cardiovascular Flashcards
how would you explain what is SBP and DBP
SBP measures the pressure in the arteries when the heart beats
DBP measures the pressure in the arteries in between heart beats
what are the factors to consider for ASCVD risk estimator
demographics
- age
- sex
- race
labs
- SBP
- DBP
- HDL-C
- total cholesterol
PMHx
- DM
- smoler
- HTN treatment
what are the risk factors of CVD
- SBP and DBP
- age (≥65yo for women; ≥55yo for male)
- FHx of premature CVD
- dyslipidemia
- DM
- obesity (BMI≥30)
what are the prognostic factors of CVD
cerebrovascular diseases
- stroke
- TIA
renal diseases
- albuminuria/ proteinuria
- CKD ≥stage 3
heart diseases
- CHF
- angina pectoris
- MI
- coronary revascularisation
- left ventricle hypertrophy
vascular diseases
- aortic aneurysm
- peripheral artery disease
- hypertensive retinopathy
atherosclerosis
what are the identifiable secondary causes of HTN
- drug-induced
- CKD
- renal artery stenosis
- thyroid or PTH diseases
- nephropathy from T1DM
- obstructive sleep apnea
- primary hyperaldosteronism
- hypercortisolism
- rare monogenic ion transport disorders
- pheochromocytoma
- coarctation of the aorta
what are the drugs that can induce HTN
- illicit substances (cocaine, amphetamine, crystal meth, ecstasy)
- corticosteroids, NSAIDs, coxibs
- OCs with estrogen
- diet pills
- decongestants (pseudoephedrine, naphazoline)
- immunosuppressants
- herbal (ma huang)
what are the non-pharmacological management for HTN
- limit alcohol intake to max 2u/day for men and 1u/day for women
- smoking cessation
- physical activity (≥150mins/w of moderate intensity where HR is elevated from baseline on ≥3d/w)
- weight management to obtain BMI ≤23
- diet modifications to include more fruits and vegetables and low-fat dairy products while reducing intake of total and saturated fats
- limit salt intake to 5-6g/d (approx 1 teaspoon) –> choose homecooked meals, eat less gravy, sauces and soup when eating out, use herbs and spices to flavor food instead of salt and sauces
- stress management through adopting meditation, deep breathing or massage techniques and ensuring adequate good quality sleep
how is BP classified
normal BP: SBP <130 and DBP <85
high-normal BP: SBP 130-139 or DBP 85-89
grade I HTN: SBP 140-159 or DBP 90-99
grade II HTN: SBP 160-179 or DBP 100-109
grade III HTN: SBP ≥180 or DBP ≥110
isolated systolic hypertension: SBP ≥140 and DBP <90
what are the target BP goals
120-130/70-80
as tolerated for >65yo
what are the general monitoring parameters and follow ups
- BP q6-12m if low risk, q3-6m if moderate to very high risk
- BMI, FBG, lipid, electrolytes q12m
- others as indicated per individual profile
what are the key things to note regarding choice of antihypertensives
- caution diuretic in DM –> increases risk of hyperglycemia
- caution BB in DM –> masking of hypoglycemic symptoms
- avoid ACEi/ARB in CKD –> can increase risk of hyperkalemia and renal failure and angioedema
- avoid Spironolactone in CKD esp with ACEi/ARB –> can increase risk of hyperkalemia and renal failure
what are the drug-specific monitoring parameters and follow up upon initiation
ACEi/ARB
- renal panel in 1-2w
- presence of cough
- ADR cross reactivity (with other classes that target RAAS)
BB
- in 2-4w
- check PR control
CCB
- in 2-4w
- check PR control for NDHP-CCB
diuretic
- renal panel in 1-2w
what are the major factors influencing BP
Arterial BP = CO x Peripheral Resistance
components of CO
- HR
- contractility
- filling pressure (as determined by venous tone and blood volume)
components of peripheral resistance
- arteriolar tone
which of the components are part of preload vs which are part of afterload and define both these terms
preload is the stretching of cardiac muscles before contraction, associated with ventricular filling
- filling pressure as determined by blood volume and venous tone
afterload is the force against which the heart has to contract to eject the blood
- peripheral resistance as determined by arteriolar tone
elaborate on the RAAS system for when there is a drop in BP
short term
