Holter monitoring in the complex analysis of sinus node dysfunction

Area of Science:

• Cardiology
• Electrophysiology

Background:

• Sick sinus syndrome diagnosis can be challenging.
• Understanding sinus node dysfunction mechanisms is crucial for effective treatment.

Purpose of the Study:

• To evaluate diagnostic methods for sinus node dysfunction.
• To elucidate the mechanisms underlying sinus node dysfunction.
• To compare intrinsic and autonomic influences on sinus node function.

Main Methods:

• Electrophysiological studies including recovery times, secondary postpacing phases, and sinoatrial conduction times.
• Pharmacologic autonomic blockade using intravenous propranolol and atropine.
• Continuous 24-hour Holter monitoring.
• Comparison of patients with normal versus pathological intrinsic heart rate (IHR).

Main Results:

• Intrinsic heart rate (IHR) proved to be the most reliable indicator of intrinsic sinus node dysfunction.
• Patients with abnormal IHR showed positive electrophysiological and Holter parameters.
• Autonomic sinus node dysfunction cases presented with normal electrophysiological parameters, necessitating repeated Holter monitoring.
• Holter monitoring revealed significant differences in minimal and average heart rates between patient groups.

Conclusions:

• Intrinsic heart rate (IHR) is the simplest and most effective diagnostic method for intrinsic sinus node dysfunction.
• For autonomic sinus node dysfunction, repeated Holter monitoring is the most valuable diagnostic tool.
• Electrophysiological parameters may appear normal in autonomic sinus node dysfunction, masking the underlying issue.