Heart Anatomy & Function

Heart Anatomy & Function

• The heart has multiple layers including the endocardium (inner layer), myocardium (muscular, responsible for contraction), epicardium (outer protective layer), and pericardium (double-layer sac that reduces friction).
• The heart chambers include the atria, which receive blood, and the ventricles which pump the blood
• Atrioventricular (AV) Valves include the Tricuspid (right) & Mitral (left)
• Semilunar Valves include the Pulmonic (right) & Aortic (left)

Coronary Circulation & Blood Flow

• Coronary arteries supply oxygen to the heart
• The Left Coronary Artery supplies the left atrium, left ventricle, and interventricular septum and includes the Left Anterior Descending (LAD) & Left Circumflex Artery
• The Right Coronary Artery supplies the right atrium, right ventricle, AV node, and part of the left ventricle
• Deoxygenated blood flows from the SVC & IVC, to the Right Atrium, through the Tricuspid Valve, to the Right Ventricle, through the Pulmonic Valve and to the Pulmonary Artery and on to the Lungs
• Oxygenated blood flows from the Pulmonary Veins, to the Left Atrium, through the Mitral Valve, to the Left Ventricle, through the Aortic Valve and to the Aorta and on to the Body

Structure & Function of Blood Vessels

• Arteries have thick, elastic walls and carry oxygenated blood away from the heart
• Veins are thin-walled, contain valves, and return deoxygenated blood to the heart
• Capillaries are one-cell thick and are the site of gas & nutrient exchange
• Endothelium is the inner lining of vessels the regulates vasodilation & clotting

Blood Pressure Regulation

• Blood Pressure is controlled by baroreceptors (detect BP changes & adjust HR/vessel tone), chemoreceptors (respond to CO2 levels; influence BP & respiration), the autonomic nervous system, and hormones
• The autonomic nervous system controls BP: Sympathetic ("Fight or Flight") increases HR and vasoconstriction, while Parasympathetic ("Rest & Digest") decreases HR and vasodilation
• The Renin-Angiotensin-Aldosterone System (RAAS) regulates BP via vasoconstriction & fluid retention

ECG Interpretation (Electrocardiogram)

• P Wave represents atrial depolarization (SA node firing)
• QRS Complex represents ventricular depolarization (contraction)
• T Wave represents ventricular repolarization
• U Wave (if present) may indicate hypokalemia

Cardiovascular System Assessment (Subjective & Objective Data)

• Subjective symptoms include chest pain, dyspnea, fatigue, or edema
• Objective data includes vital signs (BP, HR, skin color, capillary refill) and heart sounds (auscultation)
• Normal heart sounds: S1 ("Lub") is the closure of mitral & tricuspid valves (start of systole) and S2 ("Dub") is the closure of aortic & pulmonic valves (start of diastole)
• Abnormal heart sounds include murmurs (valve issues), S3 (heart failure), and S4 (stiff ventricle)

Normal vs. Abnormal Cardiovascular Findings

• Normal findings include BP <120/80 mmHg, HR 60-100 bpm, no murmurs or extra sounds
• Abnormal findings include S3 ("ventricular gallop") which may indicate heart failure, S4 ("atrial gallop") which suggests stiff ventricle (e.g., hypertension, CAD), and pulse deficit (difference between apical & radial pulses that indicates dysrhythmias)

Age-Related Cardiovascular Changes

• Common changes in older adults include increased arterial stiffness which leads to higher BP, myocardial hypertrophy which leads to reduced cardiac output, valve calcification which leads to murmurs, and baroreceptor sensitivity decreases which leads to a higher risk of orthostatic hypotension

Hemodynamic Monitoring & Patient Care

• Cardiac Output (CO) = Stroke Volume (SV) × Heart Rate (HR)
• Preload is the blood volume in ventricles before contraction
• Afterload is the resistance the heart pumps against
• Contractility is the strength of heart contractions
• Nursing Care involves monitoring vitals, assessing for complications, and educating on lifestyle changes

Diagnostic Tests & Nursing Responsibilities

• Common Diagnostic Tests include ECGs (records electrical activity of heart), Echocardiograms (assesses heart function & valve issues), and Cardiac Catheterizations (evaluates coronary artery blockages)
• Nursing role involves monitoring patient vitals before, during, and after tests and educating patients on procedures & potential complications

