Chapter 35: Cardiac and Associated Risk Disorders

Hypertension, affecting nearly half of American adults, results primarily from essential causes involving endothelial dysfunction and genetic-environmental factors, though secondary forms stem from identifiable conditions like renovascular disease or sleep apnea. Diagnosis requires repeated elevated blood pressure readings and screening for target organ damage, with management combining lifestyle interventions such as the DASH diet with pharmacological therapy using thiazide diuretics, calcium channel blockers, or renin-angiotensin system inhibitors. Dyslipidemia, characterized by abnormal plasma lipid concentrations, promotes atherosclerotic plaque formation through elevated low-density lipoprotein while high-density lipoprotein provides cardioprotective effects. Treatment emphasizes dietary modification followed by statin therapy based on individual cardiovascular risk stratification. Coronary heart disease represents the leading cause of death in the United States and develops through atherosclerotic narrowing of coronary arteries, reducing myocardial perfusion during exertion and producing angina pectoris. Diagnosis utilizes stress testing, nuclear imaging, and cardiac catheterization, while management focuses on aggressive risk factor modification and pharmacological intervention combined with potential revascularization procedures. Acute coronary syndrome encompasses a spectrum from unstable angina to myocardial infarction, occurring when atherosclerotic plaque rupture causes acute coronary artery occlusion. The twelve-lead electrocardiogram and cardiac-specific troponin measurements provide critical diagnostic information, while immediate reperfusion therapy through percutaneous coronary intervention or thrombolytics represents essential emergency management. Heart failure, characterized by insufficient cardiac output to meet metabolic demands, involves progressive hemodynamic and neurohormonal changes including sympathetic activation and renin-angiotensin-aldosterone system engagement. The condition manifests as systolic or diastolic dysfunction affecting the left ventricle, right ventricle, or both, with distinct clinical presentations including pulmonary congestion or systemic venous congestion. Management utilizes angiotensin-converting enzyme inhibitors as cornerstone therapy, combined with beta-blockers, diuretics, and advanced interventions such as cardiac resynchronization therapy for severe cases.