Middle-aged female with syncope

By Connor Brown, MD
Edited by Hani I. Kuttab, MD

Clinical Case

A middle-aged female presented to the emergency department with syncope. The patient reported having a syncopal episode while resting on her couch approximately one hour prior to arrival. She reports a history of breast cancer with known metastasis. She reported feeling increasingly fatigued prior to the episode but quickly returned to baseline. She denied chest pain, shortness of breath, and palpitations. She was noted to be hypotensive with a blood pressure of 96/61 with a heart rate of 137 beats/minute upon arrival. She was tachypneic at 22-24 breaths/minute and oxygen saturation was 93% on room air. A bedside echocardiogram (echo) was performed (Figures 1, 2, 3).

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Diagnosis

Submassive pulmonary embolism. Bedside echo demonstrated a severely enlarged right ventricle (RV) with signs of right heart strain, including bowing of the interventricular septum into the left ventricle (LV). Based on the bedside echo, patient’s medical history (active cancer), and vital signs, pulmonary embolism (PE) was highly suspected. After initial resuscitation, the patient rapidly underwent CT angiography demonstrating a saddle embolism; the patient was ultimately taken to the cardiac catheterization lab for catheter-directed thrombolysis and admitted to the intensive care unit.

Bedside echo can identify patients with PE at high risk for clinical decompensation. It is more specific for identifying right ventricular strain than CT (1).

Signs of RV strain:

1. RV size > LV size
2. RV wall hypokinesis
3. Septal wall bowing into the LV
4. McConnell’s sign: RV wall hypokinesis with sparing of the apex (e.g., apex trampoline bounces up and down)

Measuring the TAPSE

The tricuspid annular plane systolic excursion (TAPSE) is an ultrasound surrogate for RV function. With acute right heart failure, the RV will appear dilated (or ‘blown’) and the TAPSE value will be decreased. A reduced TAPSE is associated with increased mortality and increased ICU stay (2-4). The ‘cutoff’ value varies between studies, but generally, a value <16mm (<1.6cm) may suggest a high-risk patient. The benefit of the TAPSE measurement is that it is an objective, reportable measure of RV stain, and can be of utility to emergency medicine and cardiology providers.

How do I obtain a TAPSE?

1. Grab your ultrasound and obtain the apical four chamber view
2. Orient the M-mode line with the RV wall, including the annulus of the tricuspid valve (Figure 5)
3. Measure amplitude of the annulus movement on M-mode from minimum to maximum. <16mm = high risk

Teaching point

Bedside echo is quick and reliable diagnostic tool for high-risk patients with suspected PE. Signs of right heart strain include RV size > LV size, RV wall hypokinesis, septal bowing, and the McConnell’s sign. TAPSE is a quick, quantitative measurement that can also help to risk stratify patients.

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References

1. Dudzinski DM, Hariharan P, Parry BA, Chang Y, Kabrhel C. Assessment of Right Ventricular Strain by Computed Tomography Versus Echocardiography in Acute Pulmonary Embolism. Acad Emerg Med. 2017 Mar;24(3):337-343.
2. Lobo JL, Holley A, Tapson V, et al. Prognostic significance of tricuspid annular displacement in normotensive patients with acute symptomatic pulmonary embolism. J Thromb Haemost. 2014 Jul;12(7):1020-7.
3. Pruszczyk P, Goliszek S, Lichodziejewska B, et al. Prognostic value of echocardiography in normotensive patients with acute pulmonary embolism. JACC Cardiovasc Imaging. 2014 Jun;7(6):553-60.
4. Zanobetti M, Converti C, Conti A, et al. Prognostic value of emergency physician performed echocardiography in patients with acute pulmonary thromboembolism. West J Emerg Med. 2013 Sep;14(5):509-17.
5. Tips & Tricks: Right Heart Strain: Rapid evaluation in the acutely dyspneic patient. https://www.acep.org/how-we-serve/sections/emergency-ultrasound/news/dece/tips–tricks-right-heart-strain-rapid-evaluation-in-the-acutely-dyspneic-patient