Article, Cardiology

Acute myocardial infarction in the setting of left bundle branch block: Chapman’s sign

a b s t r a c t

Acute myocardial infarction (AMI) diagnosis in patients with pre-existing Left bundle branch block can be difficult. Undiagnosed or delayed diagnosis of AMI in these patients can put them at risk of having shock, mechan- ical complications, and death. We present a case of 77-year-old Caucasian male with a known LBBB and coronary artery bypass surgery for coronary artery disease who presented to the emergency department with a chief com- plaint of chest pain and shortness of breath. The patient had recurrent chest pain despite using aspirin, nitroglyc- erine, and morphine. An electrocardiogram (ECG) showed a new notch in the upslope of the R wave in leads I, AVL that indicated a positive Chapman’s sign. Troponin levels were initially normal, but serial troponin showed elevated enzyme giving evidence of acute coronary syndrome (ACS). The patient was started on heparin drip and underwent subsequent coronary catheterization. Physicians should be aware of Chapman’s sign on ECG in pa- tients presenting with chest pain who have baseline LBBB as it might represent myocardial ischemia and warrant emergent treatment for ACS.

(C) 2019

Introduction

The diagnosis of acute myocardial infarction (AMI) can be challeng- ing in the presence of left bundle branch block (LBBB). Emergency med- icine physicians are usually the first to evaluate patients presenting with chest pain (CP) in the emergency department (ED). Patients with AMI with either new or existing LBBB have higher morbidity and mortality [1]. Therefore, the correctly interpreting the electrocardiogram (ECG) in these patients is extremely important as it can affect treatment and subsequently the outcomes.

Case report

A 77-year-old Caucasian male with a history of coronary artery dis- ease (CAD) and severe aortic valve stenosis status post-coronary artery bypass surgery and aortic valve replacement with bovine pericardial valve complicated by a heart block requiring pacemaker implant, pre- sented to the ED with a chief complaint of CP with shortness of breath.

Abbreviations: ACS, Acute coronary syndrome; AMI, Acute myocardial infarction; CAD, Coronary artery disease; CP, Chest pain; ED, Emergency department; ECG, Electrocardiogram; EMS, Emergency medical service; LBBB, Left bundle branch block.

* Corresponding author at: University of Central Florida College of Medicine, Graduate Medical Education, North Florida Regional Medical Center, Suite 101-B Medical Arts Bldg 6400, W Newberry Road, Gainesville, FL 32605, USA.

E-mail address: [email protected] (A. Idris).

The CP started 45 min before calling emergency medical service (EMS) and presenting to the ED. The patient described the pain as sharp, substernal without radiation, constant, at rest, and 10 out of 10 in severity that decreased to 8 out of 10 in severity after EMS gave him aspirin 324 mg and placed a nitroglycerine patch.

Physical exam: The patient was alert, oriented, and in no acute dis- tress except for his chest pain. He had normal vital signs and physical exam except for a well-healed mid-sternal scar due to coronary artery bypass surgery.

ECG: Showed sinus rhythm, left axis deviation, LBBB, prolonged QT/ QTc intervals 484/547 ms (Fig. 1).

Repeated troponin every 3 h showed elevation from 0.023 ng/ml upon presentation to the ED to 0.045 ng/ml followed by 0.292 ng/ml. At 6 h interval, he started having pain again that was relieved by sublin- gual 0.4 mg nitroglycerine twice and one dose of morphine 2 mg. A re- peat ECG was obtained and showed a new notch in the upslope of the R wave in leads I, AVL that indicated a positive Chapman’s sign (Fig. 2).

Due to elevated troponin, the patient was started on heparin drip for acute coronary syndrome (ACS). Subsequent troponin showed evidence of ACS with an increase up to 1.69 ng/ml. Upon starting the heparin, the patient was free of pain. A repeat ECG showed resolution of the Chapman’s sign. He underwent cardiac catheterization that showed well-revascularized coronary disease and likely had a Plaque rupture with spontaneous reperfusion. The patient was treated medically with complete resolution of the chest pain.

https://doi.org/10.1016/j.ajem.2019.158378

0735-6757/(C) 2019

1991.e6 A. Idris et al. / American Journal of Emergency Medicine 37 (2019) 1991.e51991.e7

Image of Fig. 1

Fig. 1. The patient’s 12 lead ECG showed sinus rhythm, left axis deviation, left bundle branch block, prolonged QT/QTc intervals 484/547 ms.

Discussion

LBBB is a common finding in ECG and can be found up to 7% of pa- tients with AMI [2]. With LBBB or during ventricular pacing, the diagno- sis of AMI is challenging because of the left ventricular activation is delayed; the directional change of septal activation from right to left in- stead from left to right; and the secondary ST-T wave changes in LBBB. In the current guidelines, LBBB is not always considered an ST segment elevation myocardial infarction (STEMI) equivalent and should not be

used as a sole diagnostic criteria of AMI. It is recommended to use trans- thoracic echocardiogram, cardiac troponin, the patient’s clinical status and possible cardiac angiography for helping in the diagnosis of AMI [3]. Several signs in the past 60 years have been proposed for diagnosing AMI in LBBB including the widely used Sgarbossa’s criteria [4], Cabrera’s

sign [5], and Chapman’s sign [6].

