L12 - Coronary Artery Disease and Cardiac Failure

_______________ is the most common cause of coronary heart disease

Atherosclerosis

_________ build-up increases the risk of clot formation (coronary artery disease)

Plaque

A PT that has artery stenosis (narrowing) < 60% occuluded results in ____________

Normal coronary blood flow at rest and during exertion

A PT that has artery stenosis (narrowing) of around 70% occluded results in _________________

-normal at rest

-coronary flow reserve is reduced, causing ischemia during exertion,

A PT that has artery stenosis (narrowing) of > 90% occluded results in ____________

ischemia at rest and even worse with exertion

Acute Coronary Syndrome I — spectrum of acute ischemic heart disease ranging from _____________ to ______________

unstable ischemia to acute myocardial infarction (MI)

Acute Coronary Syndrome I is classified based on _____________ on the EKG

ST segment elevation

Acute Coronary Syndrome categories:

• _____________ — (no ST elevation)

• _____________ — (present ST elevation)

• Unstable Angina (UA) and Non-ST Elevation Myocardian Infarction (NSTEMI) — no ST elevation

• ST Elevation Myocardian Infarction (STEMI) — present ST elevation

What are the implications of unstable angina being caused by the disruption of atherosclerotic plaque with partial thrombosis?

Acute Myocardial Infarction is imminent (aka Preinfarction)

Characteristics of unstable angina

• no serum biomarkers are present

• pain

  • occurs at rest, lasting less than 20 minutes

  • severe and of new onset, not within 1 month

Characteristics of NSTEMI

• type of heart attack, minor artery of the heart is blocked or a major artery of the heart is partially blocked

• less serious than a “classic” heart attack

• serum biomarkers may be present

Characteristics of STEMI

• “heart attack”, is a serious event, one of the heart’s major arteries is blocked

• characterized by ischemic death necrosis of myocardial tissue

• area of infarction is determined by the affected coronary artery and its distribution of blood flow

• elevated ST segment

What are the symptoms associated with STEMI?

• severe, crushing pain

• constricting chest pain

• pain that is not relieved with nitroglycerine

What are the symptoms of STEMI in women?

• pain in arms, back, neck, jaw

• stomach pain

• fatigue

• SOB

• nausea

• lightheadedness

• sweating

Acute myocardial infacrtion (AMI) leads to _____________

necrosis (cell death)

What are the serum biomarkers of acute coronary syndrome?

• ___________ — not cardiac specific (1 through 4-8 hrs)

• ___________ — highly specific for myocardial tissue

• ___________ — myocardial tissue specific

• Myoglobin — not cardiac specific (1 through 4-8 hrs)

• Creatine Kinase MB (CK-MB) — highly specific for myocardial tissue

• Troponins — myocardial tissue specific

Identify the following type of chronic ischemic heart disease:

• fixed coronary obstruction creates blood flow and metabolic demand mismatch

• initial manifestation of ischemic heart disease

  • not present in all patients due to coronary collateral growth

• angina due to exercise, emotional stress; relieved by rest or nitroglycerin

Chronic Stable Angina

Identify the following type of chronic ischemic heart disease:

• more common in women

• absence of angina

• impaired blood flow due to atherosclerosis or vasospasm

• observed in people with diabetes due to neuropathies (commonly in elderly)

Silent myocardial ischemia

Identify the following type of chronic ischemic heart disease:

• ischemia/angina caused by coronary artery spasm

• mechanisms not understood

• occurs during rest and at night

• associated with migrains and Raynaud’s syndrome

Variant (Vasospastic) Angina

What are the triggers for ischemia?

• exercise

• assuming upright posture

• smoking

• cold exposure

• mental stress

What are the physiological responses to ischemia?

