Echocardiography in Detecting Mechanical Complications in Acute Coronary Syndrome

Open AccessPublished:August 06, 2020DOI:https://doi.org/10.1016/j.case.2020.07.002

      Highlights

      • ACS encompasses a wide variety of complex symptoms and presentations.
      • The use of echocardiography in ACS assists in early clinical decision-making.
      • Echocardiography can aid in detecting early and late mechanical complications of ACS.
      • Early detection of complications of ACS on echocardiography can improve outcomes.

      Graphical abstract

      Keywords

      Introduction

      Acute coronary syndrome (ACS) is well known for both its breadth of clinical presentations and its complications. Rapid echocardiographic assessment in ACS has assumed a distinguished role in detecting early and late mechanical complications, assessing function, and guiding emergent clinical decision-making. Because of its noninvasive nature, broad accessibility, and rapid acquisition, echocardiography holds particular promise for implementation in a standardized algorithm for initial evaluation.

      Case Presentations

       Case 1

      An 85-year-old woman with a medical history of coronary artery disease who had undergone drug-eluting stent placement presented to the emergency department after experiencing acute-onset chest pain and dyspnea. The patient arrived diaphoretic and hemodynamically unstable, with hypotension and tachycardia. Physical examination revealed jugular venous distension, tachycardia, and cool, clammy extremities. Initial electrocardiography demonstrated ST-segment elevation in leads II, III, and aVF with anterolateral T-wave inversions.
      Given the patient's clinical presentation and electrocardiographic changes, emergent cardiac catheterization was performed. Coronary angiography demonstrated a 90% calcific stenosis of the left main coronary artery extending distally to the ostium of the left anterior descending coronary artery and left circumflex coronary artery. The left anterior descending coronary artery showed a 70% to 80% midvessel stenosis with Thrombolysis in Myocardial Infarction grade 2 flow distally. The right coronary artery was the dominant vessel, with 60% stenosis proximally and 70% stenosis distally and probable distal occlusion of the posterolateral branches. There was a patent stent in the midportion of the vessel with mild in-stent stenosis.
      Although severe three-vessel disease was demonstrated, it was thought that the coronary anatomy could not fully explain the patient's hemodynamic instability. Therefore, urgent transthoracic echocardiography was performed with the patient on the catheterization laboratory table. This revealed a large pericardial effusion with significant thrombus burden suggestive of acute free wall rupture (FWR; Figures 1 and 2, Videos 1 and 2).
      Figure thumbnail gr1
      Figure 1Baseline subcostal view from a prior year demonstrating no evidence of significant effusion or mass.
      Figure thumbnail gr2
      Figure 2Subcostal four-chamber view showing an echogenic mass within the pericardial space anterior to the right ventricle (arrow); the appearance of this mass is consistent with thrombus.
      An intra-aortic balloon pump was placed and inotropic therapy was initiated for concurrent cardiogenic shock. Cardiothoracic surgery was consulted. The patient refused surgical intervention. At her request, her code status was changed to “do not resuscitate—comfort care arrest”. She was transferred to the cardiac care unit, where she continued to deteriorate and died shortly thereafter.
      FWR is a known and feared complication of myocardial infarction (MI) that typically occurs within the first 5 days following MI in about half of cases and within 2 weeks in more than 90% of cases.
      • Pineda-De Paz D.O.
      • Hernández-del Rio J.E.
      • González-Padilla C.
      • Esturau-Santaló R.M.
      • Romero-Palafox J.
      • Grover-Paez F.
      • et al.
      Left ventricular free-wall rupture, a potentially lethal mechanical complication of acute myocardial infarction: an unusual and illustrative case report.
      It results from extensive myocardial tissue necrosis, structural compromise, and eventual perforation of the free wall, rapid accumulation of blood within the pericardium, and ultimately tamponade physiology. In most cases, the left anterior descending artery is involved, but the phenomenon can occur with any coronary vessel. Survival depends primarily upon the rapid recognition of wall rupture and immediate treatment, including advanced circulatory support and surgical consultation.
      Echocardiography can quickly identify mechanical complications of MI in hemodynamically unstable patients. Although many cases of FWR result in death, some cases may be subacute, allowing a small window for treatment. Rapid echocardiographic assessment in a patient with cardiogenic shock can accurately quantify the severity of dysfunction and catch early mechanical complications, thus allowing more timely intervention.
      In this patient's case, the presence of pericardial fluid and thrombus confirmed acute or subacute FWR. Percutaneous revascularization would likely not have changed the outcome. In essence, the earlier the ultrasound assessment is performed in the setting of a mechanical complication, the greater the window of opportunity to undertake a clinically significant intervention.

