Lengthening the atrioventricular delay reduces large left atrial v waves and dyspnea after atrial fibrillation and tachycardia ablation

Introduction Pulmonary vein isolation (PVI) remains the cornerstone of therapy for patients with drug-refractory paroxysmal atrial fibrillation; and recent studies have suggested that even for patients with persistent atrial fibrillation, addition of linear lesions to PVI may not confer any advantage in efficacy. Despite this, patients with significant left atrial fibrosis and chamber enlargement may have additional substrate for atrial fibrillation or tachycardia that remains after PVI because of nonpulmonary vein (PV) substrate requiring further ablation. These additional lesions may have effects on left atrial conduction and physiology through a variety of mechanisms including alteration of left atrial compliance as suspected in stiff left atrial syndrome and alteration of left atrial and left ventricular synchrony. Two cases are presented here in patients with previous permanent pacemakers undergoing PV and substrate ablation for atrial fibrillation and/or atrial tachycardia, leading to variable degrees of left atrial appendage (LAA) delay causing abnormal hemodynamics and symptoms, which were improved by lengthening the pacemaker atrioventricular delay (AVD).