Heart Anatomy, Function, and Blood Flow

Heart Anatomy & Function

• The endocardium serves as the inner layer providing a smooth lining
• The myocardium is the middle, muscular layer responsible for contraction
• The epicardium is the outer protective layer of the heart
• The pericardium functions as a double-layer sac to reduce friction
• Atria (right and left) recieve blood
• Ventricles (right and left) pump the blood
• Heart valves ensure one-way blood flow
• Atrioventricular valves include the tricuspid (right) and mitral (left) valves
• Semilunar valves include the pulmonic (right) and aortic (left) valves

Coronary Circulation & Blood Flow

• Coronary arteries provide oxygen to the heart muscle
• The left coronary artery supplies blood to the left atrium, left ventricle, and interventricular septum
• The left coronary artery branches into the left anterior descending (LAD) and left circumflex artery
• The right coronary artery supplies blood to the right atrium, right ventricle, AV node, and part of the left ventricle

Blood Flow Through the Heart

• The right side of the heart (deoxygenated) blood flow: SVC & IVC → Right Atrium → Tricuspid Valve → Right Ventricle → Pulmonic Valve → Pulmonary Artery → Lungs
• The left side of the heart (oxygenated) blood flow: Pulmonary Veins → Left Atrium → Mitral Valve → Left Ventricle → Aortic Valve → Aorta → Body

Structure & Function of Blood Vessels

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

Blood Pressure Regulation

• Monitored by baroreceptors that detect BP changes and adjust HR/vessel tone
• Chemoreceptors respond to CO2 levels, influencing BP and respiration
• The autonomic nervous system regulates BP
• Sympathetic ("Fight or Flight") increases HR, vasoconstriction
• Parasympathetic ("Rest & Digest") decreases HR, vasodilation
• Hormonal control, specifically the Renin-Angiotensin-Aldosterone System (RAAS), regulates BP via vasoconstriction & fluid retention

ECG Interpretation (Electrocardiogram)

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

Cardiovascular System Assessment (Subjective & Objective Data)

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

Normal vs. Abnormal Cardiovascular Findings

• Normal findings include:
• BP 1 mmHg
• 1 kg loss results in decreased BP by 1 mmHg
• Stop smoking and limit alcohol intake (men: 2 drinks/day; women: 1 drink/day)

Interprofessional Care: Drug Therapy & Lifestyle Changes

• Medications used act to either decrease blood volume or reduce systemic vascular resistance (SVR)
• Common antihypertensive drugs include:
• Diuretics reduce fluid volume, examples being Hydrochlorothiazide
• Beta-Blockers decrease HR & CO, example being Metoprolol
• ACE Inhibitors such as Lisinopril prevent vasoconstriction
• Calcium Channel Blockers such as Amlodipine cause vasodilation
• Patient education includes:
• Monitoring BP regularly
• Reporting side effects such as dizziness, fatigue, and sexual dysfunction
• Sticking to medication regime is crucial

Hypertension in Older Adults

• Age-related arterial stiffness leads to increased BP
• Decreased kidney function results in altered drug metabolism
• Blunted baroreceptor reflex increases the risk of orthostatic hypotension
• Treatment considerations:
• To start with low-dose medications
• To monitor for dizziness & falls
• To encourage slow position changes to prevent syncope

Nursing Management for Hypertension

• Assessment includes subjective and objective data
• Medical History: includes family history, smoking, alcohol use, diet, medications
• BP Monitoring includes orthostatic hypotension check (BP lying, sitting, standing)
• Nursing interventions include:
• Providing education on lifestyle changes
• Encouraging sodium restriction
• Promoting physical activity
• Emphasizing medication compliance

Hypertensive Crisis: Emergency Care

• Hypertensive Emergency is indicated by BP >180/120 + organ damage
• Requires hospitalization & IV meds (Nitroprusside, Labetalol)
• Monitor BP closely, avoiding rapid drops to prevent ischemia
• Target MAP = 110-115 mmHg (Mean Arterial Pressure)
• Hypertensive Urgency includes BP >180/120, but there's No Organ Damage
• Treatment includes outpatient care with oral meds (Captopril, Clonidine, Labetalol) with - Follow-up within 24 hours

Quick Mnemonics for Hypertension

• BLOOD PRESSURE CONTROL
• DASH Diet: Dietary Approaches to Stop Hypertension
• ABCDE for HTN Meds:
• ACE inhibitors
• Beta-blockers
• Calcium channel blockers
• Diuretics
• 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) includes:
• Problem: Ventricles can't pump effectively (EF Diarrhea after eating high-sugar meals

