CASE REPORT

Diagnosis of in a Patient With Left and Negative Sgarbossa Criteria

Bryan Beaty, OMS III; David Park, DO

From the Rocky Vista Left bundle branch block complicates electrocardiogram interpretation of University College of acute myocardial infarction (MI) because ST segment elevations, commonly Osteopathic Medicine Southern Utah Campus in used as evidence of MIs, are largely hidden by the repolarization vector. To Ivins, Utah. better diagnose acute MI in cases of left bundle branch block, modified Financial Disclosures: Sgarbossa criteria can be used as a clinical tool to help diagnose or exclude None reported. MI with high specificity and sensitivity. However, while clinical tools are often Support: None reported. helpful, a clinician cannot solely rely on clinical decision-making algorithms. Address correspondence to We describe the case of an 84-year-old man experiencing acute cardiopul- David Park, DO, 255 E Center monary symptoms who was negative for modified Sgarbossa criteria, but St, Ivins, UT 84738-6790. later had a confirmed diagnosis of MI on transfer to a cardiac center. This Email: [email protected] case illustrates the necessity of good clinical judgment and a high index of Submitted suspicion for atypical presentation alongside any diagnostic algorithm. October 25, 2019; accepted J Am Osteopath Assoc. 2020;120(10):655-659. Published online August 4, 2020. November 19, 2019. doi:10.7556/jaoa.2020.107

Keywords: myocardial infarction, Sgarbossa criteria

T elevations on an electrocardiogram (ECG) are difficult to assess in patients with left bundle branch block (LBBB), complicating decision making for physi- S cians when acute myocardial infarction (MI) is in the differential diagnosis. Studies suggest the prevalence of LBBB is up to 1.4% in the general population.1-4 Adults with past myocardial injury may develop LBBB due to ischemic or fibrotic damage to the left bundle branch fibers of the His-Purkinje system.5 ECG changes that meet criteria for LBBB include QRS duration of greater than 120 ms, dominant S wave in V1, broad monophasic R wave in lateral leads (I, aVL, V5-V6), absence of Q waves in lateral leads (I, V5-V6), and prolonged R wave peak time greater than 60ms in left pre- cordial leads (V5-6; Figure 1).6 Damage to the left bundle branch fibers leads to altered pathways for ventricular depolarization and repolarization. This change in the cardiac electrical pathway will affect the vector of the repolarization pattern, such that ST- vectors on ECG will be opposite to the QRS vector. This often hides ST segment changes in the QRS complex. ECG evidence of ST depression, ST elevation, or T wave inversion are indicators of ischemic injury in clinical settings. The Sgarbossa criteria were conceived in 1996 and provided a means to more accurately diagnose an acute MI in patients with a LBBB using a 10-point scoring system.7 A score greater than or equal to 3 was shown to have a summary sensitivity of 20% and specificity of 98% for diagnosis of acute MI in patients with a LBBB

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1. QRS duration of > 120 ms 2. Dominant S wave in V1 3. Broad monophasic R wave in lateral leads (I, aVL, V5-V6) 4. Absence of Q waves in lateral leads (I, V5-V6) 5. Prolonged R wave peak time > 60 ms in left precordial leads (V5-V6)

