Ch. 17 Heart Failure

Ventricular Remodeling in HF

A weakened heart muscle activates the secretion of molecular substances such as angiotensin II, aldosterone, endothelin, TNF-alpha, catecholamines, insulinlike growth factor, and growth hormone; these provoke genetic changes, apoptosis, and hypertrophy of cardiac myocytes, as well as collagen deposits and myocardial fibrosis. -->During the course of HF, these molecules cause changes in the heart that lead to enlargement and dilation of the left ventricle, which worsen HF.

Inotropic

of the heart refers to the force of contraction of the cardiac muscle

What happens if RVF is severe?

peripheral edema can be massive and gradually affect most of the tissues in the body, a condition called *anasarca*.

Summary of LVF Backward Effects

Dyspnea Cough Orthopnea Paroxysmal nocturnal dyspnea Crackles in lungs

Pt's Symptoms in HF

Dyspnea upon exertion Dyspnea when lying flat for more than a few minutes Nocturnal cough Confusion Difficulty concentrating Cold, pale legs and feet Swelling in the ankles or fingers Tight rings or shoes because of fluid retention Abdominal swelling -->Gastrointestinal symptoms, such as anorexia or a feeling of fullness -->Increased frequency of urination Nocturia caused by excess fluid accumulation -->Weight gain of 2 pounds or more per day because of fluid retention

Summary of Effects of RVF

Jugular vein distension (JVD) Ascites Hepatomegaly Splenomegaly Ankle edema or sacral edema

Backward Effects in LVF

The backward effects consist of a buildup of hydrostatic pressure backward up into the left atrium and pulmonary vasculature, which causes fluid extravasation into the pulmonary interstitial and intracellular spaces (*pulmonary edema*). --> The opening and closing of alveoli against this fluid is heard as *crackles* through a stethoscope and is exhibited as *cough, dyspnea, orthopnea, and paroxysmal nocturnal dyspnea* by the patient

Left Ventricular Failure

The next slides describe an "academic" way of learning about LVF -->In the clinical setting, LVF and RVF usually affect the patient at the same time. --->Academically, it is easiest to learn the effects of each side separately (backward vs. forward effects).

S3 Gallop in HF

The third heart sound (S3) is a low-pitched sound heard after S2, during rapid filling of the ventricle in the early part of diastole. -->In adults older than age 40 years, the presence of an S3 is abnormal and indicative of heart failure. -->High ventricular end-diastolic volume and increased pressure within the chambers consequent to heart failure are responsible for

Diastolic HF

*diastolic dysfunction*, also known as diastolic heart failure, the ventricle has difficulty relaxing, is less elastic, and cannot expand fully. ---> The stiff ventricle cannot fill with blood adequately; therefore, it pumps out insufficient blood volume -->Stroke volume and cardiac output are diminished because there is low blood volume in the ventricle.

Systolic HF

*systolic dysfunction*, also known as systolic heart failure, the weakened ventricle has difficulty ejecting blood out of the chamber --> The ventricle is a poor forward pump which, in turn, causes inadequate ventricular emptying. --> Stroke volume and cardiac output, both functions of forward heart pumping action, are diminished ---> Blood accumulates in the weakened ventricle, elevating pressure within the chamber, causing a backup of hydrostatic pressure into the atrium above it.

Heart Failure (HF)

---> HF is the most common cause of hospitalization. ---> As the treatment for acute cardiovascular diseases has improved, more persons are surviving into old age with chronic cardiovascular conditions. ---> Persons with cardiovascular disease are surviving acute cardiac events and living longer with heart failure.

Disparity in Incidence of HF

---> Women are often diagnosed with HF at an older age than men because natural estrogen is cardioprotective. --> After menopause, the risk of cardiovascular disease for men and women is equal. --> Within the U.S. population, there is a greater prevalence of HF among African Americans compared with Caucasian Americans.

Hypokalemia IN HF

--->In heart failure, blood volume increases because of excess water within the bloodstream. This excess water commonly dilutes the serum electrolytes, sodium and potassium, causing dilutional hyponatremia and hypokalemia. --->In addition, with the constant cycling of the RAAS in heart failure, aldosterone causes potassium excretion from the kidneys. The repeated simulation of the RAAS increases the risk of hypokalemia.

Hepatojugular Reflux

--->To confirm hepatic congestion caused by RVF, the clinician can elicit positive *hepatojugular reflux*. --->In order to elicit hepatojugular reflux, the patient is supine and the clinician presses on the liver. Pressure on the liver increases portal venous pressure and in turn raises jugular venous pressure, producing visible JVD.

