Cardio Anatomy, ECG and Blood Vessels

• Cardio assessment and management involves reviewing the anatomy and physiology of the heart

Anatomy of Blood Vessels and Heart

• Blood flows in the sequence: IVC/SVC → RA → Tricuspid Valve → RV → Pulmonic Valve → Pulmonary Artery → Lungs (Gas Exchange) → Pulmonary Veins → LA → Mitral Valve → LV → Aortic Valve → Aorta → Body & R/L Coronary Arteries
• The left coronary artery (LCA) supplies both ventricles, the anterior wall, the septum, and the left atrium (LA).
• The right coronary artery (RCA) supplies the right atrium (RA), sinoatrial (SA) node, right ventricle (RV), posterior walls of both ventricles, and atrioventricular (AV) node

Electrical Conduction System and ECG

• The SA node fires, causing the atria to depolarize, seen as the P wave on an ECG
• The PRI interval, lasting 0.12-0.20 seconds, represents atrial depolarization through the AV node
• The QRS complex, lasting 0.06-0.12 seconds, represents ventricular depolarization
• The ST segment marks the end of depolarization and the beginning of repolarization
• The T wave represents ventricular repolarization

Cardiac Cycle and Blood Pressure

• During diastole, the heart is at rest, the AV valves are open, and the heart fills passively with blood
• The SA node fires 60-100 times per minute, causing an impulse to spread through the atria, depolarizing the right atrium (RA) and left atrium (LA), and causing them to contract, ejecting 20-30% more blood into the right ventricle (RV) and left ventricle (LV), which is known as preload
• The AV node holds the impulse for a fraction of a second (PR segment) before transmitting the signal through the Bundle of His, down both bundle branches, and to the terminal filaments of the Purkinje fibers
• The ventricles depolarize at the apex (QRS), closing the AV valves ("lub"), then upward, generating enough pressure to open the pulmonic and aortic valves
• Blood is ejected into the pulmonary artery and aorta
• When systole is complete, the ventricles begin to relax, and the backflow of blood closes the semilunar valves ("dub")
• The ventricles repolarize, represented by the (T) wave on an ECG
• Blood pressure (BP) is determined by cardiac output (CO) and vascular resistance (VR)
• Systolic pressure is the peak pressure during ventricular contraction
• Diastolic pressure is the minimum pressure maintained during rest
• MAP, mean arterial pressure, is the average pressure throughout the cardiac cycle (calculated as 1/3 Systolic + 2/3 Diastolic)
• Factors increasing cardiac output or vascular tone will increase blood pressure, including norepinephrine, epinephrine, angiotensin II, aldosterone, and ADH
• Factors decreasing cardiac output or vascular tone will decrease blood pressure, including bradycardia, hypovolemia, and hypothermia
• Beta-blockers, calcium channel blockers, ACE-Inhibitors, and ARBs will decrease blood pressure
• Cardiac Output (CO)= SV (stroke volume) x HR (heart rate)
• Preload is influenced by the end-diastolic ventricular volume (CVP monitor)
• Afterload is the resistance to ventricular flow and increases with hypertension and stenosis
• Contractility is the ventricular contraction force and decreases with hypoxia and acidosis
• Heart rate, force, preload, afterload, atrial kick, and Starling's law affect cardiac output
• Sympathetic stimulation (Beta 1/epi) increases rate, force, and automaticity
• Parasympathetic stimulation (Vagus nerve) decreases hear rate
• Baroreceptors in aortic and carotid arches sense blood pressure changes
• Chemoreceptors in carotid bodies of carotid arteries and aortic bodies of aortic arches
• Recognize non-modifiable risk factors like genetics/heredity (family history), age, gender, and race
• Identify chronic diseases, such as diabetes, where tight control is important, and hyperlipidemia requires modification with diet, exercise, and medication
• Modify lifestyle factors such as tobacco use (smoking & second-hand exposure), activity levels, stress management, weight/obesity, diet, and alcohol

Assessment

• Assess for current complaints like chest pain, shortness of breath, fatigue, palpitations, edema, and syncope
• In the physical exam, assess appearance, lungs (respiratory rate, depth, effort, sounds), cardiac (pulses, heart rate, regularity, sounds), any new murmurs, S3 or S4 sounds, skin color and edema, and condition of hair and nails
• Recognize age-related changes like hypertension, CAD, A fib, CHF, stenosis, murmurs, atherosclerosis, and increased risk of MI, PE, and CVA

