Heart failure: Pathology review

on the Cardiology Ward there were two people who had been admitted to the hospital repeatedly the first one is 70-year-old Lydia who had a myocardial infarction about 3 years ago she presents with fatigue and dnia she says that she usually wakes up at night because of shortness of breath but using more pillows when sleeping helps relieve it somewhat on examination she has pitting edema in her legs and on oscilation an S3 sound is heard the other person is 81-year-old Richard who has been a smoker for the past 50 years he is also experiencing fatigue and

has pitting edema but on further examination there's also jugular Venus distension and hepatomegaly okay so both these individuals suffer from heart failure heart failure is a clinical syndrome used to describe the inability of the heart to pump enough blood or a point at which the heart can't supply enough blood to meet the body's demands this can happen in two ways either the heart's ventricles can't pump blood hard enough during syy called systolic heart failure or not enough blood fills into the ventricles during diast called diastolic heart failure in both cases blood backs up into the

lungs causing congestion or fluid buildup which is why it's also known as congestive heart failure or just CHF all right first up is systolic heart failure one way to think about this is that the heart needs to squeeze out a certain volume of blood each minute called cardiac output which can be calculated as the heart rate multiplied by the stroke volume the heart rate is pretty intuitive but the stroke volume is a little tricky an adult heart might beat 70 times per minute and the left ventricle might squeeze out 70 ml per beat so 70

* 70 equals a cardiac output of 4 4,900 m per minute which is almost 5 L per minute now the stroke volume is only a fraction of the total volume the total volume might be closer to 110 ml and 70 ml is the fraction that got ejected out with each beat the other 40 mlit kind of lingers in the left ventricle until the next beat in this example the ejection fraction would be 70 ml divided 110 ml or about 64% a normal ejection fraction is about 50 to 70% now in systolic heart failure there's decreased

contractility of the left ventricle which causes a decreased cardiac output because the stroke volume is low this means that there's also a decreased ejection fraction during diast blood returns to the ventricles and combines with the leftover blood that didn't get pumped out during syy and this is called the edv or enddiastolic pressure volume with systolic heart failure don't forget that edv is high because there's more blood left over after each heartbeat regarding the enddiastolic blood pressure or EDP which is the pressure that's found in The ventricle at the end of diast this will also be

high because the volume at the end of diast is high as well systolic heart failure is mainly caused by low contractility which can happen with esea caused by myocard Cal infarction where a part of the cardiac tissue is damaged so it doesn't contract properly anymore another cause is dilated cardiomyopathy where the ventricle is dilated and weakened now in addition to cystolic heart failure you've also got diastolic heart failure which is where the cardiac contractility is sufficient but not enough blood is returning to the ventricles in this case again the stroke volume is low but the

ejection fraction is normal so for example the total volume might be lower than normal say about 69 ML and we pump out 44 millit so if we divide 44 by 69 we get 64% which is within the normal range with diastolic heart failure we need to look at the end diastolic pressure or the EDP as well the problem is that the left ventricle isn't compliant enough so when The ventricle is filling during diast the pressure within will rise so keep in mind that EDP is elevated during diastolic heart failure also remember that with diastolic heart

failure edv is normal at least in the beginning because the Atria are capable of squeezing more blood into The ventricle one cause of diastolic heart failure is ventricular hypertrophy where the ventricular myocardium gets thicker and this decreases the ability of the chamber to stretch when filling all right so heart failure can be systolic or diastolic and can affect the right ventricle or the left ventricle or both which is called B ventricular heart failure having said that if less blood exits either ventricle it'll affect the other since they work in series so these terms really refer

to the primary problem affecting the heart basically which one was first for your exams it's important to remember that the main cause of right heart failure is left heart failure when right heart failure isn't caused by left heart failure but by a pulmonary cause we refer to this as core pulmonale in terms of symptoms in left heart failure The Blood starts to back up into the lungs specifically in the pulmonary vein and capillary beds which can increase the pressure in these vessels this leads to fluid moving from the blood vessels to the interstitial space causing

pulmonary edema or congestion this is a very important sign and must be remembered in the Alvi of the lungs all the extra fluid makes oxygen and carbon dioxide exchange a lot harder and therefore patients have disia or trouble breathing another symptom is orthopnea which is difficulty breathing when lying down flat this is because there's more Venus return from the legs and the gut to the heart which increases the amount of blood backing up into the pulmonary circulation this also explains why these people experience paroxysmal nocturnal dpia which is when the sensation of not being able

to breathe wakes a person up at night such individuals often sleep using more pillows in order to keep their upper body a bit elevated this will lower the Venus return and ease lung congestion extra fluid in the lungs causes crackles or RS on oscilation if enough fluid fills the capillaries in the lungs they can rupture causing blood to leak into the alvioli Alvar macroasia then eat up these red blood cells which causes them to take on this brownish color from Iron buildup and then they're called hemosin Laden macroasia also known as heart failure cells next

since there's a decreased cardiac output not enough blood is reaching vital organs as a result an individual with heart failure may also present with fatigue decreased blood flow to the kidneys activates the renin Angiotensin aldosterone system which will increase sodium and water reabsorption in the kidneys ultimately causing fluid retention now you'd think this is good because it increases blood volume which increases end diastolic volume and based on the Frank Starling mechanism it will increase contractility unfortunately in the longterm large portions of this extra fluid will end up leaking into the tissues which worsens the pulmonary

