Myocardial Ischemia, Infarction, and Wall Motion Abnormalities
Carlos E. Vazquez
Pamela Y.F. Hsu
Eli L. Torgeson
Neal S. Gerstein
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1. A 79-year-old patient with a known history of coronary artery disease (CAD) was admitted to the Emergency Department (ED) with chest pain radiating to the left shoulder and diaphoresis. Which of the following findings on the initial transthoracic echocardiogram (TTE) is most consistent with noncardiac causes of chest pain?
A. Severe mitral regurgitation due to torn papillary muscle
B. Depressed left ventricular (LV) systolic function
C. Extensive regional wall motion abnormalities (RWMAs) with multiple hypokinetic and akinetic segments
D. Myocardial wall thickening >40% during systole
E. Dilated right ventricle with tricuspid annular plane systolic excursion (TAPSE) <16 mm
1. Correct Answer: D. Myocardial wall thickening >40% during systole
Rationale: Acute myocardial ischemia manifests as impairment of systolic myocardial wall motion. There are two components to this motion, endocardial excursion and wall thickening. Reduced wall thickening is a more reliable sign of myocardial ischemia than endocardial excursion, which may be affected by tethering from adjacent unaffected myocardium. The following sequence of events occurs during the ischemic cascade: diastolic dysfunction followed by systolic dysfunction (RWMAs), with subsequent development of ECG changes, symptoms, and finally a reduction in cardiac output. The myocardial wall motion can be quickly and accurately assessed by TTE, which allows the earliest diagnosis of acute myocardial ischemia.
Normal myocardial thickening is defined as >40% during systole. A myocardial thickening value >40% is not a sign of acute myocardial ischemia/infarction. Option 4 is incorrect.
1. Sidebotham D. Practical Perioperative Transesophageal Echocardiography. 3rd ed. Oxford University Press; 2018.
2. Which among the following is the most specific sign/symptom of acute myocardial ischemia?
A. Chest pain and shortness of breath
B. T-wave abnormalities on electrocardiogram (ECG)
D. More than three B-lines per intercostal space on lung ultrasound
2. Correct Answer: C. RWMAs
Rationale/Critique: Acute myocardial ischemia manifests as an impairment of systolic myocardial wall motion. There are two components to this motion: endocardial excursion and wall thickening. Wall thickening is a more reliable sign of myocardial ischemia than endocardial excursion, which may be affected by tethering from adjacent unaffected myocardium. The following sequence of events occurs with the “ischemic cascade”: diastolic dysfunction followed by systolic dysfunction (RWMAs), with subsequent development of ECG changes, symptoms, and finally a reduction in cardiac output. The myocardial wall motion can be quickly and accurately assessed by TTE. Normal regional myocardial function makes an acute myocardial ischemia very unlikely.
1. Otto C. Echocardiography Review Guide: Companion to the Textbook of Clinical Echocardiography. 4th ed. Elsevier; 2019.
2. Sidebotham D. Practical Perioperative Transesophageal Echocardiography. 3rd ed. Oxford University Press; 2018.
3. A 68-year-old female with a long history of insulin-dependent diabetes mellitus and hypertension arrives at the emergency room (ER) with acute onset of shortness of breath and chest discomfort. Which of the following TTE views would be the most helpful in evaluating distribution of all three major coronary arteries in a single view?
A. Parasternal long-axis view
B. Parasternal short-axis midpapillary view
C. Apical four-chamber view
D. Subcostal view
3. Correct Answer: B. Parasternal short-axis midpapillary view
Rationale: The midpapillary view allows assessment of coronary perfusion in all the three major coronary vessels (i.e., the LAD, right coronary artery [RCA], and circumflex).
LAD: anterior and anteroseptal segments
Circumflex: anterolateral and inferolateral segments
RCA: Inferior and inferoseptal segments
New RWMAs are an early sign of myocardial ischemia and usually precede electrocardiographic changes and angina. (See Figure 34.13 and Chapter 22, Figure 22.13 for further details.)
1. Denault AY, Langevin S, Lessard MR, Courval JF, Desjardins G. Transthoracic echocardiographic evaluation of the heart and great vessels. Can J Anaesth. 2018 Apr;65(4):449-472.
2. Lang RM, Badano LP, Mor-Avi V, et al. Recommendations for cardiac chamber quantification by echocardiography in adults: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. J Am Soc Echocardiogr. 2015;28(1):1-39.e14.
4. In a patient presenting with shock, which of the following ultrasound findings supports a cardiogenic etiology for the shock?
A. LV fractional shortening of 45%
B. More than three B-lines per intercostal space
C. Mitral annular plane systolic excursion (MAPSE) >14 mm
D. E/e′ ratio <8
E. E-point septal separation (EPSS) <3 mm
4. Correct Answer: B. More than three B-lines per intercostal space
Rationale: Cardiogenic shock is one of the life-threatening complications of large acute MI. Clinically, it manifests as severe hypotension due to impaired myocardial contractility and cardiogenic pulmonary edema. Patients may have echocardiographic findings of LV systolic and/or diastolic dysfunction, and yet not manifest cardiogenic shock; none of answers A, C, and E indicate abnormal LV systolic function, and answer D can be normal LV diastolic function.
