Cardiac Contractility/Positive Inotropic medications Flashcards
- LV End Diastolic Volume (EDV)-
amount of blood in left ventricle at the
end of diastole
* LV EDV = Preload
- Afterload-
pressure heart has to overcome to eject blood
Afterload = Systemic blood pressure
- LV End Systolic Volume (ESV)-
amount of blood in left ventricle at the end
of systole
- Stroke Volume (SV):
- Ejection Fraction (EF):
- Cardiac Output (CO):
SV= EDV – ESV (mL)
EF= SV/EDV X 100% (%)
CO= HR X SV (mL/min)
ionotrophy
the ability of the heart to contract
Positive Inotropic medications
(5)
- Cardiac glycosides
- Digoxin- inhibits Na-K ATPase
- DOBUTamine- b1 adrenocepter agonist
- Milrinone- phosphodiesterase inhibitor
- Levosimendan- calcium sensitizer
Positive Inotropic medications
Digoxin
* Brand name: (3)
* MOA:
* Use: (2)
Digitek, Lanoxicaps, Lanoxin (available IV/PO)
inhibition of Na+-K+ ATPase/ vagal tone to heart
heart failure, atrial fibrillation (rate-control)
Positive Inotropic medications
Digoxin
ADRs (narrow therapeutic index medication):
(3)
- Nausea, vomiting, diarrhea
- Bradycardia/ heart block
- Visual disturbances (green-yellow halo)
Positive Inotropic medications
Digoxin
Drug-Drug interactions:
(3)
- Other drugs that cause bradycardia or hypokalemia
- Increased levels with macrolide antibiotic
- Increase risk of arrhythmia with adrenergic agonists or succinylcholine
Digoxin
— effects with – K+
increase
decrease
Positive Inotropic medications
Digoxin- Dental Implications
* Monitor …
* Increased — may make dental procedures,
such as taking radiographs or impressions difficult
* After supine positioning, …
* Use — with caution (adrenergic stimulation)
* Avoid ..
* — protocol
vital signs
gag reflex
have patient sit upright
for at least 2 minutes before standing to avoid
orthostatic hypotension (bradycardia)
vasoconstrictors
dental light in patient’s eye/offer dark glasses
Stress reduction
Positive Inotropic medications
DOBUTamine
* Brand name:
* MOA:
* Use: (2)
Dobutrex (only available IV)
b1- adrenergic receptor agonist
acute decompensated heart failure, cardiogenic shock
Positive Inotropic medications
DOBUTamine
ADRs:
(3)
* Drug-Drug interactions: none of significance
* Dental Implications: none
- Increased heart rate and blood pressure
- Arrhythmias
- Chest pain
Positive Inotropic medications
Levosimendan
* Brand name:
* MOA:
* Use:
Simdax (not available in the U.S.)
Sensitize troponin to Ca2+ (inotropy) and KATP channel activation
in smooth muscle (vasodilation)
acute decompensated heart failure
Positive Inotropic medications
Levosimendan
* ADRs:
(3)
* Drug-Drug interactions: none of significance
* Dental Implications: none
- Arrhythmias (ectopic beats, NSVT, VT)- supposedly less than DOBUTamine
- Hypotension
- Headache
Myocardial Oxygen Supply
Function of:
(2)
- Arterial O2 content
- Coronary blood flow
- Arterial O2 content
- decreased anemia and hypoxia
- Coronary blood flow
- decreased atherosclerosis and vasospasm
Myocardial Oxygen Supply is a function of
Heart Rate
Cardiac myocytes supplied with blood during diastole
increased Heart rate = dcereased time in diastole
Myocardial Oxygen Demand (MVO2)
MVO2Determinants
(3)
- Heart rate
- Myocardial contractility
- Myocardial wall stress
* Preload
* Afterload
Surrogate marker for MVO2
Double Product= HR X SBP
SYMPATHETIC Nervous System
b1 adrenoreceptors
(5)
- increased force of contraction
(positive inotropic effect) - increased heart rate (positive
chronotropic effect) - increased automaticity
- Repolarization
- Reduced cardiac efficiency
PARASYMPATHETIC Nervous System
Muscarinic (M2) receptors
(3)
- Cardiac slowing
- decreased automaticity
- Inhibition of AV node
conduction
- Organic nitrates-
increased myocardial O2 supply
- Calcium channel blockers-
increased myocardial O2 supply and decreased O2 demand
- b-adrenocepter antagonists-
decreased myocardial O2 demand
- Ranolazine-
improves angina w/o changing BP or HR
- Ivabradine-
not approved for angina in U.S.