       Case 2

      A 59-year-old man with a medical history of type 2 diabetes mellitus presented with persistent chest pain starting 1 week prior, as well as hemodynamic instability with a heart rate of 127 beats/min and systemic blood pressure of 51/29 mm Hg. Initial electrocardiography revealed ST-segment elevation as well as large q waves in the anterolateral leads. The patient was emergently intubated and started on vasopressors shortly after arrival.
      Immediate coronary angiography revealed complete thrombotic occlusion of the left anterior descending coronary artery. Hemodynamics on right heart catheterization demonstrated severely elevated pulmonary artery oxygen saturation of 95% consistent with a significant left-to-right shunt. An intra-aortic balloon pump and a Swan-Ganz catheter were inserted for ongoing monitoring and circulatory support.
      Urgent echocardiography demonstrated severely reduced right ventricular systolic function with a large distal ventricular septal defect (VSD) with significant left-to-right shunting (Figure 3, Video 3, Video 4, Video 5). Cardiothoracic surgery was consulted for consideration of closure, but the patient was deemed too unstable for open correction. The following day, the patient underwent percutaneous VSD closure using an Amplatzer septal occluder (Figure 4, Videos 6 and 7). Initially, a VSD occluder was attempted, but because of the large size of the VSD, an atrial septal defect occluder was used. Transesophageal echocardiography was performed and confirmed the closure device to be in a stable position, with significant improvement of the left-to-right shunt.
      Figure thumbnail gr3
      Figure 3Parasternal short-axis view showing a large VSD. Arrow is showing a ventricular septal defect (VSD).
      Figure thumbnail gr4
      Figure 4Apical four-chamber view showing closure of the VSD using an atrial septal defect occluder (arrow).
      Unfortunately, the patient's stay was further complicated by a number of comorbid developments, including both ongoing bleeding as well as pneumonia. He continued to deteriorate clinically, and ultimately, after extensive discussion with the involved family, further care was withdrawn. The patient was extubated and died shortly thereafter.
      Development of a VSD because of myocardial ischemia requires extensive tissue necrosis and perforation, with open communication between the left and right ventricles. It leads to massive left-to-right shunting of oxygenated blood, a profound drop in left ventricular (LV) afterload, reduced cardiac output to the aorta, and resultant cardiogenic shock. As with FWR as previously discussed, the use of echocardiography in a hemodynamically unstable patient can quickly identify this mechanical complication. In addition, a VSD is clinically difficult to distinguish from severe mitral regurgitation by physical examination, which is a much more common confounder of ischemia. Transthoracic echocardiography can identify the size and location of the rupture, providing rapid confirmation of the diagnosis as well as an assessment of the hemodynamic severity of the lesion. Again, the window for treatment is typically small, and rapid surgical or percutaneous closure is indicated if feasible. Early recognition of the complication by right heart hemodynamics as well as rapid ultrasound has the capacity to improve outcomes in these rare cases.

      Discussion

       Advantages

      The rapid use of echocardiography as a clinical decision-making tool in the setting of unstable ACS carries a number of potential advantages. These include early detection of regional wall motion abnormalities (WMAs) confirming a likely ischemic etiology and potentially for anatomic localization, estimation of LV function, early recognition of mechanical complications, and, perhaps most important, recognition of alternate etiologies with the potential to decrease unnecessary invasive procedures. We discuss each of these components in further detail.

