Complex cardiac anatomy and catheter access: the role of imaging in patients referred for catheter ablation.

A 66-year-old man with Kartagener's syndrome, situs inversus totalis, and recurrent supraventricular tachycardia and a 49-year-old man with atrial fibrillation and drug-refractory rapid ventricular rate response were referred for catheter ablation. In the first case, the mirrored anatomy of the right atrium was reconstructed using three-dimensional electroanatomical mapping, which guided successful ablation of a typical atrioventricular nodal reentrant tachycardia. In the second case, computerized tomography showed the presence of left atrial isomerism with interruption of the inferior vena cava and azygous continuation into the superior vena cava, guiding advancement of the ablation catheter for access into the positionally right atrial ablation site. These cases illustrate the role of imaging in patients with unusual anatomy of the cardiac chambers and major blood vessels guiding optimal catheter access for catheter ablation.