ischemic heart disease

• ischemic heart disease also known as coronary artery disease
• ischemic heart disease is atherosclerotic plaque that develops in coronary artery
• coronary vessels supply oxygenated blood to the myocardium
• in ischemic heart disease there is a decrease in delivery of oxygen to the myocardium
• common cause of ischemic heart disease is atherosclerosis
• risk factors of atherosclerosis include mnemonic " bad heart" : BMI>30 , Age>65, DM, HTN, Alcohol abuse, increase LDL and decreased HDL, relatives with CAD, Tobacco use
• causes of a decrease in oxygen supply include: atherosclerosis, embolus, vasculitis, vasospasm
• the following lead to high oxygen demand in the heart: tachycardia, left ventricular hypertrophy(HTN,aotic stenosis&hypertrophic obstructive cardiomyopathy), and exercising they can all increase oxygen demand
• types of ischemic heart disease include: stable angina,unstable angina,subendocardial infarct(NSTEMI),transmural infarct and prinzmetals (vasospatic) angina.
• in stable angina: there is stable plaque,subendocardial ischemia and chest pain during exertion/physical activity
• unstable angina there is: unstable plaque(ruptured plaque), ischemia with high oxygen demand and chest pain at rest. and thrombus is formed on exposed ruptured plaque due to platelets sticking on there
• unstable angina can lead to subendocardial ischemia
• subendocardial infarcts(NSTEMI) is associated with unstable plaque(can rupture) and patient have chest pain at rest. Here the ischemia happened for too long(more than 30min) and myocardial cells are starting to die
• trasmural infarct(STEMI) is associated with unstable plaque and there is total occlussion of the vessel lumen meaning there is a complete loss of supply to the myocardium(the entire myocardium will be affected,from epicardial to endocardial). patient experience chest pain at rest
• NSTEMI,STEMI and Unstable angina are all types of acute coronary syndrome
• prinzmetal(vasospastic) angina is caused by vasospasm/vasocontriction not atherosclerosis
• in vasospastic angina, has no/few risk factors of cardiac disease, the patient is younger than 65yrs,female,smoke cocaine, drink alcohol and maybe have history of migraine(and they take tryptans for it),they usually experience chest pain at night or in the morning,in this case think about vasospastic angina
• in vasospastic angina we have transmural ischemia."transmural" because the entire myocardium is affected, but this is not an infarction
• vasospastic angina is associated with ST elevation and negative troponin. troponin is negative because this is ischemia not infarction. and if the patient is taking medication like acetylcholine or ergonovine(alkaloid), the medication will bind on the beta1 receptors and cause vasoconstriction leading to ST elevation
• for vasospastic angina we give CCB and Nitroglycerin, both they can dilate the vessels.
• do not give beta blockers in vasospastic angina ,because the drug will block beta1-receptor(vasodilation), and cause more vasoconstriction
• when take patient history,we use OPQRST approaach. Onset(how did chest pain start,how long does it last),Provocative(anything making pain worse or better) factors, quality(sharp pain?), radiation, severity, time(pain is constant or not)
• patients with ischemic heart disease the pain radiates mostly to the left arm, left side of the neck and left jaw. if they have inferior STEMI, pain may radiate to the epigastric area and have epigastric pain
• stable angina pain last for 5-10 min, in acute coronary syndrome pain last for more than 10min
• their pain improves with nitroglycerine(nitrates-relax blood vessels)
• MI without chest pain is found in diabetic patients,elderly patients and post-heart operation due to neuropathy of some nerves
• signs of right ventricular MI include: jvd, edema of lower extremeties, hypotension, lungs are clear(no fluid), due to av node disturbance this may lead to AV block or sinus bradycardia
• signs of left ventricular MI include: pulmonary edema,hypotension, reflex tachycardia,pale/cold /mottled or bluish skin, present with s4 heart sound(because of fibrotic heart)
• complications of IHD in first 24hours include(having MI within 24hrs): 1)sudden cardiac death(due to electical potential being fired abnormally leading to premature ventricular contraction that will lead to v-tach therefore lead to ventricular fibrillation). 2) acute heart failure due to reflexesd tachycardia
• complications within 24hrs to 3days of MI: rupture syndrome. 1)intraventricular septum gets infarcted and tissue starts becoming weak and rupture,this is called ventricular septal defect(murmur sounds).2) free wall rupture,3)papillary muscle rupture, 4)left ventricular pseudoaneurysm.
• complications if they had MI for 3 to 14days: pericarditis,
• complications if they had MI for 14days to 1month: left ventricular anerysm, dressler syndrome(pericarditis due to antibodies attacking the pericardium)
• to diagnose stable angina,on ecg there is no st elevation,there will be no biomarkers like troponin and ckmb because this is not an infarction.
• to diagnose prinzmetal(vasospatic) angina, there will be st elevation since this is a transmural ischemia, this st elevation is not permanent and the troponins and ckmb are negative because this is an ischemia.
• to diagnose unstable angina, on ecg there will be st depression, t-wave inversion but no troponin or ckmbs elevation
• to diagnose NSTEMI, there will be signs of st depression and t-wave inversion and this is a subendocardial infarct so troponins and ckmbs will be positive.
• to diagnose STEMI, we will see st elevation because this is a transmural infarction,and troponin and ckmb are positive
• if we have st elevation(STEMI),the following is the suspected vessel that is involved. 1)Left anterior descending artery supplies anterior septum, and anterior of the heart. 2)LAD branch-Left circumflex artery supplies lateral wall and a little bit of posterior. 3)right coronary artery supplies right ventricles. 4)RCA marginal branch supply right ventricle, apex of the heart and posterior part of the right ventricle and posterior septum. 5)RCA marginal branch,branches into Posterior descending artery that supplies posterior left ventricle and some of posterior parts of the heart.
• for signs of anterior MI,anterior septal,anterior apical or anterior lateral.LAD artery is involved,on ecg there will be changes at v1 to v4.
• if left circumflex artery is involved, there will be changes on lead 1,avL,V5-v6.