Quick Mnemonics for Cardiovascular System

• Heart Valves: TPMA – "Toilet Paper My Ass" (Tricuspid, Pulmonic, Mitral, Aortic)
• Blood Flow Through the Heart: RA → RV → Lungs → LA → LV → Body
• ECG Waves: PQRST - "Please Quick Read The Summary" (P wave = Atrial depolarization, QRS complex = Ventricular depolarization, T wave = Ventricular repolarization)
• BP Regulation: BARO – "Baroreceptors Adjust Rapidly to Overload" (Baroreceptors, Autonomic NS, RAAS, Oxygen demand)

Pathophysiology of Primary Hypertension

• Primary Hypertension: Chronic high blood pressure with no known cause (90-95% of cases)
• Modifiable risk factors include obesity, smoking, high sodium intake, sedentary lifestyle, stress, and excessive alcohol
• Non-Modifiable: Age, genetics, ethnicity (higher in Black populations), gender (men < middle age; women > menopause)
• Often asymptomatic (Silent Killer), severe HTN Symptoms include fatigue, dizziness, chest pain, dyspnea, or vision changes
• Complications (Target Organ Damage) for the Heart include CAD, left ventricular hypertrophy, and heart failure, for the Brain include stroke and hypertensive encephalopathy, for the Kidneys include chronic kidney disease (nephrosclerosis), and for the Eyes include retinopathy (vision loss, hemorrhage)

Prevention Strategies

• Lifestyle Modifications (AHA "Life's Simple 7") include managing BP (Regular monitoring), controlling cholesterol (Limit saturated fats, increase HDL), reducing blood sugar (Manage diabetes, lower carb intake), getting active (Exercise 30 min/day, 5x per week), eating better (DASH diet: Fruits, veggies, whole grains, lean proteins, low sodium), losing weight (1 kg loss = ↓ BP by 1 mmHg), and stop smoking & limit alcohol (Men: 2 drinks/day; Women: 1 drink/day)

Interprofessional Care: Drug Therapy & Lifestyle Changes

• Medications (2 Main Actions) include those that decrease Blood Volume (Diuretics) and those that reduce Systemic Vascular Resistance (SVR) e.g. Vasodilators, Beta-blockers, and ACE inhibitors
• Common Antihypertensive Drugs include Diuretics (e.g., Hydrochlorothiazide) which reduces fluid volume, Beta-Blockers (e.g., Metoprolol) which reduces HR & CO, ACE Inhibitors (e.g., Lisinopril) which prevents vasoconstriction, and Calcium Channel Blockers (e.g., Amlodipine) which triggers Vasodilation
• Patients should monitor BP regularly, report side effects (Dizziness, fatigue, sexual dysfunction), and adhere to a medication regimen

Hypertension in Older Adults

• Age-Related Changes: Arterial stiffness leads to Increased BP
• Decreased kidney function leads to altered drug metabolism, and blunted baroreceptor reflex Increased risk of orthostatic hypotension
• Treatment Considerations include starting with low-dose medications, monitoring for dizziness & falls, and encouraging slow position changes to prevent syncope

Nursing Management for Hypertension

• Assessment includes health history and BP monitoring for orthostatic hypotension check (BP lying, sitting, standing)
• Nursing Interventions include education on lifestyle changes, encouraging sodium restriction, promoting physical activity, and emphasizing medication compliance

Hypertensive Crisis: Emergency Care

• Hypertensive Emergency (BP >180/120 + Organ Damage) requires hospitalization & IV meds (Nitroprusside, Labetalol), close BP monitoring avoiding rapid drops to prevent ischemia), and targeting a MAP of 110-115 mmHg, (Mean Arterial Pressure)
• Hypertensive Urgency (BP >180/120, No Organ Damage) can be treated outpatient with oral meds (Captopril, Clonidine, Labetalol) with follow-up within 24 hours

Quick Mnemonics for Hypertension

• DASH Diet: Dietary Approaches to Stop Hypertension.
• ABCDE for HTN Meds: ACE inhibitors, Beta-blockers, Calcium channel blockers, Diuretics, and Everything else (ARBs, Vasodilators).
• SPICES for Lifestyle Changes: Sodium restriction, Physical activity, Intake of alcohol limited, Cessation of smoking, Eat healthy.

