Heart failure is defined as the inability of the heart to supply sufficient blood flow to meet the body's needs. Left ventricular dysfunction is a key pathophysiology and leads to compensatory mechanisms like RAAS and sympathetic system activation that form a vicious cycle. Common treatments include ACE inhibitors, ARBs, beta-blockers, aldosterone antagonists, and diuretics which help relieve symptoms and prolong survival by reversing remodeling. Inotropic drugs like digoxin, milrinone, and dobutamine are used short-term to improve cardiac output.
4. LV Dysfunction
Decreased cardiac output
RAAS activation
Sympathetic activation
Increased cardiac output (via increased
contractility and heart rate)
Increased blood pressure (via vasoconstriction
and increased blood volume)
Salt and water retention
Increased cardiac workload
(increased preload and afterload)
Vicious Cycle of Heart Failure
Pathophysiology of HF
Left ventricular dysfunction
5. Pathophysiology of HF
Left ventricular dysfunction
Left ventricular
dysfunction
Compensatory
mechanisms
-RAAS activation
-Sympathetic system
activation
-Vicious cycle
Ischemic heart disease
Cigarette smoking
Hypertension
Obesity
Diabetes
Valvular heart disease
6.
7. Cardiac performance is a function
of 4 primary factors
Preload
Afterload
Contractility
Heart rate
In CHF
↑
↑
↓
↑
8. LV remodeling
changes in size, shape, and function of the heart after injury to
the ventricles -- implies a decline in function of heart
Angiotensin II
Aldosterone
Sympathetic
stimulation
↑after load , fluid & Na+ retention
↑ expression of growth factors
↑synthesis of extracellular matrix
Hypertrophy of myocytes
ACE inhibitors
,ARBs
β blockers
Spironolactone Improve survival
↓ mortality
10. STAGE DISABILITY
CLASS 1
MILD
No symptoms - Can perform ordinary activities
without any limitations
CLASS 2
MILD
Mild symptoms - Somewhat limited in ability to
exercise or do other strenuous activities
CLASS 3
MODERATE
Noticeable limitations in ability to exercise
Comfortable only at rest
CLASS 4
SEVERE
Unable to do any physical activity without
discomfort Some HF symptoms at rest
10
NYHA classification = New York Heart Association
12. • 2) Arrest/reversal of disease progression and
prolongation of survival
• ACE inhibitors/ ARBs
• beta blockers
• Aldosterone antagonist-Spironolactone,
eplerenone
• Neprilysin inhihiror- Sacubitril
13. ACE inhibitors / ARBs
Hemodynamic benefits
↓ preload & afterload
↓ Pulmonary capillary wedge
pressure
Exercise capacity ↑
reverse ventricular
remodeling
prevents or delays the
progression of heart failure
Drug of
choice
14. Drugs = β blockers
•Decreasing the frequency of unstable tachyarrhythmias
•antagonism of ventricular wall stress enhancing, apoptosis promoting
and pathological remodeling effects- Through inhibition of sustained
sympathetic nervous system activation
•Used in NYHA class 2/3
•no place for beta blockers in decompensate patients
•Should be combined with ACEI / ARBs
•Start with low dose ----- titrated to target dose
Metoprolol
Carvidilol
Bisoprolol
CHF patients are
prone to
arrhythmias
15. Aldosterone antagonist
Aldosterone :
Na & water retension
(a) Expansion of e.c.f. volume → increased
cardiac preload
(b) Fibroblast proliferation and fibrotic change
in myocardium → worsening systolic dysfunction
and pathological remodeling.
16. Contd.
(c) Hypokalemia and hypomagnesemia →
increased risk of ventricular arrhythmias and
sudden cardiac death.
d) Enhancement of cardiotoxic and remodeling
effect of sympathetic overactivity
17. Contd.
• Drugs: spironolactone , eplerenone
• Indicated as add-on therapy to ACE inhibitors
+ other drugs in moderate-to-severe CHF
• Retard disease progression, reduce episodes
of decompensation and death
• Low doses (12.5–25 mg/day) of
spironolactone to avoid hyperkalaemia
• Help restoration of diuretic response to
furosemide when refractoriness has
developed
20. Pre- and after load reduction
• Sodium nitropruside
• high efficacy i.v. dilator
• Action is very fast and brief
21. Cardiac Glycosides = Digitalis compounds
DIGOXIN
Positive Inotropic effect
•increase the myocardial contractility and improves cardiac
output without proportionate increase in Oxygen
consumption
22.
23.
24. Cardiac glycoside
Digoxin
Acts by blockade of Na+K+ATPase pump in phosphorylated state
– action is slow
(Hyperkalemia cause dephosphorylation of the ATPase --- reducing the drug's binding
and effect)
Positive inotropic effect - CO↑
↓HR – due increased vagal tone
AV conduction ↓
PR interval prolongation
Given orally
Once a day
Renal excretion
Large Vd – 6-8L/kg
T1/2 – 36-48hrs
25. Cardiac glycoside = Digoxin
ADR
Cardiac
Bradycardia –Rx by atropine
Tachyarrhythmias – KCl IV/oral
For supraventricular arrhythmias
Propranolol
Ventricular tachycardia – lignocaine
Severe toxicity can be Rx by
Digitalis Immune Fab – neutralizing
effect
Digoxin can cause all almost
every type of arrhythmia
Extracardiac
Nausea vomiting
Headache dizziness
Psychoses
Visual disturbances
Gynecomastia
26. Current status of Digoxin in HF
Other use
• Atrial Fibrillation (atrial rate -500/min)