edema and will also lead to peripheral edema this is sometimes called pitting edema because the tissue is visibly swollen and when you apply pressure to it it leaves a pit apart from this the low cardiac output will also activate the simp athetic nervous system which increases left ventricle contractility but also activates the reenan Angiotensin aldosterone system finally an important thing to remember is that with left heart failure on oscilation you can hear an extra sound either S3 or less commonly S4 S3 is a low pitched sound that comes right after S2 this occurs when there's

a lot of blood filling Into The ventricle rapidly normally you you wouldn't hear this but in systolic heart failure The ventricle is overly compliant allowing more blood to gush into the chamber so S3 is also called ventricular Gallop S4 on the other hand comes right before S1 once again this is not normally heard but in diastolic heart failure when the ventricles are extra stiff the Atria have to contract extra hard to push that blood in when this blood is forcefully pushed into The ventricle and hits the chamber wall it produces an S4 or atrial Gallop

now let's switch gears and talk about right-sided heart failure and remember the most common cause is left-sided heart failure since left heart failure increases the pressure in the pulmonary artery this will make it harder for the right ventricle to pump blood into it other causes of right-sided heart failure include chronic lung disease lung diseases such as empyema or pulmonary embolism make oxygen exchange harder in response to low oxygen levels or hypoxia the pulmonary arterials constrict and the pulmonary blood pressure Rises this makes it harder for the right side of the heart to pump against and

can lead to right-sided hypertrophy and heart failure in right-sided heart failure blood gets backed up to the body and so individuals will have congestion in the veins of the systemic circulation one common manifestation of this is jugular Venus distension where the jugular vein that's relatively close to the heart becomes enlarged and distended also in the body when blood backs up to the liver it causes Venus congestion there and eventually fluid can move into its interstitial spaces causing the liver to become enlarged which is called hepatomegaly there's a special name for this particular type of hepatopathy

called congestive hepatopathy on pathology there's a so-called nutmeg liver because you can see the congested hepatic venules and veins as dark spots and it actually looks like a graded nutmeg if the liver is congested for long periods of time patients can eventually develop therosis and liver failure which is called cardiac curosis finally fluid that backs up into the interstitial space in the soft tissues of the legs causes pitting edema in terms of treatment a high yield topic for your exams is the list of medications that decrease mortality and slow down the progression of heart failure

this includes Angiotensin converting enzyme or ACE inhibitors Angiotensin receptor blockers or arbs aldosterone receptor antagonists like spironolactone and certain beta blockers specifically carvol bopol and metalol baron in mind though that beta blockers must be used with caution in decompensated heart failure which is when the heart failure rapidly worsens that's because of their ability to decrease heart rate and their negative inotropic effect meaning that they decrease the force of a Hearts contraction in contrast thite or Loop Diuretics may be used to relieve symptoms by reducing the overall fluid buildup in the body and then hydraline combined

with nitrates as vasodilators has been shown to improve both symptoms and mortality in select patients finally a new type of medication focuses on endogenous peptides which promote natriuresis or sodium excretion in the urine as well as vasod dilation they are broken down by an enzyme called napin so Inhibitors of napin improve outcomes in patients with heart failure okay let's review heart failure is a clinical syndrome where the heart is unable ble to pump enough blood or a point at which the heart can't supply enough blood to meet the body's demands this can happen in two

ways either the heart's ventricles can't pump blood hard enough during syst called systolic heart failure or not enough blood fills into the ventricles during diast called diastolic heart failure heart failure can affect the right ventricle or the left ventricle or both if less blood exits either ventricle it'll affect the other since they work in series so left-sided failure could cause right-sided failure and vice versa so these terms really refer to the primary problem affecting the heart basically which one was first actually the main cause of right heart failure is left heart failure when right heart

failure isn't caused by left heart failure but by a pulmonary cause we refer to this as core pulmonal now since both ventricles are affected let's remember remember that symptoms of heart failure include dpia orthopnea fatigue due to low profusion RWS jugular Venus distension pitting edema and an S3 or rarely an S4 heart sound on oscilation treatment includes medications that decrease mortality and ones that are used for symptom relief and finally we come back to our cases Lydia came in with a history of myocardial infarction she's experienced fat fatigue and shortness of breath examination shows pitting

edema in an S3 sound an echocardiogram showed that her ejection fraction was pretty low which indicates systolic heart failure her other symptoms Point towards a left heart failure and the key symptoms were disia paroxysmal nocturnal dpia and orthopnea next is 81-year-old Richard who presents with fatigue pitting edema jugular Venus distension and hepatomegaly his echocardiogram showed that his ejection fraction is normal but there's hypertrophy in his right ventricle this and his symptoms like jugular Venus distension and hepatomegaly point towards right heart failure with a pulmonary cause now since Richard has been a smoker for the past

50 years pulmonary empyema could be the cause of his right-sided heart failure so the next steps involve doing a chest x-ray and spirometry helping current future clinicians Focus learn retain and Thrive learn more