HFrEF vs. HFpEF (Types of Heart Failure)

• Heart Failure with Reduced Ejection Fraction (HFrEF – Systolic HF) features ventricles that can't pump effectively (EF <40%), caused by weakened heart muscle (usually from MI, CAD, or HTN), and low Left Ventricular Ejection Fraction (LVEF)
• Heart Failure with Preserved Ejection Fraction (HFpEF – Diastolic HF) features ventricles that can't relax & fill properly, caused by LV stiffness that’s often due to aging, HTN, or obesity, it has normal EF but low diastolic function
• Left-Sided HF causes blood back up into the lungs causing pulmonary congestion, dyspnea, and fatigue
• Right-Sided HF causes blood back up into systemic circulation causing peripheral edema, JVD, and hepatomegaly, usually caused by Left HF

Compensatory Mechanisms & Decompensated HF

• Short-Term Compensation involves RAAS Activation which retains sodium & water leading to increased BP & fluid overload, SNS Activation which increases HR & vasoconstriction increasing heart workload, and Ventricular Remodeling (Bad Long-Term) that causes hypertrophy & dilation which leads to worsening HF
• Counterregulatory Mechanisms (Help Reduce Workload): Natriuretic Peptides (ANP & BNP) which promote diuresis & vasodilation, and Nitric Oxide & Prostaglandins which reduce workload by vasodilation
• Decompensated HF becomes Acute Decompensated HF (ADHF) when the heart can no longer maintain adequate CO, leading to symptoms of sudden fluid overload, pulmonary congestion, and decreased functional status

Nursing & Interprofessional Care for Acute Decompensated HF (ADHF)

• Symptoms of ADHF include pulmonary congestion (crackles, dyspnea, pink frothy sputum) and severe fluid overload which is most commonly the wet-warm type, with congestion but adequate perfusion
• Management of ADHF includes oxygen therapy, diuretics which reduces fluid overload, vasodilators which reduce preload & afterload, and morphine which reduces pulmonary congestion & anxiety, while monitoring VS, urine output, & weight daily

Nursing & Interprofessional Care for Chronic HF

• Symptoms of Chronic HF include fatigue, dyspnea, persistent cough, edema, weight gain (>3 lbs in 2 days), nocturia, palpitations, and mental status changes
• Chronic HF Management includes daily Weights (report gain of >3-5 lbs in a week), sodium restriction to <2g/day, fluid restriction to <2L/day for severe cases, and medications such as diuretics and beta-blockers

Advanced Therapies for Stage D Heart Failure

• Advanced therapies for Stage D Heart Failure is reserved for patients who no longer respond to standard treatment, and includes mechanical circulatory support, palliative care for symptom management, and heart transplantation, the gold standard for end-stage HF
• The Intraaortic Balloon Pump (IABP) aids the heart pump more efficiently.
• A Left Ventricular Assist Device (LVAD) pumps blood from LV to Aorta when the heart is too weak. and are used for patients waiting for heart transplant or those who can't receive one, and patients may not have a palpable pulse with only BP readings available via Doppler.

Heart Transplantation & Post-Op Care

• Indications for Heart Transplant include end-stage HF unresponsive to therapy and severe cardiomyopathy or congenital defects
• Post-Transplant Considerations include the risk of infection & rejection as the most common cause of death in the 1st year and necessitates lifelong immunosuppressants and monitoring for signs of rejection, such as fatigue, SOB, weight gain, and fever

Quick Mnemonics for Heart Failure

• HFrEF vs. HFpEF – "PUMP vs. FILL" (HFrEF: PUMP problem (Systolic), HFpEF: FILL problem (Diastolic))
• Right vs. Left HF – "LEFT = LUNGS, RIGHT = REST OF BODY" (Left-Sided HF: Pulmonary Congestion, Right-Sided HF: Peripheral Edema, JVD, Hepatomegaly)
• HF Symptoms – "FACES" (Fatigue, Activity intolerance, Congestion/cough, Edema, Shortness of breath)
• ADHF Management – "LMNOP" (Lasix, Morphine, Nitroglycerin, Oxygen Therapy, Positioning)

