2Blood Supply To The Heart The left and right coronary arteries and their branches supply arterial blood to the heart. These arteries originate from the aorta just above the aortic valve leaflets. The heart has large metabolic requirements, extracting approximately 70% to 80% of the oxygen delivered (other organs consume, on average, 25%). Unlike other arteries, the coronary arteries are perfused during diastole. An increase in heart rate shortens diastole and decrease myocardial perfusion. Patients, particularly those with coronary artery disease (CAD), can develop myocardial ischemia (inadequate oxygen supply) when the heart rate accelerates.
3The left coronary artery has three branches The left coronary artery has three branches. The artery from the point of origin to the first major branch is called the left main coronary artery. Two bifurcations arise off the left main coronary artery. These are the left anterior descending artery, which courses down the anterior wall of the heart, and the circumflex artery, which circles around to the lateral left wall of the heart. The right side of the heart is supplied by the right coronary artery, which progresses around to the bottom or inferior wall of the heart. The posterior wall of the heart receives its blood supply by an additional branch from the right coronary artery called the posterior descending artery. Superficial to the coronary arteries are the coronary veins. Venous blood from these veins returns to the heart primarily through the coronary sinus, which is located posteriorly in the right atrium.
4Coronary arteries (red vessels) arise from the aorta and encircle the heart. Coronary veins are shown in blue.
5What is Heart Disease?Called Coronary Heart Disease or Coronary Artery DiseaseDiagnosed when arteries that supply blood to heart muscle becomes hardened and narrowedCaused by plaque on inner walls and called atherosclerosisEventually Heart suffers from lack of oxygen and causesChest painAnginaHeart Attack (Myocardial infarction)
6Acute Coronary Syndrome: Definitions The term acute coronary syndromes is used to collectively describe acute myocardial infarction (heart attack) and unstable angina (chest pain occurring at rest, new onset of pain with exertion, or angina that is more frequent, longer in duration or lower in threshold than before).Chest pain:Angina: Severe constricting pain w/the sensation of choking/suffocatingHeart attack: Blockage of a coronary artery causing tissue damage/death.
7Acute: Sudden onset w/severe, sharp pain (compare to chronic) Syndrome: Group of symptoms characteristic of disease/disorderMyocardial: Referring to the heart muscleIschemia: Decrease of blood supply
8Transient Myocardial ischemia Definition :Myocardial Blood FlowMyocardial O2 DemandsTransient Myocardial ischemiaACSSevere Chest pain=8BACK MAIN EXIT INDEX NEXT
10Atheroscelerotic changes The underlying cause isFissuring of atheroscelerotic plaquesPlatelet aggregationThrombosisCoronary artery spasmAtheroscelerotic changes10BACK MAIN EXIT INDEX NEXT
11Who can developing Coronary Artery Disease? (Risk Factors ) Nonmodifiable Risk FactorsFamily history of coronary heart diseaseIncreasing ageGender (heart disease occurs three times more often in men than in premenopausal women)Race (higher incidence of heart disease in African Americans than in Caucasians)Modifiable Risk FactorsHigh blood cholesterol levelCigarette smoking, tobacco useHypertensionDiabetes mellitusLack of estrogen in womenPhysical inactivityObesity
12Signs and SymptomsNone: This is referred to as silent ischemia. Blood to your heart may be restricted due to CAD, but you don’t feel any effects.Chest pain: If your coronary arteries can’t supply enough blood to meet the oxygen demands of your heart, the result may be chest pain.Shortness of breath: Some people may not be aware they have CAD until they develop symptoms of congestive heart failure- extreme fatigue with exertion, shortness of breath and swelling in their feet and ankles.Heart attack: Results when an artery to your heart muscle becomes completely blocked and the party of your heart muscles fed by that artery dies.
