Download Congestive Heart Failure and CAD

Congestive Heart Failure and
CAD
Heart Rate
• Is the number of beats per minute
Stroke Volume
• Is the volume of blood pumped per beat, let’s
say about 70ml
Cardiac Output
• CO = SV x HR
• = is the volume of blood pumped over one
minute. About 5 liters per minute
Preload
• - volume of blood in ventricle before
contraction, end diastolic volume
Afterload
• Volume of blood in ventricle after contraction,
end systolic volume
Stroke Volume
• Volume of blood pumped during a single beat,
preload minus afterload
Ejection Fraction
• Percentage of blood pumped during a single
beat, stroke volume divided by preload
Stroke Volume and Ejection Fraction
• An elephant has a much larger stroke volume
than a mouse, but similar ejection fractions
A healthy heart is like a spring
• The Frank-Starling law of contractility is the
same as the Hooke’s law of springs
• More stretch, more force
• The Frank-Starling law states that the more
the heart fills, the stronger the force of
contraction
Frank-Starling Curve
• Just like a spring if the heart is overstretched,
it loses it’s capacity to return force
Starlings Curve
• Healthy hearts are like a spring, more filling
results in more contractile force
Starlings Curve
• Just like springs, if the heart is overstretched,
it loses it’s capacity to return force
Dilated Cardiomyopathy picture
Congestive Heart Failure
• Is a common debilitating condition defined by
the heart’s mechanical ability to pump blood
Normal Cardiac Output
• CO = SV x HR
Dilated Cardiomyopathy
• - thin, weak floppy heart muscle
• - low EF, low CO, high preload, high afterload
Ventricular Hypertrophy picture
• Thick, weak stiff heart muscle
• Low EF, low CO
Starlings Curve
• Just like springs, if the heart is too stiff, it loses
it’s capacity to return force
Congestive Heart Failure
CHF
• Results in a decrease of blood circulation,
which decreases oxygen supply to the organs,
and fluid accumulation in the tissues. This is
called edema
CHF and edema
• Congestive heart failure results in edema
– Pulmonary edema
– Systemic edema
- legs
- total body (anasarca)
Pitting edema picture
• Edema can be mild and localized, like a pitting
of the feet
Congestive Heart Failure
• CHF can cause the lungs to fill with fluid
causing shortness of breath, difficulty
breathing, fluid retention and swollen legs,
and decreased blood flow to organs
NYHA Classification of CHF
• Class 1 Asymptomatic
• No limitation of physical ability. Ordinary
physical activity does not cause undue fatigue,
palpitation, or dyspnea (shortness of breath).
NYHA classification of CHF
• Class 2 Mild
• Slight limitation of physical activity.
Comfortable at rest, but ordinary physical
activity results in fatigue, palpitation or
dyspnea
NYHA Classification of CHF
• Class 3 moderate
• Marked limitation of physical activity.
Comfortable at rest, but less than ordinary
activity causes fatigue, palpitation or dyspnea.
NYHA Classification of CHF
• Class 4 severe
• Unable to carry out any physical activity
without discomfort. Symptoms of cardiac
insufficiency at rest. If any physical activity is
undertaken, discomfort is increased.
Drugs to treat CHF
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ACE inhibitors
- also prevents scarring of the cardiac muscle
Calcium channel blockers
Β-Blockers
Diuretics
CHF
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Rx: Dobutamine
- adrenergic agonist
Rx: Natrecor
- NONadrenergic vasodilator
• Rx: Digoxin
• - action on Na/K Pumps
• - increased cardiotoxic effects with
hypokalemia (remember diuretics?)
• Mostly used in atrial fibrillation
• Digitalis purpurea
• Foxglove
Rx: Digitalis Digoxin
• Cardiac glycosides work by inhibiting the
Na+/K+ pump. This eventually causes an
increase in calcium flowing into the cardiac
muscle cell, improving cardiac output and
reducing distention of the heart.