to control ventricular rate – by ↓AV conduction and ↑ERP of AV node
• Atrial flutter
– atrial rate is 200–350/ min
– convert AFl to AF
does not reduce mortality
Patients who remain symptomatic despite
maximal therapy with ACE inhibitors and beta
blockers
27. Contd.
• Paroxysmal supraventricular
tachycardia
– common arrhythmia with a rate 150–200/min and
1 : 1 A-V conduction
– i.v. digitalis increases vagal tone and depresses the
path through the SA/A-V node, or the ectopic
focus, and terminates the arrhythmia
– Adenosine and verapamil are more effective, less
toxic and act faster
– Digitalis:reserved for preventing recurrences
29. Inotropic agents
Dopamine
•Low dose infusion :2- 5 μg/kg/min
D1 action –renal vasodilation ↑ renal blood flow + Na+ excretion
• Intermediate dose infusion 5-10μg/kg/min – is used in Rx
β1 action – inotropic effect
• High dose infusion - >10 μg/kg/min
α action - vasoconstriction
Dobutamine
β1 agonist – prominent inotropic effect
IV infusion
No effect on
Dopamine
receptor
30. Inotropic agents
Inodilators = PDE III inhibitors = Milrinone Amrinone
Mechanism:
•↑ level of intracellular cAMP
• Positive inotropic + vasodilator effect
ADR
•Amrinone – thrombocytopenia
• less with Milrinone
Short term IV infusion
31. Levosimendan
• calcium sensitizer –increases the sensitivity of
the heart to calcium + Vasodilator effect
• opens ATP-sensitive K+ channel in vascular
smooth muscle cells to cause vasodilatation
• Inodilator
• infused i.v. short term
32. Nesiritide
Recombinant Brain Natriuretic Peptide (BNP)
Vasodilation + salt & water excretion↑
Sacubitril+valsatran
combination
•orally active neprilysin in inhibitor
•Prevents the degradation of endogenous
ANP, BNP and other vasodilator peptides
•Actions:Vasodilatation,natriuresis,diuresis
•Combined with valsartran:prevents death
&decompensation
33. Tolvaptan
• V2 receptor antagonist
•Uses:SIADH &advanced CHF
•Short term improvement by increasing water
excretion
•No long term benefit
34. Digoxin is not indicated in
(a) Atrial flutter
(b) Atrial fibrillation
(c) High output failure
(d) PSVT
35. 19) Drugs that reduce myocardial remodelling
in CHF include all of the following except:
(a) Carvedilol
(b) Digoxin
(c) Enalapril
(d) Spironolactone
36. • All are true about starting of beta-blocker
therapy in a patient with congestive heart
failure except:
(a) They should be started with optimum doses
(b) They should be gradually increased over weeks
(c) Special precautions should be taken in cases of
NYHA class III and IV
(d) Carvedilol and metoprolol are the preferred
drugs
37. • All of the following drugs are used for the
treatment of congestive heart failure except:
• (a) Nitroglycerine
• (b) Spironolactone
• (c) Nesiritide
• (d) Trimetazidine
38. • Which of the following is a venodilator?
• (a) Hydralazine
• (b) Minoxidil
• (c) Nitroprusside
• (d) Nifedipine
39. • Which of the following drugs can prolong
survival in patients with CHF?
• (a) Furosemide
• (b) Inamrinone
• (c) Losartan
• (d) Digoxin
40. • Which of the following drugs can prolong
survival in patients with CHF?
• (a) Furosemide
• (b) Inamrinone
• (c) Losartan
• (d) Digoxin
41. • Drugs associated with clinically useful or
physiologically important positive inotropic
effects include all of the following except:
• (a) Amrinone
• (b) Enalapril
• (c) Digoxin
• (d) Dobutamine
42. • Which of the following drugs is beneficial in a
refractory congestive heart failure by
increasing cardiac contractility and
decreasing preload and afterload?
• (a) Amiloride
• (b) Amiodarone
• (c) Amrinone
• (d) Carvedilol
Notes de l'éditeur
In addition to maintaining normal cardiovascular homeostasis, the hormones and neurohormonal systems described in the last few slides also play an important role in compensating for the diminished cardiac output seen in patients with early heart failure. But it is also known that over time, these same neurohormone systems eventually become detrimental and contribute to the progression of heart failure. Why does this happen?
Physiologists now recognize that the neurohormonal mechanisms activated in heart failure are identical to those normally triggered when cardiac output and blood pressure are threatened (e.g., intense physical exercise, hemorrhage), but with an important difference. Under normal circumstances, the release of neurohormones is generally successful in reversing the hemodynamic abnormalities seen in acute low volume/low output states, and consequently, neurohormonal activity eventually subsides.
In contrast, neurohormonal activation never “turns off” in the setting of heart failure; rather, is always “on” in an attempt to compensate for the failing heart’s chronic inability to maintain normal cardiovascular homeostasis. Furthermore, the chronic presence of circulating neurohormones tends to exacerbate the hemodynamic abnormalities in heart failure, which only encourages further remodeling and neurohormone release and, thus, further hemodynamic deterioration. Thus, a vicious cycle develops whose end result is progressive ventricular dysfunction and death.
Cardiac performance is a function of four primary factors
Preload
Afterload
Contractility
Heart rate
Safety margin is low
Levosimendan
calcium sensitizer – it increases the sensitivity of the heart to calcium
+ Vasodilator effect