Cardiac Flashcards
How many Americans have myocardial ischemia? How many have myocardial infarction?
Ischemia: 10 million
Infarction: 1.5 million, mortality is 1/3
Causes of myocardial ischemia
Decreased supply due to narrowing of coronaries due to atherosclerosis (most common cause), coronary artery vasospasm, hypotension
Increased demand due to hypertension, tachycardia
Other: hypoxia, anemia, aortic insufficiency or stenosis
Major/other risk factors for myocardial ischemia?
Major: Age, male, hypercholestremia, diabetes, hypertension, smoker, family history
Other: Obesity, CV disease, PVD, menopause, high-estrogen contraceptives, sedentary, type A personality
Characteristics of an atherosclerotic plaque at high risk of rupturing?
- T cells recruited to shoulder
- macrophages clustered around T cells
- thin fibrous cap
- lipid-rich core
- newly formed intrawall capillaries
- lymphocyte and mast cell infiltration to adventitia
Stable vs. unstable angina
Stable: associated with narrowing (over 75%), O2 demand can be normal, relieved by rest or nitroglycerine
Unstable: increases in frequency and duration, can cause infarction or thrombosis
What is Prinzmetal Angina?
Coronary spasm at rest in a plaque area or normal vessel. This can be associated with vasospastic disease such as Raynaud’s.
What is infarction, how quickly does it occur?
Necrosis caused by ischemia, occurs within 20-30 min of ischemia typically in the subendocardial regions
Full size of infarction reached in 3-6 hours
Size depends on proximity of lesion and collateral circulation
Complications of an MI
Papillary muscle dysfunction, valvular disease
day 4-7 rupture of infarct, tamponade, death
Mural throbi can lead to stroke
Acute pericarditis day 2-4
Ventricular aneurysm (most common in anteroapical region)
Arrythmias, thromboembolism
LVF, pulmonary edema
Cardiogenic shock (rare)
Rubture of wall, septum, papillary muscle
What type of MI is associated with occlusion of..
RCA LCA, LAD, LCX?
RCA: posterior/inferior MI
LCA: anterolateral MI
LAD: anteroseptal MI
LCX: lateral MI
How is hypertension defined? What is the incidence?
Systolic over 140, diastolic over 90, sustained, 3 readings to diagnose
25% of general public
*90% of hypertension is idiopathic/primary
*10% of hypertension is secondary to renal disease, also can be secondary due to endocrine, CV, or neurologic diseases
What does BP depend on? (hint: it’s an equation)
BP = CO x PVR
What are risk factors for primary hypertension?
Genetic: polygenic and heterogenous, polymorphisms in several genes
Environmental: stress, obesity, smoking, salt, sedentary
What are two theories of the mechanism of hypertension?
1- renal retention of excess sodium due to genetics leads to decreased sodium excretion, increased fluid volume/ CO, increased BP
2- Vasoconstriction and vascular hypertrophy, increased PVR caused by neurogenic factors, release of vasoconstrictor agents, or genetic defect in Na/Ca transport. This can be added to stimulus that induces structural. changes in vessel walls
What are some pathogenesis of secondary hypertension?
Oral contraceptives Renal parenchymal disease Renin-secreting tumors Primary aldosteronism Cushing's Pheochromocytoma
What is a hypertensive crisis and what is the treatment?
DBP: over 130
Treatment: decrease DBP to 100 over several min to hours, controlled, use artline and foley
Mitral stenosis: explanation and causes
Mitral stenosis impairs blood flow from LA to LV. Autoimmunity to antigens leads to inflammation and scarring of the valvular leaflets. Scarring causes leaflets to become fibrous and fused and the chordae tendinae become shortened. Enlargement of LA increases risk of A fib. Stasis of blood in the LA predisposes to formation of thrombi.
Most commonly caused by rheumatic fever.
Increase vs. Decrease
Mitral stenosis: ____ LA emptying, ____ LA preload, ___ oxygen supply, ___ force of LA contraction
DECREASE LA emptying
INCREASE LA preload
DECREASE oxygen supply leading to RV failure
DECREASE force of LA contraction leading to decreased LV output and LV failure
Untreated, severe mitral stenosis leads to what?
Pulmonary hypertension, edema, RV failure, CHF
Also these pts are at higher risk of systemic thromboembolism and venous thrombosis
S/S of mitral stenosis? (from book)
Diastolic murmur over cardiac apex, “opening snap” which is a loud/delayed S1 due to increased LA pressure
Other s/s of pulmonary congestion and R heart failure
Aortic stenosis causes?
Congenital
Calcific degeneration from aging
Rheumatic heart disease
Note: Aortic stenosis is the most common valve disorder
Aortic stenosis pathophysiology?
Aortic semilunar valve narrows causing diminished blood flow from LV to aorta. LV hypertrophy develops, increasing myocardial oxygen demand which can lead to ischemia, MI, dysrhythmias, and heart failure
Aortic stenosis s/s
Triad: Syncope, Angina (in absence of ischemic heart disease), Dyspnea on exertion
Also in the book: dec SBP, narrow pulse pressure, slow HR, faint pulses, murmur (2nd intercostal space)
Aortic stenosis early : ___ LV mass, ___ LV compliance, ___ contractility, ____ preload, ____ stroke volume
Aortic stenosis late: ___ contractility, LV dilation, ___ stroke volume
Early: inc LV mass (these people have MASSIVE hearts), dec LV compliance, no change contractility, inc preload, no change stroke volume yet
Late: dec contractility, dec stroke volume
Mitral stenosis and aortic stenosis treatment?
Valve replacement or repair surgery
This is also the treatment for mitral and aortic regurgitation.
Mitral regurgitation causes?
Most commonly rheumatic fever, also caused by (from book) mitral valve prolapse, infective endocarditis, CAD, connective tissue disease, congestive cardiomyopathy.
Note: almost always associated with mitral stenosis
Mitral regurgitation pathophysiology?
Allows back flow of blood from LV to LA during systole, leads to atrial dilation which can cause A fib. LV function can become impaired and LV failure can occur. Increased atrial pressure can cause pulmonary hypertension and RV failure.
Regurgitant flow is responsible for ___ wave on PAOP.
V wave
Note: the size of the V wave correlates with the magnitude of the regurgitant flow.
What murmur would you hear on a patient with mitral regurgitation? (from the book)
Loud pansystolic murmur at apex
Aortic regurgitation causes?
Acute: infective endocarditis, trauma, dissection of thoracic aneurysm
Chronic: rheumatic fever, persistant systemic hypertension