CHF

Question 1

number of americans with CHF

Answer 1

• 5 million

- most frequent medicare primary discharge diagnosis

Question 2

prevalence of CHF in AA population

Answer 2

25% higher than whites

-greater portion of risk attributable to modifiable factors

Question 3

CHF stats

Answer 3

• HTN doubles risk
• pts with NYHA class 4 HF have 50% 1 yr mortality
• 5 yr survival is 25% in men and 38% in women

Question 4

pathogenesis of CHF

Answer 4

• MISMATCH BETWEEN OUTPUT AND NEED
• mismatch could happen because there isnt enough volume in the ventricle (diastolic HF) or the ventricle is unable to overcome the pressure in the system (systolic HF)
  1. myocardial hypertrophy
  2. increased sympathetic activity
  3. fluid retention

Question 5

pressure overload

Answer 5

elevated systolic BP

-forces heart to overcome excess pressure

Question 6

volume overload

Answer 6

increased diastolic volume

-causing dilation of the ventricle

Question 7

MCC CHF

Answer 7

• diabetes and coronary disease

- HTN and valve disease

Question 8

myocardial hypertrophy

Answer 8

• heart size increases and the chambers dilate
• heart muscle stretches: stronger contraction initially
• excessive elongation of the fibers results in weaker contractions - eventually you pull too far and you can’t generate any tension at all
• NORMAL MYOCARDIAL CELLS HYPERTROPHY TO MAINTAIN CONTRACTILE FORCE
• increases myocardial oxygen consumption because muscle is bigger and needs more food

Question 9

characteristics of hypertrophic myocardium

Answer 9

• slowed contraction time
• increased time to develop maximum tension
• delayed relaxation
• ultimately constricts chamber cells

Question 10

increased sympathetic activity in CHF

Answer 10

• activation of beta-adrenergic receptors in the heart: increased HR (tachy), greater force of contraction of heart muscle
• vasoconstriction enhances venous return and increases cardiac output
• decreased diastolic filling time

Question 11

RAAS activation in CHF

Answer 11

• decreased CO means the kidneys think blood volume is decreased
• release renin etc. to retain sodium and water

Question 12

effect of angio II on the heart

Answer 12

• CARDIOTOXIC!!

- causes cardiac hypertrophy and ventricular remodeling

Question 13

Vasodilator peptides

Answer 13

• Atrial natriuretic peptide (ANP)
• Brain natriuretic peptide (BNP): released by dilated heart by stimulation of stretch receptors
• elevated BNP correlates with more severe HF and poorer prognosis

Question 14

Effect of ANP and BNP

Answer 14

• diuresis of fluid and sodium
• decreased vascular resistance
• decreased renin/angio/aldo

Question 15

underlying causes of CHF

Answer 15

• myocardial injury: MI, ischemia, cardiomyopathy, myocarditis
• ischemic heart dz/CAD (DM) causes 75% of all CHF
• HTN
• Valvular heart dz

Question 16

precipitating factors for CHF

Answer 16

• acute infections
• arrhythmias (tachy, afib, brady, AV block)
• excess exertion
• excess Na intake
• PE
• anemia (causes tachy)
• thyrotoxicosis
• pregnancy
• cardiac toxins (i.e. alcohol or chemo agents)
• fluid overload (i.e. IV or transfusion)

Question 17

Systolic failure

Answer 17

-failure is at systole where we are supposed to have ejection

Caused by:

• decreased contractility (i.e. MI, ischemia, infection, myocarditis, other injury); volume overload due to MR, AR
• pressure overload (i.e. aortic stenosis, uncontrolled HTN)

-decreased ejection fraction measured via ECHO (<0.4)

Question 18

diastolic failure

Answer 18

• ventricle doesnt fill well and this often has to do with compliance of ventricular wall - its stiff and doesnt expand to accept volume (i.e. from scar tissue, obstruction, or concentric hypertrophy)
• contractility is normal, ejection fraction 55-78%

