Exam 5 · Week 10 · BIO 280 Pathophysiology
M10 · CAD · Heart Failure · Valves
Supply and demand in the coronary arteries, which side of the heart failed and where the fluid went, and the four valve lesions.
▸M10CAD · Heart Failure · ValvesWeek 10
💡 The one idea
Coronary disease is a supply-and-demand problem. Angina is demand outrunning supply and it is reversible. Infarction is supply cut off and it is not.
Angina goes away with rest. An MI does not.
🩸 Atherosclerosis → angina → infarction
Endothelial injury → LDL enters the wall → macrophages engulf it and become foam cells → a fatty streak → a fibrous plaque. The plaque narrows the lumen; when it ruptures, a clot forms on it and occludes the vessel.
| Stable angina | Unstable angina | MI | |
|---|---|---|---|
| Trigger | Exertion, stress, cold, heavy meal | Comes at rest; new, worse or longer | Any time |
| Relief | Rest and nitroglycerin | Poorly relieved | Not relieved |
| Troponin | Normal | Normal | Raised — this is what makes it an infarct |
| Damage | None | None yet | Necrosis |
Troponin is the marker: rises within 3–4 h, peaks around
24 h, stays up for 10–14 days, and it is specific to cardiac
muscle.
Women, older adults and people with diabetes often present atypically — fatigue, breathlessness, nausea, jaw or back discomfort, or nothing but a feeling of doom. Absence of crushing chest pain does not rule out an MI.
🚨 STEMI vs NSTEMI
STEMI — full thickness occlusion, ST elevation on ECG. The
vessel is completely blocked and the priority is to open it: PCI ideally within
90 minutes of arrival, or thrombolysis if PCI is not available.
NSTEMI — partial thickness. ST depression or T-wave inversion, with a raised troponin. Managed medically first, angiography soon after.
Which artery: LAD → anterior wall, the largest infarcts (the widow-maker). RCA → inferior wall and often the SA/AV node — watch for bradycardia and heart block. Circumflex → lateral wall.
In a suspected right ventricular infarct, nitroglycerin can cause catastrophic hypotension — that ventricle depends on preload, and nitrates drop it.
💧 Heart failure — which side, and where the fluid goes
| Left-sided | Right-sided | |
|---|---|---|
| Backs up into | The lungs | The body |
| Signs | Dyspnea, orthopnea, paroxysmal nocturnal dyspnea, crackles, cough with frothy pink sputum, S3 | Peripheral edema, JVD, hepatomegaly, ascites, weight gain, nausea |
| Commonest cause | Hypertension, MI | Left-sided failure; also cor pulmonale from lung disease |
Left → Lungs. Right → Rest of the body.
Systolic failure (HFrEF) — the ventricle cannot squeeze; EF
<40%. Diastolic failure (HFpEF) — it cannot relax and fill;
EF is preserved but the chamber is stiff.
BNP is released when the ventricle is stretched — it rises in heart failure and helps separate cardiac from pulmonary breathlessness.
Daily weight is the earliest and most reliable sign of fluid retention. A gain of 2–3 lb in a day, or 5 lb in a week, is a red flag.
🧵 Cardiomyopathy and inflammatory heart disease
- Dilated — chambers stretch and thin; poor contraction. The commonest kind.
- Hypertrophic — the septum thickens and obstructs outflow. Often genetic; a cause of sudden cardiac death in young athletes.
- Restrictive — stiff walls that cannot fill. The least common.
- Pericarditis — sharp pleuritic chest pain, relieved by sitting forward, with a friction rub. Can progress to effusion and tamponade.
- Endocarditis — infection of the valves. Fever, new murmur, splinter hemorrhages, Janeway lesions, Osler nodes.
Cardiac tamponade — Beck triad: hypotension, muffled heart sounds, distended neck veins, plus pulsus paradoxus. The heart cannot fill because fluid is squeezing it. This is a surgical emergency.
⭐ The four valve lesions
Stenosis = the valve will not open — pressure builds behind it. Regurgitation = the valve will not close — blood flows backwards.
| Lesion | Heard during | Backs up into | Classic feature |
|---|---|---|---|
| Mitral stenosis | Diastole | Left atrium → lungs | Rheumatic fever is the commonest cause; atrial enlargement → atrial fibrillation → stroke risk |
| Mitral regurgitation | Systole | Left atrium → lungs | Volume overload; prolapse, MI, endocarditis |
| Aortic stenosis | Systole | Left ventricle → hypertrophy | Classic triad: chest pain, syncope, dyspnea. Age-related calcification or a bicuspid valve. Risk of sudden death. |
| Aortic regurgitation | Diastole | Left ventricle → dilation | Wide pulse pressure, bounding pulses; endocarditis, rheumatic fever, aortic root dilation |
Both stenoses of the "exit" valves are systolic; both regurgitations of those valves are diastolic — work out when the valve should be shut and the murmur timing follows.
🎯 Module quiz
Questions for this module.
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