Para Hisian Pacing: Is There More Than One Way to Conduct From The Ventricle Back to The atria?

A 72 year old male with past medical history of hypertension and dyslipidemia presented with a 10 year history of palpitations associated with dizziness. His physical exam was within normal limits. His LV function was 62% and left atrial size was within normal limits. He was euthyroid and a recent stress test was negative for inducible ischemia. During the stress test he developed a LBBB morphology tachycardia that converted to narrow complex tachycardia without any appreciable change in rate on the surface EKG. As he had symptomatic recurrences on beta blockers he was brought to the electrophysiology lab for a diagnostic study and possible ablation.