CHF

1. Drugs used in congestive
heart failure

2. Heart failure
 Heart’s ability to pump blood is
decreased below that required to
maintain adequate circulation

3. Symptoms are due toSymptoms are due to
Blood back-up behind the failing
ventricles

4. Pathophysiology of CHFPathophysiology of CHF

5. Left ventricular failureLeft ventricular failure
left ventricle is not able to pump blood
Not able to accept blood from left atrium
Decreased blood flow to atrium from lungs
Pulmonary congestion

7. Right ventricular failure
Right ventricle is not able to pump blood
Not able to accept blood from right atrium
Decreased venous return
Blood stagnation in the peripheral organs
Peripheral edema

8. SymptomsSymptoms

9. DefinitionsDefinitions
a. Inotropica. Inotropic – increased FOC– increased FOC
b. Chronotropicb. Chronotropic – Increased heart rate– Increased heart rate
c. Preloadc. Preload – initial stretching of the– initial stretching of the
cardiac myocytes prior to contractioncardiac myocytes prior to contraction
(venous return)(venous return)
d. Afterloadd. Afterload ––the pressure against whichthe pressure against which
the left ventricle has to push the bloodthe left ventricle has to push the blood
to the aortato the aorta
e. Cardiac outpute. Cardiac output – volume of blood– volume of blood
pumped by the heart per minutepumped by the heart per minute

10. Drugs for CHFDrugs for CHF
 Angiotensin Converting Enzyme (ACE)
inhibitors: enalapril, lisinopril, captopril,
ramipril
 AT1 blockers (ARBs): losartan, valsartan
 Diuretics: furosemide, hydrochlorothiazide,
spironolactone
 Beta-blockers: metoprolol, bisoprolol,
carvedilol
 Inotropic drugs: Digoxin
 Vasodilators: hydralazine, sodium nitroprusside

12. Mechanism of Positive Inotropic ActionMechanism of Positive Inotropic Action
2K+
3Na+
3Na+
Ca2+
Na+
Actin & myosin
Digoxin
Ca2+
Ca2+
conc. low
Ca2+
conc. High Cardiac cell

13. Mechanism of Positive Inotropic ActionMechanism of Positive Inotropic Action
2K+
3Na+
3Na+
Ca2+
Na+
Actin & myosin
Digoxin
Ca2+
Ca2+
Ca2+ Ca2+
Ca2+ Ca2+
Ca2+
↑↑Ca2+
↑↑↑↑Ca2+
Cardiac cell

14. Digoxin Mechanism of ActionDigoxin Mechanism of Action
Inhibition of cardiac NaInhibition of cardiac Na++
-K-K++
ATPaseATPase 
↑↑ intracellularintracellular NaNa++

↓↓ NaNa++
/Ca/Ca2+2+
exchangeexchange 
↑↑ intracellular Caintracellular Ca2+2+

↑↑ intracellular Caintracellular Ca2+2+
release from SRrelease from SR 
↑↑ actin-myosin interactionactin-myosin interaction 
↑↑ contractioncontraction  ↑CO↑CO