Figure 1. Electrocardiogram criteria for left bundle branch block.6

according to a 2008 meta-analysis of 11 studies with Report of Case 2,100 patients.8 The Sgarbossa criteria was later An 84-year-old man presented to the emergency depart- revised 2012, with the modified criteria demonstrating ment (ED) of a small community hospital with short- asignificantly higher sensitivity of 91% (from 20%) ness of breath and diaphoresis. Approximately 2 weeks and a slightly lower specificity of 90% (from 98%).9 prior, the patient presented to the same ED and was The modified Sgarbossa criteria include 3 measures, diagnosed with clostridium difficile colitis. He was hos- the presence of any 1 of which highly suggests pitalized for 2 days and treated with antibiotics and an acute MI: (1) ST elevation of 1 mm or more intravenous hydration, then transferred to a skilled concordant as the QRS complex in any lead, (2) ST nursing facility for continued antibiotics and acute depression of 1 mm or more in any of leads V1-V3, rehabilitation. He was discharged home from the or (3) an ST/S ratio of less than −0.25 (Figure 2).9 skilled nursing facility 5 days later. The patient was The absence of all 3 criteria highly suggests no acute home for 1 week when he noticed mild shortness of MI. breath on exertion, which lasted for 3 days until it sud- In this case report, we present an 84-year-old denly developed into severe difficulty breathing 2 hours man with a history of LBBB on ECG and MI before he arrived in the ED by ambulance. The patient despite not meeting any modified Sgarbossa criteria. denied any chest pain, palpitations, cough, fever, or In discussing this case, we hope to show that the chills. His history was otherwise unremarkable. The modified Sgarbossa criteria is a good clinical tool patient also denied any history of previous MI, congest- to help diagnose MI in patients with LBBB, but also ive failure, or other known cardiac disease. There to demonstrate that the use of any single clinical was no history of chronic obstructive pulmonary tool is not foolproof and should not replace clinical disease or other lung disease. The patient’s other past judgement. medical history included diabetes, gastroesophageal

If any of the below criteria are met, patient should be managed for a STEMI: • ST elevation of 1 mm or more concordant as the QRS complex in any lead • ST depression of 1 mm or more in any of leads V1-V3 • ST/S ratio less than −0.25. All measurements made from the PR segment, and ST segment is measured from the J-point.

Figure 2. Modified Sgarbossa criteria for diagnosing acute myocardial infarction in patients with left bundle branch block.9 Abbreviation: STEMI, ST-elevation myocardial infarction.

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Figure 3. A 12-lead electrocardiogram (ECG) from an 84-year-old man who presented to the emergency department with a primary complaint of shortness of breath. Results showed sinus at 112 beats per minute and left bundle branch block. reflux disease, hyperlipidemia, hypertension, and the (>120 ms), and there was a dominant S wave in V1, a recent clostridium difficile infection. His surgical broad monophasic R wave in lateral leads (I, aVL, history was notable for bilateral knee operation and a V5-V6), absence of Q waves in lateral leads (I, right hip replacement. Home medications included lisi- V5-V6),andaprolongedRwavepeaktime(>60ms) nopril, finasteride, lovastatin, lantus, nifedipine, ome- in left precordial leads (V5-6), consistent with an prazole, and tamsulosin. LBBB diagnosis.6 (Figure 1) Evaluating according to On arrival to the ED, the patient was afebrile with a the modified Sgarbossa criteria, there were no ST blood pressure of 158/75 mmHg, pulse of 113 beats per segment elevations in the same direction as the QRS minute, 22 respirations per minute, and pulse oximetry vectors in leads V1, V2, V3, and V4 (negative criter- of 88% on nonrebreather oxygen mask. On physical ion). There were no ST segment depressions in any examination, the patient exhibited severe respiratory dis- leads (negative criterion). The ST/S ratio was not less tress with accessory muscle use, bibasilar rales, scattered than −0.25 in any leads (negative criterion). In short, rhonchi, and scattered wheezes. He was tachycardic with this patient did not meet the modified Sgarbossa criteria a regular rhythm and a 1/6 systolic murmur; 3+ pitting for an MI. Before laboratory test results were available, ankle edema was also noted. No jugular venous disten- the patient was placed on bilevel positive airway pres- sion or pulse deficits were appreciated. The patient’s sure after failure to raise oxygen saturation with nonreb- abdomen was moderately distended, but soft and non- reather mask. Furosemide was given intravenously for tender. There was no tenderness of his lower extremities. suspected acute congestive and fluid over- A 12 lead ECG showed at 112 load. A chest radiography showed central vascular con- beats per minute (Figure 3). Axis and PR intervals gestion and bilateral small pleural effusions (Figure 4). were normal. The QRS interval was prolonged Laboratory test results showed a white blood cell count

