Electrocardiogram Manifestation And Its Prognostic Significance In Acute Pulmonary Embolism

Acute pulmonary embolism (APE) is a frequent cause of cardiovascular morbidity and mortality. Timely diagnosis of APE can be challenging and many deaths from APE occur prior to diagnosis. With improved diagnostic and treatment modalities, overall mortality for APE has improved. The European Society of Cardiology recently published a guideline on the diagnosis and management of APE. In this guideline, several diagnostic modalities are carefully discussed in terms of their value in assisting with diagnosis of APE. These include:D-dimer measurement, computed tomographic pulmonary angiography (CTPA), lung scintigraphy, pulmonary angiography, magnetic resonance angiography, echocardiography, and compression venous ultrasonography. The utility of various clinical tools in prognostication is also assessed and it is recommended that this occur via clinical parameters such as hemodynamics, imaging of the RV by echocardiogram or CTPA, and laboratory biomarkers (e.g. BNP, NT-proBNP, Troponin), etc. Of notable absence in the clinical tools for diagnosis and prognostication in the ESC guideline is the role for electrocardiogram (ECG). Though reference is made to potential ECG changes in APE, the relative value of ECG is underreported and is not listed in the recommended modalities suggested to assist with prognostic assessment of APE. ECG is one of the first tests to be performed in the emergency department when a patient presents with cardiac or respiratory symptoms. It is a rapidly interpretable, non-invasive test with minimal associated risk or cost, and it is available in remote areas where modern technology may not be. While no isolated ECG abnormality is definitively associated with PE, certain constellations of ECG abnormalities have been shown to be reasonably specific. Furthermore, mounting evidence suggests that ECG plays a valuable role in prognostication for APE. As such, we performed some researches to evaluate and summarize the ECG manifestation and its prognostic significance in APE.THE FIRST PART:Electrocardiogram patterns during hemodynamic instability in patients with acute pulmonary embolismBackground:The ECG characteristics of patients with APE during hemodynamic instability are not fully described. We have previously demonstrated a new ECG findings with massive APE, namely ST-segment elevation in lead aVR with concomitant ST-segment depression in leads Ⅰ and Ⅴ4 to Ⅴ6. The aim of the study is to investigate the ECG patterns during hemodynamic instability.Methods:We compared the differences between the ECG at baseline and after deterioration during hemodynamic instability in twenty patients with APE.Results:Compared with the ECG at baseline, three ischemic ECG patterns were found during clinical deterioration with hemodynamic instability:ST-segment elevation in lead aVR with concomitant ST-segment depression in leads Ⅰ and Ⅴ4 to V6, ST-segment elevation in leads Ⅴ1 to Ⅴ3/Ⅴ4, and ST-segment elevation in leads Ⅲ and/or Ⅴ1/Ⅴ2 with concomitant ST-segment depression in leads Ⅴ4/Ⅴ5 to V6. Ischemic ECG patterns with concomitant S1Q3 and/or abnormal QRS morphology in lead Ⅴ1 were more common (90%) during hemodynamic instability than at baseline (5%) (p=0.001).Conclusions:Hemodynamic instability in APE is reflected by signs of myocardial ischemia combined with the right ventricular strain pattern in the 12-lead ECG.THE SECOND PART:Correlation between ST-segment Elevation and Negative T Waves in the Precordial Leads in Acute Pulmonary Embolism:Insights into Serial Electrocardiogram ChangesBackground:APE is often misdiagnosed as acute coronary syndrome because of the similarity of the presenting symptoms and of the ECG manifestations. In APE, ST-segment elevation (STE) in leads Ⅴ1 to Ⅴ3/Ⅴ4, mimicking anteroseptal myocardial infarction, is not a rare phenomenon. Negative T waves (NTW) in the precordial leads mimicking the "Wellens’syndrome" is an important ECG manifestation of APE. The evolution of these ECG changes-STE and NTW- in APE has not been thoroughly studied.Methods:we present two patient cases with APE and their evolving serial ECGs to analyze the correlation between STE and NTW.Results:we found that NTW developing later than STE and the persistence of NTW beyond recovery of the right ventricular dysfunction (RVD) and the deepest NTW developing later after the acute event.Conclusions:NTW might represent a "post-ischemic" ECG pattern indicating a previous stage with transmural myocardial ischemia.THE THIRD PART:Electrocardiographic findings in accessory right precordial leads in adults and seniors with notched S waves in lead Ⅴ1-A preliminary studyBackground:Atypical right bundle branch block (RBBB) may present with an rS pattern and notched S wave in lead Ⅴ1. The notched S wave may represent slowed conduction or delayed activation of the right ventricular conduction system or ventricular myocardium.Methods:We retrospectively analyzed the QRS patterns in accessory right precordial leads (from V3R to V5R) in 15 adults/senior individuals with notched S wave in lead Ⅴ1.Results:In the right accessory precordial leads,13 showed triphasic QRS pattern with final R’ wave in their QRS complexes. This QRS pattern in association