Cardiovascular - Heart Failure Midterm Notes PDF

3 1 CARDIOVASCULAR – Heart Failure Heart Failure (HF) Heart failure (HF) occurs when the heart is unable to pump blood effec:vely to meet the body's metabolic demands. HF can be categorized into: Heart Fai...

3 1 CARDIOVASCULAR – Heart Failure Heart Failure (HF) Heart failure (HF) occurs when the heart is unable to pump blood effec:vely to meet the body's metabolic demands. HF can be categorized into: Heart Failure with Reduced Ejec4on Frac4on (HFrEF): Ejec:on frac:on ≤ 40% (systolic heart failure). Heart Failure with Preserved Ejec4on Frac4on (HFpEF): Ejec:on frac:on ≥ 50% (diastolic heart failure). 1. Most Likely Cause Cause: o Ischemic Heart Disease: Myocardial infarc:on (MI) can weaken the heart muscle, leading to heart failure due to loss of myocardial contrac:lity. o Hypertension: Chronic hypertension increases the workload on the leO ventricle, leading to leF ventricular hypertrophy and eventually HF. o Cardiomyopathy: Structural heart disease can impair the heart's ability to pump blood, as seen in dilated, hypertrophic, or restric:ve cardiomyopathies. o Valvular Heart Disease: Stenosis or regurgita:on increases cardiac workload, which can eventually cause HF. o Other Causes: Arrhythmias (like atrial fibrilla:on), infec:ons, anemia, and high- output heart failure due to metabolic demands. 2. Pathophysiology The pathophysiology of heart failure depends on whether it is HFrEF (systolic HF) or HFpEF (diastolic HF), but the general process involves neurohormonal and mechanical compensatory mechanisms that worsen over :me. Heart Failure with Reduced Ejec4on Frac4on (HFrEF) 1. Reduced Contrac4lity: o Myocardial injury (like myocardial infarc4on) or cell death weakens the heart muscle, reducing its ability to pump blood effec:vely【97:0†source】. o Impaired contrac4on occurs due to changes in the heart muscle's structure or contrac:le ability. 2. Reduced Cardiac Output: o The reduc:on in stroke volume (amount of blood ejected per beat) leads to a reduc4on in ejec4on frac4on (EF ≤ 40%). 3. Compensatory Mechanisms: o The body ac:vates the renin-angiotensin-aldosterone system (RAAS), increasing blood pressure and preload (fluid reten:on) to maintain cardiac output. o Sympathe4c nervous system (SNS) ac4va4on increases heart rate and contrac:lity, but prolonged s:mula:on increases myocardial oxygen demand and leads to cardiomyocyte apoptosis. o Chronic ac:va:on of the RAAS and SNS causes ventricular remodeling, resul:ng in leO ventricular dila4on and wall thinning.  2 Heart Failure with Preserved Ejec4on Frac4on (HFpEF) 1. Impaired Relaxa4on (Diastolic Dysfunc4on): o In HFpEF, the leO ventricle's ability to relax and fill with blood is impaired. o This occurs due to leF ventricular hypertrophy or fibrosis, which increases s:ffness, making it more difficult for the ventricle to fill with blood during diastole. 2. Increased LeF Ventricular End-Diastolic Pressure (LVEDP): o Because the heart cannot fill properly, there is an increase in leF ventricular end- diastolic pressure, which backs up blood into the leF atrium and pulmonary circula4on, causing pulmonary edema and shortness of breath. 3. Increased AFerload: o Elevated blood pressure increases resistance against which the heart must pump blood, worsening HFpEF. 4. Neurohormonal Ac4va4on: o Similar to HFrEF, RAAS and SNS ac4va4on occur, leading to fibrosis and s:ffening of the cardiac muscle, further exacerba:ng diastolic dysfunc:on. 3. Disease Transmission Transmission: o Heart failure is a non-infec4ous disease and is not transmissible from person to person. o However, heart failure can be secondary to an infec4ous cause, such as viral myocardi4s or endocardi:s, but the failure itself is not transmissible. 4. Risk Factors Risk factors for HF are classified into modifiable and non-modifiable factors. Modifiable Risk Factors Hypertension: Chronic high blood pressure increases aOerload, promo:ng leO ventricular hypertrophy (LVH) and heart failure. Coronary Artery Disease (CAD): Plaque buildup in coronary arteries can lead to myocardial infarc4on, which may cause HFrEF due to myocardial cell death. Obesity: Increases the heart's workload and predisposes individuals to hypertension, insulin resistance, and diabetes. Diabetes Mellitus: Accelerates atherosclerosis and damages the microvasculature of the heart, leading to myocardial dysfunc:on. Smoking: Increases oxida:ve stress, damages endothelial cells, and promotes atherosclerosis, indirectly increasing HF risk. Physical Inac4vity: Sedentary behavior promotes obesity, hypertension, and insulin resistance. High Alcohol Intake: Chronic excessive alcohol consump:on can cause alcoholic cardiomyopathy, a major cause of HF. Diet: Diets high in salt, trans fats, and refined sugars promote hypertension, obesity, and metabolic syndrome. Non-Modifiable Risk Factors  3 Age: Aging increases risk due to a decline in cardiovascular func:on and increased exposure to cardiovascular risk factors. Sex: Men are at greater risk for HFrEF, while women are more likely to develop HFpEF. Gene4cs/Family History: Gene:c predisposi:on to cardiomyopathy or other cardiovascular diseases increases HF risk. Ethnicity: Some popula:ons (e.g., African Americans) are at higher risk for HF due to higher rates of hypertension and other cardiovascular risk factors. Summary Table Criteria Heart Failure (HF) Most Likely Myocardial infarc:on (MI), hypertension, valvular heart disease, Cause cardiomyopathy. HFrEF: Impaired contrac:on (EF ≤ 40%), reduced cardiac output, ac:va:on of Pathophysiology RAAS and SNS. HFpEF: S:ff heart (EF ≥ 50%), impaired filling, increased LVEDP, pulmonary conges:on. Not transmissible. Heart failure is a non-infec:ous disease. However, Transmission myocardi:s (viral infec:on) can lead to heart failure. Modifiable: Hypertension, CAD, obesity, diabetes, smoking, physical Risk Factors inac:vity, high alcohol consump:on, poor diet. Non-Modifiable: Age, sex, family history, gene:c predisposi:on, ethnicity.