Coronary artery disease Notes

NOTES NOTES CORONARY ARTERY DISEASE STABLE ANGINA PECTORIS osms.it/stable-angina PATHOLOGY & CAUSES ▪ Episodic chest pain because of inadequate oxygen supply to the heart, most often due to obstruction in the coronary arteries ▪ Most common type of angina ▫ Angina pectoris refers to a specific type of chest pain caused by lack of blood flow to the heart muscle. Pain often presents as pressure, fullness, squeezing pain in the center of the chest ▫ In angina → ischemia in the subendocardium → triggers release of adenosine and bradykinin → pain CAUSES Atherosclerosis ▪ Causes plaque buildup in vessel; blood flow to heart muscle limited ▫ As plaque becomes larger and blocks more flow, pain arises with lower levels of exertion Tachyarrhythmias ▪ Increased heart rate increases heart’s demand for oxygen that cannot be delivered, thus causing pain Pulmonary hypertension ▪ Left main coronary artery can become compressed by enlarged pulmonary artery trunk, leading to reduced perfusion and pain Increased myocardial oxygen demand ▪ Consequence of increased left ventricular mass secondary to concentric hypertrophy, and an increased afterload due to the fixed obstruction to left ventricular outflow Genetic hypertrophic cardiomyopathy ▪ Cardiac hypertrophy leads to increased oxygen demand of heart muscle. In times of high exertion, the heart cannot supply enough oxygen and ischemia results RISK FACTORS ▪ Smoking, hypertension, diabetes, dyslipidemia (high LDL, low HDL, and high triglycerides), obesity, family history of coronary artery disease Protective factors ▪ Modest alcohol consumption (~one drink/ day), healthy diet (e.g., lots of vegetables, grains, and nuts), and regular exercise SIGNS & SYMPTOMS ▪ Chest pain coinciding with increased exertion or stress. Pain described as pressure, squeezing, burning, or tightness; can radiate to the either/both arms, jaw, shoulders, and back ▫ Pain usually lasts less than 20 minutes ▪ Other symptoms: Levine’s sign (a clenched fist held over the chest), dyspnea, diaphoresis, fatigue, nausea, and epigastric pain ▫ Angina equivalent: These “other symptoms” felt without chest pain during periods of coronary ischemia (more common in diabetics, biologicallyfemale individuals, elderly) OSMOSIS.ORG 41

DIAGNOSIS ▪ Primarily based on signs/symptoms; “clinical diagnosis” OTHER DIAGNOSTICS Electrocardiogram (ECG) ▪ Stable angina can present with ST segment depression ▫ May also present with T wave inversions ▫ Illustrates subendocardial ischemia ▫ Dynamic ECG changes: changes in ECG are seen for duration of symptoms, but can reduce in intensity or disappear when symptoms abate (e.g. individual may start with 2mm ST depressions with no chest pain, but then get 4mm ST depressions during an episode of unstable angina at rest, which revert to 2mm ST depressions once episode is concluded) ▪ Other tests may be required to obtain more specific information TREATMENT MEDICATIONS Sublingual nitroglycerin ▪ The classic regimen for stable angina; as needed, daily aspirin, beta blockers and statin Nitrates and Vasodilator ▪ Nitrates treat immediate pain ▪ Vasodilator causes venodilation, which decreases preload, reducing oxygen demand of the heart ▪ Nitroglycerin ▫ Used to treat immediate pain on asneeded basis ▪ Isosorbide mononitrate ▫ Used for prevention Beta blockers ▪ Reduce myocardial oxygen demand by reducing heart rate and contractility ▪ First line medication for stable angina Statins ▪ Preventative. Lowers low density lipoproteins, improves dyslipidemia Aspirin ▪ Preventative. Prevents thrombosis by blocking platelet activation, reduces chance of stable angina → unstable angina 42 OSMOSIS.ORG