Cardiology Flashcards

Hypertension

• Hypertension is defined as high blood pressure, with systolic blood pressure (SBP) greater than 140 mmHg and diastolic blood pressure (DBP) greater than 90 mmHg.
• Types of Hypertension:
  • Pre-hypertension: SBP between 120-139 mmHg or DBP between 80-89 mmHg.
  • Stage I: SBP between 140-159 mmHg or DBP between 90-99 mmHg.
  • Stage II: SBP greater than 160 mmHg or DBP greater than 100 mmHg.
  • Pregnancy-induced hypertension: Caused by increased hormones and enzymes during pregnancy (hormonal change).
• Causes of Hypertension:
  • Primary: Idiopathic (90-95% of cases).
  • Secondary:
    • Renal Disease: Phaeochromocytoma, Chronic Kidney Disease (CKD).
    • Endocrine disorders: Cushing syndrome.
    • Neurological disorders: Brain tumor.
    • Medications: Oral contraceptives, NSAIDs.
    • Cirrhosis.
• Risk Factors for Hypertension:
  • Age: Greater than 50 years.
  • Gender.
  • Obesity.
  • Stress.
  • Family history.
  • Lifestyle: Alcohol and smoking.
• Pathophysiology of Hypertension:
  • BP = CO \times SVR, where CO = HR \times Stroke Volume
  • Sympathetic Nervous System (SNS) activities:
    • SNS activation leads to vasoconstriction and increased heart rate (HR), resulting in hypertension.
  • Vasoconstriction:
    • Leads to kidney release of renin, which activates the Renin-Angiotensin-Aldosterone System (RAAS), resulting in hypertension.
  • Vasoactive substances (Nitric oxide, endothelin):
    • Lead to vasoconstriction and increased Systemic Vascular Resistance (SVR).
  • RAAS system:
    • Adrenal cortex secretes aldosterone, leading to sodium and water retention, resulting in hypertension.
• Clinical Features of Hypertension:
  • Asymptomatic in some cases (silent killer disease).
  • Severe headache.
  • Blurred vision.
  • Chest pain.
  • Dizziness.
  • Arrhythmia.
  • Diaphoresis (excessive sweating).
  • Papilledema.
• Diagnostic Evaluation for Hypertension:
  • History, clinical features, and physical examination (PE).
  • Complete Blood Count (CBC).
  • Chest X-ray.
  • Electrocardiogram (ECG).
• Management of Hypertension:
  • Lifestyle changes:
    • Weight reduction.
    • Exercise.
    • Stress management.
    • Healthy diet.
  • Medications:
    • Calcium Channel Blockers (CCB): Amlodipine, Nicardipine, Nifedipine.
    • Angiotensin II Receptor Blockers (ARB): Losartan.
    • Angiotensin-Converting Enzyme Inhibitors (ACEI): Captopril, Ramipril.
    • Diuretics: Furosemide, Chlorothiazide.
    • Beta-blockers: Atenolol, Propranolol.
    • Alpha-blockers: Prazosin.
    • Vasodilators: Nitroglycerin, Sodium nitroprusside, Hydralazine.

Stable Angina

• Angina Pectoris: Chest pain or discomfort (transient) that occurs during heart cell ischemia related to a mismatch of oxygen demand and supply to the myocardium.
  • Induced by exercise, emotional stress, or can occur spontaneously.
• Etiology:
  • Coronary artery disease (most common).
  • Hypertension (HTN).
  • Diabetes Mellitus Type II (DMII).
  • Smoking.
  • Family history.
  • Obesity (increased LDL).
  • Rare causes: Cold weather, exercise, stress, alcohol.
• Pathophysiology:
  • Atherosclerosis leads to plaque formation in the heart artery, decreasing blood flow to the myocardium, resulting in ischemia/hypoxia.
• Symptoms:
  • Chest pain/discomfort (retrosternal): Pain during exercise (1-5 minutes) and relieved by rest or nitroglycerin (2 minutes onset of drugs).
  • Pain characteristic: Pressure, heaviness.
  • Pain radiated to the back, neck, jaw, or shoulder (mostly left side).
• Diagnosis:
• Management:
  • Lifestyle changes: Diet, exercise.
  • Medication: Nitroglycerin (can be used if SBP > 100 mmHg).
  • Surgery: Coronary artery angiogram / Percutaneous Coronary Intervention (PCI), Coronary artery bypass graft (CABG) (safe but requires thoracotomy).
• Complication: Unstable angina, NSTEMI, STEMI, sudden death.