- drop in BP –> activation of sympathetic nervous system –> (i) activation of beta1 receptors in heart (ii) activation of beta1 receptors in smooth muscle –> (i) increases cardiac output (ii) increases peripheral resistance –> both (i) and (ii) lead to increase in BP
long term
- drop in BP –> decreased renal blood flow –> increases renin –> increased angiotensin II –> increases aldosterone –> increase Na+ and H2O retention –> increases blood volume –> increases BP
- drop in BP –> decreased renal blood flow –> decreases GFR –> increases Na+ and H2O retention –> increases in blood volume –> increase BP
what are the determinants of vascular tone, outline the r/s
- ca2+ channel
- Ca2+ ions forms a complex with calmodulin that activates MLCK to phosphorylate myosin-LC, leading to muscle contraction - adenylyl cyclase
- adenylyl cyclase converts ATP into cAMP that activates protein kinase A to increase reuptake of Ca2+, thus reducing formation of complex, subsequent activation of MLCK and phosphorylation of myosin-LC - guanylyl cyclase
- guanylyl cyclase converts GTP into cGMP which increases de-phosphorylation of myosin-LC, leading to muscle relaxation
what are the key functions of angiotensin II
angiotensin II causes vasoconstriction and stimulates secretion of aldosterone from adrenal cortex
what is the role of aldosterone
aldosterone is a hormone that acts on the kidneys to increase reabsorption of Na+ and H2O from the urine back into the bloodstream, leading to salt and water retention in the kidneys, leading to increased blood volume and BP
what is the moa of ACEi and list the drugs in this class
lisinopril, enalapril, captopril, ramipril
- ACE enzyme is involved in conversion of angiotensin I to angiotensin II, inhibition of this path reduces the ability of angiotensin II to induce vasoconstriction and aldosterone secretion, causing reduced peripheral vascular resistance and salt and water retention, leading to a drop in BP
- ACE enzyme is also involved in inactivation of bradykinin, thus inhibiting this path causes reduced inactivation of bradykinin which is the component largely responsible for dry cough s/e; bradykinin also activates NO and PG to further induce vasodilation and decrease BP
what are the available formulations and max dosing for each ACEi
lisinopril
- avail in 5, 10mg
- max 40mg/day
enalapril
- avail in 5, 10mg
- max 40mg/day
captopril
- avail in 12.5, 25mg
- max 150mg/day
what are the c/i and s/e of ACEi
- c/i in pregnancy
- s/e are severe hypotension, acute renal failure, hyperkalemia, dry cough, angioedema
what is the moa of ARB and list the drugs in this class
losartan, valsartan, telmisartan, candesartan, irbesartan, eprosartan
- works by direct antagonism of angiotensin II receptors and produce BP lowering effects by antagonising AT1-induced vasoconstriction, aldosterone release, catecholamine release, arginine vasopressin release, water intake and hypertrophic response
what are the c/i and s/e of ARBs
- c/i in pregnancy
- s/e include (less) dry cough, acute renal failure, hypotension, hyperkalemia, angioedema
what is the moa of BB and list the drugs in this class
non-selective
- propranolol
- pindolol
- carvedilol
selective
- atenolol
- bisoprolol
- metoprolol
- BB competitively block beta adrenergic receptors to prevent epinephrine and norepinephrine from binding to the beta receptors
- this blockade reduces activation of adenylyl cyclase that would have typically resulted from interaction of epinephrine and norepinephrine with beta receptors –> reduced formation of cAMP from ATP –> reduced activation of MLCK –> reduced phosphorylation of myosin-LC –> reduced muscle contraction
what are the c/i and s/e of BB
- c/i in asthmatics (due to risk of bronchoconstriction upon blockade of beta2 receptors on bronchial smooth muscle)
- caution in CCB+BB as risk of excessive suppression of sympathetic activity
- s/e include bradycardia, hypotension, decreased exercise capacity and bronchoconstriction
what is the moa of CCB and list the drugs in this class
DHP CCB
- amlodipine
- nifedipine
NDHP CCB
- verapamil
- diltiazem
- CCB primarily block L-type calcium channels in cardiac and smooth muscle cells which are responsible for allowing Ca2+ to enter the cells during depolarisation thus causing muscle contraction
