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