       Diagnostic Utility and Clarification

      Echocardiography stands as a fairly rapid, noninvasive, and accurate test to detect early myocardial dysfunction.
      • Cheitlin M.D.
      • Armstrong W.F.
      • Aurigemma G.P.
      • Beller G.A.
      • Bierman F.Z.
      • Davis J.L.
      • et al.
      ACC/AHA/ASE 2003 guideline update for the clinical application of echocardiography: summary article: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (ACC/AHA/ASE Committee to Update the 1997 Guidelines for the Clinical Application of Echocardiography).
      Given that WMAs may manifest before the development of electrocardiographic changes or troponin elevation, it also has the potential for ruling in ischemia early in a patient's clinical course.
      • Douglas P.S.
      • Garcia M.J.
      • Haines D.E.
      • Lai W.W.
      • Manning W.J.
      • Patel A.R.
      • et al.
      ACCF/ASE/AHA/ASNC/HFSA/HRS/SCAI/SCCM/SCCT/SCMR 2011 appropriate use criteria for echocardiography. A Report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, American Society of Echocardiography, American Heart Association, American Society of Nuclear Cardiology, Heart Failure Society of America, Heart Rhythm Society, Society for Cardiovascular Angiography and Interventions, Society of Critical Care Medicine, Society of Cardiovascular Computed Tomography, and Society for Cardiovascular Magnetic Resonance Endorsed by the American College of Chest Physicians.
      Perhaps one of the best uses of echocardiography is in the setting of mixed or atypical presentations of chest discomfort. In this context, it plays a crucial rule in ruling out other known culprits, such as tamponade, endocarditis, aortic dissection, severe valvular disease, hypertrophic cardiomyopathy, acute pulmonary embolism, and pericarditis, for which immediate cardiac catheterization would commit the patient to additional risks without the potential for benefit.
      The focused cardiac ultrasound (FoCUS) examination has been described in the literature as an adjunct to physical examination to emergently recognize structural causes of cardiac dysfunction. The examination focuses on systolic function, chamber sizes, valvular abnormalities, the presence of pericardial effusion or tamponade, and the likelihood of volume responsiveness.
      • Spencer K.T.
      • Kimura B.J.
      • Korcarz C.E.
      • Pellikka P.A.
      • Rahko P.S.
      • Siegel R.J.
      Focused cardiac ultrasound: recommendations from the American Society of Echocardiography.
      The use of echocardiography in this application can both guide and expedite treatment. For patients with cardiogenic shock, the FoCUS examination also serves as a critical guide ahead of mechanical circulatory support.
      One recent study investigating the use of echocardiography in the evaluation of patients with ACS in the prehospital setting demonstrated sensitivity and specificity of prehospital transthoracic echocardiography for non–ST-segment elevation MI of 90.9% and 100%, respectively.
      • Bergmann I.
      • Büttner B.
      • Teut E.
      • Jacobshagen C.
      • Hinz J.
      • Quintel M.
      • et al.
      Pre-hospital transthoracic echocardiography for early identification of non-ST-elevation myocardial infarction in patients with acute coronary syndrome.
      This demonstrates clear potential for the use of echocardiography as a standardized initial evaluation strategy.
      In addition, the FoCUS examination can detect contraindications to certain cardiac mechanical support devices that may have resulted from ACS. Examples include LV Impella placement, which carries a strict contraindication in patients with LV thrombus; intra-aortic balloon pump placement, which has an absolute contraindication to moderate to severe aortic regurgitation; and the TandemHeart, which is contraindicated in the presence of left atrial thrombus. Any suspicion for these findings before or during cardiac catheterization should lead to further evaluation by FoCUS examination before proceeding with mechanical circulatory support.