Antianginal medications
Organic nitrates
* Forms:
(4)
- Organic nitrates
-Nitroglycerin - Isosorbide dinitrate/mononitrate
- Sodium Nitroprusside
Antianginal medications
Organic nitrates
* Major side effects
(5)
- Headache
- Syncope/hypotension
- Tachycardia
- Tolerance
- Methemoglobinemia
Antianginal medications
Organic nitrates
* Contraindicated with
PDE-5 Inhibitors
Antianginal medications
Organic nitrates- Available products
- SL tablets
- Spray
- Intravenous
- Ointment
- Patch
- Capsules
- LA tablets
- Isosorbide mononitrate (ISMN)
- Isosorbide dinitrate (ISDN)
Immediate relief
- SL tablets
- Spray
- Intravenous
- Ointment
Prevention
- Patch
- Capsules
- LA tablets
- Isosorbide mononitrate (ISMN)
- Isosorbide dinitrate (ISDN)
Antianginal medications
Organic nitrates
Isosorbide Mononitrate
* Brand name: (2)
* MOA:
* Use: (2)
Imdur, Ismo
Stimulate production of intracellular cGMP
Angina and heart failure
Antianginal medications
Organic nitrates
Isosorbide Mononitrate
ADRs:
(4)
- Headache (common), flushing, dizziness, postural hypotension
Antianginal medications
Organic nitrates
Isosorbide Mononitrate
Drug-Drug interactions:
- Increased effects with other vasodilator type medications
Antianginal medications
Organic nitrates- Dental Implications
* Monitor …
* — protocol
* After supine positioning,
* Use — with caution
* — available for acute angina attack
vital signs
Stress reduction
have patient sit upright
for at least 2 minutes before standing to avoid
orthostatic hypotension
vasoconstrictors
Sublingual nitroglycerin
Antianginal Medications
Calcium Channel Blockers
MOA:
Block calcium from entering cell through voltage
sensitive “slow” L-type channels
* Slow conduction in SA and AV node (non-dihydropyridine)
* heart rate
* AV block
* Vasodilatation of arterioles
* Decrease arterial pressure and wall tension
* Decrease myocardial contractility
* Increase flow through areas of fixed coronary obstruction
Antianginal Medications
Calcium channel blockers
Amlodpine
* Brand name:
* MOA:
* Use: (3)
Norvasc
Dihydropyridine calcium channel blocker
Angina, hypertension, also vasospastic angina
Antianginal Medications
Calcium channel blockers
Amlodpine
ADRs:
(6)
- Edema (common), dizziness, lightheadedness, hypotension, flushing,
gingival enlargement (rare- but more common than non-DHP)
Antianginal Medications
Calcium channel blockers
Amlodpine
Drug-Drug interactions:
(2)
- Hypotension with sedatives, opioids, general and inhaled anesthetics
- NSAIDS reduce blood pressure lowering effect
Antianginal Medications
Calcium channel blockers- Dental Implications
* Monitor …
* Consider …
* — appointments
* After supine positioning,
* Use (2) with caution
* Place on frequent recall to monitor for —
vital signs
stress reduction protocol
Shorter
have patient sit upright
for at least 2 minutes before standing to avoid
orthostatic hypotension
vasoconstrictors and inhaled anesthetics
gingival hyperplasia
Antianginal medications
β-adrenoceptor blockers
* Block sympathetic stimulation to the heart
(4)
- Decrease heart rate
- Decrease automaticity
- block NE’s effects on Ca2+ channels
- Slow conduction through AV node (increase
refractory period)
Antianginal medications
β-adrenoceptor blockers
Prevent
ischemia
* Decrease myocardial oxygen demand
* decrease HR, decrease contractility, decrease SBP
Antianginal medications
β-adrenoceptor blockers
* Prefer —acting b1 selective agents for angina
long
Antianginal medications
β-adrenoceptor blockers
Dental implications
* Monitor …
* — protocol
* — appointments
* After supine positioning,
* Use (2) with caution
* Use – effective dose of local anesthetics
vital signs (heart rate should be low)
Stress reduction
Shorter
have patient sit upright for at least 2
minutes before standing to avoid orthostatic hypotension
vasoconstrictors and inhaled anesthetics
lowest
Antianginal Medications
Ranolazine
* MOA:
(2)
- inhibits late inward sodium current (Ina) in ischemic myocardium reduced
myocardial wall tension and O2 consumption - At higher concentrations inhibits rapid delayed rectifier potassium current (Ikr)
prolonged action potential and QT interval
Antianginal Medications
Ranolazine
* Brand name:
* MOA:
* Use:
Ranexa
Inhibition of late inward sodium current (Ina)
Angina
Antianginal Medications
Ranolazine
* ADRs:
(6)
- Bradycardia, hypotension, dizziness, QT prolongation, TdP, xerostomia
Antianginal Medications
Ranolazine
* Drug-Drug interactions:
(1)
- Many due to CYP 450 3A4 metabolism
Antianginal Medications
Ranolazine
Dental implications:
(2)
- Assess salivary flow as a factor in caries, periodontal disease, and candidiasis
- Use vasoconstrictors and inhaled anesthetics with caution