. 

Criticisms

• This study can only shed light into epidemiological factors - it is purely an observational study with no control population
• This study analyzes data from 1994 to 2006. Other recent studies demonstrate that we have achieved dramatic reductions in mortality over the last decade, especially with women.

Reviewed by A Xavier

Reference
Canto JG, Rogers WJ, Goldberg RJ, Peterson ED, Wenger NK, Vaccarino V, Kiefe CI, Frederick PD, Sopko G, Zheng ZJ; NRMI Investigators. Association of age and sex with myocardial infarction symptom presentation and in-hospital mortality. JAMA. 2012 Feb 22;307(8):813-22. Pubmed

MIA 2012 = Most Interesting Articles series of 2012

MIA 2012: Campagna JD, et al. The use of cephalosporins in penicillin-allergic patients: a literature review. J Emerg Med. 2012 May;42(5):612-20

Bottom Line

• For patients with penicillin (PCN) allergies, it is safe to administer third- and fourth-generation cephalosporins (CPN) with no fear of cross reaction. 
• Use of first- and second-generation CPN should only be avoided when the penicillin antibiotic shares structurally similar R1 side chains. 

Why It’s Important for Emergency Medicine

Avoidance of antibiotics considered to be first line treatment in many medical conditions because of concern for allergic cross reaction leads to administration of antibiotics less effective for the disease condition as well as development of antibiotic resistance. 

Major Points

Classic teaching states that PCN allergic patients have a 10% risk of adverse reaction if they are given a CPN antibiotic. This risk is based on flawed studies from contaminated samples used some 50 years ago. Newer studies have shown the true rate of cross reactivity to be 1-2.25% mostly applying to first-generation CPN, and negligible for third- and fourth-generation CPN. EM practitioners should expect a rate of allergy to third- and fourth-generation CPN no greater than in those patients without a PCN allergy.

Design

A medline literature review (from 1950 to present) yielded 406 articles concerning PCN and CPN allergies, of which 27 were relevant to this review. These 27 articles were then evaluated for their level of evidence and methodology by at least two of the authors. 

Criticisms

The articles included in the analysis include only two meta-analyses, and while these articles are outstanding, the majority of the evidence could be considered ‘adequate’.  EM doctors might also be intimidated when considering which first- and second-generation CPN’s have similar R1 side chains to the PCN antibiotic allergy in question. Suffice it to say if your patient has an allergy to amoxicillin or ampicillin, avoid only first- and second-generation CPN antibiotics. But if you’re admitting a PCN allergic patient has community acquired pneumonia, please give them the correct antibiotic.

Reference
Campagna JD, Bond MC, Schabelman E, Hayes BD. The use of cephalosporins in penicillin-allergic patients: a literature review. J Emerg Med. 2012 May;42(5):612-20. Pubmed

MIA 2012 = Most Interesting Articles series of 2012