heart failure-bds 2012

8/2/2019 Heart Failure-bds 2012

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Heart FailureDr. Ibrahim Y Hachim

The FrankStarling law

states that the greater the

volume of blood entering the

heart during diastole (end-

diastolic volume), the greater

the volume of blood ejected

during systolic contraction

(stroke volume) and vice-

versa.
http://upload.wikimedia.org/wikipedia/commons/0/01/Starling_RAP_combined.svg


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What is Heart Failure? I t i s a pathologic state in which impaired

cardiac function renders the heart unable to

maintain output sufficient for the metabolic

requirements of the body.

Common end point of many forms of heart

disease .

Heart Failure CHF is ccc by diminished cardiac output

(forward failure) , accumulation of blood in thevenous system ( backward failure) , or both.

cardiac output( forward failure)

accumulation ofblood in the venoussystem ( backwardfailure)


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Most instances of heart failure

are the consequences of

progressive detorioration of

myocardial contractilefunction (systolic

dysfunction).

Frequently due to ischemic

injury , pressure or volume

overload , or dilated

cardiomyopathy .

Occasionally , failure results

from inability of the heart

chambers to relax

sufficiently during diastole

(diastolic dysfunction) .

This can occur with massive

left ventricular

hypertrophy , deposition ofamyloid , or constrictive

pericarditis.


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Inadequate cardiac output in CHF

Tachycardia Blood volumeexpansion bysalt and waterretension.

Ventricular dilation ( improves contraction by myofiber stretchingaccording to the Frank-Starling law).

LEFT-SIDED HEART FAILURE

ischemic heart disease hypertension aortic and mitralvalvular diseases

nonischemicmyocardialdiseases

Involves the left ventricle (lower chamber) of theheart


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Morphology.The findings in the heart vary depending on the cause of the

disease process; abnormalities such as myocardial infarction or

a valvular deformity may be present. This chamber is usually

hypertrophied and often dilated, sometimes quite

massively except with obstruction at the mitral valve or other

processes that restrict the size of the left ventricle,

Secondary enlargement of the left atrium with resultant atrial

fibrillation (i.e., uncoordinated contraction of the atrium) may

either compromise stroke volume or cause blood stasis and

possible thrombus formation. A fibrillating left atrium carries a

substantially increased risk of embolic stroke..


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LungsPressure in the pulmonary veins mounts and is ultimately

transmitted retrograde to the capillaries and arteries. The result

is pulmonary congestion and edema, with heavy, wet lungs.

LungsIt is sufficient to note here that the pulmonary changes include,in sequence:-(1) a perivascular and interstitial transudate, particularly in theinterlobular septa, responsible for Kerley's B lines on x-ray


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(2) Progressive edematous widening of alveolar septa

(3) Accumulation of edema fluid in the alveolar spaces.

Moreover, hemosiderin-containing macrophages in the alveoli

(called siderophages, or heart failure cells) denote previous

episodes of pulmonary edema.

Dyspnea (breathlessness), usually the earliest and thecardinal complaint of patients in left-sided heart failure.With further impairment, there is orthopnea, which isdyspnea on lying down that is relieved by sitting orstanding. Thus the orthopneic patient must sleep whilesitting upright. Paroxysmal nocturnal dyspnea is anextension of orthopnea. Cough is a commonaccompaniment of left-sided failure.

Clinical manifestations


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Decreased cardiac outputKidneys

reduction in renal perfusion

The renin-angiotensin-aldosterone

THE RENIN ANGIOTENSIN ALDOSTERONE SYSTEM

ACE

ACE INHIBITORS

JGA

RENIN

ADRENAL

ALDOSTERONE

ANGIOTENSINOGEN ANGIOTENSIN 1

ANGIOTENSIN 2

VASOCONSTRTICTS

Na RETENTION

INCREASED BP

If the perfusion deficit of thekidney becomes sufficientlysevere, impaired excretionof nitrogenous productsmay cause azotemia, in thisinstance prerenal azotemia

Poor renal perfusion is sensed by the

juxtaglomerular apparatus, which secretesrenin. Renin converts angiotensinogen inthe blood to angiotensin1. This in turn isconverted by ACE (angiotensin convertingenzyme) to angiotensin2, which increasesblood pressure directly by vasoconstrictionand by increasing adrenal secretion ofaldosterone. ACE inhibitors are used totreat heart failure as well. as hypertension.Diuretic drugs are another mainstay oftreatment.

BrainIn far-advanced CHF, cerebral hypoxia may give rise tohypoxic encephalopathy , with irritability, loss ofattention span, and restlessness, which may evenprogress to coma.


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What is Right Heart Failure?

Isolated right-sided heart failure occurs in only a few

diseases. Usually it is a secondary consequence of left-

sided heart failure because any increase in pressure inthe pulmonary circulation incidental to left-sided heart

failure inevitably produces an increased burden on the

right side of the heart.

Cor pulmonale is the term given to heart failure due tolung disease, such as chronic obstructive airwaysdisease.

The major morphologic and clinical effects of pure right-

sided heart failure differ from those of left-sided heart

failure in that pulmonary congestion is minimal,

whereas engorgement of the systemic and portal venous

systems may be pronounced.

Right-sided HF

Liver and Portal System

Kidneys

BrainPleural and Pericardial Spaces

SubcutaneousTissues


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1

The liver is usually increased in size and weight (congestivehepatomegaly), and a cut section displays prominent

passive congestion . Congested red centers of the liverlobules are surrounded by paler, sometimes fatty, peripheralregions (nutmeg liver).

The liver

Centralvein

Right-sided heart failure also leads to elevated pressure inthe portal vein and its tributaries. Congestion produces atense, enlarged spleen (congestive splenomegaly).

Kidneys

Congestion of the kidneys is more marked with right-

sided heart failure than with left-sided heart failure,

leading to greater fluid retention, peripheral edema,

and more pronounced azotemia.

Brain

Symptoms essentially identical to those described inleft-sided heart failure may occur, representing venous

congestion and hypoxia of the central nervous system.


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Subcutaneous Tissues

Peripheral edema of dependent portions of the

body, especially ankle (pedal)

and pretibial edema, is a

hallmark of right-sided heart

failure. In chronically

bedridden patients, the

edema may be primarily

presacral. Generalizedmassive edema is called

anasarca.

heart failure-bds 2012

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