MED SURG QUICK NOTES MADE SIMPLE

Med Surg Quick Notes S 82% or Higher on Your Next Nursing Test 8 1 Cardiology I Exam Notes 1.1 Cardiology Terms & Introduction  Preload: the 20% of blood remaining in the atria at end of diastole  80% of ventricular filling occurs before atrial kick  increase preload by inspiration or valsalva  Afterload: the volume of blood in the ventricles after atrial contraction  Cardiac output: volume of blood ejected from ventricles in one minute; normally 5 L  increased by increasing HR, contractility, or blood volume (or decreasing resistance)  Stroke volume: volume of blood ejected with each heartbeat  Myocardial contractility: ability of cardiac muscle to shorten with a given load  ejection fraction: a quantification of contractility; EF = SV/EDV  Starling’s law: stroke volume increases as end diastolic volume increases due to greater stretch put on walls of ventricles  Stenosis: narrowing to forward flow  Regurgitation (insufficiency): backward leakage while valve should be closed  Collaterals: normally nonfunctioning small vessels that interconnect coronary arteries  function when blockage creates upstream pressure, forcing the collaterals open  Heart sounds review o S3 in CHF o S4 in HTN  Coronary vessel dominance: we want to identify which artery perfuses the posterior 1/3 of the interventricular septum: is it the right coronary artery or the left circumflex (or both)?  SA node typically supplied by the right coronary artery, but can also be left circumflex  AV node supplied by whichever is dominant  Coronary artery disease (CAD) (aka coronary heart disease CHD): narrowing of vessels supplying the heart caused by atherosclerosis and/or hardening of the arteries 1.2 Pharmacology: Lipid Lowering Drugs  Statins: act as analogues for liver cholesterol synthesis to inhibit the actions of HMG-CoA reductase → liver upregulates LDL-R to try and draw cholesterol out of circulation  First line medication for lower LDL!  Can decrease LDL by 20-60%, decrease TG by 7-30%, and increase HDL by 5-15%  doubling the does results in an additional lowering of LDL by ~6%, with HDL increase of ~10-15%