S4 In HTN

-->A fourth heart sound (S4) is heard when the atrium contracts against a noncompliant, stiff ventricle. -->An S4 is a low-pitched sound heard at the end of diastole, before S1. -->An S4 commonly occurs in chronic HTN because of the structural changes that occur in the left ventricle as a result of high blood pressure. -->In HTN, high aortic pressure creates high resistance and hypertrophy of the left ventricle. The hypertrophic left ventricle is less elastic and distensible. Atrial contraction against this stiff left ventricle causes an audible S4 during diastole

Forward Effects in LVF

-->The forward effects of the weak left ventricle cause inadequate ejection of blood into the aorta and diminished perfusion throughout the whole arterial circulatory system. -->The decreased perfusion of vital tissues activates a neurohormonal response that includes stimulation of the RAAS, ADH, and sympathetic nervous system

Orthopnea

-->The patient with LVF has difficulty breathing when lying flat. The patient needs to be propped up when in bed. ---> This is often referred to as: "1 pillow orthopnea, 2 pillow orthopnea." -->When propped up, the fluid in the lungs remains in the bases, thereby making it easier to breathe.

Left Ventricular Failure ( LVF) Backward vs Forward

1. The backward effect of a failing left ventricle creates a buildup of hydrostatic pressure in the left atrium, pulmonary veins, and pulmonary capillaries 2. forward failure effects cause decreased perfusion of the brain, kidneys, and other organs

What happens in Pulmonary Edema?

A bilateral pleural effusion may develop as a result of high pulmonary venous pressure, causing diffusion of fluid into the pleural cavity.

Forward Effects of LVF

Also, in response to diminished perfusion, the posterior pituitary gland releases ADH, which acts at the nephrons to increase water reabsorption into the bloodstream and, in turn, leads to increased blood volume.

Right Ventricular Failure

Backward effects are most apparent on physical examination. Hydrostatic P increases in right ventricle --> right atrium ---> inferior vena cava and superior vena cava -->jugular venous distension, ascites, hepatic venous congestion (hepatomegaly), splenic venous congestion (splenomegaly), ankle or sacral edema.

Paroxysmal Nocturnal Dyspnea (PND)

PND occurs when the patient with heart failure awakens in the middle of the night with difficulty breathing. This occurs because of pulmonary fluid buildup, which causes the patient to suffer hypoxia while asleep. Patients usually describe it as a smothering feeling or nightmare.

Backward Effects of LVF are all caused by Pulmonary Edema..

Pulmonary edema can be mild or severe. Crackles in the lungs can be heard in pulmonary edema. Fine crackles occur with mild pulmonary edema. Coarse, bubblelike crackles occur with severe pulmonary edema. Pink, frothy sputum may be seen with severe pulmonary edema.

What Cor Pulmonale is caused by?

RFV Caused by Lung Disease.

Major causes of HF

Repeated ischemic episodes of the heart (called ischemic cardiomyopathy) Myocardial infarction papillary muscle rupture Chronic HTN Chronic obstructive pulmonary disease (COPD) RVF Dysrhythmias Valvular disorders: mitral insufficiency, aortic stenosis Pulmonary embolism ---> RVF

Forward Effects of LVF III

Simultaneously, with decreased forward pumping of blood, the aorta and peripheral arteries experience diminished blood flow and baroreceptors within the artery walls sense a drop in blood pressure; this activates the sympathetic nervous system (SNS). The SNS stimulates adrenergic receptors in the heart and blood vessels to create further effects. Adrenergic stimulation of the heart increases heart rate and adrenergic stimulation of the vasculature causes vasoconstriction

Daily Weight Measurement in HF

Weight fluctuation of 2 lbs or more from day to day is often caused by fluid retention or edema.

Forward Effects of LVF II

When the kidney senses decreased perfusion, it releases renin from the nephron juxtaglomerular apparatus and initiates cycling of the RAAS. Renin --> angiotensinogen--> angiotensin I --> angiotensin II --> peripheral vasoconstriction and stimulation of the adrenal gland --> aldosterone--> Na+ and H2O reabsorption --> increase of blood volume and blood pressure

* Preload *

can be defined as the volume of blood in the heart at the end of diastole --> Preload factors are those that affect cardiac output but occur before contraction ---> *Most commonly, preload refers to the volume of blood that enters the right atrium from the venous system. *

Stroke Volume

is the amount of blood within the ventricle that is ejected with each contraction. --> * This can also be referred to as left ventricular ejection fraction.*

*Afterload*

is the amount of resistance that the ventricle must overcome in order to pump blood out of the heart --> The greater the systemic arterial vascular resistance, the greater the afterload against the left ventricle -->Pulmonary artery pressure creates high afterload for the right ventricle. ---> * Most commonly, afterload describes the resistance exerted by the pressure within the aorta against the left ventricle*

Left Ventricular Ejection Fraction ( LVEF)

is the volume of blood pumped with each ventricular contraction --> lower than 40% is indicative of heart failure.

Chronotropic

refers to heart rate

Contractility

refers to the ability of the myocardium to stretch and contract in response to the filling of the heart with blood.