Chapter 18: Alterations in cardiac functions

coronary heart disease (CHD)

characterized by insufficient delivery of oxygenated blood to the myocardium (ischemia) because of atherosclerotic coronary arteries (coronary arteries become narrowed or blocked)

• also called coronary artery disease

main cause of CHD

atherosclerosis of coronary arteries

atherosclerosis

the buildup of fatty deposits, cholesterol and inflammatory material (plaque) inside arteries

• causes progressive narrowing of the arterial lumen and predisposes to a # of processes that can precipitate myocardial ischemia including thrombus formation, coronary vasospasm, endothelial cell dysfunction

clinical syndrome

a group of signs and symptoms associated with a particular disease: for CHD

*critical narrowing of the coronary lumen overtime or sudden rupture of a plaque followed by thrombus formation and…

1. angina

2. acute coronary syndrome

3. chronic ischemic cardiomyopathy

4. sudden cardiac arrest

angina

chest pains or discomfort that occurs when the heart muscle temporarily does not receive oxygen rich blood

types:

1. stable

2. unstable

3. vasospastic

stable angina pectoris

predictable, exercise induced angina pain

• most common

• improves with rest or prescribed nitroglycerin

• signs and symptoms: chest pressure, tightness, squeezing, pain that may spread to arm, neck, jaw, or back

• characterized by stenotic atherosclerotic coronary vessels

acute coronary syndrome

refers to conditions where blood flow to the heart suddenly is reduced or blocked (group of conditions that make sudden decrease in blood flow to heart)

three types (this may present as)…

1. unstable angina

2. non ST elevation myocardial infarction

3. ST elevation myocardial infarction

patient may be asymptomatic

ECG and biomarkers used for diagnosis

unstable angina

when heart suddenly receives insufficient blood flow, often b/c a coronary plaque becomes disrupted (sudden reduction in blood flow)

• chest pain may occur at rest

• pain may be new, worsening, or more frequent

• no heart death

• troponin lvls normal, partial blood flow reduction

• occlusion is partial - artery is partially blocked = heart doesn’t receive enough oxygen = myocardial ischemia

non ST elevation MI

type of heart attack in which heart muscle damage occurs without persistent ST segment elevation on ECG

• blood flow to heart is significantly reduced, incomplete coronary artery occlusion (partial blockage)

• ECG does not show persistent ST (segment elevation) but still heart muscle death

• elevated troponin levels without persistent ST elevation

ST elevation MI

heart attack caused by sudden, severe blockage of a coronary artery

• blood flow to heart is critically reduced - complex coronary artery occlusion (complete blockage)

• ECG shows characteristics of ST elevation

• heart muscle death

• elevated troponin levels with persistent ST elevation

chronic ischemic cardiomyopathy

long term ischemic damage, coronary artery disease / previous heart attacks damage heart muscle, weakening its ability to pump blood (reduced blood supply) which leads to heart failure

• long term weakening of heart muscle due to reduced blood supply

sudden cardiac arrest

abrupt loss of heart function, heart stops pumping effectively, immediate CPR is needed

• primary cause = lethal dysrhythmia

(ventricular fibrillation, VF), pulseless ventricular tachycardia (VT)

vasospastic angina (VSA)

unpredictable type of chest pain that occurs when a coronary artery suddenly tightens or spasms reducing blood flow and oxygen to the heart muscle (sudden coronary artery spasm)

• occurs at rest, at night when patient is resting, or early mornings

• when spasm relaxes, blood flow can improve = chest pain disappears

• rare chest pain - can be severe

• caused by sudden artery tightening, can be relieved by nitroglycerin or Ca+ blockers

valvular heart disease

occurs when one or more of the heart’s valves become damaged and cannot open or close properly

• most common disease affects the aortic or mitral valves

• causes of VHD

  • inflammation

  • scarring'

  • calcification

  • congenital malformation

types of valve disorders

1. stenosis

2. regurgitation

3. prolapse

4. murmurs

stenosis

failure of a valve to open completely; significant hemodynamics consequences generally begin to occur when the valve opening is reduced to half its normal diameter

• results in extra pressure work for the heart b/c blood must be forced through the high resistance of a narrow valve opening

• progresses slowly over years = time for affected heart chambers to compensate through myocardial cell hypertrophy (increased resistance = thicker heart muscle to compensate)

regurgitation

valves do not close completely; develop suddenly from valvular infection or rupture of a supporting papillary muscle so valve does not close completely (volume overload)

• blood leaks backward through the valve, so heart must pump extra blood to maintain adequate forward circulation

prolapse

valve bulges backward into the chamber behind it when the valve closes

murmurs

turbulent blood flow, extra sound caused by turbulent blood flow through the heart

mitral stenosis

when the mitral valve becomes narrow and cannot open completely

• blood flow from left atrium to left ventricle is difficult

• BP increases in LA

• main symptom is expertional dyspnea (SOB from physical activity)

mitral regurgitation

mitral valve does not close tightly, so back flow of blood from LV to LA during systole

• blood has to pump more blood to compensate

mitral valve prolapse

mitral valve leaflets bulge backward into the LA during ventricular contraction

• can lead to regurgitation if valve isn’t sealed properly

aortic stenosis

aortic valve becomes narrowed and cannot open completely; the aortic cusps (the flaps that make up the valve become stiff due to calcium deposits, LV to aorta flow difficulty