- intracellular calcium concentration is essential for activating MLCK which phosphorylates myosin-LC and initiate contraction process
- by inhibiting calcium entry, CCB reduce the availability of Ca2+ available for MLCK activation, leading to decreased phosphorylation and ultimately allow for muscle relaxation
what are the c/i and s/e of CCBs
- c/i in pre-existing depressed cardiac function (due negative inotropic effects, increased risk of hypotension)
- s/e: edema, ankle swelling, HA, dizziness, sleepiness, palpitations, flushing, SOB, GI discomfort, muscle pain
compare the actions between DHP CCB and NDHP CCB
DHP CCB selectively block L-type calcium channels in the cardiac and smooth muscle cells
NDHP CCB in addition to blocking L-type calcium channels, they also have additional effects on cardiac conduction tissues specifically in SA and AV nodes, slowing the conduction through these nodes
what is the moa of diuretics and list the drugs in this class
loop diuretics
- furosemide
- bumetanide
thiazides
- hydrochlorothiazide
- indapamide
illustrate what occurs at the loop of henle
- the thin descending limb is permeable to water but not to ions and water is extracted from it by osmotic forces because the surrounding interstitial fluid becomes increasingly hypertonic as it descends
- the thick ascending limb is impermeable to water, has a basolateral Na/K/ATPase transporter that transports Na+ into the interstitium and K+ into the tubular epithelial cells –> energy from this transporter is used for Na/K/2Cl co transporter to transport Na+ K+ and Cl- from tubular fluid into tubular epithelial cells –> accumulation of K+ in tubular epithelial positive electrical potential –> facilitate paracellular reabsorption of Mg2+ and Ca2+ –> while Na+ and Cl- are reabsorbed into the interstitium via other transporters and pathway
what is the moa of loop diuretics and list the drugs in this class
furosemide, bumetanide
- loop diuretics selectively inhibits the luminal Na/K/2Cl cotransporter –> increase excretion of Na+, Cl- and K+ –> thus also increase excretion of Mg2+ and Ca2+
- loop diuretics also induce PG synthesis, esp PGE2 to induce vasodilating effect –> increases renal blood flow –> enhance delivery of filtered fluid to the tubules –> increasing urine output ie. diuresis
what are the c/i and s/e of loop diuretics
- c/i are sulphonamide allergy, electrolyte deficiency, renal failure (CrCl <30), concomitant K supplement or K-sparing diuretic
- s/e are hypoK, hypoNa, hypoMg, hypoCa, hyperuricemia, ototoxicity
what is the moa of thiazide diuretics and list the drugs in this class
hydrochlorothiazide, indapamide
- at the DCT, Na+ and Cl- are reabsorbed into tubular epithelial cells via apical Na/Cl transporter, and Ca2+ are reabsorbed via apical Ca2+ channel and basolateral Na/Ca exchanger
- thiazide diuretics block the Na/Cl transporter leading to decreased Na+ and Cl- reabsorption thus increasing excretion in the urine, along with water, and can lead to increased K+ excretion as well
what is the c/i and s/e of thiazide diuretics
- c/i in sulphonamide allergy, renal failure (CrCl <30), hepatic encephalopathy (can cause worsening of neurological sx), DM, hypokalemia
- s/e include hypokalemic metabolic alkalosis, hyponatremia, hyperglycemia, hyperlipidemia, hyperuricemia
what is the moa of vasodilators and list the drugs in this class
- works by promoting the production or release of nitric oxide which is a potent vasodilator –> NO diffuses into nearby smooth muscle cells and activates guanylyl cyclase which converts GTP into cGMP –> dephosphorylation of myosin-LC –> muscle relaxation
what are the third line agents for add-ons to resistant hypertension or if additional compelling indications
- mineralocorticoid receptor antagonist (spironolactone, eplerenone)
- alpha antagonists (alpa1: terazosin, prazosin, doxazosin; alpha2: methyldopa, clonidine)
list the recommended, add-on and c/i drugs for the following comorbidities: HF, angina, hx of stroke/AF, AF (rate), DM, DM+albuminuria, recurrent stroke prevention, CKD 3, CKD 1/2 + albuminuria, CKD 5, BPH, heart block, ISH, asthma and COPD, gout
