Case report: An elderly woman with recurrent syncope after pacemaker implantation

Area of Science:

• Cardiology
• Pulmonology
• Electrophysiology

Background:

• Syncope can be caused by atrioventricular block, potentially related to cardiac reflexes.
• High-grade atrioventricular block necessitates interventions like pacemaker implantation.

Observation:

• An 80-year-old woman presented with recurrent syncope and high-grade atrioventricular block post-pacemaker implantation.
• Pacemaker testing showed stable impedance and sensing, but an increased ventricular capture threshold.

Findings:

• The patient was diagnosed with pulmonary embolism (PE) based on elevated D-dimer, hypoxemia, and CT scan.
• Following anticoagulant therapy for PE, the ventricular capture threshold normalized, and syncope resolved.
• This case is the first to report an electrophysiological phenomenon detected by pacemaker testing in a patient with syncope secondary to PE.

Implications:

• Pulmonary embolism should be considered in the differential diagnosis of syncope, even with apparent cardiac conduction abnormalities.
• Pacemaker testing may reveal subtle electrophysiological changes related to non-cardiac conditions like PE.
• Resolution of PE can lead to the normalization of pacemaker parameters and resolution of syncope.