UWorld-Cardiology Flashcards
what drug would you use to treat beta blocker overdose and why
glucagon; it activates GPCRs in cardiac myocytes leading to increased adenylyl cyclase activity –> increased cAMP leading to increased contractility and heart rate in cardiac myocytes
tetralogy of Fallot, transposition of the great vessels and truncus arteriosus all result from what impaired process during embryologic development
migration of the neural crest cells into the truncus arteriosus and bulbus cordis in preparation to grow in spiraling fashion and separate the aorta from the pulmonary artery
which artery usually supplies the diaphragmatic surface of the heart
the right coronary artery (b/c it usually supplies the PDA and the PDA supplies the inferior left ventricle, which lies against the diaphragm)
name the four features of Tetralogy of Fallot
pulmonic stenosis, RVH, overriding aorta, and VSD
how long after onset of total ischemia does cardiac myocyte contraction cease
less then 60 seconds
explain the mechanism of action by which NO causes relaxation of smooth muscle
NO activates guanylate cyclase leading to increased cGMP, cGMP downregulates intracellular calcium, which decreases myosin light chain kinase activity leading to myosin dephosphorylation and consequent relaxation of smooth muscle
what is the equation for the maintenance dose
maintenance dose= (steady state plasma conc.) X (clearance) / (bioavailability)
which cardiac disease is characterized by an opening snap followed by a low-pitched late diastolic rumble
mitral stenosis (opening snap= abrupt halting of mitral valve leaflets due to fusion of the valve tips)
which cardiac disease is characterized by a mid-systolic click followed by a crescendo murmur
mitral valve prolapse
mid-systolic click= sudden tensing of chordae tendinae
which anti-arrhythmic drug used to treat ventricular tachycardia is most selective for ischemic myocardium over normal cardiac tissue
lidocaine suppresses rapidly depolarizing and depolarized cells (though it is being replaced by amiodarone for management of v. tach)
explain pulsus paradoxus, what it is and when you would see it
pulsus paradoxus is a decrease in SBP during inhalation that is greater than 10mmHg; this occurs in disease that impair right heart expansion into the paricardial space; the right ventricle must instead push the interventricular septum into the left ventricular side decreasing EDV and thereby decreasing SBP
what does an S3 indicate
left ventricular failure or increased left end systolic volume
what is milrinone and what effect does it have in the heart vs. vascular smooth muscle
milrinone is a phosphodiesterase isoenzyme 3 inhibitor;
it increases cAMP to increase contractility in the heart and vasodilation in vascular smooth muscle
what is the main way that nitrates work to treat angina pectoris
nitrates decrease preload (thereby lowering ventricular work and O2 demand)
which of these three tissues have beta-1 receptors:
cardiac muscle
vascular smooth muscle
juxtaglomerular cells
beta-1 receptors are found in cardiac muscle, juxtaglomerular cells and vascular smooth muscle
what keeps a patent ductus arteriosus open?
what closes a patent ductus arteriosus?
prostaglandins keep a PDA open
indomethacin or NSAIDS close a PDA
what is amyl nitrite and why isn’t it used anymore
a volatile inhalant historically used to treat angina pectoris;
discontinued because of side effects of cutaneous flushing and postural hypotension
bounding femoral and carotid pulses with head bobbing indicates what cardiac abnormality
aortic regurgitation (note: head bobbing due to bounding carotid pulse= de Musset's sign
what are the resting potentials for cardiac vs. skeletal myocytes
cardiac myocytes: -90mV
skeletal myocytes: -75mV
which bacteria synthesize dextrans from glucose
strep viridans bacteria;
this enables them to colonize enamel and valves
what reaction is catalyzed by endothelial nitric oxide synthase (eNOS)
in response to ACh, bradykinin or shear stress, intracellular calcium increases triggering eNOS to catalyze this reaction:
Argining + O2 —-> NO + citrulline
what is the commonest cause and location of aortic rupture
motor vehicle accident;
aortic isthmus: the connection between the ascending and descending, just distal to the branch point of the left subclavian arterty
what group of drugs and what particular drug from that class has been proven to slow progression and lower mortality for CHF
beta blockers; particularly carvedilol
what is seen under the microscope for cardiac tissue 3 hours after myocardial infarction
trick question! minimal change is detectable before 4 hours
what is Trousseau’s syndrome
migratory thrombophlebitis due to hypercoagulability (often seen in patients with disseminated cancers)
list the ventricular muscle, atrial muscle, AV node and Purkinje system in order from fastest to slowest in terms of action potential velocity
Purkinje system is fastest (2.2 m/sec), then the atrial muscle (1.1 m/sec), then ventricular muscle (0.3 m/sec), and the AV node is slowest (0.05 m/sec)
which drug for MRSA has a side effect of myopathy and increased Cr kinase;
how does it work?
daptomycin can cause myopathy and increased creatinine kinase;
it works by depolarizing the bacterial cellular membrane
best indicator of severity of mitral regurgitation =?
audible S3 (suggests high volume of regurgitant flow into LV)
name the proteins associated with the following types of amyloidosis:
- localized cardiac atria (isolated atrial amyloidosis)
- localized thyroid gland
- localized pancreatic
- localized pituitary gland
- Alzheimer’s and Cerebral Amyloid Angiopathy
- systemic amyloidosis
- cardiac atria: atrial natriuretic peptide
- thyroid gland: calcitonin
- pancreatic: amylin
- pituitary gland: prolactin
- Alzheimer’s and CAA: beta-amyloid
- systemic amyloidosis: immune globulin light chain
in the lung, a cavitary lesion with an air-fluid level =?
lung abscess (most common cause is aspiration => abscess with normal mouth flora)
why should you advise your patient to take 8-10 hour breaks from taking their nitroglycerin
nitroglycerine (much like nasal decongestants) exhibit tachyphylaxis; after prolonged use buildup of the chemical mediator (NO) feeds back negatively on the system
why would an anti-anginal drug seek to inhibit fatty acid oxidation
fatty acid oxidation is a major source of energy, but it utilized more oxygen per ATP generated and so it would be better to shift ATP production to more glycolysis and oxidative phosphorylation
differentiate valve findings for infective endocarditis vs. rhematic fever
infective endocarditis causes larger vegetations and degeneration of the valve;
rhematic fever causes smaller vegetations and thickening or fibrosis of the valve
