Case

A 51-year-old female presented to the ED with a complaint of 1 week of bilateral lower extremity edema and worsening shortness of breath. The patient had a history of breast cancer with metastases to the lungs and recurrent malignant pleural effusions.

On physical exam the patient appeared ill despite relatively normal vital signs. The patient was noted to have mild JVD, tachycardia and decreased breath sounds in both lung bases with rales, and bilateral lower extremity edema.

A transverse view of the proximal IVC revealed distension, and decreased respiratory variation and compressibility, consistent with right heart failure (IVC Video).

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Discussion

Although free floating right atrial thrombus occurs in up to 7% to 18% of patient with pulmonary embolism, the diagnosis is rarely encountered clinically (1;2). Right atrial thrombus are in transit from the deep venous system of the leg and pelvis to the pulmonary vasculature (3). Patients most commonly presented with cardiogenic shock (4). The most common echocardiographic findings are right ventricular overload, paradoxical intraventricular septal motion, and pulmonary hypertension (4). Such thrombi carry a greater than 40% mortality rate even with treatment (5) Patients with signs and symptoms of shock are ideal candidates for limited ED ultrasound. These patients cannot be transported from the ED for imaging studies such as CT making bedside modalities ideal. Using limited ED echocardiography emergency physicians rapidly can assess for hypovolemia, pulmonary embolism, cardiogenic shock, PEA and pericardial tamponade. The primary views are the subxyphoid view, the four chamber apical view, and the parasternal view.

With pulmonary embolism right heart strain is the most notable finding. Enlargement of the right ventricle relative to the left ventricle is best seen best in the apical and parasternal views. Other signs include right ventricular hypokinesis and paradoxical septal motion where the intraventricular septum bows into the left ventricle during systole. In addition, decreased respiratory variation and compressibility of the IVC correlates with fluid overload and right heart failure (6). Further, the right heart mass itself is a significant finding. Right heart thrombi most often appears as a serpentine mass within the atrium and occasionally the ventricle.

The demonstrated sensitivity and specificity of echocardiography for pulmonary embolism is 68% and 89% respectively (7). This is compared to a sensitivity and specificity of 86% and 93% for spiral CT. The positive and negative likelihood ratios for echocardiography are 5.0 and 0.59, compared to 24.1 and 0.11 for CT (8). This data confirms that echocardiography is not a replacement for spiral CT for the typical stable patients with a possible pulmonary embolism. However, the unstable patient with a high clinical suspicion for the disease will undoubtedly benefit from the rapid availability of bedside ultrasound.

Conclusion

Following the limited ED ultrasound, a CT scan was performed and revealed large bilateral pulmonary emboli. After discussing the treatment options and potential outcomes the patient elected to undergo thrombolytic therapy.

Within the Emergency Department of Cook County Hospital the immediate availability of limited emergency ultrasound provides the ability to rapidly diagnosis patients with undifferentiated shock. Using limited ED US as an extension of their physical exam, trained emergency physician more rapidly diagnosis and begin appropriate treatment of critically ill patients with cardiac tamponade, pulmonary embolism hypovolemia, and severe congestive heart failure.

References

1. Chapoutot L, Nazeyrollas P, Metz D, Maes D, Maillier B, Jennesseaux C et al. Floating right heart thrombi and pulmonary embolism: diagnosis, outcome and therapeutic management. Cardiology 1996; 87(2):169-174.
2. Casazza F, Bongarzoni A, Centonze F, Morpurgo M. Prevalence and prognostic significance of right-sided cardiac mobile thrombi in acute massive pulmonary embolism. Am J Cardiol 1997; 79(10):1433-1435.
3. Panidis IP, Kotler MN, Mintz GS, Ross J. Clinical and echocardiographic features of right atrial masses. Am Heart J 1984; 107(4):745-758.
4. Chartier L, Bera J, Delomez M, Asseman P, Beregi JP, Bauchart JJ et al. Free-floating thrombi in the right heart: diagnosis, management, and prognostic indexes in 38 consecutive patients. Circulation 1999; 99(21):2779-2783.
5. European Working Group on Echocardiography. The European cooperative study on the clinical significance of right heart thrombi. Eur Heart J 1989; 10:1046-1059.
6. Nachimuthu S, Ashby K, Humphers G, Balasundaram P, Kerut EK. Utility of echocardiography and serum troponin levels in pulmonary embolism. Echocardiography 2005; 22(2):151-153.
7. Kline JA, Johns KL, Colucciello SA, Israel EG. New diagnostic tests for pulmonary embolism. Ann Emerg Med 2000; 35(2):168-180.
8. Roy PM, Colombet I, Durieux P, Chatellier G, Sors H, Meyer G. Systematic review and meta-analysis of strategies for the diagnosis of suspected pulmonary embolism. BMJ 2005; 331(7511):259.