Bidirectional superior vena cava: right atrial conduction delay during tachycardia

The superior vena cava, like all the thoracic veins, has myocardial sleeves and plays a role in initiation and perpetuation of atrial fibrillation. Conduction delay between it and the right atrium has been shown previously. This case study shows delay in both directions during different arrhythmias in the same patient.