Effect of electrolytes on cardiac rhythm

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Effect of electrolytes on cardiac rhythm

  1. 1. EFFECT OF ELECTROLYTES ON CARDIAC RHYTHM Prepared by: Ahmad Thanin
  2. 2. OBJECTIVES: By the end of session learners will be able to: • Define Electrolytes. • Discuss the function of electrolytes • Describe the relationship of electrolyte with heart • List down common electrolytes responsible for cardiac function • Explain the effect of electrolytes on heart • Interpret the ECG features of different electrolyte imbalances • Summarize the main key points of the session
  3. 3. What are Electrolytes? Chemically, electrolytes are substances that become ions in solution and acquire the capacity to conduct electricity. Electrolytes are present in the human body, and the balance of the electrolytes in our bodies is essential for normal function of our cells and our organs.
  4. 4. FUNCTIONS:
  5. 5. Electrolytes and Heart: • The normal state of cardiac cell membrane polarization is dependent upon the maintenance of a normal ionic balance across the membranes
  6. 6. Common Electrolytes responsible for cardiac arrhythmias • Potassium • Magnesium • Calcium
  7. 7. HYPERKALEMIA Background •Potassium is vital for regulating the normal electrical activity of the heart. •Increased extracellular potassium reduces myocardial excitability, with depression of both pacemaking and conducting tissues. •Progressively worsening hyperkalemia leads to suppression of impulse generation by the SA node and reduced conduction by the AV node and His-Purkinje system, resulting in bradycardia and conduction blocks and ultimately cardiac arrest.
  8. 8. ECG features of Hyperkalemia: • Rhythm: Atrial and ventricular rhythms are regular • Rate: Atrial and ventricular rates are within normal limits • P Wave: Mild-low amplitude, moderate-wide flattened, severe-indiscernible • PR interval: Normal or prolonged; unmeasureable if P wave cant be detected • QRS complex: Widened because ventricular depolarization takes longer • QT interval: Shortened • ST segment: May be elevated in severe hyperkalemia • T wave: Tall, Peaked.
  9. 9. Peaked T waves in Hyperkalemia Prolonged PR segment in Hyperkalemia
  10. 10. Broad P waves and QRS complexes Loss of P waves
  11. 11. Bradycardia
  12. 12. HYPOKALEMIA Background •Potassium is vital for regulating the normal electrical activity of the heart •Decreased extracellular potassium causes myocardial hyper excitability with the potential to develop re-entrant arrhythmias
  13. 13. ECG features of Hypokalemia: • Rhythm: : Atrial and ventricular rhythms are regular • Rate: Atrial and ventricular rates are within normal limits • P Wave: Usually normal size and configuration • PR interval: May be prolonged • QRS complex: Within normal limits or possibly widened; prolonged in hypokalemia • QT interval: Usually indiscernible as T wave flattens • ST segment: Depressed • T wave: Amplitude is decreased. Inverted T wave U wave may appear.
  14. 14. T inversion and prominent U wave in Hypokalemia Long QT interval in Hypokalemia
  15. 15. HYPOCALCEMIA Background •Calcium is important in cardiac function; it exerts a positive inotropic effect on heart •Decreased calcium levels may cause decreased myocardial contraction.
  16. 16. ECG features of Hypocalcaemia: • Rhythm: Atrial and ventricular rhythms are regular • Rate: Atrial and ventricular rates are within normal limits • P Wave: Normal size and configuration • PR interval: Within normal limits • QRS complex: Within normal limits • QT interval: Prolonged • ST segment: Prolonged • T wave: Normal size and configuration, may be flattened
  17. 17. Prolong QT interval in Hypocalcaemia
  18. 18. HYPERCALCAEMIA Background •Calcium is important in cardiac function; it exerts a positive inotropic effect on heart •Increased calcium levels may block the conduction pathways of electrical impulse.
  19. 19. ECG features of Hypercalcemia: • Rhythm: Atrial and ventricular rhythms are regular • Rate: Atrial and ventricular rates are within normal limits, bradycardia or heart block may occur • P Wave: Normal size and configuration • PR interval: May be prolonged. • QRS complex: Within normal limits, may be prolonged • QT interval: Prolonged • ST segment: Normal • T wave: Normal size and configuration; may be depressed.
  20. 20. Shortened QT interval in Hypercalcemia
  21. 21. HYPOMAGMESAEMIA Background •Magnesium is required to support the heart muscle’s normal contraction-relaxation actions. •Decreased magnesium levels may cause irregular contraction of ventricles leading to arrhythmias.
  22. 22. ECG features of Hypomagnesaemia: • Rhythm: Irregular ventricular rhythm • Rate: Atrial and ventricular rates may be regular • P Wave: May be normal • PR interval: Normal • QRS complex: Normal • QT interval: Normal • ST segment: Depressed • T wave: Tall T waves
  23. 23. Tall T waves in Hypomagnesaemia Torsades de pointes
  24. 24. Depressed ST segment in Hypomagnesaemia
  25. 25. HYPERMAGMESAEMIA Background •Magnesium is required to support the heart muscle’s normal contraction-relaxation actions. •Increased magnesium levels may cause delayed conduction of electrical impulse.
  26. 26. ECG features of Hypermagnesemia • Rhythm: Atrial or ventricular rhythm may be regular • Rate: Atrial and ventricular rates may be regular • P Wave: May be normal • PR interval: prolonged • QRS complex: Widened • QT interval: Normal • ST segment: Normal • T wave: Normal
  27. 27. Prolonged PR interval in Hypermagnesemia Wide QRS complex in Hypermagnesemia
  28. 28. In a nut shell Hypocalcaemia- Prolonged ST and QT intervals Hyperkalemia- shortened ST segment - widened T wave Hypokalemia- ST depression - shallow, flat, inverted T wave - Prominent U wave Hyperkalemia- Tall, peaked T waves - Flat P waves - widened QRS complex - Prolonged PR interval Hypomagnesaemia- Tall T waves - Depressed ST segment Hypermagnesemia- Prolonged PR interval - widened QRS complexes
  29. 29. Treatment: • Hyperkalemia Cocktail • Hypokalemia Potassium replacement • Hypercalcemia Magnesium • Hypocalcemia Calcium replacement • Hypermagnesemia Calcium replacement • Hypomagnesaemia Mg replacement

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