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of 17,700 K/cmm (reference range,10 4000-11,000 more than 430,000 patients with confirmed acute MI, K/cmm) with a high percent neutrophils at 86.4% one-third had no chest pain on presentation to the hos- (reference range,10 50-70%). Reflex lactic acid was 2.3 pital. Patients who were older, were women, or had dia- mmol/L (reference range,10 0.7-2.1 mmol/L). Blood betes most frequently presented without chest pain, and urea nitrogen was 43 mg/dL (reference range,10 8-20 patients with MI without chest pain had a 23.3% mg/dL) and serum creatinine was 1.67 mg/dL (reference in-hospital mortality rate compared with 9.3% among range,10 0.70-1.30 mg/dL) with estimated glomerular fil- patients with MI chest pain.11 Another study12 found tration rate of 39 mL/min (reference range,10 90-140 mL/ that the rate of missed acute MI was 2.1% and varied min). B-type natriuretic peptide was elevated at 27,218 from 0% to 29% across various EDs where patients pg/mL (reference range,10 <100 pg/mL), confirming with acute MI were mistakenly discharged. Women, congestive heart failure; serum troponin I was mildly ele- those who listed shortness of breath as their chief com- vated at 0.187 ng/mL (reference range,10 <0.04 ng/mL), plaint, and those with a normal or nondiagnostic ECG suggestive of myocardial injury. Nitroglycerin, aspirin, were less likely to be hospitalized.12 and clopidogrel were administered for suspected myo- Our patient was elderly and diabetic; he presented cardial infarction. After consultation with the receiving with no chest pain. His chief concern was shortness of hospital, the patient was started on a heparin drip and breath and his ECG was nondiagnostic for an MI due transported to a tertiary center for advanced cardiac to LBBB. LBBB makes diagnosing acute MI by ECG work-up and management. The patient was taken dir- difficult because of the hidden nature of ST segment ele- ectly for cardiac catheterization, at which point an acute vations or depressions within the QRS complexes. coronary occlusion was confirmed. Patients with chest pain and new LBBB should be assumed to have ST-elevation MI (STEMI).13 However, this guideline is not helpful when patients do Discussion not present with chest pain or if the chronicity of the MIs often present with classic symptoms of chest pain LBBB is unknown, as in the present case. Serum tropo- 11 and shortness of breath. However, in a review of nin levels are highly sensitive and specific tests for MIs14; however, may be diffi- cult to determine if troponin levels are negative or only slightly elevated, as in cases of very recent MI, since it takes approximately 3 hours for troponin levels to become elevated after myocardial injury. In this case, making a quick, definitive diagnosis of acute MI was difficult. Our case was further confounded withanegativemodified Sgarbossa criteria. To aid clin- icians, the American College of has pro- posed an algorithm for suspected MI in patients with LBBB with negative Sgarbossa criteria.15 This manage- ment algorithm recommends that patients with suspected MI and LBBB (new or old) with acute heart failure or Figure 4. hemodynamic instability undergo emergent percutan- Chest radiography of an 84-year-old man who presented to fi the emergency department with a primary complaint of eous coronary intervention or brinolysis regardless of shortness of breath showed central vascular congestion and Sgarbossa criteria.15 In patients without heart failure or bilateral small pleural effusions. hemodynamic instability, a negative Sgarbossa criteria

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result should be followed up by an echocardiogram and/ 3. Badheka AO, Singh V, Patel NJ, et al. QRS duration on and cardiovascular mortality (from the National 15 or serum cardiac biomarkers. The American College of Health and Nutrition Examination Survey-III). Am J Cardiol. 2013;112 Cardiology algorithm accounts for cases that would be (5):671-677. doi:10.1016/j.amjcard.2013.04.040 missed according to modified Sgarbossa criteria without 4. Kiehl EL, Menon V, Mandsager KT, et al. Effect of left ventricular conduction delay on all-cause and cardiovascular mortality (from the overtreating patients with LBBB. We agree with this PRECISION Trial). Am J Cardiol. 2019;124(7):1049-1055. conservative approach and believe clinical judgement at doi:10.1016/j.amjcard.2019.06.024 the patient bedside is paramount in preventing serious 5. Surkova E, Badano LP, Bellu R, et al. Left bundle branch block: from cardiac mechanics to clinical and diagnostic challenges. EP Europace. complications or death from missing an MI because of 2017;19(8):1251-1271. doi:10.1093/europace/eux061 negative Sgarbossa criteria. 6. Da Costa D,Brady WJ, Edhouse J. and atrioventricular conduction block. BMJ. 2002;324(7336):535-538. doi:10.1136/ bmj.324.7336.535

