5/12 Cardio, Mixed Flashcards
(35 cards)
Norepinephrine extravasation
Blanching of vein into which NE is being infused, induration and pallor of tissues surrounding the IV site
NE causes intense a1 mediated vasocontriction and tissue necrosis
Rx: local injection of an alpha1 blocking agent, (phentolamine)
Down Syndrome most common cause
Maternal meiotic nondisjunction
Vessels to which organs are most commonly involved in polyarteritis nodosa?
Kidneys, heart, liver, GI tract, Skin (1/3)
Lung is VERY RARELY INVOLVED
Descending thoracic aorta in relation to the esophagus and left atrium
Left atrium (anterior) Esophagus Thoracic aorta (posterior)
Ventricular response in afib
Dependent on the transmission of abnormal atrial impulses through the AV node
The AV node refractory period regulates the number of atrial impulses that reach the ventricle and determines the ventricular contraction rate in conditions where the atria undergo rapid depolarization
Complete 3rd degree AV block: what paces the ventricles?
AV nodal cells become pacemakers when conduction between the SA and AV nodes is impaired
Location of IVC at L1 on CT
IVC lies anterior to the right renal artery and to the right of the aorta
IVC is formed by the union of the right and left common iliac veins at the L4-L5 level
Effects on Nitroprusside
Venous and arterial vasodilator
Decreases left ventricular preload and afterload
Angioedema
1) Mast cell activation (T1H-IgE mediated, Direct via opioids)
2) Excess bradykinin (ACE inhibitors, C1 inhibitor deficiency)-no pruritus or urticaria
Tongue, lips, eyelids
MOA of pulmonary HTN due to L sided Heart Disease
Increases pulmonary venous pressure and congestion
Leads to passive increase in pulmonary arterial pressure, which is made worse by reactive vasoconstriction and structural remodeling of the pulmonary vasculature 2nd to impaired NO availability and increased endothelial expression
Isolated mitral stenosis vs. combined mitral/ aortic stenosis
Isolated mitral stenosis elevates left atrial diastolic pressure and can cause elevated pulmonary capillary wedge pressure, pulm HTN, decrease pulmonary vascular compliant, RV dilatation and tricuspid regurg.
Diastolic pressure in the left ventricle is usually near normal or even decreased with severe mitral stenosis.
Rx of severe hypertension
Fenoldopam is a short acting selective peripheral dopamine 1 receptor agonist (with little to no effect on a or b adrenergic receptors)
Given IV (especially in patient with renal insufficiency)
Activates adenylyl cyclase and increases cAMP, resulting in vasodilation with a corresponding decrease in BP
Increases renal perfusion, promotes diuresis and natriuresis
Dihydroergotamine
Ergot alkaloid commonly used to treat acute migraine HA
May induce vasospastic angina as it constricts vascular smooth muscle via stimulation of both a-adrenergic and serotonergic receptors
Can trigger prinzmetal angina; other triggers: cigarette smoking, cocaine/amphetamies, dihydroergotamine/triptans
Dystrophic calcification
Hallmark of cell injury and death
Occurs in all types of necrosis (coagulative, fat, caseous, liquefactive) in the setting of normal calcium levels
What determines the degree of right to left shunting and resulting cyanosis in patients with tetralogy of fallot?
Degree of right ventricular outflow tract obstruction
Class III antiarrhythmic drugs (amiodarone, sotalol, dofetilide)
Predominantly block K channels and inhibit the outward K currents during phase 3 of the cardiac action potential, thereby prolonging repolarization and total action potential duration
Hibernating myocardium
Left ventricular systolic dysfunction due to reduced coronary blood flow at rest that is partially or completely reversible by coronary revascularization
Ventricular septal defect (VSD)
Typically presents in neonatal period after pulmonary vascular resistance has declined
Clinical presentation depends on the size of the defect, which ranges from asymptomatic holosystolic murmur (small VSD) to heart failure (large VSD)
Paradoxical embolism
Occurs when a thrombus from the venous system crosses into the arterial circulation via an abnormal connection between the R and L cardiac chambers (e.g. patent foramen ovale, atrial septal defect, ventricular septal defect). Atrial left to right shunts cause wide and fixed splitting of S2 and can facilitate paradoxical embolism due to periods of transient shunt reversal (straining or coughing)
Clopidogrel
Irreversibly blocks the P2Y component of ADP receptors on the platelet surface and prevents platelet aggregation
As effective as aspirin in the prevention of cardiovascular events in patients with coronary heart disease (use in patients with aspirin allergy/asthma/rhinitis)
Sarcomere
Distance between 2 z line
Thin (actin) filaments in the I band are bound to structural proteins at Z line
Unbound ends of actin project into the middle of the sarcomere where they interact with thick (myosin) filaments during muscle contraction
Thick (myosin) filaments in the A band are bound to structural proteins at the M line
The anterior pituitary is derived from which embryonic layer
Surface ectoderm (Rathke’s pouch, anterior pituitary)
Hemoglobin A2
A2D2, 2.5% of total hemoglobin
Elevated in beta-thalassemia to compensate for the decreased synthesis of HbA due to B globin chain underproduction
Obstructed right brachiocephalic vein
Brachiocephalic vein drains the ipsilateral jugular and subclavian veins.
The bilateral brachiocephalic veins combine to form the SVC.
Brachiocephalic vein obstruction causes symptoms similar to those seen in SVC syndrome but only on one side of the body
