Focal endocardial pulsed-field ablation for the treatment of inappropriate sinus tachycardia: A case report

Inappropriate sinus tachycardia (IST) is a diagnosis of exclusion, characterized by debilitating symptoms such as a markedly elevated heart rate at rest or with minimal exertion, along with exercise intolerance. The condition is defined by a resting heart rate exceeding 100 bpm and a mean ambulatory heart rate over 90 bpm without a clear secondary cause. (1) Although the exact pathophysiology remains unclear, IST is believed to be multifactorial, involving abnormal neurohumoral modulation, antibody-mediated processes, and various receptor hyper- or hyposensitivity mechanisms.