       Early Identification of Mechanical Complications of MI

      Echocardiography remains the most accessible imaging modality to evaluate for structural cardiac disease. The management of life-threatening complications of ACS, including ventricular FWR, VSD, acute papillary muscle rupture, ventricular aneurysm, cardiac tamponade, and ventricular thrombus formation, benefits from early recognition. Although a thorough physical examination can frequently raise suspicion for one of these complications, it invariably requires confirmation by imaging.
      Any patient presenting with cardiogenic shock and a newly auscultated murmur raises suspicion for a mechanical complication of an MI. An urgent, focused echocardiographic examination offers the possibility of immediate visualization of a VSD, new valvular dysfunction, and pericardial effusion associated with FWR.
      • Smyllie J.H.
      • Sutherland G.R.
      • Geuskens R.
      • Dawkins K.
      • Conway N.
      • Roelandt J.R.
      Doppler color flow mapping in the diagnosis of ventricular septal rupture and acute mitral regurgitation after myocardial infarction.
      Mechanical complications of MI carry a poor prognosis without immediate surgical intervention, so the time to diagnosis remains a critical component of their management. Coronary angiography in most of these scenarios may delay lifesaving surgery.

       Reduction in Unnecessary Cardiac Catheterizations

      Prompt echocardiography in the setting of mixed chest pain presentation as well as secondary troponin elevations has the potential to reduce unnecessary cardiac catheterizations as well as associated procedural morbidity and mortality. Emergent coronary angiography is indicated when a thrombotic or embolic cause of ACS is suspected. In the absence of a strong indication, it may delay other more appropriate therapies and expose the patient to an invasive procedure with concomitant risks.
      In cases such as LV thrombus, echocardiography may both confirm the need for catheterization (i.e., LV thrombus with associated WMA) and decrease complication rates by identifying the need to avoid LV pressure measurements.

       Disadvantages

      The additional step of performing echocardiography up front in cases of suspected mechanical complications also carries potential drawbacks. At many institutions, the ability to obtain an immediate echocardiogram may be limited. If the etiology of ischemia is otherwise clear, any additional imaging reduces time to potential revascularization. Up-front evaluation by echocardiography relies upon a rapidly available technician and reading physician.

       Delaying Time to the Catheterization Laboratory

      Current guidelines for the treatment of ST-segment elevation MI recommend a 90-min door-to-balloon time at a catheterization-capable facility. Any delay for additional imaging should be avoided unless mechanical complications are suspected. A delay in care must be carefully balanced relative to its potential benefit. Patients to be targeted are those with troponin elevation without obvious type 1 MI and those in whom the diagnosis of a suspected mechanical complication will significantly affect outcomes.
      The purpose of the previously established FoCUS examination is to perform a more limited, high-yield examination by a skilled provider. Loss of time remains an unavoidable drawback of adding additional diagnostic testing. A useful test needs to be incorporated into a system of implementation that allows timely performance and interpretation if there is an expectation for meaningful clinical impact (i.e., a reduction in morbidity or mortality).

