Cardiology Flashcards
What are the Class III antiarrythmics?
-“tilide” drugs (dofetilide, ibutilide)
Sotalol
Amiodarone
What are some of the MANY side effects of amiodarone?
Pulmonary fibrosis Hypo OR hyper thyroidism Hypersensitivity hepatitis Risky in heart failure patients Grey corneal deposits Grey-blue skin discoloration in sun CYP450 inhibitor LOW incidence of torsades (sotalol and the ilide drugs have a higher risk)
What is the action of class III antiarrhythmics?
Block K+ channels that depolarize the myocardium thereby causing prolonged depolarization (prolonged action potential) and prolonged refractory period
How is Digoxin cleared/metabolized? What are signs of toxicity?
Renally
Toxicities: yellow tinting, anorexia, n/v, abdominal pain
Although digoxin can cause _____kalemia, toxicity is actually exacerbated by _____kalemia because it increases Digoxin binding to the Na/K ATPase pump.
Digoxin can cause hyperkalemia (blocked pump prevents sodium coming out and thus exchange for K in).
However hypokalemia increases Digoxin binding so it can make toxicity (yellow tinted vision and GI disturbances) worse.
What are the most common causes of nonbacterial thrombotic endocarditis (NBTE)?
- Advanced malignancy
- Chronic inflammatory diseases (SLE, antiphospholipid syndrome, DIC)
NBTE is characterized by sterile platelet-rich thrombi on the valves
Although Digoxin is primarily used to increase contractility, it may also be used for rate control. What is the mechanism by which Digoxin slows ventricular rate during atrial fibrillation?
Increasing parasympathetic tone via the Vagus nerve -> ultimately inhibits AV nodal conduction
What is the mechanism of action of dobutamine? What is the signaling cascade?
Beta 1 agonist:
Gs signaling -> increased cAMP -> calcium channel activation -> increased Ca2+ = increased contractility and heart rate (and thus cardiac output overall)
What cardiac defects result from doxorubicin (or other anthracyclines like daunorubicin)?
What can be co-administered to prevent these effects?
Dilated cardiomyopathy due to formation of iron-containing complexes that produce DNA-damaging free radicals.
Dexrazoxane is a chelating agent that can block the free radicals.
Which organ is most likely to suffer from infarction/thromboembolism in emboli generated in Afib?
Kidneys due to higher perfusion rate
Infarction will appear as a wedge-shaped lesion on CT
What is the classic triad of physical exam findings seen in cardiac tamponade?
- Muffled heart sounds
- JVD
- Hypotension (+ pulsus paradoxus!)
How does Digoxin increase myocardial contractility?
Competes for the Na/K ATPase, reducing its activity. This prevents Na efflux (and K influx).
Na builds up but then escapes through another Na/Ca2+ exchanger. This floods the cell with calcium, causing increased contractility.
(+) Inotropy will increase cardiac output INDEPENDENT of ______.
EDV (cardiomyocyte stretching)
Total peripheral resistance is MOSTLY determined by what vessels?
Arterioles
In what situations will you often see a decrease in TPR?
i.e. arteriolar dilation
Exercise
Arterio-venus shunts
An S4 heart sound is a sign of ______ dysfunction.
Diastolic
It occurs due to a sudden rise in end-diastolic ventricular pressure caused by atrial contraction against a stiff ventricle.
Occurs in any condition that reduces ventricular compliance (e.g. hypertensive heart disease, aortic stenosis, hypertrophic cardiomyopathy).
What causes the S3 heart sound?
Rapid passive filling of ventricles in diastole.
Sudden cessation of filling as ventricle reaches elastic limit.
Occurs in systolic heart failure, mitral regurg, and high-output states
Think of lots of blood sloshing around slamming against the wall
What is the major determining factor of severity of a case of Tetralogy of Fallot?
Degree of RVOT obstruction
What compensatory mechanisms are initiated by the kidneys in response to decreased renal perfusion (e.g. as in CHF)?
- RAAS activation: sodium retention, aldosterone production, vasoconstriction
- Sympathetic output: epinephrine and norepinephrine increase HR and contractility and increase in peripheral arterial resistance increasing afterload.
