Cardiology #2

zms2187's version from 2016-09-07 07:29


Question Answer
echo findings tamponade+ 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 tardussmall and slow carotid upstroke- common with severe AS
Tamponade, explain respiratory changes and what happens to RVduring 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 importantallows us to evaluate cardiac output among individuals of different sizes (CO/BSA) for standardization
Formula to calculate SVRbased on Ohms law where Q= P/R. R= P/Q so pressure is MAP - CVP and Q is CO
MAP = ?1/3 (Systolic aortic pressure) + 2/3 (Diastolic aortic pressure)
Frank Starling LawPreload 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 criteriaCornell criteria - R wave in aVL + S wave in V3 >28mm M and >20mm F
EKG criteria for RVHR axis deviation and dominant R wave w/secondary ST and/or T wave changes in V1/V2
Wide QRS, no P, rate 100-110accelerated idioventricular rhythm
Wide QRS, no P, rate 110-250VT or SVT w/aberrancy

Section 2

Question Answer
R axis deviation on EKG> 100 degrees. - in I and + in aVF
L axis deviation on EKGbetween -30 and -90. + in I and - in avF or II
Normal axis on EKGanywhere from 0 to 90, + in I and II or I and aVF
where are q waves common?small q waves (<0.03s) common in most leads EXCEPT V1-V3 and avR
Q wave criteria for MI?at least >1mm depth in 2 contiguous leads.
what is a U wavesmall (usually +) deflection after T wave. If faster HR U wave can be superimposed on preceding T wave. indicates afterpotentials of ventricular m vs repol of purkinje fibers
Pacemaker 4 letter code1st is chamber PACED (A, V, or dual), 2nd is chamber SENSED(A, V, or dual), 3rd is MODE (inhibit, triggered, dual), 4th is RATE RESPONSIVENESS
Meaning of VVIR pacer codepacemaker PACES the ventricle, SENSES the ventricle, INHIBITED by a sensed QRS complex, and is rate responsive
DDD pacer codePACES and SENSES the atria and ventricle. Dual mode indicates that sensed atrial activity will inhibit atrial output and trigger a ventricular output after a designated AV interval