Original Article: Acute Chest Pain in Adults: Outpatient Evaluation
Issue Date: December 15, 2020
See additional reader comments at:https://www.aafp.org/afp/2020/1215/p721.html
To the Editor: The article by McConaghy and colleagues does not address the importance of the initial electrocardiogram (ECG). The article addresses the assessment and management of patients who present to a primary care setting for chest pain; however, the first word in the title of this article is “acute,” which indicates the very different concern of assessing the patient for acute coronary syndrome (ACS). Assuming the patient is hemodynamically stable, the most important initial assessment tool for a patient with acute chest pain is the first ECG, performed as soon as possible after the patient presents for evaluation. Although most patients with true “acute” chest pain present to an emergency department—clinicians working in primary care settings will, on occasion, be the first to evaluate a patient with true ACS, and they must be ready for the occasional patient who presents to an ambulatory setting with an acutely evolving event.
The article states that ECG findings on this initial ECG in the office that “…increase the likelihood of ACS include ST segment elevation, new-onset left bundle branch block, presence of Q waves, or new T-wave inversions.” The single reference cited for this statement was written in 1983 and is outdated.1,2 Physicians must look for acute ECG changes of any kind that temporally occur in association with a history of new or recent chest pain. While impossible to fit into a single paragraph the constellation of ECG findings that suggest a patient with a history of “acute” chest pain requires immediate hospitalization to promptly rule out an acute event—the concept is to assess “patterns of leads,” including ST segment depression, reciprocal changes in other lead areas, and a series of other ECG findings that, taken together, suggest recent or acute coronary disease.1,2 Limiting oneself to looking for ST elevation, new T-wave inversions, left bundle branch block, and/or Q waves misses a significant proportion (if not the majority) of patients with “acute” chest pain who may have ACS (including acute or recent coronary occlusion) and who need immediate evaluation.1,2
In Reply: We appreciate Dr. Grauer's comments. Our article intended to provide an overview of the most common causes of chest pain. Although a minority of patients presenting with chest pain to primary care clinics have a life-threatening cause,1 ruling out acute coronary syndrome (ACS) is essential. Twelve-lead electrocardiography (ECG) is the most critical initial outpatient diagnostic test to evaluate patients presenting with chest pain. As indicated in Dr. Grauer's letter, several ECG patterns in addition to those we highlighted may be indicative of ACS, including reciprocal ST segment changes and ST segment depression. Another ECG finding that could be important is Wellens syndrome, which is a biphasic or deeply inverted T-wave in the precordial leads (commonly V2-V3).2 Wellens syndrome may indicate critical stenosis of the left anterior descending artery.
The article by Aslanger, et al., referenced in Dr. Grauer's letter to the editor, highlights that cases of acute coronary occlusion (ACO) are missed using the classic definition of ST segment elevation.3 The article notes that “…minor STE [ST-segment elevation] not fulfilling STEMI [ST-segment elevation myocardial infarction] criteria, STE disproportionate to preceding QRS, unusual patterns with contiguous leads showing opposite ST deviations and some patterns not showing STE at all” may correlate with ACO.3 Therefore, several ECG changes may indicate ACO. Although identifying more subtle ECG changes is important, the practical utility of that approach in patients presenting to the outpatient primary care setting is unclear. In the review by Aslanger, et al., the ECGs were reviewed by two cardiologists more experienced in interpreting ECGs than the average physician. The authors of the study note that “…ECG classifications may change significantly according to the experience of ECG interpreters. An obstacle to the widespread application of the ACOMI [acute coronary occlussion myocardial infarction]/non-ACOMI concept is its dependence on better ECG interpreting skills, which may be hard to achieve in the real clinical world, but this is an unavoidable necessary step for improvement.”3 Widening the criteria for ECG changes that suggest a cardiac cause of acute chest pain will likely increase the sensitivity of identifying ACO but may reduce specificity and increase false positives.