Rx: Digoxin
• GI upset
• “Yellow Vision”
• Can produce arrhythmia
Angina
• Chest pain
CAD
• Coronary artery disease
• The coronary arteries supplying the heart can
become narrowed over time
CAD
• The narrowed arteries limit the amount of
blood supplied to the myocardium especially
during strenuous activities
Angina Pectoris
• Stable – predictable chest pain, directly
related to amount of exertion, does not occur
at rest
• Unstable – unpredictable chest pain, occurs at
rest
• Vasospastic (Prinzmetal) – condition of spasm
of the coronary arteries, not associated with
atherosclerosis
Prevention
• Until now we have tried to prevent
atherosclerosis by:
• - better diet
• - more exercise
• - stop smoking
• - control HTN
• - lowering LDL and triglycerides
Drugs to treat Angina
• Nitrates
• - dilates vascular vessels
• - relaxes smooth muscle
Nitroglycerin
• Class: nitrate
• Increases coronary blood flow by dilating
coronary arteries and improving blood flow to
ischemic regions
• Produces vasodilation, dropping blood
pressure
Nitroglycerin
• Decreases left ventricular end-diastolic
pressure and left ventricular end-diastolic
volume (preload)
Dilated Cardiomyopathy
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Low EF
Low CO
High preload
High afterload
Sublingual Nitro
• SL Nitro
– Avoids first pass effect
– Better bioavailability
– DO NOT SWALLOW SL NITRO
Drugs to treat angina
• Antithrombotic agents
Rx: Digitalis Digoxin
• Cardiac glycosides work by inhibiting the
Na+/K+ pump. This eventually causes an
increase in calcium flowing into the cardiac
muscle cell, improving cardiac output and
reducing distention of the heart.
Rx: Digoxin
• GI upset
• “yellow vision”
• Can produce arrhythmia
Angina
• Chest pain
CAD
Coronary Artery Disease
• The coronary arteries supplying the heart can
become narrowed over time
CAD
• The narrowed arteries limit the amount of
blood supplied to the myocardium, especially
during strenuous activity
Angina Pectoris
• Stable – predictable chest pain, directly
related to amount of exertion, does not occur
at rest
• Unstable – unpredictable chest pain, occur at
rest
• Vasospastic (Prinzmetal) – condition of spasm
of the coronary arteries, not associated with
atherosclerosis
Prevention
• Until now we have tried to prevent
atherosclerosis by:
- Bettter diet
- More exercise
- Stop smoking
- Control HTN
- Lowering LDL and triglycerides
Anticoagulation
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Warfarin (Coumadin)
Heparin
Aspirin
Clopidogrel (Plavix)
tPA
Streptokinase
Hemostasis
• Development of a thrombus is lifesaving when
a large vessel is ruptured or is severed
• However, when a thrombus develops in the
unruptured cardiovascular system it can be life
threatening
Thrombus
• Diminish or obstruct vascular flow causing
ischemic injury to tissues and organs
• May become dislodged or fragment to create
emboli
Emboli
• An intravascular solid, liquid, or gaseous mass
that is through the blood to a different
location in the body
• - heart
• - lung
• - brain
Hemostasis
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Dependent on 3 components
- endothelium
- lining of the vascular wall
Platelets
- essential for thrombus formation
Coagulation proteins
- created by the clotting cascase
- end result is fibrin
Anticoagulants
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A-fib
Angina & Coronary Artery Disease
Myocardial Infarction
Stroke
Pulmonary embolism
Deep vein thrombosis (DVT)
Anticoagulants
• Aspirin and heparin for emergency
intervention
• Thrombolytics for emergency intervention
Clotting Factors and Related
Coagulation Tests
• Heparin therapy – intrinsic system – aPTT
• Coumadin therapy – extrinsic system – PT
Cascade Picture
Coagulation Cascade Picture
• Coagulation Cascade – thrombin
Anticoagulant Strategies
1. Interfere with platelet aggregation or clot
formation
2. Interfere with clotting proteins or their
formation
3. Dissolve thrombus
Rx: Coumadin
Warfarin
• Today’s coumadin dose affects blood clotting
two to seven days later
Rx: Coumadin
Warfarin
• Yes, the rumors are true…
• Warfarin was initially developed as a rat
poison, causing internal bleeding
• As long as the patient’s PT/INR is carefully
monitored, there are no ill effects
• Know teratogen, Cat X – contraindicated in
pregnancy
Rx: Coumadin
Warfarin
• Oral medication
• Not used much IV due to delay between dose
and effect, no better bioavailability
Rx: Heparin
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Antithrombin activator
Effect is immediate
Lab every 6 hours
- PTT (Partial Thromboplastin Time)
IV only
Rx: Heparin
• Although heparin is an anticoagulant
• It can cause a rare disorder called HIT
• - Immune mediated hypercoagulation
Rx: Heparin
• Protamine is the reversal agent for heparin
• Protamine binds to heparin and terminate it’s
action
Low Molecular Weight Heparins
• Rx: enoxaparin; Lovenox
• Does not require close lab monitoring
• Subcutaneously
Antiplatelet
• Rx: salicylates (Aspirin)
• Rx: clopidogrel (Plavix)
Thrombolytics
“clot busters”
• Rx: streptokinase
• Rx: tPA tissue plasminogen activator
• Rx: reteplase (Retevase)