Tamponade
Acute or subacute, occurs when fluid or blood builds up in the pericardial space
Typically, the pericardial space can accommodate shifts in intracardiac volume. However, as fluid accumulates in the pericardial space, the capacity to accommodate reaches an inflection point and the pressure rapidly rises, reducing cardiac filling
Pericardial compliance and capacity varies depending on whether the effusion has accumulated rapidly or slowly
Physiology: Ventricular interdependence, meaning as the RV fills with inspiration, because the free wall is restricted due to the pericardial fluid, the only direction for filling to occur is towards the septal wall, thereby inhibiting LV filling and subsequent stroke volume and pulse pressure
Clinical Signs: Classically described Beck's Triad (Muffled heart sounds due to effusion, jugular venous distension, and hypotension due to impaired filling) seen in a minority of cases
Tachycardia may be the only sign in many patients before more significant decompensation
May also see pulsus paradoxus
Echo findings: Pericardial fluid, can also see RA and RV collapse on echocardiography but important to note that cardiac tamponade is a clinical diagnosis, not an echocardiographic diagnosis
Treatment: pericardial drainage via pericardiocentesis, potentially with placement of a pericardial drainage catheter