Lung ultrasound is one of the most useful noninvasive tools for early diagnosis of acute cardiogenic pulmonary edema. It has higher diagnostic accuracy than chest radiograph and auscultation.
B-lines, also called comet tails, are defined as discrete laser-like vertical hyperechoic reverberation artifacts extending from the pleural line to the bottom of the screen. Although the presence of up to two B-lines is physiologic, having at least three B-lines between two ribs in longitudinal scan defines a positive B pattern. The number of B-lines per intercostal space correlates directly with the severity of pulmonary edema.
1. Díaz-Gómez JL, Ripoll JG, Tavazzi G, Ratzlaff RA. Perioperative lung ultrasound for the cardiothoracic anesthesiologist: emerging importance and clinical applications. J Cardiothorac Vasc Anesth. 2017;31:610-625.
2. Topalian S, Ginsberg F, Parrillo JE. Cardiogenic shock. Crit Care Med. 2008;36(1):S66-S74.
5. TTE images (Figure 34.1 and Video 34.1) were obtained from the patient with recent acute myocardial infarction (MI).
Which complication of acute MI is demonstrated here?
A. Cardiac tamponade
B. Papillary muscle rupture
C. Mitral regurgitation
D. Ventricular septal defect (VSD)
5. Correct Answer: E. Pseudoaneurysm
Rationale: LV pseudoaneurysm is the result of a contained rupture along the ventricular free wall with hemorrhage into the pericardial space that is self-contained by an organizing clot or thrombus. Although a small effusion is visible at the apex of the right ventricle, there are no signs of tamponade demonstrated in the clip. VSD and mitral regurgitation are better diagnosed with color Doppler. Papillary muscle rupture would present as a highly mobile echogenic structure attached to the mitral valve (MV). Recognition of a pseudoaneurysm is critical because of a high risk of rupture and death.
1. Quader N, Makan M, Perez P, eds. The Washington Manual of Echocardiography. 2nd ed. Wolters Kluwer; 2017.
6. For the patient in Question 5, which of the following echocardiographic findings is most helpful in differentiating a true aneurysm of the left ventricle from pseudoaneurysm?
A. Bidirectional flow through the narrow neck on color and spectral Doppler examination
B. Spontaneous echo contrast and thrombus in pericardial space
C. A small narrow neck connects the ventricular cavity with the pericardial space.
D. The neck diameter to maximal aneurysmal diameter ratio is >0.5.
6. Correct Answer: D. The neck diameter to maximal aneurysmal diameter ratio >0.5
Rationale: LV pseudoaneurysm is the result of a rupture along the ventricular free wall with hemorrhage into the pericardial space that is self-contained by an organizing clot or thrombus. A small, narrow neck connects the ventricular cavity with the walled-off pericardial space.
Pseudoaneurysms (Figure 34.14) can be differentiated from true aneurysms by the following features:
Figure 34.14 An apical pseudoaneurysm (PsA) seen on an “off-axis” apical long-axis image. Note the narrow neck and thrombus in the pericardial space (arrows).
The neck diameter to maximal aneurysmal diameter ratio is <0.5.
Color and spectral Doppler show bidirectional flow through the narrowed neck.
The identification of spontaneous echo contrast (stasis of blood) and thrombus in the pericardial space.
Recognition of a pseudoaneurysm is critical because of a high risk of rupture and death.
1. Olusesi O, Yeung M. Ischemic heart disease and complications of myocardial infarction. In: Quader N, Makan M, Perez P, eds. The Washington Manual of Echocardiography. 2nd ed. Wolters Kluwer; 2017:81-92.
7. Using TTE (Figure 34.2 and Video 34.2), a wall motion abnormality located between the arrows could be caused by decreased blood flow in which coronary artery?
B. Right coronary
C. Left anterior descending (LAD)
D. Posterior descending
7. Correct Answer: C. Left anterior descending (LAD)
Rationale/Critique: Having knowledge of coronary anatomy and perfusion is imperative for properly interpreting an echocardiography examination. Figure 34.2 in Question 7 displays a short-axis view of the left ventricle. This view reveals information on wall motion abnormalities that can be extrapolated to coronary perfusion. Typically, the LAD coronary perfuses the anteroseptum and anterior wall; the circum-flex perfuses the anterolateral and inferolateral walls; and the right coronary and posterior descending coronary perfuse the inferior and inferoseptal walls. (See also rationale for Answer 34.3.)
1. London MJ. Diagnosis of myocardial ischemia. In: Perrino AC, Reeves ST, eds. A Practical Approach to Transesophageal Echocardiography. 2nd ed. Wolters Kluwer; 2008:Chapter 4.
8. A 65-year-old male is admitted to the intensive care unit (ICU) with acute MI and cardiogenic shock. The bedside transesophageal echocardiogram (TEE) reveals mitral regurgitation (Figure 34.3).
Which among the following parameters is least reliable for quantifying the severity of this mitral regurgitation jet?