Class IB antiarrhythmics are useful for treating _____-induced ventricular arrhythmias.
Ischemia-induced
Class IC antiarrhythmics have the strongest binding to sodium channels and thus are slowest to dissociate causing cumulative effects, thus they are especially useful in treating what type of arrhythmia?
Tachyarrhythmia
Aortic regurgitation murmur is best heard in which position?
Sitting up and leaning forward with breath held at end-expiration
Midsystolic click followed by a Mid- to late systolic murmur = ?
Mitral valve prolapse with mitral regurgitation
The click results from the sudden tensing of the chordae tendineae as they are pulled taut by the ballooning valve leaflets
What are the only two murmurs that DECREASE with increased preload/venous return?
Mitral valve prolapse
Hypertrophic cardiomyopathy systolic murmur at cardiac apex
Which class of anti-arrhythmics work by blocking voltage-dependent sodium channels (i.e. depolarization) of the cardiac AP?
Class I
What do endothelial cells secrete to prevent platelet aggregation and adhesion to the vascular endothelium?
Prostacyclin
Damaged endothelial cells lose the ability to synthesize prostacyclin, predisposing them to the development of thrombi and hemostasis.
What are the 2 main effects of milrinone (a PDE3 enzyme inhibitor)?
- Positive inotropy
2. Vasodilation (arterial AND venous)
Nesiritide and is a synthetic form of what endogenous peptide?
BNP
thus causes naturesis and arteriolar and venous dilation
Due to the very high myocardial oxygen extraction (up to 75%), what vessel in the body has the absolute lowest oxygen saturation?
The coronary sinus (drains the venous blood of the heart itself)
What are the actions of nitroprusside?
Short-acting arteriolar and venous dilation
As such, it decreases both preload and afterload, allowing adequate CO to be delivered at lower LVEDPs.
What pathologies can cause wide splitting (i.e. P2 heart sound, delayed pulmonary valve closing)?
Right bundle branch block
Pulmonic valve stenosis
What pathologies can cause fixed splitting (i.e. P2 heart sound, delayed pulmonary valve closing that doesn’t change with inspiration/expiration)?
ASD
What pathologies can cause paradoxical splitting (i.e. P2 heart sound pulmonic valve closing before A2 aortic valve)?
What will bring them back closer together?
Increase in left ventricular volume
Left bundle branch block)
Aortic valve stenosis
Inspiration will bring them back together (though P2 will still occur before A2, you just won’t be able to hear it).
Hand grip increases ___load. It therefore increases the intensities of which murmurs?
Afterload
MR
AR
VSD
Rapid squatting increases ______ and _____. Ultimately what murmurs are decreased
Preload AND afterload
AS
MR
VSD
Valsalva decreases ____load.
Preload by increasing thoracic pressure
Decreases most murmurs but NOT MVP or HCM
New onset mitral valve regurgitation may be due to an infarct in _______ because it supplies the _____ valve leaflet.
RCA
Posterior valve leaflet
In what part of systole does mitral and tricuspid regurg present?
All of it! (they are holosystolic)
Patients with what type of diseases are predisposed to mitral valve prolapse?
Connective tissue diseases
VSD and tricuspid regurgitation are both holosystolic murmurs heard best at the LSB…so how can you tell them apart?
Tricuspid regurg will radiate to the right shoulder
Opening snap + diastolic rumble = ?
Mitral regurgitation
What is an important side effect of vinblastine other than the stocking glove neuropathy?
Myelosuppression
What ion is responsible for the upstroke in cardiac PACEMAKER cells?
ICa2+
What ions are responsible for Ifunny in cardiac pacemaker cells?
Na and K+
How is atrial flutter discernible from atrial fibrillation?
Atrial flutter produces a 4:1 sawtooth pattern with intact p waves and regular spacing of R-R intervals
Mobitz Type I/Wenkebach 2nd degree heart block results in what?
Gradual increase in PR intervals until you get
Dropped QRS complexes
Mobitz Type II 2nd degree heart block results in what?
Randomly dropped QRS complexes, PR interval is fixed
Should be treated with a pacemaker
Lyme disease is associated with ____ degree heart block.
3rd
An increase in BNP is used to diagnose ______.
