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