1. Correct Answer: A. Moderate RV dilation

Rationale: For qualitative assessment, the right ventricle should be evaluated in multiple tomographic planes. The right ventricle is most often compared with the left ventricle either visually or by comparing RV and LV end-diastolic areas. In any four-chamber view, a diastolic ventricular ratio of 0.6 to 1 signifies moderate RV dilation, while a ratio ≥1 like in our patient signifies severe RV dilation. Global visual assessment of RV function has been shown to be inaccurate. The consensus recommendation is to perform quantitative assessment of RV function, where TAPSE measurement of <17 mm or tricuspid lateral annular systolic velocity measurement of < 9.5 cm/s is highly suggestive of RV systolic dysfunction.

RV dilation and dysfunction are often accompanied by other findings easily identified by echocardiography, including RA or IVC dilation, TR, and IVS flattening leading to “D-shaped” LV geometric distortion. Leftward motion of the IVS during systole is suggestive of pressure overload, whereas leftward motion during diastole is suggestive of volume overload.

1. 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.

2. Ling LF, Obuchowski NA, Rodriguez L, Popovic Z, Kwon D, Marwick TH. Accuracy and interobserver concordance of echocardiographic assessment of right ventricular size and systolic function: a quality control exercise. J Am Soc Echocardiogr. 2012;25(7):709-713.

3. Schneider M, Binder T. Echocardiographic evaluation of the right heart. Wien Klin Wochenschr. 2018;130(13-14):413-420.

2. Correct Answer: D. It is crucial to augment cardiac output (CO) with catecholamines to avoid tissue hypoperfusion.

Rationale: Takotsubo cardiomyopathy was named after the Japanese octopus trap that has a shape similar to the systolic apical ballooning of the left ventricle that occurs in the most common and typical variant of the disease. Echocardiography detects the typical wall motion abnormalities that include akinetic mid- and apical LV segments with preservation of basal segment function. The pathogenesis of Takotsubo cardiomyopathy is probably multifactorial, but excess catecholamines have been postulated as a contributing mechanism. The disease is typically observed in postmenopausal women in Western countries following an emotional or physical stress, possibly causing catecholamine-induced direct myocardial toxicity or microvascular spasm. Since catecholamines are postulated as a contributing factor, catecholamine administration should be avoided.

The diagnosis of Takotsubo cardiomyopathy is challenging, especially that its initial presentation resembles acute coronary syndrome (ACS). The Mayo Clinic diagnostic criteria are most commonly used, where all four criteria are required to establish the diagnosis. Those criteria include:

Takotsubo cardiomyopathy is usually managed with supportive therapy, and most patients recover within 1 to 4 weeks. It is usually referred to as a reversible self-limiting cardiomyopathy, and the dramatic recovery of cardiac function might give the impression that it is a benign disorder. However, 21.8% of patients with Takotsubo cardiomyopathy were reported to develop serious in-hospital complications. Indeed, people who recover usually achieve full recovery, but this highlights the importance of early recognition and proper management in the acute phase of the disease to avoid and treat complications.

1. Prasad A. My approach to takotsubo (stress) cardiomyopathy. Trends Cardiovasc Med. 2015;25(8):751-752.

2. Templin C, Ghadri JR, Diekmann J, et al. Clinical features and outcomes of takotsubo (stress) cardiomyopathy. N Engl J Med. 2015;373(10):929-938.

3. Correct Answer: C. 2.8 L/min/m²

Rationale: CO measurement is a cornerstone of hemodynamic assessment in critically ill patients. Hemodynamic evaluation utilizes 2D echocardiography and PWD. The SV across a reference point such as the LVOT can be calculated as the product of two variables: (1) cross-sectional area (CSA) of that reference point and (2) VTI measured at the same reference point using PWD. For example, SV is equal to the CSA of the LVOT multiplied by the LVOT VTI. The CO is then obtained by multiplying the SV by the HR, and CI by dividing CO by the patient’s BSA.

SV (cm³) = CSA (cm²) × VTI (cm)

SV_LVOT = CSA_LVOT × VTI_LVOT

SV_LVOT = πr² × VTI_LVOT

SV_LVOT = 3.14 × (D/2)² × VTI_LVOT

SV_LVOT = 3.14 × (1.9/2)² × 26.6 = 75 cm³

CO = SV_LVOT × HR

CO = 75 × 72 = 5.4 L/min

CI = CO/BSA

CI = 5.4/1.94 = 2.8 L/min/m²

The SV can be calculated by measuring the LVOT diameter (in the parasternal long-axis view by using TTE or midesophageal long-axis view when performing TEE) and the LVOT VTI (in the apical five-chamber or apical three-chamber views using TTE or the deep transgastric or transgastric long-axis views during TEE examination). The ability to quantify LV SV becomes especially useful in the ICU, where serial measurements of SV would allow goal-directed titration of inotropic support and help guide volume resuscitation.

