http://www.detroiteus.com/2013/04/case-post-2/

History:
55yo female presents to your ED with a 1 month history of progressive dyspnea. She has a history of HTN and schizophenia, is on multiple antihypertensive medications (admits to “occasional” non-compliance) as well as Geodon (claims to be much better about taking this med than the others). Denies illicit drugs. Other than fatigue she really has no other symptoms including chest pain or fever and has an unremarkable exhaustive review of systems.

Exam:
Afebrile, BP is 185/90, HR 72, RR 16, SpO2 97% RA. Other than 1+ edema in the LE’s her exam was unremarkable; of note, neck veins were difficult to assess because of her body habitus (obese), her lungs were clear and no murmurs were appreciated. Distal pulses were full and equal bilaterally.

Evaluation and Management:
You place the patient on a cardiac monitor, and because the patient is not symptomatic at rest, no oxygen or other treatments are administered. You order and EKG, 2 view chest radiograph, and labs including CBC, BMP, and cardiac biomarkers. While PE is briefly considered on the differential, because of the long time-course and progressive nature of her chief complaint, you defer pursuing the diagnosis at this time. Rather, you choose to perform a focused echocardiogram to further elucidate her dyspnea.

Labs:

• CBC shows no anemia, nl wbc and platelet counts
• Electrolyte profile is normal, anion gap and renal function are also normal
• Troponin is negative, BNP is 75

EKG: NSR, no ischemic changes

CXR: cardiomegaly, no infiltrate or pneumothorax

Focused Echocardiogram Image Review:

• Parasternal Long axis (PLAX) window, indicator points towards patients right shoulder, machine presets are set to “cardiac”
• Right ventricle (RVOT) is the chamber nearest the top of the screen, “near field”
• Left atrium (LA) is the small chamber farthest from the probe towards the bottom of the screen, “far field”
• Left ventricle (LV) is to the immediate left of the LA, separated by the mitral valve (AML & PML= anterior and posterior mitral leaflet)
• Your patients PLAX view: PLAX tamponade
• There is a large, circumferential pericardial effusion
• The RV appears to be dysnchronous with the LV, meaning that wall motion of the RV free wall (the wall immediately adjacent to the pericardium) and LV posterior wall appears out of synch. This is your first tip-off the patient has cardiac tamponade
• To confirm that the collapse of the RV is indeed occurring during diastole (and not systole which would be normal), you can utilize M-mode by placing your line through the RV free wall and LV posterior wall
• If the RV free wall is collapsing while the LV is in diastole, the pt has echocardiographic tamponade

Case Wrap-up:
While this patient has clear echocardiographic evidence of cardiac tamponade (including the swinging of the cardiac axis to and fro…the US equivalent of electrical alternans), the patient is only mildly symptomatic at rest and is hemodynamically stable. This patient does NOT need a pericardiocentesis performed emergently in the ED, and instead needs consultation with a cardiologist for placement of a window.

Summary and Take Home Points:

1. Have a low threshold to perform a focused echocardiogram in pts with unexplained dyspnea. The attached study by Mandavia et al demonstrated an incidence of pericardial effusions of approximately 20% in ED patients with fairly broad inclusion criteria (i.e. they did not limit this to patients only with very high pretest probability).
2. Echocardiographic tamponade is NOT clinical tamponade. Patients with clinical tamponade are unstable, and need emergent pericardiocenteses, patients with only echocardiographic tamponade do not need this procedure performed in the ED.
3. Use M-mode to confirm your suspicion that the RV and LV walls are dysnchronos, and the patient in fact has RV diastolic collapse. Also assess for RA collapse in systole and IVC plethora. No one finding is pathognomic for tamponade.

Hope you find this helpful. I have attached the article by Mandavia and a document on the various echocardiographic windows, or scanning planes below.

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