Optimal site of pacemaker lead implantation for persistent atrial standstill guided by electroanatomical mapping following a cox-maze procedure: a case report

Abstract

Background: Atrial standstill is characterized by the absence of atrial activity. We report a case of a patient with extensive atrial fibrosis who underwent electrophysiologic study (EPS) and electroanatomical mapping (EAM) to identify surviving atrial sites amenable for pacemaker lead implantation.

Case summary: A 72-year-old man with persistent atrial fibrillation (AF) and atrial functional mitral regurgitation/tricuspid regurgitation (MR/TR) underwent a Cox-Maze surgery, mitral and tricuspid valve repair, and biatrial plication. He was referred because of post-operative presyncope symptoms. Electrocardiography revealed atrial standstill and junctional rhythm (JR); however, EAM revealed that both atria were almost entirely scarred and isolated fibrillation in left pulmonary veins and coronary sinus. Junctional rhythm retrogradely conducted around an atrioventricular (AV) node and pacing at this area could conduct to the ventricle through the AV node. An atrial pacing lead was implanted at this area, which yielded a QRS wave similar to the own beat. However, the atrial lead voltage was quite low; hence, ventricular pacing lead was implanted to avoid a future occurrence of pacing failure.

Discussion: This report demonstrates the benefits of EPS and EAM in informing optimal pacemaker implantation for patients with extensive scar in atrium.

Keywords: Atrial fibrillation; Case report; Electroanatomical mapping; Electrophysiologic study; Pacemaker lead implantation.

Figure 1

(A) A 12-lead electrocardiography after open heart surgery. Atrial standstill and junctional rhythm were observed. (B) A 12-lead electrocardiography performed when the patient complained of presyncope symptoms revealed tachycardia with irregular RR intervals. (C) A subsequent 24-h Holter electrocardiography revealed frequent narrow QRS tachycardias followed by pauses of ≈4 s throughout the day.

Figure 2

(A) Voltage maps revealed widespread biatrial scarring. In the right atrium, potentials were observed exclusively in the His bundle and the surrounding right atrial septum. A multielectrode catheter (Pentaray™) located at the septum of the left atrium showed a retrograde conduction of junctional rhythm (B). Electrode catheter located in coronary sinus showed a fibrillation, and there was completely no potential in the right atrium. Atrial fibrillation was isolated in the left pulmonary vein and coronary sinus by the extensive scar (C). RA, right atrium; LA, left atrium; HB, His bundle; IVC, inferior vena cava; SVC, superior vena cava; RSPV, right superior pulmonary vein; LSPV, left superior pulmonary vein; RIPV, right inferior pulmonary vein; MA, mitral annulus; TA, tricuspid annulus; CS, coronary sinus.

Figure 3

(A) Tracing of the pacing from the left atrial septum. Pacing could conduct to the ventricle through the atrioventricular node. (B) The PR interval paced by each location. Tracing A showed an electrocardiogram with the His-bundle pacing. Pacing from the right atrial septum conducted to the ventricle with different PR intervals (B and C).

Figure 4

A tracing when atrial tachycardia was started. Multielectrode catheter was placed at the left atrial septum. The first beat with late potentials was a retrograde conduction from the junctional beat. The second and third beats firing from the multiple origins of the left atrial septum were documented. JR, junctional rhythm; PAC, premature atrial contraction.

Figure 5

A final 12-lead electrocardiography.