18Treatment of an acute attack of ACS Sublingual nitroglycerin (0.5 mg ) or isosorbide dinitrate (5 mg ) orOral spray nitroglycerin (0.4 mg/metered dose), isosorbide dinitrate(1.25 mg/metered dose)Relief within 1-3 min.Persistence of painRepeat nitroglycerin at 5 min. interval (3 tab. max.)Reliefnot relievedInfarctionHOSPITALIZATION18BACK MAIN EXIT INDEX NEXT
19Detection Methods Electrocardiogram –non-invasive (85% accurate) Stress TestsAngiograms –invasive (used in other 15% of cases)Blood tests: used to evaluate kidney and thyroid function as well as to check cholesterol levels and the presence of anemia.Chest X-ray: shows the size of your heart and whether there is fluid build up around the heart and lungs.Echocardiogram: shows a graphic outline of the heart’s movementEjection fraction (EF): determines how well your heart pumps with each beat.
20Graduated exercise may open new collaterals General measuresTreat Hypertension , Hypercholestrolimia and DiabetesStop smokingReduce weightAVOIDSevereexertionHeavy mealEmotionsCold WeatherGraduated exercise may open new collaterals20BACK MAIN EXIT INDEX NEXT
21b. For immediate pre-exertional prophylaxis Drug Treatmenta. For an acute attackb. For immediate pre-exertionalprophylaxisc. For long-term prophylaxisd. Antiplatelet therapy.21BACK MAIN EXIT INDEX NEXT
22Immediate pre-exertional prophylaxis of Angina Sublingual nitroglycerin (0.5 mg) or isorbide dinitrate (5 mg) should be taken 5 min. before effort.For Long term prophylaxis:Long acting nitrates, Ca++ channel blockers,b-blockers or combinations of these drugs.Antiplatelet therapy:Aspirin in small dose ( mg daily orally)or Dipyridamole (75 mg t.d.s orally)22BACK MAIN EXIT INDEX NEXT
23Coronary Artery Revascularization Coronary artery bypass grafting (CABG)Percutaneous Transluminal coronary Angioplasty (PTCA)For patients not responding to adequate medical therapy23BACK MAIN EXIT INDEX NEXT
24Management of Unstable Angina Nitrate+b-blockerAspirin (low dose) and/orHeparin orThrombolytic (stryptokinase)to minimize risk of infarction24BACK MAIN EXIT INDEX NEXT
25Unstable AnginaCause• Thrombus partially or intermittently occludes the coronary arterySigns and Symptoms• Pain with or without radiation to arm, neck, back, or epigastric region• Shortness of breath, diaphoresis, nausea, lightheadedness, tachycardia, tachypnea, hypotension or hypertension, decreased arterial oxygen saturation (SaO2) and rhythm abnormalities• Occurs at rest or with exertion; limits activityDiagnostic Findings• ST-segment depression or T-wave inversion on electrocardiography• Cardiac biomarkers not elevated
26CONT…Treatment• Oxygen to maintain oxygen saturation level at > 90%• Nitroglycerin or morphine to control pain• b-blockers, angiotensin-converting enzyme inhibitors,), clopidogrel (Plavix), unfractionated heparin or lowmolecular- weight heparin, and glycoprotein IIb/IIIa inhibitors
27Non–ST-Segment Elevation Myocardial Infarction (NSTEMI) Signs and SymptomsLonger in duration and more severe than in unstable anginaDiagnostic Findings: Cardiac biomarkers are elevated.Treatment: Cardiac catheterization and possible percutaneous coronary intervention for patients with ongoing chest pain, hemodynamic instability, or increased risk of worsening clinical condition
28ST-Segment Elevation Myocardial Infarction (STEMI) Cause: Thrombus fully occludes the coronary artery.Diagnostic Findings:• ST-segment elevation or new left bundle branch block on electrocardiography.• Cardiac biomarkers are elevated.Treatment• b-blockers, angiotensin-converting enzyme inhibitors, statins (started on admission and continued long term), clopidogrel (Plavix), unfractionated heparin or low-molecularweight heparin• Percutaneous coronary intervention within 90 minutes of medical evaluation• Fibrinolytic therapy within 30 minutes of medical evaluation