>10mmHg change in systolic BP on inspiration
Enlarged cardiac silhouette
Often normal
Tachycardia (bradycardia is ominous finding)
Electrical alternans
Low voltage
All limb lead QRS amplitudes <5 mm or I+II+III<15;
OR All precordial QRS amplitudes <10 mm or V1+V2+V3<30
All limb lead QRS amplitudes <5 mm or I+II+III<15;
OR All precordial QRS amplitudes <10 mm or V1+V2+V3<30<unk><unk> 
In acute cases, even a relatively small build up of<unk>  fluid can lead to hemodynamic compromise
Differentiate<unk><unk>  from pleural<unk>  using the parasternal long axis view.<unk><unk> s will have an anechoic stripe between the left atrium and descending thoracic aorta.  In a pleural<unk> , the stripe will be seen behind the descending thoracic aorta.
Classical ultrasound findings
Diastolic collapse of the right atrium (in atrial diastole)
Diastolic collapse of the right ventricle
Plethoric IVC (highly sensitive but low specificity)
Evaluating systolic vs. diastolic phases with M-mode
Position in PSL view with M-mode line through where RV appears to collapse
Allow M-mode line to pass through where the anterior MV hits the septum in diastole (much like evaluation of EPSS - see Formal echocardiography)
The period of time where the anterior leaflet of the mitral valve is open (and closest to the septum) is the period of diastole. Evaluate the anterior free wall of the right ventricle for collapse. The longer period of collapse during diastole is an indicator for advanced<unk>  physiology
Valvular pulsus paradoxus
Obtain apical 4-chamber view, place doppler indicator in either MV or TV location
Doppler interrogation across the mitral valve will demonstrate exaggerated respiratory variability of transvalvular flow
MV inflow respiratory variation, difference from highest velocity to lowest, as a percentage of highest velocity
> 25%, likely<unk>  physiology
> 40% for tricuspid inflow variation
Helpful in thickened RV and RA from longstanding pulmonary hypertensive patients
In acute cases, even a relatively small build up of<unk>  fluid can lead to hemodynamic compromise
Differentiate<unk><unk>  from pleural<unk>  using the parasternal long axis view.<unk><unk> s will have an anechoic stripe between the left atrium and descending thoracic aorta.  In a pleural<unk> , the stripe will be seen behind the descending thoracic aorta.
Diastolic collapse of the right atrium (in atrial diastole)
Diastolic collapse of the right ventricle
Plethoric IVC (highly sensitive but low specificity)
Position in PSL view with M-mode line through where RV appears to collapse
Allow M-mode line to pass through where the anterior MV hits the septum in diastole (much like evaluation of EPSS - see Formal echocardiography)
The period of time where the anterior leaflet of the mitral valve is open (and closest to the septum) is the period of diastole. Evaluate the anterior free wall of the right ventricle for collapse. The longer period of collapse during diastole is an indicator for advanced<unk>  physiology
Obtain apical 4-chamber view, place doppler indicator in either MV or TV location
Doppler interrogation across the mitral valve will demonstrate exaggerated respiratory variability of transvalvular flow
MV inflow respiratory variation, difference from highest velocity to lowest, as a percentage of highest velocity
> 25%, likely<unk>  physiology
> 40% for tricuspid inflow variation
Helpful in thickened RV and RA from longstanding pulmonary hypertensive patients
> 25%, likely<unk>  physiology
> 40% for tricuspid inflow variation
Helpful in thickened RV and RA from longstanding pulmonary hypertensive patients
Pericardial effusion and tamponade
Acute coronary syndromes 
Myocardial rupture
STEMI
Immersion pulmonary edema
Non-STEMI
Acute chest syndrome
Unstable angina