Inter/Intra‐Atrial Dissociation in Patients With Maze Procedure and Its Clinical Implications: Pseudo‐Block and Pseudo‐Ventricular Tachycardia

Abstract

Background Severe conduction delay and inter/intra‐atrial dissociation may occur in patients who undergo an extensive catheter ablation or a maze procedure for atrial tachyarrhythmia. We report a series of patients with inter/intra‐atrial dissociation that mimicked complete atrioventricular block or ventricular tachycardia. Methods and Results We retrospectively reviewed the medical records of 7 patients who were referred for the evaluation of atrioventricular block (patients 1–6) or ventricular tachycardia (patient 7) that occurred after biatrial maze procedure and valvular surgery. During the electrophysiologic study, slow atrial or junctional escape rhythm dissociated from isolated atrial activity mimicked complete atrioventricular blocks. Intra‐atrial dissociation of the right atrium or left atrium was observed. Atrioventricular nodal conduction from the nondissociated atrium to the ventricle was preserved in all patients, while the conduction from the dissociated atrium was blocked. In patient 7, the pacing of the ventricle by tracking of atrial tachycardia from the nondissociated left atrium/coronary sinus mimicked ventricular tachycardia during pacemaker interrogation. A total of 5 patients received new permanent pacemaker implantations during the index hospitalization for the surgery (n=2) or as a deferred procedure (n=3) according to the treatment for sick sinus syndrome. Conclusions Pseudo‐atrioventricular block or pseudo‐ventricular tachycardia may occur because of inter/intra‐atrial dissociation after a maze procedure. The selection of patients for permanent pacemaker implantation should be determined based on the patient’s symptoms and the status of the escape pacemaker and not on the apparent atrioventricular block. Proper diagnosis is important to avoid unnecessary implantation of a pacemaker or a defibrillator.

More than meets the eye: Atrial fibrillation conversion pause with a twist

“…Do et al described interatrial and intraatrial dissociation in a small cohort of patients (n=7) undergoing a post-Cox-Maze electrophysiology study due to concern for complete heart block or ventricular tachycardia. 2 Similar to our case, the majority of these study subjects exhibited dissociation of the posterolateral RA from the rest of the RA, resulting in an electrical isolation of the sinus node. However, it should be noted that these patients were studied in the immediate post-operative period, in stark contrast to our patient in whom this phenomenon was recognized almost a full decade after the original Cox-Maze procedure.…”

Dual atrial rhythms: a case report of an unusual cause of pacemaker syndrome

“… 6 , 7 Invasive electrophysiologic study might be needed to identify AD in many cases. 1 , 7 Atrial dissociation may present with AV dissociation when there is electrical isolation between the SA node and the AV node. 1 , 2 Some patients will need a permanent pacemaker and identification of AD has a very important implication on the location of atrial lead placement, i.e.…”

“… 1 , 7 Atrial dissociation may present with AV dissociation when there is electrical isolation between the SA node and the AV node. 1 , 2 Some patients will need a permanent pacemaker and identification of AD has a very important implication on the location of atrial lead placement, i.e. the atrial lead has to be placed in the site electrically connected to the AV node.…”

“…Atrial dissociation is an uncommon condition that has been reported in patients post-heart transplant and in various other cardiac surgical procedures. 1 , 2 Atrial dissociation could lead to clinical consequences such as symptomatic atrioventricular (AV) dissociation or pseudo ventricular tachycardia (VT). 1 We report the first case of AD leading to pacemaker syndrome and congestive heart failure (CHF) from automatic mode switching.…”

“… 1 , 2 Atrial dissociation could lead to clinical consequences such as symptomatic atrioventricular (AV) dissociation or pseudo ventricular tachycardia (VT). 1 We report the first case of AD leading to pacemaker syndrome and congestive heart failure (CHF) from automatic mode switching.…”