Cardio 3 Flashcards
What heart complication is at risk with IV drug users?
Right-sided endocarditis involving the tricuspid valve, often due to S. aureus. Infective endocarditis can cause tricuspid regurgitation, w/ early systolic murmur accentuated by inspiration.
How do you treat hypovolemic shock?
Rapid infusion of blood products and crystalloid solutions (normal saline). These inc. preload, w/c will stretch myocardium and inc. end-diastolic sarcomere length, thus leading to inc, SV and CO.
What conditions may Marantic endocarditis be associated with?
This is a noninfectious endocarditis due to deposition of sterile platelet thrombi on cardiac valves. It’s commonly assctd w/ advanced malignancy as well as chronic inflam d/o and sepsis.
How does Hereditary pulmonary arterial HTN occur and how does it present?
PAH follows a 2-hit hypothesis with BMPR2 gene. The dse process involves vascular remodelling, inc. pulmo vascular resistance, and progressive pulmo HTN. It may present as dyspnea and fatigue w/ accentuated P2 of the 2nd heart sound. Severe pulmo HTN may lead to cor pulmonale.
What growth factors and cytokines are needed for the development of atherosclerotic plaques?
> PDGF is released by adherent platelets, endothelial cells, and macrophages – smooth muscle cell migration from media to intima, SMC proliferation.
TGF-beta released by platelets – chemotactic for SMCs, induces collagen production.
What frequently disposes to Infective endocarditis in Developed vs. Developing countries?
> Developed: mitral valve prolapse w/ regurgitation – endocardial injury from turbulent flow, platelet deposits, bacteremia (S. viridans).
Developing: Rheumatic HD.
What is the Fick principle equation for calculating Cardiac Output?
CO = (Rate of O2 consumption)/(A-V O2 content difference)
*Can be measured w/ Pulmonary artery (Swan-Gantz) catheter.
When are the S3 and S4 heart sounds considered abnormal?
> Abnormal S3: patients age >40, suggests ventricular enlargement and rapid passive ventricular filling.
Abnormal S4: reduced ventricular compliance (HTN heart disease, aortic stenosis, hypertrophic cardiomyopathy).
Why does the antiarrhythmic dihydropyridine CCBs (ex. amplodipine) cause peripheral edema? How can the risk of peripheral edema be reduced?
CCBs preferentially dilate precapillary vessels (arteriolar dilation), leading to inc. hydrostatic pressure and extravasation. ARBs cause postcapillary venodilation and can normalize the inc. hydrostatic pressure, reducing the risk of peripheral edema by CCBs.
Which receptors are stimulated by Dopamine at low dose, high dose, and higher dose?
> Low: D1 receptors in renal vasculature (dilatation) – inc. GFR, RBF, Na excretion.
High: B1 receptors (heart) – inc. contraction, SBP.
Higher: alpha1 receptors in systemic vasculature (constriction) – dec. CO, afterload.
How are alpha1 antagonists (terazosin, doxazosin) associated w/ Orthostatic hypotension?
As a person moves from supine to standing, blood pools to the veins below the heart and there is dec. VR and ventricular filling, leading to dec. CO and BP. The compensatory baroreceptor reflex increases sympathetic tone that inc. peripheral vascular resistance (alpha1) and HR (B1)
If the patient has an Aspirin allergy, what other drug may be given to prevent cardiovascular events?
Clopidogrel is AS EFFECTIVE as aspirin for preventing cardiovascular events. It irreversibly blocks ADP receptors on platelet surface and prevents aggregation.
