Electrocardiograms

• Electrocardiograms measure the electrical activity of the heart
• The 4 main heart problems are Tachycardia, Bradycardia, Fibrillation and Ectopic Heartbeats
• If the BPM goes below 60, this is known as bradycardia
• Bradycardia can occur due to athletic training, which increases stroke volume of the heart as the heart pumps a greater blood volume per beat, meaning the number of beats per minute decreases
• Some people develop Bradycardia as a result of disease, and these people may require an artificial pacemaker
• If the heart rate is above 100bpm, this is known as Tachycardia
• Tachycardia can be caused by short term effects such as fear, panic or exercise
• Long term Tachycardia can be caused by problems with the sino-atrial node and in this case, surgery or drugs may be required
• An Ectopic heartbeat is a random extra heartbeat
• Ectopic heartbeats are caused when the heart contracts again before the first contraction is finished
• Ectopic heartbeats are relatively common and do not pose any health risks
• If Ectopic heartbeats are frequent, however, this may indicate a more serious heart condition
• Atrial fibrillation is the irregular waves of electrical excitement that pass over the atria
• Atrial fibrillation forces the atria to contract rapidly and irregularly, up to several hundred times a minute
• In most cases of Atrial fibrillation, the electrical excitation is not translated to the ventricles which means the ventricles contract less than the atria
• As the normal rhythm of the heart is disrupted, Atrial fibrillation is known as a type of arrhythmia
• During Atrial fibrillation, the heart cannot pump blood normally, so it is often treated with medication or surgery
• P wave- the atria depolarises (atrial systole)

  QRS wave- the ventricles depolarise (ventricular systole)

  T wave- The ventricles repolarise/relax (ventricular diastole)