Which of the following is NOT a symptom of sinus tachycardia?

Sinus tachycardia is characterized by an increased heart rate originating from the sinoatrial node, typically defined as a heart rate greater than 100 beats per minute. Symptoms commonly associated with this condition can include fatigue, shortness of breath, and decreased oxygen saturation, depending on the individual's overall health and the underlying causes driving the tachycardia.

In sinus tachycardia, the heart maintains a regular rhythm despite the accelerated rate. This leads to effective and organized contractions, which generally do not produce true arrhythmias, a term typically used to describe irregular or abnormal heart rhythms. While patients may feel palpitations or an awareness of their heartbeat, this does not classify as an arrhythmia in the clinical sense. Therefore, the recognition that sinus tachycardia itself is not associated with arrhythmias helps in understanding why this option stands out among the symptoms listed.