Cardiovascular Assessment

• Red flag findings: chest pain, shortness of breath dyspnea, decreased SpO2, bradycardia, tachycardia, palpitations, irregular pulse, weakness, fatigue, dizziness, syncope, nausea, vomiting, diaphoresis, central or peripheral cyanosis, abnormal labs or ECG
• History includes nonmodifiable risk factors (demographic data, past and present health problems, family history) and modifiable risk factors (obesity, activity level, dietary habits, drug and alcohol use, smoking, and socioeconomic status)
• Assess VS (HR, BP, RR, temperature, SpO2, and pain level)
• Use OPQRST approach to assess chest pain
• Inspect for cyanosis, color, edema, and clubbing of fingers or toes. Note: Dark-skinned people, cyanosis appears gray. Look for jugular vein distention
• Palpate skin temperature, moisture, turgor, and pulses. Measure capillary refill and grade pitting edema
• Auscultate heart and lung sounds
• Evaluate ECG for ischemia
• Diagnostics include abnormal levels of electrolytes, blood counts, and cardiac enzymes
• Age-related changes: atrophy of left ventricle, decreased elasticity of aorta, stenosis of heart valves, stiffening of arterial walls, and increased fibrosis of heart chambers
• Diagnostics include health status (lipid panel, homocysteine, C-reactive protein, coagulation levels CBC, CMP), injury indicators (CK-MB, Troponin I, BNP), and imaging (EKG, chest X-ray, echocardiography (TTE/TEE), stress test, cardiac cath)

Pediatric Assessment Findings

• For congenital heart defects assess for failure to thrive, delayed physical growth, activity intolerance, poor weight gain, tachypnea, tachycardia, murmur, cyanosis, crackles, hepatomegaly, and sternal lift
• Feeding is critical, consider gavage tube if fatigue affects eating
• Atrial Septal Defect (ASD): A hole in the septum between the heart's two upper chambers, allowing oxygen-rich blood to mix with oxygen-poor blood, causing Fatigue, shortness of breath, frequent respiratory infections, heart murmur, and poor growth

Heart Defects

• If untreated, ASDs can lead to heart enlargement, arrhythmias, and pulmonary hypertension
• Small ASDs may close on their own; Larger ASDs may require surgical closure or catheter-based repair
• Ventricular Septal Defect (VSD): A hole in the septum between the heart's two lower chambers, causing oxygen-rich blood to flow into the right ventricle and lungs instead of the body causing poor feeding, rapid breathing, fatigue, heart murmur, and failure to thrive
• If untreated, VSDs can lead to congestive heart failure, pulmonary hypertension, and growth delays
• Small VSDs may close naturally; Larger VSDs often require surgical repair to prevent long-term complications
• Coarctation of the Aorta (CoA): A narrowing of the aorta that restricts blood flow, increasing pressure above the narrowing and reducing blood supply below it causing Symptoms: High blood pressure in the arms, low blood pressure in the legs, cold feet, fatigue, and headaches
• If left untreated, CoA can lead to heart failure, stroke, or aneurysm
• Treatment: Balloon angioplasty or surgical correction to widen the aorta
• Transposition of the Great Vessels (TGV): A congenital condition where the aorta and pulmonary artery are switched, causing oxygen-poor blood to circulate through the body and oxygen-rich blood to loop back to the lungs, causing Cyanosis (blue skin), shortness of breath, poor feeding, and heart failure
• If untreated, TGV is life-threatening
• Treatment: Surgical correction (arterial switch procedure) performed shortly after birth to restore normal blood flow
• Angina & Acute Coronary Syndrome (ACS): poor circulation through the blood vessels leads to chest pain
• Stable Angina: follows a predictable onset and relief pattern, moderate to prolonged exertion causes symptoms, rest and nitroglycerin relieve symptoms, and indicates myocardial ischemia
• Unstable Angina: onset occurs at rest or with less exertion than normal, relief is not achieved through usual measures, CK-MB and Troponin-I are normal, and there is no acute ST elevation on EKG

