Rare Cause of Infranodal Block

Area of Science:

• Genetics
• Cardiology
• Neurology

Background:

• Timothy syndrome is a rare, multisystem, autosomal-dominant disorder.
• Key features include prolonged QT interval, limb abnormalities, dysmorphic facial features, and intellectual disability.

Observation:

• The patient presented with clinical manifestations consistent with Timothy syndrome.
• An electrocardiogram revealed a 2:1 infranodal atrioventricular block in the context of a severely prolonged QT interval.

Findings:

• The atrioventricular block was observed to be functional.
• 1:1 atrioventricular conduction resumed upon alterations in heart rate, indicating the transient nature of the block.

Implications:

• This case highlights the variable cardiac manifestations of Timothy syndrome.
• Understanding the functional nature of AV block in this condition is crucial for patient management and risk stratification.