1. Porter TR, Shillcutt SK, Adams MS, et al. Guidelines for the use of echocardiography as a monitor for therapeutic intervention in adults: a report from the American Society of Echocardiography. J Am Soc Echocardiogr. 2015;28(1):40-56.

4. Correct Answer: B. 0.72 cm²

Rationale: 2D echocardiography can often provide important clues to the AV anatomy and morphology, including the number of leaflets and commissures, mobility, and calcification. Functional evaluation by using color flow Doppler (CFD) and spectral Doppler can assess the level of obstruction—whether it is valvular, subvalvular, or supravalvular and the severity.

Severe AS can contribute to hemodynamic instability in the ICU. Level 1 recommendations from the American Society of Echocardiography (ASE) and European Association of Echocardiography (EAE) state that grading AS is appropriate and recommended using peak AV jet velocity, mean aortic transvalvular pressure gradient, and aortic valve area (AVA) in all patients with AS. Severe AS is diagnosed in the presence of preserved LV systolic function, by the presence of one or more of the following: (a) peak AV velocity of ≥4 m/s, (b) mean AV gradient of ≥40 mm Hg, and (c) AVA of <1 cm². However, if LV function is impaired, the former two parameters may underestimate the degree of stenosis, making AVA calculation using continuity equation more accurate because it is not flow dependent.

To calculate AVA using the continuity equation, measurements are commonly taken at the AV annulus (AVA = A1, VTI_AV = V1) and within the LVOT (CSA_LVOT = A2, VTI_LVOT = V2):

A1 = A2 × (V2/V1)

AVA = (CSA_LVOT × VTI_LVOT)/VTI_AV

AVA = (⇔ × (LVOT/2)² × VTI_LVOT)/VTI_AV

1. Baumgartner H, Hung J, Bermejo J, et al. Recommendations on the echocardiographic assessment of aortic valve stenosis: a focused update from the European Association of Cardiovascular Imaging and the American Society of Echocardiography. J Am Soc Echocardiogr. 2017;30(4):372-392.

5. Correct Answer: D. Administer epinephrine boluses

Rationale: Dynamic LVOT obstruction can cause hemodynamic instability in critically ill patients. It typically occurs in patients with either hypertrophic obstructive cardiomyopathy (HOCM) or anterior mitral leaflet redundancy. Dynamic LVOT obstruction should always be suspected in patients who do not respond to inotropic support. 2D echocardiography can demonstrate a hypertrophic and hyperdynamic left ventricle with a small cavity. Doppler interrogation can show turbulent flow in the LVOT along with significant pressure gradients, possibly with acute MR caused by systolic anterior motion of the anterior mitral leaflet. Hemodynamic instability in such cases can be managed by stopping inotropic support, fluid resuscitation, slowing the HR, and increasing systemic vascular resistance with α-agonists.

1. Costachescu T, Denault A, Guimond JG, et al. The hemodynamically unstable patient in the intensive care unit: hemodynamic vs. transesophageal echocardiographic monitoring. Crit Care Med. 2002;30(6):1214-1223.

6. Correct Answer: C. Respirophasic variability in the transmitral Doppler velocities of <30%

Rationale: In a patient with hypotension or dyspnea, echocardiographic evidence that supports the diagnosis of cardiac tamponade typically requires at least the following three key findings:

A small percentage of patients with tamponade physiology (<10%) will actually have low or normal RA pressure (“low-pressure tamponade”) and thus will fail to show IVC dilation. In such cases, other echocardiographic signs of chamber compression and/or ventricular interdependence should be looked for, including the following additional signs:

1. Klein AL, Abbara S, Agler DA, et al. American Society of Echocardiography clinical recommendations for multimodality cardiovascular imaging of patients with pericardial disease: endorsed by the Society for Cardiovascular Magnetic Resonance and Society of Cardiovascular Computed Tomography. J Am Soc Echocardiogr. 2013;26(9):965-1012.e1015.

7. Correct Answer: D. Switching VA-ECMO to veno-arterial-venous (VAV)-ECMO

Rationale: Echocardiography is helpful during all phases of VA-ECMO support. A baseline examination prior to initiation of support can correct reversible causes of hemodynamic instability and confirm the need for support. Echocardiography can guide cannulation, confirm proper position of cannulas, and detect complications associated with cannulation such as tamponade or dissection. Patients on VA-ECMO are monitored with echocardiography to evaluate LV size to ensure adequate unloading and avoid LV distension. If the LV is distended, distension can be improved by increasing inotropic support, placement of IABP or Impella 2.5, LV venting either directly or by venting proximal to the LV such as LA venting via atrial septostomy or PA drainage. Switching to VAV-ECMO is performed in peripherally cannulated patients with respiratory failure due to concerns of cerebral hypoxemia. Biventricular function is periodically evaluated to detect recovery of myocardial function. AV opening is evaluated especially in peripheral cannulation, where risk of aortic root thrombosis is increased if the AV is closed.