       Literature Review

      A number of prior studies have investigated the utility of echocardiography as a preliminary diagnostic modality in evaluating patients with chest pain and suspected ACS. The results of these studies have been promising, and implementation up front in emergent ACS has yet to become a standardized protocol.
      • Kontos M.C.
      • Arrowood J.A.
      • Paulsen W.H.
      • Nixon J.V.
      Early echocardiography can predict cardiac events in emergency department patients with chest pain.
      • Kontos M.C.
      • Arrowood J.A.
      • Jesse R.L.
      • Ornato J.P.
      • Paulsen W.H.
      • Tatum J.L.
      • et al.
      Comparison between 2-dimensional echocardiography and myocardial perfusion imaging in the emergency department in patients with possible myocardial ischemia.
      • Sabia P.
      • Afrookteh A.
      • Touchstone D.A.
      • Keller M.W.
      • Esquivel L.
      • Kaul S.
      Value of regional wall motion abnormality in the emergency room diagnosis of acute myocardial infarction. A prospective study using two-dimensional echocardiography.
      • Korosoglou G.
      • Labadze N.
      • Hansen A.
      • Selter C.
      • Giannitsis E.
      • Katus H.
      • et al.
      Usefulness of real-time myocardial perfusion imaging in the evaluation of patients with first time chest pain.
      • Saeian K.
      • Rhyne T.L.
      • Sagar K.B.
      Ultrasonic tissue characterization for diagnosis of acute myocardial infarction in the coronary care unit.
      • Sasaki H.
      • Charuzi Y.
      • Beeder C.
      • Sugiki Y.
      • Lew A.S.
      Utility of echocardiography for the early assessment of patients with nondiagnostic chest pain.
      • Horowitz R.S.
      • Morganroth J.
      • Parrotto C.
      • Chen C.C.
      • Soffer J.
      • Pauletto F.J.
      Immediate diagnosis of acute myocardial infarction by two-dimensional echocardiography.
      • Peels C.H.
      • Visser C.A.
      • Kupper A.J.
      • Visser F.C.
      • Roos J.P.
      Usefulness of two dimensional echocardiography for immediate detection of myocardial ischemia in the emergency room.
      • Mohler E.R.
      • Ryan T.
      • Segar D.S.
      • Sawada S.G.
      • Sonel A.F.
      • Perkins L.
      • et al.
      Clinical utility of troponin T levels and echocardiography in the emergency department.
      Table 1 reviews nine studies that measured the accuracy of echocardiography as a predictor of cardiac events by assessing the presence and absence of WMAs. The primary end points of these studies range from major end points such as MI to revascularization, angiographic findings of coronary artery disease, and abnormal study findings.
      • Sabia P.
      • Afrookteh A.
      • Touchstone D.A.
      • Keller M.W.
      • Esquivel L.
      • Kaul S.
      Value of regional wall motion abnormality in the emergency room diagnosis of acute myocardial infarction. A prospective study using two-dimensional echocardiography.
      ,
      • Mohler E.R.
      • Ryan T.
      • Segar D.S.
      • Sawada S.G.
      • Sonel A.F.
      • Perkins L.
      • et al.
      Clinical utility of troponin T levels and echocardiography in the emergency department.
      ,
      • Lewis W.R.
      Echocardiography in the evaluation of patients in chest pain units.
      Table 1Prior studies investigating the correlation between WMA and cardiac events using echocardiography
      • Lewis W.R.
      Echocardiography in the evaluation of patients in chest pain units.
      AuthorYear publishedSample sizeWMAsAcute cardiac events, present/absentPPV, %NPV, %
      Kontos et al.
      • Kontos M.C.
      • Arrowood J.A.
      • Paulsen W.H.
      • Nixon J.V.
      Early echocardiography can predict cardiac events in emergency department patients with chest pain.
      1998260Present41/5344
      Absent4/16298
      Kontos et al.
      • Kontos M.C.
      • Arrowood J.A.
      • Jesse R.L.
      • Ornato J.P.
      • Paulsen W.H.
      • Tatum J.L.
      • et al.