•­ ↑ sympathetic activity

•­ ↑ blood pressure & HR

•­ ↑ force of cardiac contractility

What is the diurnal variation associated with ischemia?

more cases occur within first hour of waking

What method of revascularization is appropriate to use:

• less severe → mild symptoms, mild CAD

• normal left ventricle function

Medication

What method of revascularization is appropriate to use:

• mild

• 1-2 vessels are diseased (narrowed)

• not fully occluded

• ballon angioplasty/STENT

Percutaneous Coronary Intervention

What method of revascularization is appropriate to use:

• severe

• 2-3 vessels are diseased (blocked)

Coronary Artery Bypass Graft (CABG)

________________ — imbalance/failure of the heart to supply blood to meet the metabolic needs of the body

Heart Failure

NYHA Functional Classification of Heart Failure (symptom-based)

• Class I — ____________________

• Class II — ____________________

• Class III — ____________________

• Class IV — ____________________

• Class I — no physical limitations

• Class II — slight limitation of physical activity

• Class III — marked limitation of physical activity

• Class IV — symptoms at rest

ACC/AHA Heart Failure Stages (disease progression):

• Stage A — ________________

• Stage B — ________________

• Stage C — ________________

• Stage D — ________________

ACC/AHA Heart Failure Stages (disease progression):

• Stage A — PT at risk for heart failure; no structural disease

• Stage B — structural disease; no heart failure symptoms

• Stage C — structural disease; heart failure symptoms

• Stage D — end-stage disease

_____________ is the most common cause of heart failure

coronary heart disease

Cardiac Output = ______________ x _____________

Heart Rate x Stroke Volume

What influences stroke volume?

• preload

• contractility

• afterload

What are the determinants of cardiac function that can lead to heart failure?

• decreased preload (Less blood returning to the heart → less blood to pump out)

• decreased contractility (Less force → less blood ejected)

• increased afterload (The heart has to push harder → pumps less blood)

• decreased cardiac output (caused by the above 3)

What factors reduce/impair preload?

• decreased myocardial compliance (cardiomyopathy/hypertrophy)

• valvular disorders (mitral valve stenosis)

• pericardial disease (compression of heart within pericardial sac)

What factors can reduce/impair contractility?

• necrosis of heart muscle following an acute MI

What factors can increase/impair afterload?

• hypertension

• valvular disorders (aortic valve stenosis)

What are the compensatory mechanisms during heart failure?

• increased sympathetic nervous system activity

  • increased heart rate and cardiac contraction → increased CO

• activation of the Renin-Angiotensin-Aldosterone System (RAAS)

  • increased sodium and water reabsorption in kidneys → increased preload → increased CO

• increased catecholamine release

  • increased heart rate and cardiac contraction → increased CO

_____________ Ejection Fraction (HF_REF) — the inability of the ventricle to eject an adequate cardiac output (EF of < 40%)

Reduced

________ Ejection Fraction (HF_PEF) — the heart pumps normally but is too stiff to fill properly and eject blood (EF > 50%)

Preserved

Heart failure is classified by _____________ and ________________

• ejection fraction

• left-sided or right-sided failure

What are the characteristics of diastolic heart failure (HF_PEF)?

• may be due to sustained hypertension

• increased wall thickness leads to a reduced ability to fill

• reduced stroke volume, reduced preload

• compliance is decreased

Define diastolic dysfunction

resistance to filling of one or both ventricles leading to symtpoms of congestion

What are the characterstics of systolic heart failure (HF_REF)?

• results from conditions that impair contractile performance (ischemic heart disease)

• enlarged ventricles (dilated heart, unable to pump same amount of blood out, increased preload)

Define systolic dysfunction

impaired ability to eject blood at a rate to meet metabolic needs of the tissue

What is the most common cause of right ventricular heart failure (dysfunction)?

left ventricular heart failure (dysfunction), which results in pulmonary hypertension due to left artery congestion

What are the causes of left ventricular heart failure (dysfunction)?

• hypertension

• myocardial infarction

• valve defects (aortic/mitral)

What does right heart failure result in?

• congestion of peripheral tissues

• liver congestion

• GI tract congestion

What does left heart failure result in?

• decreased cardiac output

• pulmonary congestion

• imparie gas exchange

• pulmonary edema

What are the signs of heart failure?

• fatigue

• activity limitation

• congestion

• edema or ankle swelling

• shortness of breath