Arrhythmias occur when there is a disruption in how the electrical signal develops or moves throughout the heart. Factors that can cause arrhythmias include:

    
  • The heart's natural pacemaker (sinoatrial node) develops an abnormal rate or rhythm.
  • Injury or illness makes it difficult or impossible for electrical signals to move through the heart. Injury or illness may occur due to:    
  • Coronary artery disease
  • Damaged heart muscle—cardiomyopathy
  • Abnormal heart valves
  • Direct traumatic injury to the heart
  • Birth defects
  • Electrical stimulation arises from abnormal areas of the heart, other than the sinoatrial node.
  • Stimulants—Makes the heart beat faster even though there is no need.
  • Electrolyte abnormalities—Can increase or decrease the ability for muscles to contract and change ability of nerves to send signals.
  • External factors that are associated with arrhythmias include:

        
  • Stress
  • Caffeine
  • Tobacco
  • Alcohol
  • Illegal stimulants, such as cocaine and methedrine
  • Diet pills
  • Some over-the-counter medications, such as cough and cold medicines
  • Certain prescription medications, such as those that treat cardiovascular disease, asthma, depression, or thyroid disorders.