A position paper by the ECMO Network and the Extracorporeal Life Support Organization (ELSO) recommended including a physician trained in echocardiography in the team caring for patients on ECMO support.

1. Abrams D, Garan AR, Abdelbary A, et al. Position paper for the organization of ECMO programs for cardiac failure in adults. Intensive Care Med. 2018;44(6):717-729.

2. Douflé G, Roscoe A, Billia F, Fan E. Echocardiography for adult patients supported with extracorporeal membrane oxygenation. Crit Care. 2015;19:326.

8. Correct Answer: E. RV dilation/dysfunction predicts worse prognosis

Rationale: PE is a life-threatening condition that requires timely diagnosis and treatment. Although the most definitive diagnostic test is computerized tomographic pulmonary angiography (CTPA) scan, echocardiography can provide clinically useful data in many cases. In contrast to CTPA, echocardiography requires neither renally injurious IV contrast nor the transfer of potentially unstable patients to a remote location.

Echocardiography can provide both qualitative and quantitative data of value in the workup of suspected PE. First, in a patient with hemodynamic compromise, the finding of normal RV size and function practically rules out PE as the cause of hypotension. Conversely, the finding of RV dilation/dysfunction in PE is associated with a much worse prognosis, with some studies showing a doubling of the 3-month mortality compared to patients with PE and normal RV size/function.

Unfortunately, echocardiography by itself rarely confirms a definitive diagnosis of PE. Specifically, echocardiography only can rule in PE when it reveals a clot “in transit” in the right heart, including the IVC, RA, right ventricle, or PA. Because the majority of patients with PE will not demonstrate a clot “in transit” at the time of echocardiography, substantial efforts have been dedicated to determining ultrasound findings that reliably differentiate PE from other causes of RV dysfunction. For instance, it was once thought that McConnell sign was pathognomonic for PE. McConnell sign specifically describes a pattern of RV dysfunction characterized by hypokinesis of the RV free wall basal and midsegments with relative normo- or even hyperkinesis of the RV free wall apical segment. This pattern likely occurs in PE because increased RV afterload disrupts most RV function while the apical segment of the RV free wall appears to be mobile due to its physical connection to a preserved or hyperkinetic left ventricle. Although this finding can indeed be seen in PE, case reports and case series have shown that this sign is neither sensitive nor specific for PE, and it has been observed in other conditions that disrupt RV function, including RV infarct, acute respiratory distress syndrome (ARDS), and pulmonary fibrosis.

Therefore, echocardiography is an important bedside tool in the workup of patients suspected of having a PE. Although echocardiography can only rarely “rule in” PE, it can still be useful by rapidly providing information at the bedside to narrow the differential diagnosis of shock and risk-stratify patients who have PE diagnosed by CTPA.

1. Konstantinides SV, Meyer G, Becattini C, et al. 2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism developed in collaboration with the European Respiratory Society (ERS). Eur Heart J. 2019;41(4):543-603.

9. Correct Answer: D. Severe aortic insufficiency (AI) is a contraindication to Impella® device placement.

Rationale: Hemodynamic instability in critically ill patients with Impella® device requires urgent echocardiographic examination to rule out catheter migration. For proper placement, the catheter’s inlet area should be into the left ventricle about 3.5 to 4 cm from the annulus, which allows the outlet area to be in the ascending aorta distal to the AV annulus and the aortic root. Echocardiography can also diagnose complications encountered with the Impella® device such as interference with AV closure causing severe AI or interference with the MV apparatus causing severe MR.

The Impella® 2.5 and Impella® CP devices can be inserted via standard percutaneous catheterization procedure through the femoral artery, into the ascending aorta, across the AV and into the left ventricle. In contrast, the Impella® 5.0 and 5.5 devices (that deliver flow up to 5.0 and 6 L/min, respectively) can only be inserted via femoral arterial cut down or through surgical access into the axillary artery.

1. Impella®. The World’s Smallest Heart Pump. Accessed November 17, 2019. http://www.abiomed.com/impella.

2. Pappalardo F, Contri R, Pieri M, Colombo A, Zangrillo A. Fluoroless placement of Impella: a single center experience. Int J Cardiol. 2015;179:491-492.

10. Correct Answer: D. Decreased LVAD pump speed

Rationale: Echocardiography is used for ICU management of patients supported with LVAD in order to evaluate RV size compared to that of LV, RV contractility, RA and LA size, position of IVS, shunting from right to left, degree of TR, AV opening, inflow and outflow cannula positions, and optimization of LVAD pump speed.