7. Sgarbossa EB, Pinski SL, Barbagelata A, et al. Electrocardiographic diagnosis of evolving acute myocardial infarction in the presence of left Conclusion bundle-branch block. GUSTO-1 (global utilization of streptokinase and LBBB complicates ECG interpretations in the diagnosis tissue plasminogen activator for occluded coronary arteries) investigators. N Engl J Med. 1996;334(8):48-487. doi:10.1056/ of acute MI because of repolarization abnormalities NEJM199602223340801 hiding ST segment changes consistent with myocardial 8. Tabas JA, Rodriguez RM, Seligman HK, Goldschlager NF. . The modified Sgarbossa criteria provides a Electrocardiographic criteria for detecting acute myocardial infarction in patients with left bundle branch block: a meta-analysis. Ann Emerg 3-criterion algorithm to diagnose MI in patients with Med. 2008;52(4):329-336e1. doi:10.1016/j.annemergmed.2007.12.006

LBBB that is highly sensitive and highly specific (91% 9. Smith SW, Dodd KW, Henry TD, Dvorak DM, Pearce LA. Diagnosis of and 90%, respectively). As such, it is a good tool that ST-elevation myocardial infarction in the presence of left bundle branch block with the ST-elevation to S-wave ratio in a modified should be known and used by clinicians in acute care Sgarbossa rule. Ann of Emerg Med. 2012;60(6):766-776. doi:10.1016/ settings. However, it is possible that this tool could miss j.annemergmed.2012.07.119 an MI, as illustrated in our case. Our patient, who was 10. American Board of Internal Medicine. Laboratory test ranges - January 2020. Accessed July 23, 2020. https://www.abim.org/∼/media/ABIM% elderly and had diabetes presented with a respiratory 20Public/Files/pdf/exam/laboratory-reference-ranges.pdf complaint, demonstrated an LBBB on ECG and did not 11. Canto JG, Shlipak MG, Rogers WJ, et al. Prevalence, clinical fi characteristics, and mortality among patients with myocardial infarction meet the modi ed Sgarbossa criteria for MI. This presenting without chest pain. JAMA. 2000;283(24):3223-3229. patient was treated appropriately with the diagnosis of doi:10.1001/jama.283.24.3223 acute STEMI, confirmed with cardiac catheterization 12. Schull MJ, Vermeulen MJ, Stukel TA. The risk of missed diagnosis of acute myocardial infarction associated with emergency department that found coronary artery occlusion. This case is a volume. Ann Emerg Med. 2006;48(6):647-655. doi:10.1016/j. reminder that high index of suspicion for atypical presen- annemergmed.2006.03.025 tations and good clinical judgement should never replace 13. Francia P, Balla C, Paneni F, Volpe M. Left bundle-branch block--pathophysiology, prognosis, and clinical management. any diagnostic algorithm. Clin Cardiol. 2007;30(3):110-115. doi:10.1002/clc.20034

14. Hamm CW, Bassand JP, Agewall S, et al. ESC guidelines for the management of acute coronary syndromes in patients presenting without References persistent ST-segment elevation: the Task Force for the management of acute coronary syndromes (ACS) in patients presenting without persistent 1. Siegman-Igra Y, Yahini JH, Goldbourt U, Neufeld HN. Intraventricular ST-segment elevation of the European Society of Cardiology (ESC). Eur conduction disturbances: a review of prevalence, etiology, and Heart J. 2011;32(23):2999-3054. doi:10.1093/eurheartj/ehr236 progression for ten years within a stable population of Israeli adult males. Am Heart J. 1978;96(5):669. doi:10.1016/0002-8703(78)90205-3 15. Wilner B, De Lemos JA, Neeland IJ. LBBB in Patients With Suspected MI: An Evolving Paradigm. American College of Cardiology; 2017. 2. Zhang ZM, Rautaharju PM, Soliman EZ, et al. Mortality risk associated www.acc.org/latest-in-cardiology/articles/2017/02/28/14/10/ with bundle branch blocks and related repolarization abnormalities lbbb-in-patients-with-suspected-mi. Accessed August 4, 2019. (from the Women’s Health Initiative [WHI]). Am J Cardiol. 2012;110 (10):1489-1495. doi:10.1016/j.amjcard.2012.06.060 © 2020 American Osteopathic Association

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