QS Study

Sinus Arrhythmia

During respiratory cycle impulse irradiation on cardiac center from respiratory center cause alternative increase or decrease in the number of impulses. It is an irregular heartbeat that’s either too fast or too slow. It does not relate to the sinus cavities in the face but to the sinoatrial or sinus node in the heart. They are common in children and are sometimes found in adults as well.

In general, sinus arrhythmias can be:

  • Sinus tachycardia, which is a faster heart rate, beating greater than 100 beats per minute.
  • Sinus bradycardia, which is when the heart rate beats slower or less than 60 beats per minute.

Fig: Sinus Arrhythmia Heart Rate

Sick sinus syndrome

Disease processes affecting the sinus node lead to marked bradycardia accompanied by dizziness and syncope. This condition is called sick sinus syndrome. It is when the sinus node causes abnormalities in the heart rhythm. This occurs when the sinus node scars and is replaced by fibrous tissues over time.