Epidemiology & Etiology of Obesity

• 43% of U.S. adults are obese, with higher rates in Black, Hispanic, and low-income populations, the prevention of Childhood obesity being key to reducing adult obesity
• Primary Obesity is caused by excess calorie intake over energy expenditure
• Secondary Obesity is caused by medical conditions (e.g., endocrine disorders, CNS lesions, meds)
• Risk Factors include genetics, family history, hormonal influences (hypothalamus, gut hormones), environmental factors, and psychosocial factors, emotional eating, depression, or food insecurity

Health Risks Associated with Obesity

• Major complications include cardiovascular disease, metabolic syndrome, type 2 diabetes, gastrointestinal & liver issues, respiratory/sleep disorders, musculoskeletal issues, cancer risks, and psychosocial issues

Classification of Obesity (BMI & Body Shape)

• BMI Categories: Underweight: <18.5, Normal: 18.5 – 24.9, Overweight: 25 – 29.9, Obese: ≥30, and Severely Obese: ≥40
• Health risk increases with waist circumference when Men: >40 inches and Women: >35 inches
• Body Shape & Health Risks: Android (Apple-Shaped) Obesity increases the risk of heart disease, diabetes, and metabolic issues, while Gynoid (Pear-Shaped) Obesity increases the risk of varicose veins and osteoporosis

Comprehensive Therapy for Obesity

• lifestyle Modifications (First-Line Treatment) with dietary therapy (balanced low-calorie, nutrient-dense diet, avoiding fad diets, portion control & meal planning) and exercise (150 mins/week moderate or 75 mins/week vigorous; 200-300 mins/week needed for weight maintenance) is recommended
• Behavioral therapy, support groups, and medications (only if BMI ≥30 or BMI ≥27 with Comorbidities) are helpful
• Medications: Orlistat blocks fat absorption, Lorcaserin increases satiety, Phentermine/Topiramate acts as an appetite suppressant, and Liraglutide is a GLP-1 agonist which reduces hunger

Bariatric Surgery for Obesity

• Bariatric surgery is for obese candidates that have a BMI ≥40 or BMI ≥35 with comorbidities, and must commit to lifestyle changes post-op
• Restrictive Surgeries (Shrink Stomach Size): Adjustable Gastric Banding (AGB) is Reversible, Sleeve Gastrectomy removes 75% of the stomach and is irreversible, and Gastric Plication folds stomach inward, with no tissue removal
• Combination Surgery (Restrictive + Malabsorptive): Roux-en-Y Gastric Bypass (RYGB) is the most common and bypasses most of the stomach & small intestine, with the pros being improved glucose control, lowered BP & cholesterol and the cons include Dumping syndrome

Nursing & Interprofessional Management for Bariatric Surgery

• Before surgery, assess readiness for lifestyle change and educate on procedure, risks, and post-op nutrition
• Post-operatively, early ambulation prevents DVTs, monitor pain & wound healing, and progress the diet
• Long-Term Care involves monitoring for nutrient deficiencies, preventing complications, and scheduling lifelong follow-ups for weight maintenance

Metabolic Syndrome

• Metabolic Syndrome is a cluster of risk factors that increase the risk of heart disease, stroke, and diabetes, and affects 1 in 3 adults with higher prevalence in older adults
• Diagnosis Requires 3 or More risk factors: Waist circumference >40 inches in men and >35 inches in women, High triglycerides >150 mg/dL, Low HDL cholesterol <40 mg/dL in men and <50 mg/dL in women, High BP ≥130/85 mmHg, and High fasting glucose ≥100 mg/dL
• Managed with: Weight loss, a healthy diet, regular exercise, and medications

Quick Mnemonics for Obesity & Metabolic Syndrome

• Obesity Classification – "WHO'S FAT?" (Waist circumference, Hip-to-Waist Ratio, Obesity/Shape, Fat Distribution)
• Metabolic Syndrome Criteria – "BP HIGH" (Blood Pressure, Plasma glucose, HDL, Increased triglycerides, Girth, and High risk)