Caused by:
-ventricular hypertrophy, hypertrophic cardiomyopathy, restrictive cardiomyopathy (fibrosis, scarring), transient ischemia, obstruction of ventricular filling (MS, pericardial constriction [effusion, tamponade])

Question 19

Left heart failure causes and sxs

Answer 19

• onset of injury is abrupt (e.g. acute MI) heart failure may be limited to one side - wont see systemic edema but will have pulmonary edema
• sxs: pulmonary congestion, orthopnea, exercise intolerance, PND, DOE

Question 20

Right sided heart failure causes and sxs

Answer 20

• causes: cor pulmonale, pulmonary embolus with shunt, COPD (fibrosis and scarring), valvular disease)
• sxs: peripheral edema, ascites, congestion in liver

Question 21

low output failure

Answer 21

• MOST CASES OF CHF ARE LOW OUTPUT FAILURE associated with VASOCONSTRICTION
• ex) ischemic heart dz, HTN, dilated cardiomyopathy, valvular dz, pericardial dz
• sxs: cold, clammy, pale extremities, oliguria, low pulse pressure, wide arterial-venous oxygen difference

Question 22

pulse pressure

Answer 22

systolic - diastolic

Question 23

high output failure

Answer 23

• less common, caused by hyperactive circulatory condition
• ex) anemia (tachy), thyrotoxicosis, pregnancy, paget’s dz of bone, AV fistula
• VASODILATION (unlike low output failure)
• sxs: warm, flushed skin, bounding pulse, arterial-venous oxygen difference is normal
• increased CO

Question 24

Backward failure

Answer 24

• transmission of increased pressure backward

- ex) pulmonary HTN d/t problems with left side of heart

Question 25

forward failure

Answer 25

- inadequate CO - ex) altered mental status (decreased cerebral perfusion), fatigue (decreased skeletal muscle perfusion), edema (decreased renal perfusion)

Question 26

CHF diagnostic sxs

Answer 26

- DOE, dyspnea at rest, orthopnea, PND, dry cough | - fatigue/weakness, confusion, nocturia, oliguria, abdominal pain, edema

Question 27

CHF NYHA classification

Answer 27

- 1: heart dz present but no limitation of physical activity - 2: slight limitation of physical activity, sxs on significant exertion - 3: marked limitation of physical activity; less than ordinary activity leads to sxs - 4: sxs at rest

Question 28

CHF findings on PE

Answer 28

-dyspnea, hypoxia, JVD (over 4cm above sternal angle w/ pt @ 45 degrees), tachy, S3 gallop, crackles at bases of lungs, hepatomegaly, ascites, edema of feet and ankles, anasarca if severe CHF

Question 29

CHF ECG findings

Answer 29

- sinus tachy - atrial enlargement (wide P wave) - LVH or RVH may be present - LBBB may be present

Question 30

CHF CXR findings

Answer 30

-cardiomegaly, upper lung redistribution of flow (cephalization), interstitial fluid, kerley B lines, pleural effusion

Question 31

CHF ECHO findings

Answer 31

- GOLD STANDARD - establish type of cardiomyopathy (dilated, restrictive, hypertrophic) - identify causes (valvular dz, intracardiac shunts) - gives measure of LV EF

Question 32

CHF Laboratory tests

Answer 32

- theres no blood test for HF - elevated BNP = good monitoring tool - hypoxemia - respiratory acidosis - hyponatremia - elevated liver enzymes

Question 33

BNP

Answer 33

B-type natriuretic peptide - secreted in response to volume expansion and ventricular pressure overload - BNP > 80 SUGGESTS ACUTE HF - causes for BNP elevation: PE, lung CA, pulmonary TB

Question 34

Shock

Answer 34

- acute drop in CO - imminently life threatening - cardiogenic: low output (SBP <90 for 30 mins, adequate volume) - Hypovolemic: bleeding - Anaphylactic: allergic rxn - Septic: infxn

Question 35

causes of cardiogenic shock

Answer 35

- AMI: pump failure | - mechanical defect (VSD, tamponade)