Unstable Angina

• Definition: A condition where the heart doesn't get enough blood and oxygen supply due to poor blood flow through a coronary artery (Coronary Artery Disease).
• Causes:
  • Atherosclerosis (most common).
  • Microvascular dysfunction/Syndrome X.
  • Coronary artery spasm.
• Risk Factors: Diabetes, high blood pressure, increased LDL / decreased HDL, smoking, obesity, male sex.
• Clinical Features:
  • Chest pain: Occurs at rest (sleeping or sitting), lasting about 15-20 minutes.
  • Characteristic of pain: Tightness, squeezing, crushing, burning, choking, aching.
  • Pain radiates to the back, neck, jaw, or shoulder (mostly left side).
  • Shortness of breath.
  • Sweating.
  • Decreased blood pressure.
  • Does not respond well to nitroglycerin.
• Diagnosis:
  • Blood test: Troponins I and T, Creatinine phosphokinase (CPK), Myoglobin (to rule out NSTEMI).
  • ECG: ST depression and +/- T wave inversion.
  • Echocardiography.
  • Stress test (ECG during exercise).
  • Nuclear stress test/Stress echocardiogram (not available in KH).
  • Coronary angiography (most direct test to diagnose artery narrowing and find clots).
  • Coronary Computed Tomography Angiography (CCTA).
• Treatment:
  • Medication:
    • Heparin.
    • Nitroglycerin.
    • Control other associated diseases: Hypertension, anxiety, arrhythmia, cholesterol (statin).
  • Non-medication:
    • Angioplasty/Coronary Percutaneous Intervention: Procedure to open narrowed or blocked vessels.
    • Coronary artery stents.
    • Heart bypass surgery/CABG.
• Prognosis: Sign of more severe heart disease.
• Complication: Arrhythmias, heart attack, heart failure.

Acute Myocardial Infarction

• Definition: Sudden episodes of reduced or no blood flow to the heart due to narrowing or blockage of one or more coronary arteries.
• Causes:
  • Decreased blood pressure.
  • Obesity (increased cholesterol).
  • Diabetes.
  • Smoking.
  • Age.
  • Family history.
• Clinical Feature:
  • Chest pain: Retrosternal or left side, lasting greater than 30 minutes.
  • Characteristic: Pressure, tightness, sharp or squeezing.
  • Radiated: Neck, jaw, left scapular, left arm.
  • Shortness of breath.
• Diagnosis:
  • ECG (look at P wave and ST segment):
    • Right coronary artery occlusion (RCA): Look at lead II, III, AvF.
    • Left anterior descending artery blockage (Anterior wall of left ventricle): Look at V1-V4 (ST elevation).
    • Left coronary artery: Look at V5 and V6.
    • Lateral wall of left ventricle: Look at lead I, aVL, V5 and V6.
    • Posterior AMI: Look at V1, V2 (ST depression and big R wave).
  • Heart ultrasound.
  • Lab test (Troponin I/T): ASAT (SGOT) can be used if troponin not available; ASAT > ALAT x2 indicates positive.
  • Coronary artery CT scan.
  • Coronary artery angiography.
• Management:
  • First step in CCU:
    • Medication: Oxygen supply, Anti-coagulant, Clopidogrel, Aspirin, Statin, PPIs.
  • Second step:
    • Coronary artery angiogram.
    • Percutaneous coronary intervention.
• Complication: Thrombosis, Heart arrhythmia, Heart failure, Cardiac arrest.
• Advice: Small salt diet, take all the medication, return to hospital if chest pain or tightness returns.