• symptoms - angina, syncope (fainting), dyspnea (SOB) = classic triad

aortic regurgitation

aortic valve does not close completely, blood leaks backward from aorta to LV during diastole

Infective endocarditis

infection of the hearts inner lining & valves (endocardium)

• bacteria or other microorganisms enter the bloodstream, attach to the heart valves and begin multiplying

• can be acute or chronic

• Process

  • bacteria enter bloodstream

  • bacteria reach heart

  • bacteria attach to the heart valve (damaged usually)

  • multiply and form masses called vegetations

  • vegetations can damage the valve or break off and travel through bloodstream

acute endocarditis

sudden rapid progression

• high fever

chronic subacute

developing slowing, overtime

• low grade fever and mild symptoms

pericardium

protective, durable layered sac surrounding heart

pericardial effusion

means an abnormal build up of fluid inside the pericardial sac surrounding the heart

• caused by: inflammation, infection, cancer, kidney failure

cardiac tamponade

life threatening condition in which fluid accumulates around the heart and creates enough pressure to compress the heart chambers (prevents heart from filling properly with blood)

3 processes of atherosclerosis

1. thrombus formation

2. coronary vasospasm

3. endothelial cell dysfunction - vessel wall becomes damaged

three processes that are caused by atherosclerosis that can then lead to myocardial ischemia

nitroglycerin

causes vasodilation and lightens prelaod; sublingual taken PRN

• up to 3 doses, 5 mins apart

myocardial infarction

heart attack, complete occlusion

• artery is completely blocked = heart muscles become deprived = muscle death

cardio biomarkers

records troponin lvls

ECG

records whether there is ST (segment elevation)

chronic ischemic cardiomyopathy symptoms

• Chest pain or pressure

• Pain spreading to arms, neck, or jaw

• Shortness of breath, Sweating, Nausea

• Women may have different symptoms

CHD treatment options

• Medications to dissolve clots

• Catheter procedures to open blockages - catheter gets removed after procedure

• Stents to keep arteries open - stent stays in place

• Emergency surgery if needed

Implications for cardiac function

when valves do not function properly, heart must work harder

1. valve damages

2. stenosis or regurgitation develops

3. increased pressure or volume overload

4. heart muscle thickens or chambers enlarge

5. heart may eventually weaken

6. heart failure may develop

rheumatic heart disease

caused by complication of rheumatic fever

• immune attack that chronically attacks heart valves

• common in children

risk factors for infective endocarditis

• IV drug use

• previous endocarditis

• prosthetic heart valve

• HAI

• renal failure

diseases of the endocardium

1. rheumatic heart disease

2. infective endocarditis

myocardial diseases

1. myocarditis

2. cardiomyopathy

myocarditis

inflammation of heart muscle; necrosis and degeneration of heart muscle

cardiomyopathy

1. dilated cardiomyopathy

2. hypertrophic cardiomyopathy

3. restrictive cardiomyopathy

dilated cardiomyopathy

Dilation of one or both ventricular chambers (cardiac failure)

Hypertrophic cardiomyopathy

• Thickened, hyperkinetic ventricular muscle mass

• Left ventricle most affected

Restrictive cardiomyopathy

Stiff, fibrotic ventricle - resist diastolic filling

• heart can’t fill properly due to restriction

pericardial diseases

1. pericardial effusion - cardiac tamponade

2. pericarditis

pericardial effusion

accumulation of fluid in pericardial sac

• can be blood or serous fluid

pericardial effusion cm and treatment

• Reduced stroke volume - amount of blood pumped out of one ventricle with each heartbeat (not enough blood = less blood pumped out)

• Compensatory increases in heart rate - tachycardia b/c body tries to maintain CO by increasing HR

• Pulsus paradoxus - abnormally large decrease in systolic BP during inspiration

• Hypotension, distended neck veins and muffled heart sounds―called Beck’s triad

• treatment: pericardiocentesis

pericardiocentesis

insertion of needle or catheter into pericardial space to remove excess fluid

pericarditis

inflammation of the pericardium

• acute or chronic

acute pericarditis

• Assumed to be viral: viral infection may trigger inflammation

• Uncomplicated acute pericarditis resolves spontaneously within 2 weeks

• causes sticking and rubbing of visceral pericardium layers = pericardial friction rub sound may be heard

• symptoms: back pain, chest pain that worsens when deep breathing or lying flat, can be reduced by sitting up or leaning forward

chronic pericarditis

• Adhesion - surrounding mediastinal structures (scar tissue can form around heart)

• destruction of pericardial sac

• Constrictive pericarditis

  • fibrous, scarred pericardium

  • secondary to tuberculosis

  • impair cardiac contractions

management

• Lifestyle: diet, exercise, smoking cessation

• Medications: angiotensin-converting enzyme (ACE) inhibitors, beta-blockers, diuretics, anticoagulants

• Surgical: valve repair, Coronary Artery Bypass Graft (CABG), pacemaker, transplant

treatment

aims to resture funcitons, relieve symptoms, and prevent progression

becks triad

1. Hypotension

2. distended neck veins

3. muffled heart sounds

clinical manifestations for pericardial effusion

classic triad

1. angina,

2. syncope (fainting),

3. dyspnea (SOB)

clinical manifestations for aortic stenosis