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Echocardiographic Evaluation of Pericardial Effusion and Cardiac Tamponade

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Estudo acima, bem recente, cita estudo antigo mas muito confiável sobre o colapso diastólico do ventrículo direito no tamponamento verdadeiro.

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https://www.ncbi.nlm.nih.gov/pubmed/3953452/

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Right atrium collapse is commonly observed during systole. In early systole (near the peak of the R wave), intracavity pressure is lower and the atrial indentation of the thin free wall is seen. Moreover, duration of atrial collapse (collapse longer than one-third of the cardiac cycle) has been described as an almost 100% sensitive and specific sign of clinical cardiac tamponade . While isolated RA collapse is frequently observed, collapse of the left atrium is, although described, rarely observed as a single chamber collapse (28). It is usually seen in cardiac tamponade along with collapse of the RA . Collapse of both atria increases the sensitivity and specificity of cardiac tamponade.

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Right ventricle collapse is commonly observed in diastole. During early diastole (at the end of the T wave), intracavity pressures are lower . Collapse of the free wall appears with moderate increases in pericardial pressures and will decrease stroke volume, initially without significant changes in the systemic blood pressure due to compensatory mechanisms (29). Initially, collapse of the RV free wall will only be present during expiration, but as collapse progresses, detection is possible throughout the respiratory cycle. Duration of collapse of the RV free wall is again an indicator of severity (30). Collapse will last as long as pericardial pressures remain higher than RV filling pressures. Thus, the longer the indentation on the free wall, the more severe the tamponade. M-mode through the affected wall (always along with appropriate EKG tracing) is useful to assess duration and timing of collapse. Experimental studies demonstrate that RV diastolic indentation is more sensitive, specific, and has a better predictive value of cardiac tamponade than pulsus paradoxus (26). Collapse of the LV is unusual, due to its thicker wall and may be seen in patients with severe pulmonary hypertension (31) or loculated PEff, typically around the free posterior wall of the LV following cardiac surgery (32) .

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