Original contribution
Electrocardiographic findings in Emergency Department patients with pulmonary embolism

https://doi.org/10.1016/j.jemermed.2004.04.007Get rights and content

Abstract

To assess the pre-study, null hypothesis that there is no difference in the electrocardiogram (EKG) findings for Emergency Department (ED) patients who rule in vs. rule out for suspected pulmonary embolism, a retrospective review of a cohort of patients with pulmonary embolism and their controls was conducted in an academic, suburban ED. Patients who were evaluated in the ED during a one-year study period for symptoms suggestive of pulmonary embolism were eligible for inclusion. All patients with pulmonary embolism and sex- and age-matched controls comprised the final study groups. Two board-certified cardiologists reviewed each patient's EKG. There were 350 eligible patients identified; 49 patients with pulmonary embolism and 49 controls were entered into the study. The most common rhythm observed in both groups was normal sinus rhythm (67.3% cases vs. 68.6 % controls; p = 1.0). Abnormalities believed to be associated with pulmonary embolism occurred with similar frequency in both case and control groups (sinus tachycardia [18.8 % vs. 11.8%, respectively; p = 0.40]), incomplete right bundle branch block (4.2% vs. 0.0%, respectively; p = 0.24), complete right bundle branch block (4.2% vs. 6.0, respectively; p = 1.0), S1Q3T3 pattern (2.1 vs. 0.0, respectively; p = 0.49), S1Q3 pattern (0.0 vs. 0.0), and extreme right axis (0.0 vs. 0.0). New EKG changes were identified more frequently for patients with pulmonary embolism (33.3% vs. 12.5% controls; p = 0.03), but specific findings were rarely different between cases and controls. In our cohort of ED patients, we did not identify EKG features that are likely to help distinguish patients with pulmonary embolism from those who rule out for the disease.

Introduction

Recent investigations suggest that low risk Emergency Department (ED) patients may be screened for possible thromboembolic disease without the use of radiological imaging. Most notably, two distinct and highly sensitive clinical decision rules have been described for this purpose 1, 2. Wells et al. developed an algorithm that includes a scoring system for clinical features to define low-risk patients (1). These patients are subsequently screened for possible pulmonary embolism (PE) by blood D-dimer measurements. Similarly, Kline et al. have designed a clinical algorithm that also incorporates historical and physical examination findings to screen out low-risk patients who may be ruled out for PE by normal D-dimer or alveolar deadspace measurement (2).

The value of other nonradiological tests to screen ED patients for possible thromboembolic disease is not so well understood. Although most patients with symptoms suspicious for cardiopulmonary disease have an EKG during initial evaluation in the ED, the utility of this test for the evaluation of possible PE is not clear. Previous studies designed to evaluate EKG findings associated with PE were limited with respect to the ED population. These studies tended to combine inpatient and outpatient groups for analysis 3, 4, 5, 6, 7, 8. Furthermore, even when ED populations were specifically assessed, the study populations were small and represented only a selected subset of ED patients with PE (9). The purpose of our study was to examine differences in the EKG findings for a more general population of patients who were evaluated exclusively in the ED for possible PE. Specifically, we conducted a retrospective analysis of a series of ED patients with PE versus age- and sex-matched controls to test the null hypothesis that there would be no difference between the EKG findings in ED patients who rule in vs. rule out for PE.

Section snippets

Study design

This was a retrospective review of a cohort of ED patients diagnosed with PE and selected controls.

Setting

The study was conducted in the ED at Mayo Clinic Hospital, an academic, suburban center located in Scottsdale, Arizona. The ED has an annual patient census of approximately 27,000 and an active research program.

Population

All ED patients with symptoms suspicious for PE for whom an Emergency Physician (EP) ordered our institution's computed tomography (CT) protocol to rule out thromboembolic disease were

Results

A total 350 patients were evaluated for PE during the study period; 51 patients with PE and 51 age- and sex-matched controls were identified. EKGs were available for 49 patients with PE whose controls also had EKGs performed at point of care in the ED. Thus, the final study group was comprised of 98 patients. The cases and controls within the study group were similar with respect to mean age (68.5 years, controls vs. 69.4 years cases) as well as the prevalence of chest pain (59% vs. 51%,

Discussion

We conducted this study to determine whether routine electrocardiography might reveal findings that were associated with the diagnosis of PE in ED patients. Most previous investigations that have examined EKG abnormalities observed in patients with thromboembolic disease have focused on non-ED populations. Petrov analyzed the EKGs of 50 patients who ultimately died and had autopsy-confirmed PE (3). He found that 80% of the patients (16 cases) with massive trunk obstruction had a new right

Limitations and future questions

The major limitation of this study is the retrospective design, which may have lead to unintended selection bias. We did not track patients with clinical symptoms suspicious for PE who underwent other diagnostic modalities without having our institution's CT protocol performed. However, this protocol is the diagnostic modality of choice for such patients in our ED, as we do not have the more sensitive ELISA D-dimer test to screen low-risk patients before imaging. Typically, the only patients

Conclusion

In our cohort of ED patients with PE, we did not identify EKG features that are likely to help distinguish these patients from those who rule out for thromboembolic disease.

References (19)

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