The original Sgarbossa’s criteria was first described in 1996 using a scale of 0 to 5 to aid in diagnosing AMI in the presence of LBBB [4]. The original Sgarbossa’s criteria has been modified to enhance its

Image of Fig. 2

Fig. 2. The patient’s 12 lead ECG showed a new notch in the upslope of the R wave in leads I, AVL that indicates positive chapman’s signs.

A. Idris et al. / American Journal of Emergency Medicine 37 (2019) 1991.e51991.e7 1991.e7

Chapman’s sign

R >=0.05 S

S

P

T

Q

Chapman’s sign is a notching >= 0.05 s of upslope of the R wave in leads I, AVL or V6

Fig. 3. Chapman’s sign with a notching >=0.05 s of upslope of the R wave in leads I, AVL or V6.

sensitivity which was later validated in a different study [7,8]. According to the modified Sgarbossa’s criteria study, the sensitivity improved from 52 to 91%, but reduced the specificity from 98% to 90%. Despite modify- ing the Sgarbossa’s criteria, it is still not sensitive enough to detect some patients with LBBB and ACS and can have false negative results [9]. Therefore, if Sgarbossa’s criteria is met, it can be helpful in diagnosing AMI, but its absence cannot eliminate the possibility of AMI.

Chapman’s sign is a notching >=0.05 s of upslope of the R wave in leads I, AVL or V6 and was first described in 1957 [6] Fig. 3. It has a low sensitivity, but a high specificity reaching up to 92% [10]. Chapman’s sign can enhance diagnosing AMI in patients who have LBBB and do not meet the original Sgarbossa’s criteria.

Our case showed that the diagnosis of AMI can be challenging in the presence of LBBB and highlights the importance of carefully interpreting the ECG in patients presenting with CP.

Performing serial ECGs in patients with LBBB may be helpful and re- veal evolving changes as seen in our case. Serial ECG changes have been reported to be as sensitive as 67% [11].

Conclusion

A thorough ECG interpretation of all leads and serial ECGs are impor- tant for evaluating patients with cardiac ischemia. Chapman’s sign may be suggestive of AMI in patients with complicated ECGs and can be use- ful to help make therapeutic decisions.

Disclaimer

This research was supported (in whole or in part) by HCA Healthcare and/or an HCA Healthcare affiliated entity. The views expressed in this publication represent those of the author(s) and do not necessarily rep- resent the official views of HCA Healthcare or any of its affiliated entities.

Declaration of Competing Interest

The authors have no conflicts of interest to declare.

References

  1. Newby KH, Pisano E, Krucoff MW, et al. Incidence and clinical relevance of the occur- rence of bundle-branch block in patients treated with thrombolytic therapy. Circula- tion 1996;94(10):2424-8 Nov 15.
  2. Go AS, Barron HV, Rundle AC, et al. Bundle-branch block and in-hospital mortality in acute myocardial infarction. National Registry of Myocardial Infarction 2 Investiga- tors. Ann Intern Med 1998;129(9):690-7 Nov 1.
  3. O’Gara PT, Kushner FG, Ascheim DD, et al. ACCF/AHA guideline for the management of ST-elevation myocardial infarction: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2013;61:e78-140 2013.
  4. Sgarbossa EB, Pinski SL, Barbagelata A, et al. Electrocardiographic diagnosis of evolv- ing acute myocardial infarction in the presence of Left bundle-branch block. N Engl J Med 1996;334:481-7.
  5. Cabrera E, Friedland C. Wave of ventricular activation in left branch block with in- farct; new electrocardiographic sign. Arch Inst Cardiol Mex 1953;23:441-60.
  6. Chapman MG, Pearce ML. Electrocardiographic diagnosis of myocardial infarction in the presence of left bundle-branch block. Circulation 1957;16:558-71.
  7. Smith SW, Dodd KW, Henry TD, et al. Diagnosis of ST-elevation myocardial infarc- tion 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;60:766-76.
  8. Meyers HP, Limkakeng Jr AT, Jaffa EJ, et al. Validation of the modified Sgarbossa criteria for acute coronary occlusion in the setting of left bundle branch block: a ret- rospective case-control study. Am Heart J 2015;170:1255-64.
  9. Shlipak MG, Lyons WL, Go AS, et al. Should the electrocardiogram be used to guide therapy for patients with left bundle-branch block and suspected myocardial infarc- tion? JAMA 1999 Feb 24;281(8):714-9.
  10. Maynard SJ, Menown IB, Manoharan G, et al. Body surface mapping improves early diagnosis of acute myocardial infarction in patients with chest pain and left bundle branch block. Heart 2003 Sep;89(9):998-1002.
  11. Wackers FJ. The diagnosis of myocardial infarction in the presence of left bundle branch block. Cardiol Clin 1987;5(3):393-401 Aug.

Leave a Reply

Your email address will not be published. Required fields are marked *