Myocardial Ischemia and Chest Pain

• Worsening myocardial ischemia or even injury can lead to Myocardial Infarction (MI)
• MI: EKG changes (STEMI) and/or elevations in CK-MB or Troponin-I, can lead to lethal dysrhythmias, and myocardial death
• Chest Pain Treatment: Rest & reassurance, 12-lead EKG, Aspirin (81-324 mg PO chewed), Oxygen (maintain SpO2 ≥ 94%), Chest X-ray (assess size, fluid, mass), Nitroglycerin (SL, paste, or IV), Fentanyl (if pain persists), Beta-blockers (HTN control), Anticoagulants/antiplatelets, Thrombolytics (for STEMI), PCI (cath lab) for STEMI

Angina Management

• Educate to rest and take nitro, proper storage and use
• Nitroglycerin Use: Take 1 tablet, wait 5 minutes. Call 911 if pain persists
• Avoid PDE Inhibitors (Viagra, Cialis, Levitra) - risk of severe hypotension

Cardiac Arrest Treatment

• Cardiac Arrest Treatment: CPR, Scene Safety, Check Responsiveness, Get Help, Call 911 and get the AED, Look, Listen, Feel 10 sec, Compressions 100-120/min, 30 compressions/2 breaths, push hard and fast in the center of the chest, Defibrillate (Vfib, Pulseless Vtach)
• Rhythm Management: Defibrillate for V-fib, pulseless V-tach, Cardioversion for SVT, Afib, Pacing for Sinus brady, complete heart block
• Treat shockable rhythms v-fib and pulseless vtach by defibrillating

Cardiac Pacing and Cardioversion

• Cardiovert for SVT & A-Fib using synchronized cardioversion
• Pace for Sinus Brady or Complete Heart Block, external, transvenous, or permanent

Heart Failure Assessment

• Right-Sided (Peripheral): increased pressure RA/SVC, JVD, abdominal girth, hepatomegaly, edema, weight gain
• Left-Sided (Pulmonary): increased pressure LV/LA and pulmonary circulation, Crackles, cough, dyspnea, fatigue

Valvular Heart Disease

• Artificial valves require prophylactic antibiotics
• Mitral Valve Stenosis: Rheumatic Fever, left atrial flow into LV is obstructed, backs up into lungs, congestive heart failure/pulmonary edema occurs, can lead to right-sided heart failure
• Mitral Valve Regurgitation: cannot close all the way due to aging or infective endocarditis/vegetation, high-pitched holosystolic murmur, S3
• Mitral Valve Prolapse: enlarged valve leaflet prolapses into atrium

Aortic Heart Diseases

• Aortic Stenosis: narrows and obstructs outflow of blood from LV, Rheumatic Fever/HD, CHD, atherosclerosis, degenerative calcification, causes FIXED CO symptoms, Narrow Pulse Pressure
• Aortic Regurgitation: incompetent valve allows backflow of blood from aorta into LV due to Infective endocarditis, CHD, HTN, Marfan's
• Infective Endocarditis can be caused by Staph, strep, IVDA, sepsis/SIRS, structural defects, causing fever, murmur, HF, Embolic stroke or PE, petechial hemorrhages
• Monitor for acute fevers, anxiety, chest pain, dyspnea

Pericarditis and Tamponade

• Pericarditis causes: viral, Inflammation of pericardial sac, abnormal Ekg & labs, Pericardial friction rub, hear at end of expiration, NSAIDs, rest, After viral URI
• Tamponade : Acute, life-threatening, Can be seen after pericarditis, MI, chest trauma, tumor, creates diastolic HF, causes tachy, hypertension, JVD, trachea midline
• INTERVENTION: Pericardiocentesis is implemented to insert Large needle into LV to remove blood in the pericardial sac

Cardiomyopathy and Cardiac Patient Care

• Cardiomyopathy has a reduced CO due to low stroke volume in LV, increased risk of BP changes with HR/PVR shifts , goals are to maintain CO, control HF symptoms
• Provide Stool softeners, to avoid straining
• Keep in mind: Know lab values, precautions, sodium (S), potassium (K)
• ABCD:Airway, Breathing(O2 to maintain SpO2 ≥ 94%), Circulation(IV access, fluid monitoring, watch for pulmonary edema), Disability(Neuro exam), Expose inspect for lesions, open areas, etc... Medications(Pressure, perfusion, platelets, pain, lipids))
• Know purpose, procedure, risks, recovery
• Educate patient to decrease anxiety
• Screen for shellfish/iodine allergy
• Monitor VS, puncture site, internal/external bleeding, arrhythmias afterwards
• To avoid kidney damage: IV fluids, acetylcysteine (to help clear up the dye), monitor labs