Supraventricular Tachycardia in a Patient with an Interrupted Inferior Vena Cava.

The noncoronary cusp and aortomitral continuity should be evaluated for early atrial activation when atrial tachycardias are noted to arise near the His bundle region, especially when the activation is diffuse around the His and when the P-wave morphology predicts a left atrial focus. In patients with congenital anomalies, alternate routes for catheter position need to be explored, including retrograde access for left atrial tachycardias and positioning of intracardiac echocardiography in the azygous vein for visualization of intracardiac structures. Consideration of remote magnetic navigation, if available, is another approach.