Pharmacology of Heart Failure 1 & 2 Flashcards
What is the 5 year survival for heart failure?
What causes mortality?
50%
- Sudden death is the most common COD (5x that of general population)
What is this?
Heart failure (nL heart is less than 1/2 the thoracic cage)
What are the physiological problems in congestive heart failure?
Marks of systolic/diastolic failure?
- Decreased contractility (e.g. muscle replaced by fibrous tissue)
a. Systolic heart failure (decreased contractility)
b. Diastolic heart failure (decreased compliance)
- Increased afterload (e.g. atherosclerosis, HTN, less elastic BVs)
- Increased preload (e.g. defective heart valves)
What are characteristics of L vs. R heart failure? Which is more common?
Left heart failure- more common
- Pulmonary congestion
- Blood accumulates in lungs/pulmonary edema
- Eventually systemic edema
Right heart failure
- Ischemia due to blocked coronary arteries
- Systemic congestion
- Blood accumulates in periphery/peripheral edema
What are the broad compensatory changes in response to primary insult in CHF?
- Neurohormonal activation
- Activation of RAAAS system
- Inflammatory cascade activation
- Structural changes to myocardium
What does neurohormonal compensation involve?
- Increased sympathetic neuronal activation (increased NE, increased SVR)
- Decreased PS tone (increased HR)
- Increased vasopressin (ADH)
- Increased aldosterone
- Increased endothelin-1 (constricts sm)
- Increased BNP (B-type natriuretic peptide)
Plasma __ levels predict mortality in patients with CHF. Higher levels = poor prognosis.
Circulating ___ levels correlate with severity of CHF
Mortality
- Plasma NE
- Plasma pro BNP and plasma endothelin (big ET-1)
Severity
- Circulating TNF-a
What is involved in the inflammatory cascade activation in compensation for heart failure?
- Increased reactive oxygen species formation
- Increased cytokine production (e.g. TNFa)
- Circulating inflammatory cell infiltration
- Local inflammatory cell activation
What is involved in the structural changes to myocardium in compensation for heart failure?
- Myocardial architectural disruption
- Abnormal ECM formation
- Myocardial cell realignment (remodeling)
All of the following increase in patients with heart failure, except:
A. Sympathetic input
B. Tumor necrosis factor
C. Angiotensin II
D. Parasympathetic input
E. Aldosterone
F. ADH (Vasopressin)
All of the following increase in patients with heart failure, except:
A. Sympathetic input
B. Tumor necrosis factor
C. Angiotensin II
D. Parasympathetic input
E. Aldosterone
F. ADH (Vasopressin)
Progression from HTN to heart failure (cool pic)
(:
What are the goals for therapy with drugs for heart failure?
- Rapid relief of symptoms
- Reduce mortality, hospitalizations, improve quality of life
- Change the natural history of the disease
- Safe and well tolerated
What drug classes are used in the treatment of heart failure?
- ACEI/ARBs (blockers of ang-aldost syst)
- Inotropic agents (cardiac glycosides)
- Beta adrenergic agonists (Dobutamine, Dopamine, NE)
- PDE3 (PDE inhibs)
- Diuretics (decrease BV/preload)
- Beta blockers (decrease work load on heart)
- CCBs (decrease work load on heart/decrease afterload)
- Vasodilators (decrease afterload)
What drugs are used in acute heart failure?
Chronic heart failure?
What are some cardiac glycosides?
What do they do?
Digitoxin and Digoxin
- Inotropic agents; increase contractility of the heart
- Differ by a single OH group and have differences in kinetics and metabolism (most pts in US are on Digoxin; Digitoxin has a longer half life with less control)
What is the mechanism of action of digitalis?
- Blocks K portion of Na-K-ATPase
- Increases intracellular Na
- Decreases action of Ca-Na exchanger
- Increases intracellular Ca
- Positive inotropic effect
What are the physiological benefits of Digoxin?
- Increased contractility
- > Increased stroke volume
- > Increased cardiac output
- Decreased ventricular EDP
How does increased contractility change the P-V loop response?
- Decreased EDV (?)
- Increased SV
- Increased LV pressure
T/F: Digoxin helps people with CHF feel better?
False- just improved quality of life for the remainder of it
Which of the following class of drugs are NOT recommended to treat ACUTE heart failure?
A. Diuretics
B. Digoxin
C. Beta 1 agonsits
D. Beta blockers
E. ACEI/ARBs
Which of the following class of drugs are NOT recommended to treat ACUTE heart failure?
A. Diuretics
B. Digoxin
C. Beta 1 agonsits
D. Beta blockers
E. ACEI/ARBs
- Not well tolerated at the beginning, but huge advantages chronically (including increased life span)
Explanation for the physiological effects of cardiac glycosides (lengthy)…
Normal heart
- Within limits, when cardiac muscle is stretches, its force of contraction increases and CO increases
- However, if the ventricle is overly stretched, the effect of ventricular contraction is diminished
Decompensated heart failure
- Initial reduction of contractility
- Symptoms of low CO develop (dyspnea, edema) Compensated heart failure
- Ventricular end diastolic pressure increases in an effort to maintain an adequate cardiac output
- The increased ventricular end-diastolic pressure causes symptoms of of congestion (dyspnea)
Digitalis treatment
- Administration of digitalis shifts the ventricular function curve toward normal
- Increased contractility leads to increased CO
- Decreased sympathetic reflexes and vascular tone cause a decrease in the ventricular end diastolic pressure
What are the beneficial kinetic characteristics of digoxin?
- Bioavailability
- Onset of action
- Half life
- Excretion method/amt
- Volume of distribution
- Bioavailability: oral ~ 75%
- Rapid onset of action, ~20%
- Half-life of 36 hours (Digitoxin is about 5 days)
- Renal excretion (~90%)
- Large volume of distribution; binds to Na/K ATPase in skeletal muscle
What kind of heart failure are cardiac glycosides good for?
What other cardiac conditions?
- SYSTOLIC heart failure
- Supraventricular arrhythmias (NOT ventricular)
What are some adverse effects of cardiac glycosides?
- Arrhythmias
- PVCs (premature ventricular contractions)
- Muscle weakness (drug inhibits muscle Na/K ATPase enzyme)
- Fatigue
What condition increases digitalis toxicity?
Hypokalemia
- Careful if pt is on diuretics which alter K balance (or steroids)!
- Digitalis/digoxin have narrow therapeutic window (~2); toxicity is very common
How can you treat digitalis toxicity?
- Stop digoxin/digitalis
- Control arrhythmias (propranolol, lidocaine, phenytoin, atropine; NOT quinidine)
- Give potassium
- Antiglycoside antibodies (since digoxin is not readily dialyzable)
Digoxin increase cardiac output by:
A. Activating Na/K ATPase pump
B. Inhibiting Na/K ATPase pump
C. Inhibiting Na/Ca exchanger
D. Inhibiting Calcium pump
E. By inhibiting cAMP phosphodiesterase 3
Digoxin increase cardiac output by:
A. Activating Na/K ATPase pump
B. Inhibiting Na/K ATPase pump
C. Inhibiting Na/Ca exchanger
D. Inhibiting Calcium pump
E. By inhibiting cAMP phosphodiesterase 3
What are some phosphodiesterase type III inhibitors?
–rinone
Amrinone (IV) and Milrinone (IV and PO)