[Torsades de Pointes: a cause of syncope in sinus node dysfunction]

Area of Science:

• Cardiology
• Electrophysiology

Background:

• Torsade de Pointes (TdP) is a ventricular arrhythmia linked to QT interval prolongation.
• Bradyarrhythmias, particularly atrioventricular block, are known TdP triggers.
• Sinus node dysfunction as a cause of syncope with TdP is uncommon.

Observation:

• This case report details a patient experiencing recurrent syncope.
• The patient presented with sinus bradycardia and intermittent atrioventricular nodal rhythm.
• These cardiac conditions induced a prolonged QT interval.

Findings:

• The prolonged QT interval and TdP were associated with bradycardia and pauses.
• Experimental data suggests pause-dependent early afterdepolarizations contribute to TdP.
• The patient's syncope was directly related to Torsade de Pointes episodes.

Implications:

• Sinus node dysfunction should be considered in syncope evaluations, especially with QT prolongation.
• Pacing offers a potential treatment for TdP secondary to bradycardia-induced long QT.
• Understanding the link between bradycardia and TdP may improve patient management.