+ effusion, diastolic RV collapse, respiratory increase of inter-ventricular dependence, by doppler will see respiratory variations > 25% in mitral, aortic and/or tricuspid flow
Parvus et tardus
small and slow carotid upstroke- common with severe AS
Tamponade, explain respiratory changes and what happens to RV
during inspiration, the negative intra-thoracic pressure is transmitted to the cardiac chambers, creating a depression in the right ventricle and atrium which suctions the venous caval flow into the right atrium. The right ventricle expands while the left ventricle volume decreases. During expiration, the pressure in the thorax and in the pericardium are summed, superior to the pressure in the right chambers. The right ventricle is compressed. This consequence of ventricular inter-dependence can be assessed from parasternal long or short axis viewing both right and left ventricles. Mmode will allow the comparison of the right ventricle size between inspiration and expiration.
Why is Cardiac Index important
allows us to evaluate cardiac output among individuals of different sizes (CO/BSA) for standardization
Formula to calculate SVR
based on Ohms law where Q= P/R. R= P/Q so pressure is MAP - CVP and Q is CO
Preload for the ventricles is defined as amount of passive tension or stretch exerted on the ventricular walls (i.e. intraventricular pressure) just prior to the initiation of systole. This load determines end-diastolic sarcomere length and thus the force of contraction. The Frank–Starling law states that the passive length to which the myocardial cells are stretched at the end of diastole determines the active tension they develop when stimulated to contract. The Frank–Starling law is an intrinsic property of myocytes and is not dependent upon extrinsic nerves or hormones. The general principle is that increased preload causes increased force of contraction, which increases stroke volume and thus cardiac output. The Frank–Starling law (or mechanism) helps the heart match cardiac output to venous return.
Good LVH criteria
Cornell criteria - R wave in aVL + S wave in V3 >28mm M and >20mm F
EKG criteria for RVH
R axis deviation and dominant R wave w/secondary ST and/or T wave changes in V1/V2