Cardiogenic Shock

• Definition: A condition in which a suddenly weakened heart isn’t able to pump enough blood to the body.
• Epidemiology:
  • Men > Women.
  • Mortality 80-90%.
• Risk Factor:
  • Old age.
  • History of heart failure/attack.
  • Coronary artery disease (blockage of several heart’s main arteries).
  • DM/HTN.
  • Existing heart disease.
• Causes:
  • Myocardial ischemic: Heart tries to compensate, increasing O2 demand, leading to myocardial compromise.
  • Myocardial infarction: Left ventricle dysfunction, heart compensates for decreased CO, myocardial compromised.
  • Myocarditis.
  • Endocarditis.
  • Drugs or substances affect heart’s pumping ability.
• Classification:
  • Coronary (common): Most often with MI.
  • Non-coronary: Stress myocardium.
• Symptoms:
  • Clammy skin.
  • Decreased SBP.
  • Tachycardia.
  • Rapid respiration.
  • Oliguria.
  • Cyanosis.
  • Mental confusion.
• Diagnosis:
  • History + PE.
  • Chest x-ray: Look for cardiomegaly.
  • ECG.
  • Echo-cardiogram: look for Endocarditis/Pericardial effusion.
  • Cardiac catheterization (Angiogram).
• Treatment:
  • Inotropes:
    • Norepinephrine: Strong effect at both (B1 and A1); A1 effect leads to hypertension.
    • Epinephrine: Same as norepinephrine.
    • Dopamine: Medium effect at B1 receptor.
    • Dobutamine: Strong effect at Beta 1 receptor and less at alpha 1 receptor.
    • Isoproterenol
  • Thrombolytic drugs: Streptokinase, Urokinase.
  • Antiplatelet: Aspirin, Clopidogrel, prasugrel.
  • Angioplasty and stenting (if the blockage is found).
  • Balloon pump: To make the blood flow to the important organs (Brain, Heart, Kidneys) and reduce blood flow to peripheric (extremities).
  • Surgery:
    • Coronary artery bypass.
    • Heart transplant
    • Ventricular assist device: Implanted into the abdomen to help heart pump.
• Prevention:
  • Avoid smoking & Alcohol.
  • Maintain body weight.
  • Limit added sugar.
  • Exercise regularly

Atherosclerosis

• Definition: Is a disease of arteries which causes the formation of plaques in the artery’s wall.
  • The plaque consists of fat, cholesterol, Calcium and macrophage.
• Risk factor:
  • Smoking
  • HTN → Endothelial damage → Formation of fatty streak
  • High LDL cholesterol
  • Diabetes
    • Chronic hyperglycemia → Increased local angiotensine II production
  • Family
  • Age (Women: >55y, Men: >45y)
  • Lifestyle: Obesity, physical inactivity
• Pathophysiology:
  • Lipoprotein in the intima → Oxidized LDL induced local cytokine → Monocyte stimuli macrophage
  • Macrophage uptake Oxidized LDL → Foam cells → Development of foam cell → atherosclerotic plague and calcification
• Symptoms: Depend on which arteries are affected:
  • Heart arteries: Chest pain (Angina)
  • Arteries leading to brain: Sudden arm or leg numbness or weakness, difficulty speaking, drooping face
  • Arm and leg arteries: peripheral artery occlusive disease (PAOD) → Leg pain when walking
  • Erectile dysfunction in male
• Diagnosis:
  • Find sign of narrowed, enlarged or hardened arteries:
    • Weak or absent pulse
    • Decreased BP in affected limb
    • Whooshing sounds (bruits)
    • Sign of a pulsating bulge (Aneurism) in the abdomen or knee
    • Poor wound healing
  • Blood test: Lipid profile (Total cholesterol, HDL, LDL, Triglyceride)
  • Doppler ultrasound
  • ECG
  • Echo-cardio
  • CT scan
  • Angiogram
• Treatment:
  • Life style change: Eat healthy food, Exercise
  • Medications:
    • Statins (Decreased LDL) or Fenofibrates (Decreased TG)
    • Antiplatelets
    • Anti coagulation drugs
    • Antihypertensive
    • Diabetic drugs
  • Surgery:
    • Endarterectomy (to remove plague)
    • Thrombolytic therapy
    • Bypass surgery
    • Angioplasty (Stent)
    • Interventional Revascularization (PCI)
• Complication: Depend on arteries that affected.
• Prevention: Life style, Treatment DM and HTN