A. Vena contracta
B. Regurgitant volume
C. Jet area
D. Pulmonary vein Doppler waveform
8. Correct Answer: C. Jet area
Rationale: Mitral regurgitant jets can present during acute MIs, due to ischemic cardiomyopathy or papillary muscle rupture. Knowledge of the anatomy of the MV is imperative in addressing and assessing these regurgitant jets. The above image shows a mid-esophageal aortic valve long-axis view revealing an eccentric (wall hugging) regurgitant jet into the left atrium through the MV. Measuring jet area in wall hugging jets underestimates the severity of regurgitation. The regurgitant jet spreads around the wall (Coanda effect), making the cross-sectional area of the jet in this plane appear small. Also, being adjacent to the left atrial wall could slow down the jet. Other parameters like vena contracta, regurgitant volume, and pulmonary vein flow are less affected by the eccentric nature of the jet.
1. Lamabert AS. Mitral regurgitation. In: Perrino AC, Reeves ST, eds. A Practical Approach to Transesophageal Echocardiography. 2nd ed. Wolters Kluwer; 2008:171-188.
9. A 52-year-old male presents to the ED with chest pain. An ECG demonstrates ST changes suspicious of ischemia, and hence a troponin and TTE is ordered. What does the asterisk in the TTE in Figure 34.4 denote? (See also Video 34.3.)
A. A normal interventricular septum
B. A thickened interventricular septum
C. A large interventricular hematoma
D. An aortic root abscess
9. Correct Answer: B. A thickened interventricular septum
Rationale: TTE image in Figure 34.15 reveals a thickened interventricular septum suspicious of hypertrophic cardiomyopathy (HCM).
The normal interventricular wall diameter (IVSd) in males is <1.2 cm. IVSd >2.0 cm is consistent with severe LV wall hypertrophy. Myocardial ischemia is a recognized complication of HCM. The suggested mechanisms of myocardial ischemia in patients with HCM include structural abnormalities in arteriolar architecture, intramural vessels (myocardial bridging), imbalance of myocardial oxygen supply and demand due to hypertrophied myocardium, and impaired coronary vasodilatory reserve.
1. Holley CL. Cardiomyopathies. In: Rasalingam R, Majesh M, Pérez JE, eds. The Washington Manual of Echocardiography. Philadelphia, PA: Wolters Kluwer; 2012:89-105.
2. Gupta T, Harikrishnan P, Kolte D, et al. Outcomes of acute myocardial infarction in patients with hypertrophic cardiomyopathy. Am J Med. 2015;28(8):879-887.
10. In Question 9, the patient was started on inotropic support, he became profoundly hypotensive and was transferred to ICU for further management. TTE images as shown in Figure 34.5A and B were obtained.
A. Acute LV ischemia
B. Low systemic vascular resistance
C. Acute pulmonary embolism
D. Dynamic left ventricular outflow tract (LVOT) obstruction
E. Cardiac tamponade
10. Correct Answer: D. Dynamic LVOT obstruction
Rationale/Critique: HCM can predispose to a dynamic LV outflow obstruction (as opposed to a “fixed” obstruction in aortic stenosis) and remains an important cause of sudden cardiac death in young adults. The following anatomic factors predispose to this condition:
Redundant MV leaflets
Papillary muscle displacement
Interventricular septal hypertrophy
The apical four-chamber view (Figure 34.5A) with continuous-wave Doppler interrogation of LVOT (Figure 34.5B) demonstrates typical late-peaking Doppler profile (“dagger” shape) indicative of a severe subvalvular obstruction with blood flow velocity of 5.1 m/s (>4.0 m/s is severe), and peak pressure gradient of 104 mm Hg (>70 mm Hg is severe). A mean pressure gradient of >40 mm Hg is also considered severe. The color flow Doppler (Figure 34.5A) confirms a high-velocity turbulent flow in LVOT and also shows eccentric mitral regurgitation both of which are consistent with dynamic LVOT obstruction.
1. Holley CL. Cardiomyopathies. In: Rasalingam R, Majesh M, Pérez JE, eds. The Washington Manual of Echocardiography. Wolters Kluwer; 2012:89-105.
11. A 75-year-old presents to the ED with symptoms of cardiac ischemia and syncope causing a hip fracture. The patient underwent a TTE and apical four-chamber view with continuous-wave Doppler image in Figure 34.6 was obtained. What does Figure 34.6 most likely show?
A. Moderate-to-severe diastolic dysfunction
B. Mild aortic stenosis
C. Severe mitral regurgitation
D. Severe aortic stenosis
E. Severe aortic regurgitation
11. Correct Answer: D. Severe aortic stenosis
Rationale/Critique: Figure 34.6 TTE image shows an apical four-chamber view with continuous-wave Doppler interrogating the aortic valve. Since the “jet” is oriented down or away from the probe, the blood is traveling through the aortic valve and exiting the left ventricle during systole. The velocity of the blood (see the Y-axis) approximates 4.5 m/s (>4.0 m/s is severe), leading to a peak gradient of 81 mm Hg (simplified Bernoulli equation: Peak gradient (mm Hg) = 4 × (aortic peak velocity)2). Based on this velocity, the aortic stenosis can be quantified as severe.
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