Clinical Physiology Presentation Topics

Group 1: ECG (Electrocardiogram)

Basic Principles of Cardiac Electrophysiology:

• Resting Membrane Potential: -90mV maintained by Na+/K+ ATPase pump.
• Action Potential Phases:
  • Phase 0 (Depolarization): Na+ influx.
  • Phase 1 (Early Repolarization): K+ outflow.
  • Phase 2 (Plateau): Ca2+ influx balanced by K+ outflow.
  • Phase 3 (Repolarization): K+ outflow.
  • Phase 4 (Resting Potential): Maintained by pumps/channels.

Conductivity of the Heart:

• SA Node: Pacemaker in right atrium.
• Internodal Pathways: SA to AV node.
• AV Node: Delays impulse.
• Bundle of His & Branches: Conduct impulse to ventricles.
• Purkinje Fibers: Distribute impulse across ventricles.

ECG Components:

• P Wave: Atrial depolarization.
• QRS Complex: Ventricular depolarization.
• T Wave: Ventricular repolarization.
• U Wave: Late repolarization (sometimes visible).

ECG Intervals & Segments:

• PR Interval: Atrial depolarization to ventricular depolarization.
• QT Interval: Ventricular depolarization to repolarization.
• ST Segment: Ventricles depolarized.

ECG Recording Technique:

• Leads: 12-lead ECG (Limb and Precordial leads).
• Electrode Placement: Critical for accuracy.
• Calibration: Standard settings.

Clinical Significance of Abnormalities:

• Arrhythmias: Bradycardia, Tachycardia, Fibrillation, Heart Blocks.
• Ischemia/Infarction: ST changes, T wave inversion, Q waves.
• Hypertrophy: Changes in QRS, ST-T waves.
• Electrolyte Imbalances: Characteristic changes.
• Drug Effects: Alter waveforms.

Group 2: Pathophysiology of Sickle Cell Disease

Genetic Basis:

• Mutation: β-globin gene mutation on chromosome 11.
• Hemoglobin S (HbS): Abnormal hemoglobin.
• Inheritance: Autosomal recessive.

Pathophysiological Mechanisms:

• Polymerization of HbS: Under low oxygen, HbS forms fibers.
• Sickling of RBCs: Sickled shape impairs function.

Consequences:

• Chronic Hemolytic Anemia: Reduced RBC lifespan.
• Vaso-occlusion: Pain crises, acute chest syndrome, stroke.

Influencing Factors:

• Oxygen tension, pH, dehydration, temperature.

Diagnosis & Management:

• Diagnosis: Hemoglobin electrophoresis.
• Management: Prevent crises, manage symptoms.

Group 3: Renal Function Test

Overview of Renal Functions:

• Filtration, Reabsorption, Secretion, Excretion.
• Endocrine Functions: EPO, renin, vitamin D activation.

Common Tests:

• Serum Creatinine & BUN: Indicators of kidney function.
• eGFR: Estimates filtration rate.
• Urine Analysis: Includes pH, proteinuria, glucose, etc.
• Creatinine Clearance: Measures plasma clearance by kidneys.

Clinical Interpretation:

• Correlate tests with clinical history for diagnosis.

Group 4: Liver Function Test

Overview of Liver Functions:

• Metabolism, Synthesis, Storage, Detoxification.

Common Tests:

• Aminotransferases (ALT, AST): Indicate cell injury.
• Alkaline Phosphatase (ALP): Indicates cholestasis.
• Bilirubin: Indicates liver function and hemolysis.
• Albumin & PT/INR: Reflective of liver synthetic function.