Recurrent syncope in patients with carotid sinus hypersensitivity.

Area of Science:

• Cardiology
• Autonomic Neuroscience

Background:

• Syncope recurrence is a concern in pacemaker patients with cardio-inhibitory responses.
• Carotid sinus hypersensitivity can lead to syncope, often involving vasodepressor or cardio-inhibitory mechanisms.

Purpose of the Study:

• To investigate syncope recurrence in pacemaker recipients with cardio-inhibitory responses to sinus carotid massage (SCM).
• To determine if vasodepressor responses contribute to recurrent loss of consciousness in these patients.

Main Methods:

• A cohort of 46 patients (16 with syncope, 30 controls) implanted with pacemakers for cardio-inhibitory syncope was followed for 5-7 years.
• Patients underwent repeated evaluations of hemodynamic responses to SCM, including systolic blood pressure (SAP) and symptomatic responses.

Main Results:

• Patients exhibited significantly lower mean SCM SAP and greater reductions in SAP compared to controls.
• More patients reported symptoms post-SCM and experienced orthostatic hypotension.
• A subgroup of 13 patients demonstrated altered hypotensive responses to SCM over time.

Conclusions:

• Recurrent syncope in pacemaker patients with cardio-inhibitory responses may be linked to evolving vasodepressor components.
• Changes in hemodynamic patterns following SCM suggest underlying autonomic dysregulation.
• These findings highlight the dynamic nature of autonomic responses in individuals with carotid sinus hypersensitivity.