with notched S wave in lead Ⅴ1 is suggestive of the presence of RBBB (incomplete or complete).Conclusions:A notched S wave in lead Ⅴ1 and in the right precordial accessory leads associated with a final R’ wave suggests the possibility of concealed RBBB (incomplete or complete).THE FORTH PART:Clinical and electrocardiographic characteristics of acute pulmonary embolism with ST elevation in the right precordial leadsBackground:ST-segment elevation (STE) in the right precordial leads is an ECG manifestation of APE; some patients present with concomitant STE in the inferior leads. These patients are often misdiagnosed as acute ST-segment elevation myocardial infarction resulting in unnecessary and inappropriate diagnostic measures and treatment delays. The aims of this study were to describe the clinical and ECG characteristics of APE patients with STE in the right precordial leads and to compare the patients with and without STE in the inferior leads with respect to these characteristics.Methods:We included 42 APE patients presenting with≥0.1mV STE in leads V1-V3/V4. Clinical and ECG characteristics in 15 patients with and 22 without STE in the inferior leads were compared.Results:Of the 42 patients,98% were classified as high or intermediate risk patients,95% presented with RVD on the echocardiogram,79% showed ECG signs of right ventricular strain (RVS) and 83% showed the maximal amplitude of STE in leads Ⅴ1-Ⅴ2. The patients with STE in the inferior leads presented with faster heart rate (131±30 vs.108±21 beats/min, p=0.015), lower systolic blood pressure (107±22 vs.123±26 mmHg, p=0.043), higher incidence of elevated troponin (87% vs.56%, p=0.040) and need to intensify therapy (73% vs.33%, p=0.013) than patients without STE in the inferior leads.Conclusions:STE in the right precordial leads is an ECG manifestation of intermediate to high risk in APE patients. The ECG characteristics include the maximal amplitude of STE in leads Ⅴ1-Ⅴ2 and the RVS pattern. Simultaneous STE in the inferior and right precordial leads is associated with hemodynamic instability and need for intensified therapy.THE FIFTH PART:Diagnosing acute pulmonary embolism masquerading as inferior myocardial infarctionAPE masquerading as inferior myocardial infarction was sporadically reported by several authors. We analyzed the clinical and electrocardiographic characteristics of the 8 patients reported in the English literature. The clinical manifestations included chest pain (37.5%), dyspnea (37.5%), sweating (25%), sinus tachycardia (62.5%) and hemodynamic instability (50%). The majority (62.5%) of the patients presented the right ventricular strain pattern. In conclusion, patients presenting with chest pain and/or dyspnea can be experiencing a range of syndromes, including acute myocardial infarction and APE. The clinician should consider APE in patients with findings consistent with both inferior wall ST-segment elevation myocardial infarction and APE when the ECG demonstrates findings consistent with right ventricular strain.THE SIXTH PART:Significance of ST-segment deviation in patients with acute pulmonary embolism and negative T wavesBackground:Common ECG manifestations in APE include ST-segment deviation (STDV) along with NTW. STDV could occur in three typical ischemic patterns:(ⅰ) the left ventricular (LV) subendocardial ischemic pattern; (ⅱ) the right ventricular (RV) transmural ischemic pattern; and (ⅲ) the LV subendocardial plus RV transmural ischemic pattern. The purpose of this study was to evaluate the relationship of STDV and adverse clinical outcomes and to identify the relationship of relatively normal ECG and favorable clinical outcomes.Methods:Retrospective analysis of electronic charts in APE patients was performed in a tertiary hospital. ECGs on admission were obtained and classified as with or without STDV. Adverse clinical outcomes were defined as need to intensify therapy and 30-day mortality. Relatively normal ECG was defined as without any ST-segment deviations, abnormal QRS morphology in lead V1 and S1Q3T3.Results:From a total of 210 patients with NTW,131 had STDV≥0.1 mV, while 79 did not. Patients with STDV had worse evolution:higher incidence of dyspnea, hypotension, cardiogenic shock, intensification of therapy, and death compared to patients without STDV (p< 0.01 for each variable). The majority (89%) of the patients with STDV presented with one of the three typical ischemic ECG patterns. LV subendocardial ischemic pattern (OR=4.963, p=0.004), RV transmural ischemic pattern (OR=3.128, p=0.021) and LV subendocardial plus RV transmural ischemic pattern (OR=3.036, p=0.017) independently predicted the need to intensify therapy. RV transmural ischemic pattern (OR=4.227, p=0.031) and LV subendocardial plus RV transmural ischemic pattern (OR=4.022, p=0.032) independently predicted 30-day mortality. Compared to the patients with abnormal ECG, the patients with relatively normal ECG had a significant lower incidence of death (0% vs.16%; p=0.001) and need to intensify therapy during hospitalization (6% vs.30%; p=0.002).Conclusions:Ischemic ECG patterns are common ECG manifestations of APE and predict worse evolution and 30-day mortality. Additionally, relatively normal ECGs may associate with favorable clinical outcomes.