Heart failure
Oxygen is only sense by chemoreceptors in the ______ nervous system.
Peripheral
What will a tetralogy of fallot heart look like on CXR?
A boot
Do VSDs usually close on their own?
Yes
Endothelin is a vaso______
constrictor
What is the most common congenital heart defect in Down syndrome and what are the sequelae?
Endocardial cushion defects ->
i.e. causes AV defect, ASD, VSD
What is the most common congenital heart defect associated with babies born to moms with DM? What about a spinal defect?
Transposition
Caudal regression syndrome (problems forming the lumbar, sacrum, coccyx regions)
What congenital heart defects are associated with Marfans?
Mitral Valve Prolapse
Aortic aneurysms and aortic dissection
What congenital heart defects are associated with Turner Syndrome?
Bicuspid aortic valve and coarctation
What congenital heart defects are associated with Williams Syndrome?
Supravalvular aortic stenosis
22q11 defect patients have problems with their ______ cells, leading to what common heart defects?
Neural crest cells
Aorticopulmonary defects
Persistent truncus arteriosus
TOF
If you see symptoms of superior vena cava syndrome but it is UNILATERAL rather than bilateral, you’ve likely occlude what vein?
Brachiocephalic
S3 heart sounds may be normal in which patients?
Young individuals and pregnant women
What are the 2 major local effectors of coronary vasodilation (i.e. myocardial oxygen supply) involved in autoregulation?
Adenosine and NO
Which class of calcium channel blocker has effects the SA node and can cause bradycardia?
Non-dihydropyridine (i.e. verapamil, diltiazem)
Which antiarrhythmic class is efficacious in ischemia-induced ventricular arrhythmias?
Class IB (lidocaine, mexilitine, phenytoin)
They are the weakest sodium channel blockers and thus dissociate the fastest. Ischemic myocardium has higher than normal (less negative)
How does adenosine work as an antiarrhythmic? What are the side effects?
Adenosine blocks conduction through the AV node and can thus be used to treat PSVTs.
Side effects = rapid-onset and short-lived flushing, chest burning (due to bronchospasm), hypotension, and high-grade AV block
What are the side effects of niacin?
Cutaneous flushing, warmth, and itching mostly mediated by the release of prostaglandins.
Pre-treatment with aspirin can reduce niacin side effects.
What is acute decompensated heart failure?
Reduced cardiac output from excessive ventricular filling pressures triggers a compensatory neurohumoral stimulation:
- Sympathetic nervous system activation
- RAAS activation
- Antidiuretic hormone secretion
All of which can cause vasoconstriction, edema, and deleterious cardiac remodeling which exacerbate problems with cardiac output.
What is Ortner syndrome?
A rare cardiovocal syndrome and refers to recurrent laryngeal nerve palsy from cardiovascular disease.
Most common cause is a dilated left atrium due to mitral stenosis, but other causes, including pulmonary hypertension, thoracic aortic aneurysms, an enlarged pulmonary artery and aberrant subclavian artery syndrome have been reported compressing the nerve.
DM (elevated blood glucose) leads to what type of arteriolosclerosis?
Non-enzymatic glycation leads to hyaline deposition -> hyalinosis ateriolosclerosis
HTN leads to what type of arteriolosclerosis?
Fibrinous/”onion skinning” arteriolosclerosis
Monckeberg sclerosis aka ?
Medial calcific sclerosis
Often occur in popliteal. Does NOT decrease size of the lumen because it only thickens the medial layer
What type of aortic aneurysm is seen in tertiary syphilis?
Thoracic AA due to spirochetes embedding themselves in the vasa vasorum causing cystic medial inflammation/fibrosus
What distinguishes type A vs type B aortic aneurysms? Which is more stable (and thus can be treated medically)?
Type B begins after the aortic arch
B = more stable
can be treated with a Beta Blocker
Remember: B = beyond (aortic a.), Beta Blocker
What vessels are at risk of compression from Type A and B aortic aneurysms?
Left subclavian vessels -> leads to uneven pressure readings between L and R arms
Chronic/stable angina is _______, while prinzmetal/vasospastic is ___________.
Subendocardial
Transmural
Chronic/stable angina will cause ST _______, while prinzmetal/vasospastic will cause ST ___________. Unstable angina will cause ST _____.
