Prevalence of inappropriate sinus tachycardia among patients with sinus tachycardia

Background: The inappropriate sinus tachycardia (IST) is a syndrome characterized by increased heart rate with disturbing symptoms without obvious cause. IST is defined as a sinus heart rate > 100 bpm at rest with a mean 24-hour heart rate >90 bpm not due to primary causes and is associated with distressing symptoms. This study aims to assess the prevalence of inappropriate sinus tachycardia (IST) among patients presented with sinus tachycardia. Methods: This study enrolled 107 patients. All had been referred to the cardiac center of Shar teaching hospital of Sulaimaniyah city/Iraq, for tachycardia assessment. All candidates had been evaluated first by ECG, those who had resting heart rate more than 100 and had sinus rhythm were selected and further assessed by 24 hours cardiac Holter monitoring. Patients met criteria for IST when a sinus heart rate of ≥100 beats/minute at rest with a mean 24-hour HR of ≥90 bpm , in the absence of any primary cause. Results: One hundred seven patients were enrolled, majority ( 70.1%) were females . 40.2 % of them were in age group of 20-29 years old. The prevalence of IST is 4.7% ( 5 patients ).