ECG's

• What is a ECG?

  A trace of changes produced by the heart, detected by electrodes on the skin
• Label this ECG

  A) P

  B) Q

  C) R

  D) S

  E) T

  F) PR interval

  G) QRS complex

  H) ST segment

  
• What is the P wave?

  Wave of depolarisation from the sinoatrial node of the atrial walls (atrial systole)
• What is the QRS complex?

  depolarisation/contraction of the ventricular walls causing ventricular systole
• What is the T wave?

  repolarisation of ventricular walls during ventricular diastole
• What is the isoelectric line?

  The baseline of the trace. It is in between the T wave and P wave of the next cycle
• How is atrial fibrillation shown on an ECG?

  Rapid heart rate and lack of P wave
• How is a heart attack shown on an ECG?

  Wide QRS complex
• How are enlarged ventricle walls shown on an ECG?

  QRS complex with greater voltage change
• How is insufficient blood supply to the heart muscle shown on an ECG?

  -changes of height of T wave and length of ST segment

  -may be related to lack of blood flow and are signs of blocked coronary arteries and atherosclerosis