Cardiac Flashcards
Pathogenesis of atherosclerosis:
- Chronic endothelial injury - hypertension, tobacco use, hyperlipidaemia, diabetes
- Fatty streak - lipids accumulate at the place of injury and migrate into smooth muscle cells
- Fibrous plaque - collagen covers the fatty streak, narrowing the vessel lumen and reducing blood flow
- Complicated lesion - plaque rupture and thrombus formation, further narrowing or total occlusion of the vessel
Management of CAD:
- Controlling cholesterol abnormalities
- Managing hypertension
- Promoting cessation of tobacco use
- Maintaining exercise and healthy diet
- Reducing stress
- Controlling diabetes
Unmodifiable risk factors for CAD:
- Genetic predisposition
- Age
- Gender
Modifiable risk factors for CAD:
- gout
- cigarette smoking
- sedentary lifestyle
- high stress levels
- hypertension
- obesity
- diabetes
- untreated bacterial infections
What is angina caused by?
Insufficient coronary blood flow, hence, a disruption in the balance between oxygen supply and oxygen demand
Stable angina:
- Angina symptoms during moderate physical activity or when you are pushing yourself physically
- symptoms go away with rest/medication
- atheroma narrows the vessel and still allows blood to flow
Unstable angina
- Angina symptoms while doing very little or resting
- Thombus occluding the vessel
- increasingly severe and frequent chest pain associated with ST segment depression
Define:
- Atheromas
- Atherosclerosis
- Myocardial infarction
- Atheroma: fatty deposits in the intima of the heart vessels
- Atherosclerosis: narrowing of the heart vessels
- Myocardial infarction: cells in the myocardium become necrotic and die
What is acute coronary syndrome?
- Culmination of atherosclerosis and angina and NSTEMI/STEMI
Unstable angina
Ischaemia without infarction
ECG changes: Normal or transient ST depression
Cardiac troponin: normal or slightly elevated
Often precedes MI
NSTEMI
Non-ST elevated MI
No ECG changes
Cardiac marker (troponin) levels are elevated (cell death)
STEMI
ST elevated MI
Complete occlusion of coronary artery
Cardiac markers elevated
ECG changes: ST segment elevation
Treatment for ACS
- Antiplatelets (aspirin), angina meds (nitroglycerin), O2 therapy
- Confirmed ACS treatment = anticoags, beta blockers, ACE inhibitors, statins
- STEMI patients (emergency): cardiac catheterisation –> PCI (stent) or fibrinolytic therapy if PCI N/A + aspirin
- Unstable angina/NSTEMI: angiography, fibrinolytic therapy not indicated
Surgical interventions for CAD and ACS
- PCI = percutaneous coronary intervention (angioplasty with a stent)
- CABG = coronary artery bypass graft - take veins from leg or mammary artery and connect to coronary arteries in order to bypass a blockage
Conduction pathway of the heart:
- Sinoatrial (SA) node
- Atrioventricular (AV) node
- Bundle of His
- Left and right bundle branches
- Purkinje fibres
How to calculate rate in bpm?
Count number of P waves (atrial rate) or QRS complexes (ventricular rate) in 30 square (6 seconds)
Multiply number by 10 (1min)
Clinical manifestations associated with angina:
Signs: SOB, sweating, vomiting
Symptoms: fatigue, crushing chest pain (burning, squeezing), dizziness, nausea, pain in the arms, shoulder, neck, back or jaw