Pathophysiology & Clinical Manifestations of Diabetes

• Diabetes is a chronic multisystem disease related to insulin production & utilization, with the key problem being hyperglycemia due to defective insulin secretion or action
• Organs Affected: Pancreas, liver, kidneys, cardiovascular system, and nervous system
• Type 1 DM causes sudden onset, includes the 3 P's (Polydipsia, Polyuria, Polyphagia), weight loss, fatigue, weakness, and ketoacidosis risk
• Type 2 DM causes gradual onset, often diagnosed during routine screening, and nonspecific symptoms of fatigue, recurrent infections, prolonged wound healing, and blurred vision

Type 1 vs. Type 2 Diabetes

• Type 1 Diabetes (Autoimmune, Insulin-Dependent) has an onset of <40 years (often childhood), involves autoimmune destruction of beta-cells leading to no insulin production, requires insulin for life, and the risk of DKA
• Type 2 Diabetes (Insulin Resistance, Non-Insulin-Dependent) has a gradual onset, insulin resistance/inadequate insulin production, it is linked to obesity, sedentary lifestyle, and family history, and is often managed with diet, exercise, and oral meds, with a possibility of requiring insulin later

Interprofessional Care for Diabetes

• The goal is to maintain blood glucose levels near normal to prevent complications
• Components of Care include Drug Therapy, Nutritional Therapy, Exercise, Blood Glucose Monitoring (BGM), and Patient Education

Role of Nutrition & Exercise in Diabetes Management

• Diet considerations include carbohydrate counting, a balanced diet with portion control, and limiting saturated fats and processed sugars
• Increasing fiber slows glucose absorption, but limit alcohol to avoid the risk of hypoglycemia
• Exercise therapy includes 150 min/week moderate exercise and resistance training 2x/week to increase insulin sensitivity, with monitoring for hypoglycemia

Nursing Management: Newly Diagnosed Diabetes

• Nursing consists of education on diabetes basics (insulin use, nutrition, exercise), on how to self-monitor blood glucose, and on medication management (how to administer insulin/oral meds)
• Patients should be educated on recognizing hypoglycemia vs hyperglycemia symptoms and foot care
• Patients should adhere to sick day rules when ill

Nursing Management in Ambulatory & Home Care Settings

• Focuses on ongoing education & support, daily BGM & medication adherence, diet & exercise plans, and monitoring for complications
• Patients should have routine check-ups A1C every 3-6 months, and eye & foot exams annually
• Patients should perform foot care for diabetic neuropathy by inspecting feet daily, avoiding walking barefoot, wearing proper footwear
• To prevent hypoglycemia at home, educate patients on treating low BG using the "Rule of 15"

Acute & Chronic Complications of Diabetes

• Acute Complications include Diabetic Ketoacidosis (DKA) (Type 1 DM) and Hyperosmolar Hyperglycemia Syndrome (HHS) (Type 2 DM)
• Chronic Complications can be macrovascular, microvascular, and infections
• Macrovascular (Large Blood Vessels) complications include heart disease, stroke, peripheral vascular disease
• Microvascular (Small Blood Vessels) complications include retinopathy, nephropathy, and neuropathy
• Infections: Higher risk of UTIs, wound infections, and delayed healing

Nursing & Interprofessional Management of Complications

• For Acute Complications, monitor glucose, electrolytes, and hydration status, administer IV fluids, insulin, and correct potassium levels, prevent hypoglycemia through education
• For Chronic Complications, schedule annual dilated retinal exams, monitor BUN, creatinine, and urine albumin for kidney care, foot care and daily inspections for neuropathy care, and control BP, cholesterol, and smoking cessation for heart disease prevention

Quick Mnemonics for Diabetes Management

• Mnemonic Type 1 vs. Type 2: "1 NEEDS insulin, 2 CAN avoid insulin"
• Hypoglycemia Symptoms: "TIRED" (Tachycardia, Irritability, Restlessness, Excessive Hunger, Diaphoresis)
• DKA vs. HHS – "DKA = Ketones, HHS = Dehydration"