Stable: Depression
Prinzmetal: Elevation
Unstable: Depression (and also possibly T wave inversion)
What is Brugada Syndrome?
AD disorder most common in Asian males.
ECG pattern of pseudo-right bundle branch block and ST elevations in V1-V3. Increased risk of Vtach and SCD.
What type of heart defect is seen in Friedrich’s Ataxia?
Hypertrophic cardiomyopathy
In which type of shock will patients be cold and clammy due to increased peripheral resistance (SVR and CVP elevated)?
Cardiogenic shock
In which type of shock will patients be warm and dry due to decreased peripheral resistance (SVR and CVP DROP, vessels wide open)?
Distributive shock: Septic shock /anaphylaxis/CNS failure
HR will increase to compensate
The first sign of shock will always be:
Tachycardia
What are the major drugs that cause drug-induced Lupus?
Procainimide
Hydralazine
look up the rest
Nitroprusside can actually cause cyanide poisoning. How is it treated?
Thiosulfate
Nitrates primarily cause ____dilation.
Venodilation
Which antiarrhythmic class is best post MI?
Class IB (lidocaine)
Which antiarrhythmic class is contraindicated post MI?
Class IC (fleicanide, propafenone)
Generally bad in any heart with structural defect or previous ischemia
Mg2+ can be used to treat ______ toxicity.
Digoxin
Ivabradine inhibits _________ which prolongs phase _____ of the pacemaker cells.
funny current
Phase 4 by decreasing the slope of depolarization
Does not hurt contractility!
Acetazolamide inhibits _______ (enzyme) resulting in reduced _______ reabsorption in the PCT.
What are the metabolic consequences of this inhibition?
Carbonic anhydrase
Sodium bicarb reabsorption inhibited
Causes a normal anion gap metabolic acidosis/hyperchloremia
Note that the efficacy of acetazolamide decreases because the body will start to absorb more Na distally to compensate
Loop diuretics and thiazides can cause contraction ____osis.
Alkalosis
Hypovolemia caused by the diuretics can cause an upregulation of RAAS which pulls in Na in exchange for H+
Unlike other diuretics, K-sparing diuretics (triamterenes, spironolactone, eplerenone) cause metabolic _____osis/
Acidosis
How do calcium channel blockers/class 4 antiarrhythmics (diltiazem, verapamil) work as rate control?
Slow the funny current/slow depolarization phase/phase 4 in the pacemaker cells. Most dramatic effect is slowing the rate at the AV node.
Migratory thrombophlebitis, known as Trousseau syndrome, should raise suspicious for ______.
Cancer
esp visceral adenocarcinomas of the pancreas, colon, and lung due to hypercoaguable state.
Cyanosis that affects the lower extremities more than the upper extremities is indicative of what congenital heart defect?
PDA
What drug is given to treat beta blocker overdose?
Glucagon
What is the cellular signaling/MOA of glucagon in beta blocker overdose.
Increases HR and contractility independent of adrenergic receptors via:
Increased G-protein-coupled receptors on cardiac myocytes -> increased adenylate cyclase -> increased cAMP -> increased calcium release from internal stores and SA nodal firing
Beta blockers slow the AV nodal conduction, prolonging the ___ interval.
They do not have any specific effects on QRS or QT interval durations.
What is Osler-Weber-Rendu syndrome?
AKA hereditary hemorrhagic telangiectasia
AD condition marked by congenital telangiectasias to the skin and mucous membranes. May involve mucosa of lips, oronasopharynx, resp tract, GI tract, or urinary tract. They may cause epistaxis, GI bleeding, and hematuria.
Rarely can occur in the brain.
What is another name for Neurofibromatosis Type I?
Von Recklinghausen’s disease
This is marked by cafe au lait spots, lisch nodules, optic nerve gliomas, and of course neurofibromas
How do small VSDs present?
Loud blowing holosystolic murmurs mid/lower LSB and NO SYMPTOMS!
The murmur is usually not detectable at birth, but rather 4-10 days later as pulmonary vascular resistance continues to decline, permitting L to R shunting.
Cardiomyocytes stop contracting within __________(time) of ischemia.
60 seconds