ECG Aspect of Coronary Artery Disease

• Unstable angina & NSTEMI have the same ECG (We look at ST segment & T wave)
• Using cardiac enzyme to divide them:
  • Unstable angina: Troponin (-)
  • NSTEMI: Troponin (+)
• ECG is a graphic recording of electric potential generated by the heart. Its use in:
  • Detecting arrhythmia
  • Conduction disturbance
  • Myocardial ischemia
  • Metabolic disturbance (Hyper/Hypokalemia…)
• Cardiac conduction system:
  • Heart function as a pump. It depends on its intrinsic conduction system (ICS)
  • ICS: specialized muscle cells, which can generate electricity and make the heart to pump. Electricity was made by:
    • SA node
    • AV node
    • AV bundle
    • Bundle branches
    • Purkinje Fibers
• ECG wave:
  • P wave: Atrials depolarization
  • QRS: Ventriculars depolarization
    • Q: Septal depolarization
    • R: Ventricles depolarization
    • S: High lateral Ventricle
    • J point: Terminal QRS to ST segment
  • ST segment: beginning of ventriculars repolarization
  • T wave: Ventriculars repolarization
• ECG diagnostic tool:
  • 12 leads: 6 limbs, 6 chest leads → look at all directions of heart (frontal & temporal)
  • Electrode of chest leads are (+) → upward deflection, R wave is gradually taller from V1-V6
• ECG tracing:
  • Usually speed: 25mm/s
  • Usually amplitude: 10mm/mV
  • 1 small box = 1mm = 0.04s
• ECG Analysis:
  • We look at:
    • Calculate: Rate (HR)
    • Determine: Rhythm
    • Calculate: P wave, PR interval, QRS, T wave
    • Determine AXIS
    • Look for evidence of: ST depression, T wave inverted
    • Conclusion
• Heart rate:
  • R wave regular:
    • Between R wave to another R wave (if 1big square=300, 2big square=150…), 300, 150, 100, 75, 60, 50
    • Use 1500/small square between R to another R
    • Use 300/Big square between R wave to another wave
  • R wave irregular:
    • Count 30 big square then count R wave in it, Amount R x 10
    • If there aren’t enough 30 big square use monitor scope
• Rhythm:
  • Sinus: Normal P wave follows by normal QRST (Upright P in lead II)
• P wave:
  • <2.5mm height
  • <3mm wide (0.04-0.12s)
• Intervals:
  • PR: 0.12-0.20s
  • QRS: 0.06-0.12s
  • QT: <0.43s
• QRS Complex:
  • Normal 0.06-0.10s
  • Wide: >0.12s (>3 small box)
  • Narrow: <0.06
• Q wave:
  • Pathology Q wave see:
    • Amplitude: less than 1/4 R
    • Duration: \leq0.03s
• R wave:
  • First upward wave after P or Q waves
  • If there are other R wave, they are named R’, R”, etc
• S wave:
  • Downward wave after R wave
• ST segment:
  • Iso electric line
  • From end of QRS to the start of T wave
  • Persistent ST Depression = NSTEMI (Non ST Elevation MI)
• T wave:
  • Upright at I, II, and V3 to V6
  • Inverted at aVR
  • Variable at III, aVF, V1 and V2
• U wave:
  • Final phase of Purkinje repolarization
  • K+ plays a critical role in repolarization
  • Visible in hypokalemia, in V2, V3

ECG Aspect of Injury

• STEMI: caused by complete thrombus occlusion, LBBB
  • ECG: ST elevated
  • Elevated cardiac enzyme (Troponin)
• Coronary artery supply:
  • RCA:
    • Right ventricle
    • Inferior wall of LV
    • Posterior wall of LV (75%)
    • SA Node (60%)
    • AV Node (>80%)
  • LCA:
    • Septal wall of LV
    • Anterior wall of LV
    • Lateral wall of LV
    • Posterior wall of LV(10%)
    • Inferior wall of LV
    • Antero-posterior wall of RV
    • SA node, AV node
• We use Q wave to evaluate acute or chronic MI:
  • If ST elevation → Acute MI
  • If no ST elevation → Chronic MI
  • Q wave with persistent ST elevation >3weeks → consider LV aneurysm