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53 Cards in this Set
- Front
- Back
CHF Definition
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Syndrome comprising left. ventricular fxn and neuronhormonal regulation...accompanied by effort intolerance, fluid retention, and decreased longevity.
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CHF trends
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500 K new pts. in US/year
100-300K deaths/yr. |
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4 Stages of treatment
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Prevention
Treatment aimed at prolonging life Treatment aimed at reducing symptoms End-stage considerations |
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Two major consequences of CHF
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decreased CO
decreased venous congestion |
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Decreased CO consequences
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Decreased delivery of O2 blood leading to forward failure
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Characteristics of forward failure
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Decrease exercise tolerance, increased fatigue, decreased renal perfusion, azotemia, cachexia, hypotension
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Venous congestion consequences
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More blood left behind in atrium-- Backward failure
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Characteristics of backward failure
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Increase venous pressure leads to neurohormonal response causing Na/fluid retention
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Manifestations of backward failure
6 things |
Atrial enlargement (A-fib)
Thromboembolism (venous stasis) Pulmonary edema (lft. HF) Peripheral edema (rt. HF) Hypoxia/Hypoxemia Dyspnea |
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What causes venous congestion in most CHF pts? Define the cause.
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Excess preload
Tension in the ventricle at end diastole |
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Kinds of treatment for xs preload
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Diuretics
Nitrates Morphine Na restriction H2O restriction |
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Mainstay for xs preload treatment
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Furosemide (loop diuretic)
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What did the Rales Study find?
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27% decrease in total mortality w/addition of K+ sparing diuretics in pts. with severe HF
Also drugs that improve forward fxn indirectly help |
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Example of K+ sparing diuretic
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Spironolactone
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Example of drugs that improve forward fxn.
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ACEi : digoxin
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Why do you need to avoid xs diuretic use?
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Causes dehydration--inadequate preload--forward failure
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Afterload
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Wall stress during systole
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What can cause increase afterload.
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Decrease CO and the ensuing neurohormonal response.
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What drugs break the viscious cycle of increase afterload?
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ACEi
Angiotensin receptor blockers |
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Contractility
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Squeezing of the pump
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Definition of systolic dysfunction
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Ejection fraction <45%
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Causes of systolic dysfxn.
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MI, idiopathic dilated cardiomyopathy, HTN, ischemia, toxin (EtOH, adriamycin), infection (Chagas), viral myocarditis, tachycardia
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Drugs that directly improve systolic fxn.
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Digoxin, B-adrenergic agonists (DOPA, dobutamine, epi), phosphodiesterase inhibitors and vesnarinone
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Which drug is routinely used to treat sys dysfxn? Why?
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Digoxin, the others have increase risk of mortality
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Why should we use caution with using B-blockers early on in the treatment of systolic dysfxn?
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Reduce contractility in the short term, can make it worse.
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The result of chronic B-blocker use in sys. dysfxn.
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significant increase in ejection fraction
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What did the CIBIS II and Carvedilol trials find?
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Addition of B-1 or non-selective B-blockers to an ACEi reduces tot. mortality in HF over ACEi alone
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Should you use Ca blockers to treat sys. dysfxn.
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No they reduce contractility leading to increased mortality.
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Diastolic dysfxn.
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Abnormally increased contractility
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Who gets diastolic dysfxn
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Left ventricular hypertrophy
HOCM HTN* most common **LVH and HOCM may have supranormal dP/dT |
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Why would pts. w/LVH or HOCM get diastolic dysfxn
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Impaired cardiac filling leads to need to increase diastolic pressure (preload) to achieve adequate CO
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How many pts w/CHF have diastolic dysfxn?
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1/3
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What eventually happens to stroke volume in diastolic dysfxn (DD)? What is the consequence?
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Decreased SV --- decreased CO with increased EF
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Ideal therapy for DD?
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We don't know
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DD aka
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"Little old lady's heart"
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Why should we use caution when using diuretics to treat DD.
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Hypotension and low preload can result
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Why is excessive afterload dangerous?
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Can result in cavity obliteration (the ventricle empties completely @ end-systole) which can lead to syncope or pulmonary edema (due to tachycardia)
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What is the reflex bradicardia causing syncope in cavity obliteration called?
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Bezold-Jarisch response
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Just remeber....
CO = SV * HR |
:)
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Compare sys dysfxn and diastolic dysfxn with dP/dT
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Sys: ↓↓
Dias: ↑ |
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Compare sys vs. diastolic dysfxn for EF
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Sys: ↓↓
Dias:↑↑ |
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Compare sys vs. diastolic dysfxn for chamber volumes
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Sys:↑↑
Dias:↓ |
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Compare sys vs. diastolic dysfxn fo LV diastolic pressure
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Sys: ↑
Dias: ↑ |
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Name the associated use for the drug listed in sys dysfxn
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ACEi...+++ (first line Rx)
Ca blockers..CONTRAINDICATED B-blockers..++ Diuretics..+ (spironolactone) Digoxin..++ (symptomatic use) |
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Name the associated use for the drug listed in diastolic dysfxn.
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ACEi + (esp. in BP is increase)
Ca blockers ++ (verpamil) B-blockers +++ (esp if angina) Diuretics +/- (beware hypotension) Digoxin CONTRAINDICATED |
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Treatment for acute bradycardia
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Atropine
B stimulants (dobutamine, epi) |
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How does chronic tachycardia decreased CO
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Limits diastolic filling and can lead to sys. dysfxn
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How does chronic tachycardia decreased CO
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Limits diastolic filling and can lead to sys. dysfxn
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What is an unrecognized cause of CHF?
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A-fib w/rapid ventricular response
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What is the drug of choice for maintaining sinus rhythm in HF?
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Amiodarone
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What drug is most often used to control ventricular rate in HF pts?
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Digoxin
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Last line treatment for those w/uncontrollable tachycardia
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AV ablation
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Four factors of ventricular performance
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Preload
Afterload Contractility Heart rate and rhythm |