Ch. 17: Heart Failure

Cardiac Output

the volume of blood ejected by the left ventricle per minute

CO= __ x __

SV x HR

Stroke Volume

Blood ejected per beat by left ventricle

Clinical impact: Stroke Volume

cardiac output; affected by preload, afterload, contractility

Preload

end-diastolic ventricular filling/stretch

Clinical impact: Preload

increased by fluid overload; influences SV via Frank-Starling law

Afterload

resistance ventricle must overcome to eject blood

Clinical Impact: Afterload

elevated in HTN; lowering afterload improves SV

Contractility

intrinsic myocardial ability to contract

Clinical Impact: Contractility

enhanced by sympathetic activity or inotropes; reduced in LV failure

Systole ventricles ______

Contract

Diastole ventricles ______

Relax

Ejection fraction % =

SV/total blood in ventricle

Left Ventricular Ejection Fraction (LVEF)

volume of blood pumped with each ventricular contraction

What percentage of blood volume in the left ventricle is pumped out with each contraction

60 - 70

A LVEF < 40% is indicative of

heart failure

Heart Failure

impaired function of the heart

Heart Failure is classified by

Ejection Fraction (EF)

In heart failure the heart muscle is...

weak and does not pump effectively or fill properly

Systolic HF

weakened ventricle has difficulty ejecting blood out of the chamber

In systolic HF where does blood accumulate?

the weakened ventricle

In systolic HF the ventricle has a poor ____ which causes ______

poor forward pump which causes inadequate ventricular emptying

Diastolic HF

ventricle has difficulty relaxing is less elastic and cannot expand fully

In Diastolic HF the stiff ventricle cannot...

fill with blood adequately

In Diastolic HF _____ and _____ are diminished

Stroke volume and Cardiac output

Causes of Left-sided HF

HTN, CAD/MI, Cardiomyopathy, Valvular Dysfunction

Manifestations of Left-sided HF

crackles, cough, dyspnea, paroxysmal nocturnal dyspnea, pulmonary edema

Paroxysmal Nocturnal Dyspnea occurs when

patient with left-sided HF wakes in the middle of the night with difficulty breathing

Causes of Right-sided HF

Left-sided HF, Chronic Lung Disease (Cor Pulmonale), Right Ventricular MI, Pulmonic Valve Disease

Manifestations of Right-sided HF

Peripheral edema, JVD, Hepatomegaly, Ascites

Cor Pulmonale is...

right ventricular failure caused by lung disease

If RVF is severe peripheral edema can be massive and gradually affect most tissues in the body this condition is called

Anasarca

Neurohormonal Activation in HF causes activation of (2)

RAAS, andSNS

Activation of RAAS in HF leads to

BP increase initially, Fluid volume increases (Na and Water retention)

Activation of the SNS in HF leads to

HR increase initially, Blood vessels constrict

Over time with HF the heart starts remodeling and _____ occurs

fibrosis

Main problem in Left-sided HF

poor forward pumping to systemic circulation

Main problem in Right-sided HF

poor pumping to lungs

Where blood backs up in Left-sided HF

Lungs

Where blood backs up in Right-sided HF

Body/systemic veins

Most essential lab for diagnosing and assessing severity of HF

B-Type Natriuretic Peptide (BNP)

BNP > ___ is strongly indicative of HF

500

BNP helps differentiate HF from

other causes of dyspnea

Labs for HF

BNP, Potassium(hypokalemia), Sodium (hyponatremia), Renal function (BUN/creatinine), Troponin (cardiac markers)

Treatment of HF (lifestyle modifications)

Low-fat diet, nonsmoking, low salt (1,500mg), physical activity, low alcohol use, weight loss (if obese), medications

Complex Heart Failure mechanisms: HF

Heart failure arises from changes in preload, afterload, contractility, and LF EF

Risk factors and structural changes: HF

HTN, CAD, diabetes, lead to structural heart changes causing LV or RV failure

Diagnostics and Assessment: HF

Biomarkers, imaging, and invasive hemodynamics are essential for heart failure diagnosis and staging

Management and Future therapies: HF

treatment targets neurohormonal pathways and volume status; future options include device therapy and personalized medicine