      Comparison between 2-dimensional echocardiography and myocardial perfusion imaging in the emergency department in patients with possible myocardial ischemia.
      1998130Present15/2934
      Absent6/8093
      Sabia et al.
      • Sabia P.
      • Afrookteh A.
      • Touchstone D.A.
      • Keller M.W.
      • Esquivel L.
      • Kaul S.
      Value of regional wall motion abnormality in the emergency room diagnosis of acute myocardial infarction. A prospective study using two-dimensional echocardiography.
      1991169Present27/6031
      Absent2/8098
      Korosoglou et al.
      • Korosoglou G.
      • Labadze N.
      • Hansen A.
      • Selter C.
      • Giannitsis E.
      • Katus H.
      • et al.
      Usefulness of real-time myocardial perfusion imaging in the evaluation of patients with first time chest pain.
      200498Present19/290
      Absent18/5977
      Saeian et al.
      • Saeian K.
      • Rhyne T.L.
      • Sagar K.B.
      Ultrasonic tissue characterization for diagnosis of acute myocardial infarction in the coronary care unit.
      199460Present22/388
      Absent2/3394
      Sasaki et al.
      • Sasaki H.
      • Charuzi Y.
      • Beeder C.
      • Sugiki Y.
      • Lew A.S.
      Utility of echocardiography for the early assessment of patients with nondiagnostic chest pain.
      198646Present17/194
      Absent6/2279
      Horowitz et al.
      • Horowitz R.S.
      • Morganroth J.
      • Parrotto C.
      • Chen C.C.
      • Soffer J.
      • Pauletto F.J.
      Immediate diagnosis of acute myocardial infarction by two-dimensional echocardiography.
      198265Present34/294
      Absent2/2793
      Peels et al.
      • Peels C.H.
      • Visser C.A.
      • Kupper A.J.
      • Visser F.C.
      • Roos J.P.
      Usefulness of two dimensional echocardiography for immediate detection of myocardial ischemia in the emergency room.
      199035Present22/485
      Absent3/1482
      Mohler et al.
      • Mohler E.R.
      • Ryan T.
      • Segar D.S.
      • Sawada S.G.
      • Sonel A.F.
      • Perkins L.
      • et al.
      Clinical utility of troponin T levels and echocardiography in the emergency department.
      199892Present27/0100
      Absent28/3757
      The positive predictive value (PPV) has wide variability from 31% to 100%, but it is important to note that PPV correlates with low-risk and high-risk patients. Conducting echocardiography for the assessment of ACS in a high-risk population, as in a study by Mohler et al.,
      • Mohler E.R.
      • Ryan T.
      • Segar D.S.
      • Sawada S.G.
      • Sonel A.F.
      • Perkins L.
      • et al.
      Clinical utility of troponin T levels and echocardiography in the emergency department.
      reveals high PPV in high-risk patients. This study identified all patients with new WMAs; of those, MI was identified in 43%, for a PPV of 100% and a negative predictive value (NPV) of 57%.
      However, in low-risk populations, initial echocardiography seems to be less predictive. In a study by Sabia et al.,
      • Sabia P.
      • Afrookteh A.
      • Touchstone D.A.
      • Keller M.W.
      • Esquivel L.
      • Kaul S.
      Value of regional wall motion abnormality in the emergency room diagnosis of acute myocardial infarction. A prospective study using two-dimensional echocardiography.
      who had a lower risk population, the overall prevalence of cardiac events was 17%, giving echocardiography a PPV of 31% and an NPV of 98%. In addition, Kontos et al.
      • Kontos M.C.
      • Arrowood J.A.
      • Paulsen W.H.
      • Nixon J.V.
      Early echocardiography can predict cardiac events in emergency department patients with chest pain.
      found that the PPV and NPV between echocardiography and electrocardiography in the low-risk population were similar, with PPV of 44% and 60% and NPV of 98% and 44%, respectively. Overall, echocardiography is more useful in evaluating for ACS in moderate- to high-risk populations. Its value in low-risk populations is nonsuperior to that of standard electrocardiography.

