Inappropriate sinus tachycardia: a review.

Area of Science:

• Cardiology
• Electrophysiology
• Autonomic Nervous System Function

Background:

• Inappropriate sinus tachycardia (IST) is characterized by a resting heart rate exceeding 100 bpm and a 24-hour average above 90 bpm, accompanied by significant symptoms.
• Affecting approximately 1% of the middle-aged population, predominantly females, IST can also occur in elderly patients.

Purpose of the Study:

• To elucidate the pathophysiological underpinnings of inappropriate sinus tachycardia.
• To comprehensively review current and emerging management strategies for IST.

Main Methods:

• Review of existing literature on IST pathophysiology, including intrinsic sinus node abnormalities, receptor-related mechanisms, and autonomic dysfunction.
• Analysis of various treatment modalities, encompassing pharmacological agents, psychiatric interventions, exercise training, and advanced ablation techniques.

Main Results:

• IST mechanisms are diverse, involving sinus node dysfunction, autoantibodies, altered receptor sensitivity, and impaired baroreflex control.
• While IST causes significant symptoms like palpitations and fatigue, it is not linked to cardiomyopathy or major adverse cardiovascular events.
• Pharmacological treatments (e.g., ivabradine, beta-blockers) and lifestyle modifications are primary management options.

Conclusions:

• Effective management of IST requires understanding its complex pathophysiology.
• Refractory IST presents challenges, with ablation techniques showing limited success and ongoing research into optimized approaches.
• A multidisciplinary approach is often necessary for comprehensive patient care.