Interatrial

From the SA node, the heart beat spreads rapidly throughout both atria by way of the gap junctions. As mentioned previously, the atria are stimulated to contract simultaneously. An interatrial conduction pathway extends from the SA node to the left atrium. Its function is to facilitate conduction of the impulse through the left atrium, creating the atrial syncytium (see Figure 13.3). 

Figure 13.3 Route of excitation and conduction in the heart. The heart beat is initiated in the sinoatrial (SA) node, or the pacemaker, in the right atrium of the heart. The electrical impulse is transmitted to the left atrium through the interatrial conduction pathway and to the atrioventricular (AV) node through the intemodal pathway. From the AV node, the electrical impulse enters the ventricles and is conducted through the AV bundle, the left and right bundle branches, and, finally, the Purkinje fibers, which terminate on the true cardiac muscle cells of the ventricles.

There was no effect on interatrial conduction and negligible effeets on haemodynamic parameters. 

Palacios IF. Closure of interatrial communications using the CardioSEAL/ STARFlex devices. In S. J. D. Brecker, ed. Percutaneous Device Closure of the Atrial Septum. United Kingdom Informa Heathcare 2006. 

Rigatelh G, Cardaioh F, Giordan M, Aggio S, ChinagUa M, Braggion G and Roncon L. Nickel allergy in interatrial shunt device-based closure patients. 

Daubert C, Gras D, Berder V, Leclercq C, Mabo P. Permanent atrial resynchronization by synchronous bi-atrial pacing in the preventive treatment of atrial flutter associated with high degree interatrial block. Arch Mai Coeur Vaiss. 1994 87 1535-1546. 

Bennett et al. reported that atrial activation times were similar when pacing from the CS os, Bachmann s Bnndle or the interatrial septum (30). Of these three options, septal lead placement may be preferable given its relative lack of technical complexity. Indeed, Hermida et al. showed no difference in feasibility and reliability comparing septal and RAA pacing sites, whereas septal pacing was associated with shorter interatrial activation times and reduced left atrial electromechanical delay (36). 

Padeletti L, Pieragnoli P, Ciapetti C, et al. Randomized crossover comparison of right atrial appendage pacing versus interatrial septum pacing for prevention of paroxysmal atrial fibrillation in patients with sinus bradycardia. Am Heart J 2001 142 1045-55. 

Hermida J, Carpentier C, Kubala M, et al. Atrial septal versus atrial appendage pacing feasibility and effects on atrial conduction, interatrial synchronization and atrioventricular sequence. Pacing Cfin Electrophysiol 2003 26 [Pt. l] 26-35. 

Strunk, B.L., Cheitlin, M.D., Stulbarg, M.S., Schiller, N.B., 1987. Right-to-left interatrial shunting through a patent foramen ovale despite normal intracardiac pressures. American Journal of Cardiology 60,413-415. 

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