Suction events can result from:

All those factors can result in a collapsed left ventricle with leftward shift of the IVS, which distorts the RV geometry and worsens TR, with subsequent worsening of RV function. Suction events can be mitigated by lowering LVAD speed.

Hypotension or loss of arterial pulsatility in patients with LVAD can be caused by several factors, most of which can be diagnosed with echocardiography. These include hypovolemia, RV failure, LVAD-associated continuous AI, LVAD-related MR, inflow cannula malposition or obstruction, outflow graft kinking or thrombosis, and LVAD pump malfunction.

1. Ammar KA, Umland MM, Kramer C, et al. The ABCs of left ventricular assist device echocardiography: a systematic approach. Eur Heart J Cardiovasc Imaging. 2012;13(11):885-899.

2. Stainback RF, Estep JD, Agler DA, et al. Echocardiography in the management of patients with left ventricular assist devices: recommendations from the American Society of Echocardiography. J Am Soc Echocardiogr. 2015;28(8):853-909.

11. Correct Answer: C. Determine intra-abdominal pressure

Rationale: The presence of intra-abdominal hypertension (intra-abdominal pressure >12 mm Hg) is common in cardiac surgical patients (33%-46%). Importantly, intra-abdominal hypertension in postoperative cardiac surgical patients is associated with acute kidney injury. The risk factors in cardiac surgical patients include positive fluid balance and low CO/shock. Importantly, this entity can overlap with postoperative cardiogenic shock. Thus, it can be difficult to discriminate those diagnoses and to rule out associated problems such as postoperative cardiac tamponade. The clinical picture of abdominal compartment syndrome includes progressive intra-abdominal hypertension with elevated airway pressure, low tidal volume, and an isolated increase in CVP along with progressive development of acute kidney injury.

The diagnosis is confirmed by measurement of an elevated intra-abdominal pressure. It is a fast, reliable, and noninvasive procedure performed at the bedside that will rule out the diagnosis. Performing an abdominal CT scan carries the risks of transporting an unstable patient outside of the ICU and potentially delaying therapeutic intervention. In contrast, TEE evaluation is considered when intra-abdominal hypertension is ruled out and in order to evaluate the presence of cardiogenic shock. More importantly, TEE is the diagnostic modality of choice to confirm the diagnosis of postoperative cardiac tamponade and an emergent surgical exploration is only considered when the diagnosis is formally established. In a similar fashion, during this situation a diagnostic laparotomy or laparoscopy is not warranted unless there is evidence of acute abdomen or mesenteric/visceral ischemia or necrosis.

1. Dalfino L, Sicolo A, Paparella D, Mongelli M, Rubino G, Brienza N. Intra-abdominal hypertension in cardiac surgery. Interact Cardiovasc Thorac Surg. 2013 Oct;17(4):644-651.

2. Mazzeffi MA, Stafford P, Wallace K, et al. Intra-abdominal hypertension and postoperative kidney dysfunction in cardiac surgery patients. J Cardiothorac Vasc Anesth. 2016 Dec;30(6):1571-1577.

12. Correct Answer: D. To obtain a focused bedside TTE

Rationale: This question addresses the clinical suspicion and confirmatory diagnosis of delayed pericardial tamponade after open cardiac surgery. In the clinical scenario, the patient presents with common risk factors for cardiac tamponade in such a setting (valvular surgery, postoperative coagulopathy, bleeding, and multiple transfusions). There are also common signs and symptoms of postoperative cardiac tamponade (dyspnea, tachycardia, hypotension, oliguria, and elevated CVP). The clinical picture is nonspecific, and diagnosis needs confirmation in order to proceed with therapeutic intervention.

Echocardiography is the method of choice to confirm the clinical diagnosis. In this acute setting, a focused cardiac ultrasound at the bedside in order to specifically look for pericardial effusion or evidence of cardiac tamponade should be attempted first and if imaging is inconclusive or technically difficult (i.e., postoperative patients, decubitus position, obese body habitus, chronic obstructive lung disease, or mechanical ventilation), a TEE examination is necessary. Nevertheless, TTE may fail to visualize early postoperative pericardial effusions in cardiac surgical patients.1 Performing a comprehensive TTE in those circumstances is likely unnecessary and could delay a therapeutic intervention. In addition, such examination is out of the scope of critical care echocardiography and would require a level of expertise usually not available in the ICU at all times.

Although TEE is more sensitive, specific, and suitable to demonstrate regional tamponade—a common finding in delayed postoperative pericardial tamponade, it is also invasive, requires sedation/anesthesia with risk of aspiration, and could potentially increase hemodynamic instability. Therefore, it is not usually recommended as first choice. Otherwise, a CT scan would be useful but carries the risk of delaying diagnosis and removing patients from the controlled environment of the ICU to a remote location. Chest X-ray in this situation can present with widened mediastinum. Nonetheless, such a finding does not provide confirmation of diagnosis.