Treadmill exercise testing in three patients with normal resting AV conduction induced high-grade AV block localized distal to the AV node, indicating His-Purkinje conduction disease.
Case Report (n=3)
High grade AV block appearing during exercise reflects conduction disease of the His-Purkinje system rather than the AV node, suggesting these patients should be considered for permanent cardiac pacing.
Three patients with 1:1 atrioventricular (AV) conduction at rest developed fixed 2:1 or 3:1 AV block during treadmill exercise testing. Electrophysiologic study documented block distal to the AV node in all three patients, and suggested that the exercise-induced block occurred because of increased atrial rate and abnormal refractoriness of the His-Purkinje conduction system. The findings in these three patients suggest that high grade AV block appearing during exercise reflects conduction disease of the His-Purkinje system rather than of the AV node, even in the absence of bundle branch block. Patients with this diagnosis should be considered for permanent cardiac pacing.
Woelfel et al. (Thu,) conducted a case report in Exercise-induced distal atrioventricular block (n=3). Treadmill exercise testing and electrophysiologic study was evaluated on Site of AV block during exercise. Treadmill exercise testing in three patients with normal resting AV conduction induced high-grade AV block localized distal to the AV node, indicating His-Purkinje conduction disease.