Alternate Site Atrial Pacing in the Young: Conventional Echocardiography and Tissue Doppler Analysis of the Effects on Atrial Function and Ventricular Filling

BACKGROUND: Although the right atrial appendage (RAA) is typically used for atrial pacing lead implant, recent studies have shown benefits of alternate site atrial pacing (ASAP) in the elderly. However, comparable studies in the young are lacking. METHODS: To investigate effects of ASAP on cardiac function and atrioventricular mechanical interactions in the young, 26 subjects (ages 10 to 23 years) with normal cardiac anatomy, function, and atrioventricular node conduction underwent echocardiography during electrophysiology studies while in sinus rhythm (NSR), and with temporary pacing from high right atrium (HRA), RAA, mid septal right atrium approximating Bachmann's bundle (BB), and left atrium (LA) via the distal coronary sinus (CS). After a paced steady state of 10 minutes, left atrial total and systolic ejection fractions, color-guided mitral inflow, and annular tissue Doppler indices were obtained. Left ventricular ejection fraction and myocardial performance indexes (MPI) were calculated. RESULTS: The total and systolic LA ejection fractions were higher during the NSR compared to all ASAP. Mitral inflow velocities changed significantly with ASAP. The passive/active ventricular filling ratio (E/A) deteriorated from NSR to HRA to BB to CS. There were significant changes in late diastolic tissue Doppler velocities during ASAP compared to NSR. The MPI during ASAP differed from those during the NSR. HRA and Bachmann bundle pacing provided better MPIs than RAA or CS pacing. CONCLUSION: The location of atrial pacing leads has an acute impact on cardiac function and atrioventricular mechanical interaction. Pacing close to sinus node location may be beneficial in the young.