       Prior Studies Regarding the Use of Echocardiography in Patients with ACS

      Most of the studies previously published evaluating the utility of early echocardiography in patients with ACS were completed by cardiac sonographers or cardiologists.
      • Kontos M.C.
      • Arrowood J.A.
      • Paulsen W.H.
      • Nixon J.V.
      Early echocardiography can predict cardiac events in emergency department patients with chest pain.
      ,
      • Sabia P.
      • Afrookteh A.
      • Touchstone D.A.
      • Keller M.W.
      • Esquivel L.
      • Kaul S.
      Value of regional wall motion abnormality in the emergency room diagnosis of acute myocardial infarction. A prospective study using two-dimensional echocardiography.
      ,
      • Fleischmann K.E.
      • Lee T.H.
      • Come P.C.
      • Goldman L.
      • Cook E.F.
      • Caguoia E.
      • et al.
      Echocardiographic prediction of complications in patients with chest pain.
      However, one prospective study did show that basic echocardiography training for emergency department physicians greatly improved their ability to interpret WMAs.
      • Kerwin C.
      • Tommaso L.
      • Kulstad E.
      A brief training module improves recognition of echocardiographic wall-motion abnormalities by emergency medicine physicians.
      Two previous case series evaluating the use of point-of-care echocardiography by emergency department physicians concluded that echocardiography can provide a rapid detailed assessment of WMAs that may help speed clinical decision-making.
      • Frenkel O.
      • Riguzzi C.
      • Nagdev A.
      Identification of high-risk patients with acute coronary syndrome using point-of-care echocardiography in the ED.
      ,
      • Yee S.
      • Swaminathan A.
      Identification of high-risk ACS patients using POC echo. Core EM.
      Detecting early WMAs may be imperative, as these occur even before electrocardiographic changes or chest pain in patients with ACS.
      • Sabia P.
      • Afrookteh A.
      • Touchstone D.A.
      • Keller M.W.
      • Esquivel L.
      • Kaul S.
      Value of regional wall motion abnormality in the emergency room diagnosis of acute myocardial infarction. A prospective study using two-dimensional echocardiography.
      Another more recent study investigated the use of echocardiography in the evaluation of patients with ACS in the prehospital setting. The study demonstrated very high sensitivity (90%) and specificity (100%) for the early detection of non–ST-segment elevation MI.
      • Bergmann I.
      • Büttner B.
      • Teut E.
      • Jacobshagen C.
      • Hinz J.
      • Quintel M.
      • et al.
      Pre-hospital transthoracic echocardiography for early identification of non-ST-elevation myocardial infarction in patients with acute coronary syndrome.

       Implementation Strategy

      As previously demonstrated, WMAs in ACS may occur before electrocardiographic changes and before significant chest pain.
      • Fleischmann K.E.
      • Lee T.H.
      • Come P.C.
      • Goldman L.
      • Cook E.F.
      • Caguoia E.
      • et al.
      Echocardiographic prediction of complications in patients with chest pain.
      Here we suggest the implementation of rapid echocardiographic assessment for either suspected complications of ACS or undifferentiated chest discomfort in moderate- to high-risk patients presenting to the emergency department after initial electrocardiography is negative for ST-segment elevation MI (Figure 5). This may aid in identifying new WMAs for early categorization into an ischemic etiology while blood work is pending, as well as early identification of the previously discussed complications. A moderate- to high-risk patient who presents with an ST-segment elevation MI may also benefit from emergent echocardiography just before cardiac catheterization if the study does not delay door-to-balloon time (i.e., an “on-table examination”). This may be especially useful in patients with hemodynamic compromise to identify possible mechanical complications of the MI, in whom further interventions before coronary angiography (e.g., circulatory support, surgical consultation) may be critical. This algorithm is intended to be used in addition to traditional standard ACS management and not as a replacement. The assessment should be performed by a trained ultrasonographer in the emergency department or on the catherization table immediately preceding the procedure.
      Figure thumbnail gr5
      Figure 5Algorithm for suspected ACS. An acute cardiac sonographer and an acute echocardiography reader are assigned. The goal is to perform and interpret acute echocardiography within a 45-min window. EKG, Electrocardiography; ER, emergency room; STEMI, ST-segment elevation MI.

      Conclusion

      Echocardiography applied in the acute setting is an invaluable tool in the early assessment of both mixed ACS presentations and hemodynamically unstable patients. It can provide a rapid evaluation of global systolic function, rule in evidence of ischemia by identification of focal WMAs, assist in ruling out ischemia by demonstration of normal function, and identify mechanical and valvular complications. All of these findings may significantly alter the ideal course of treatment for a given patient. As an initial adjunct in the triage process, it carries notable promise for the reduction of catheterization laboratory complications by both guiding subsequent procedures and ruling out unnecessary procedures with an ultimate goal of reducing morbidity and mortality. Further study with a standardized implementation system is required to confirm this suspicion.

      Supplementary Data

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