Welcome to our USMLE guide on cardiovascular diseases! In this article, we will provide you with a comprehensive overview of various cardiovascular diseases that you may encounter in your medical practice. We will cover the etiology, pathophysiology, clinical presentation, diagnosis, and management of these conditions. This guide aims to help you prepare for the usmle exams and enhance your understanding of cardiovascular diseases.
Atherosclerosis is a chronic inflammatory disease characterized by the accumulation of plaques within the arterial walls. The exact cause of atherosclerosis is multifactorial, involving genetic predisposition, lifestyle factors (e.g., smoking, poor diet), and comorbidities (e.g., diabetes, hypertension).
The process begins with endothelial dysfunction, followed by the migration of monocytes into the arterial intima. These monocytes differentiate into macrophages, which engulf oxidized low-density lipoproteins (LDL) to form foam cells. Over time, a fibrous cap forms over the fatty plaque, leading to plaque instability and potential rupture.
Atherosclerosis can manifest in various ways, depending on the affected arteries. Common presentations include angina pectoris (coronary artery disease), claudication (peripheral artery disease), and transient ischemic attacks/stroke (carotid artery disease).
Diagnosis is often made through a combination of patient history, physical examination, and diagnostic tests. These may include lipid profile assessment, electrocardiography (ECG), stress tests, and imaging modalities such as angiography or ultrasound.
Management of atherosclerosis involves lifestyle modifications (e.g., smoking cessation, healthy diet), control of comorbidities, and pharmacological interventions. Medications commonly used include statins, antiplatelet agents, and antihypertensives.
Coronary artery disease (CAD) refers to the narrowing or blockage of the coronary arteries, usually due to atherosclerosis. Risk factors include smoking, hypertension, dyslipidemia, diabetes, obesity, and a family history of CAD.
Atherosclerosis causes the formation of plaques within the coronary arteries, leading to reduced blood flow to the myocardium. This imbalance between oxygen supply and demand results in myocardial ischemia.
Patients with CAD may present with angina pectoris (chest pain or discomfort), which can be stable or unstable. Acute coronary syndromes, such as unstable angina, non-ST segment elevation myocardial infarction (NSTEMI), or ST-segment elevation myocardial infarction (STEMI), can also occur.
Diagnosis is made based on the patient's symptoms, electrocardiography (ECG) findings, cardiac biomarker levels (e.g., troponin), and imaging studies (e.g., coronary angiography, stress tests).
Management of CAD involves lifestyle modifications (e.g., exercise, diet), risk factor control, and medical interventions. Medications include antiplatelet agents, beta-blockers, nitroglycerin, and statins. In severe cases, revascularization procedures like percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) may be necessary.
Myocardial infarction (MI) occurs when there is a sudden blockage of blood flow to a part of the heart, leading to ischemia and tissue death. The most common cause is the rupture of an atherosclerotic plaque, resulting in thrombus formation and coronary artery occlusion.
The lack of blood supply to the myocardium causes irreversible damage, leading to necrosis. The extent of damage depends on the duration and location of the