Nursing & Interprofessional Management

• Preoperative considerations include: Assess readiness for lifestyle change Educate on the surgical procedure, risks, and post-op nutrition
• Postoperative care includes: Early ambulation to prevent DVTs Monitoring pain & wound healing Diet progression with clear liquids Slowly advancing to solid foods
• Long-term care includes: Monitoring for nutrient deficiencies (iron, calcium, B12) preventing complications like dumping syndrome and dehydration Lifelong follow-ups for weight maintenance

Metabolic Syndrome

• Metabolic syndrome is defined by a cluster of risk factors that increase the risk of heart disease, stroke, and diabetes
• It affects 1 in 3 adults with higher prevalence in older adults
• Diagnosis requires 3 or more of the following risk factors:
• Waist circumference: Men >40 inches, Women >35 inches
• High triglycerides: >150 mg/dL
• Low HDL cholesterol:
  • Men 1.0
• Fat Distribution (Visceral = More dangerous)
• Android (Apple) vs. Thighs (Pear)
• Metabolic Syndrome Criteria – "BP HIGH"
• BP (≥130/85 mmHg)
• Plasma glucose (≥100 mg/dL)
• HDL low (Men 40" men, >35" women)
• High risk for diabetes & heart disease

Pathophysiology & Clinical Manifestations of Diabetes

• The pathology is a chronic multisystem disease related to insulin production & utilization
• Its key problem is hyperglycemia due to defective insulin secretion or action
• Organs affected: Pancreas, liver, kidneys, cardiovascular system, nervous system
• Clinical Manifestations for Type 1 DM:
• Sudden onset
• 3 P’s: Polydipsia, Polyuria, Polyphagia
• Weight loss, fatigue, weakness, ketoacidosis risk
• Clinical Manifestations for Type 2 DM:
• Gradual onset with often diagnosed during routine screening.
• Non-specific symptoms: Fatigue, recurrent infections (yeast, UTI), prolonged wound healing, blurred vision

Type 1 vs. Type 2 Diabetes

• Type 1 Diabetes is Autoimmune, Insulin-Dependent and includes:
• Onset: 150 mins/week moderate aerobic activity + resistance training
• Blood Glucose Monitoring (BGM):
• Includes self-monitoring (fingerstick or CGM)
• Patient Education:
• Includes education on medication adherence, lifestyle changes, monitoring BG

Role of Nutrition & Exercise in Diabetes Management

• Focus includes on Nutrition Therapy to maintain glucose, lipid, & BP levels by;
• Carb counting (adjust Insulin based on carb intake)
• Reducing saturated fats & processed sugars
• Increase fiber to slow glucose absorption
• Limit alcohol to reduce risk for hypoglycemia
• Exercise Therapy:
• Includes 150 min/week moderate exercise (walking, cycling, swimming)
• Includes resistance training 2x/week to increase insulin sensitivity
• includes monitoring for hypoglycemia (especially if on insulin)

Nursing Management: Newly Diagnosed Diabetes

• Emphasis on Priority Nursing Actions:
• Education on diabetes basics (insulin use, nutrition, exercise)
• How to self-monitor blood glucose (BGM)
• Medication management including;
• How to administer insulin/oral meds
• Education on Recognizing hypoglycemia vs. hyperglycemia symptoms
• Foot care (inspect daily, wear proper shoes)
• Sick day rules include to Check BG every 4 hours, stay hydrated
• Psychosocial Support to assess for diabetes distress, anxiety, and depression
• Connect with Support groups & diabetes educators

Nursing Management in Ambulatory & Home Care Settings

• Emphasis on continuous Ongoing Education & Support
• Daily BGM & medication adherence
• Diet & exercise plans to Encourage weight loss for Type 2 DM
• Monitor for complications (neuropathy, retinopathy)
• Routine check-ups include A1C every 3-6 months, eye & foot exams annually
• Foot Care for Diabetic Neuropathy includes:
• Inspect feet daily for cuts and ulcers
• Avoiding walking barefoot
• and Wearing Proper footwear
• Preventing Hypoglycemia at Home is accomplished via;
• The "Rule of 15" for treating low BG where, If BG Give 15g carbs, recheck BG in 15 min

Acute & Chronic Complications of Diabetes

• Acute Complications:
• Included Diabetic Ketoacidosis (DKA) (Type 1 DM) that includes:
• Severe hyperglycemia, ketones in urine, acidosis
• Symptoms of DKA are Kussmaul respirations, fruity breath, dehydration
• Treatment for DKA includes delivering; IV fluids, insulin drip, monitoring of potassium levels

DKA vs. HHS Mnemonic

• "DKA = Ketones, HHS = Dehydration"
• DKA → Type 1, ketones, Kussmaul breathing
• HHS → Type 2, no ketones, severe dehydration