HF
- recommended beta1-BB, ACEi/ARB/ARNi
- add on diuretic/ aldosterone antagonist
- c/i NDHP CCB
angina
- recommended: DHP CCB, BB
- add on: ACEi/ARB/DHP CCB/ diuretic
hx of stroke/AF:
- recommended BB
- add on ACEi/ARB (ARB may prevent recurrence of AF)
AF (rate)
- recommended NDHP CCB, BB
DM
- recommended ACEi/ARB (any first line)
DM+Albuminuria
- recommended ACEi/ARB
recurrent stroke prevention
- recommended thiazide + ACEi
CKD 3 or CKD1/2+Albuminuria
- recommended ACEi/ARB
CKD 5
- recommended ACEi/ARB
- c/i spironolactone (aldosterone antagonist)
BPH
- alpha antaonist
heart block
- c/i NDHP CCB, BB
ISH
- recommended diuretic, DHP CCB
asthma and copd
- c/i BB
gout
- c/i diuretic
what is the definition of OH
a decrease in SBP of 20mmHg or a decrease in DBP of 10mmHg within 3 mins of standing when compared with BP from sitting/ supine
what is the management strategy for OH
- avoid large carb rich meals
- limit alcohol intake
- ensure adequate hydration
- investigate root cause
- titrate antihypertensives slowly
how to counsel on home BP monitoring
- measure your BP two times a day, once in the morning before breakfast, medications and exercise and once in the evening, both at the same time each day
- avoid food, caffeine, alcohol 30 mins prior to the measurement
- sit quietly during monitoring, sit with legs and ankles uncrossed and back supported against a chair, stay calm and do not talk while measuring your BP
- position your arm at rest, at level of your heart on a table or a chair arm, use a pillow as needed to elevate (hand above heart level reduces BP vs below heart level increases BP)
- place cuff on bare skin and not over clothing, avoid rolling long sleeves up (ensure appropriate cuff size, measure circumference of upper arm midway between elbow and shoulder and choose a cuff size with this measurement; undersized cuff increases BP while oversized lowers BP)
- wait for at least one minute before repeating, write the two readings down in a BP log book and average them
how would you explain what is arrhythmia
abnormal heart rhythm due to defects in impulse generation, defects in impulse conduction or both
how can arrhythmias be classified
- by speed of HR
- tachy-arrhythmias (HR >100) includes AF/flutter, ventricular fibrillation/ tachycardia, supraventricular tachycardia
- brady-arrhythmias (HR<60) includes conduction blockas - by origin in the heart
- atrial
- ventricular
what is the pathophysiology of AF
AF arises when depolarization signals fires off from abnormal areas in the atria instead of from the sinus nodes –> stimuli bombards the AV node with multiple signals instead of a single signal from the sinus node –> atrial quivers and results in the loss of meaningful contraction
what are the typical conditions that AF is associated with
AF is commonly associated with underlying heart disorders leading to atrial distension (stretching of the atria)
- HFrEF, HFpEF
- HTN
- disorders of the heart valves
but also associated with
- ischemia/ infarction (IHD)
- pulmonary embolism
- chronic lung disease resulting in pulmonary HTN
- states of high adrenergic tone (alcohol withdrawal, sepsis, viral illness)
- drug-induced states
- cardiac surgery
what comorbidity is AF commonly associated with
HF
- close pathophysiological r/s and share many predisposing risk factors
what is the major consequence of AF
AF increases the risk of stroke
what are the goals of therapy for AF
- relieving symptoms through rate (slow down AF) or rhythm control (revert back to normal rhythm)
- stroke prevention
- addressing risk factors and triggers
what is the key pharmacological approach for AF
ABC
Anticoagulation (Avoid stroke)
Better symptom control through rate or rhythm control
CV risk factors and concomitant diseases
what are the drugs for AF pharmacological management
- class IC - flecainide, propafenone
- class II - BB (esmolol IV, metoprolol IV, bisoprolol PO, atenolol PO, carvedilol PO, metoprolol PO)
- class III - amiodarone, sotalol
- class IV - NDHP CCB (verapamil IV/PO, diltiazem IV/PO)
- digoxin (cardiac glycoside)