MORPHOMETRIC CHARACTERISTICS OF THE RIGHT ATRIUM AND BACHMANN BUNDLE IN RESPECT TO ELECTROPHYSIOLOGICAL TREATMENT OF CARDIAC ARRHYTHMIAS

To study morphological and morphometric peculiar features of the right atrium (RA) and the Bachmann bundle structure with regard to the implantation technique of electrodes for atrial pacing, 84 hearts from 49 male and 35 female corpses aged 34 75 years were studied. Morphometry of the heart chambers and separate heart structures, macro-and micro-preparations, diaphanoscopy of preparations, injection of bi-color polymeric compound with subsequent soft tissue corrosion were performed; and methods of polymerase embalming was used. The heart and heart chambers’ size, dimensions of the right atrium (RA) structures, as well as the RA morphometric indices affecting the endocardial electrode positioning during pacemaker implantation were assessed. The antero-posterior (longitudinal) heart size, superio-inferior heart size at the level of tricuspid valve, superio-inferior RA size, transversal RA size, superio-inferior and transversal left atrium (LA) size, basis of the right auricle, diameters of the superior and inferior cave veins (SCV and ICV), oval fossa (both cranio-caudal and antero-posterior axes), coronary sinus diameter, distance from the lateral edge of SCV to the right auricle apex, distance from the lateral edge of SCV to the Bachmann bundle area, distances from the Bachmann bundle area to the Koch triangle apex, from the right auricle apex to the Koch triangle apex, from the anterior edge of the oval fossa to the Bachmann bundle area, and mean myocardial thickness in the areas of RA am Bachmann bundle were measured. The antero-posterior (longitudinal) heart size was 159.9±6.5 mm (140 173 mm), the superio-inferior heart diameter at the level of tricuspid valve was 93.9±3.3 mm (86 102 mm), the superio-inferior RA size was 49.3±2.6 mm (43 57 mm), the transversal RA size was 40.6±2.5 mm (35 50 mm), the superio-inferior LA size was 39.3±2.7 mm (34 46 mm), the transversal LA size was 42.1±3.1 mm (35 51 mm). The SCV diameter was 18.2±1.5 mm (14.6 21.7 mm). The ICV diameter was longer by 3.1 mm on the average and made up 21.3±1.3 mm (17.8 24.8 mm). The superio-inferior oval fossa diameter was 23.7±2.6 mm (18 31 mm) and the antero-posterior diameter, 22.6±3.0 mm (16 30 mm). The distance from the superio-anterior edge of the oval fossa to the Bachmann bundle area was 16.6±2.3 mm. The distance of excitation wave from the Bachmann bundle area to the compact part of AV node was on the average shorter by 17.9 mm than that from the right auricle (40.6±4.6 mm and 58.5±2.8 mm, respectively, p<0.001). The Bachmann bundle thickness and width were 5.1±0.7 mm and 15.3±3.1 mm, respectively. The atrial wall thickness in the Bachmann bundle area (from 2.2±0.5 mm through 3.7±0.7 mm) was bigger than in the right auricle (from 1.6±0.3 mm through 3.5±0.7 mm). Thus, the electrode positioning in the Bachmann bundle area, unlike its implantation into the right auricle, is more grounded from the morphological viewpoint.

cardiac pacing, atrial electrode, right atrium, inter-atrial septum, Bachmann bundle, atrio-ven-tricular conduction

1. Диденко М.В. Имплантация электрокардиостимулятора. Техника операции: краткое руководство / под ред. Г.Г.Хубулава. 2006: «Роза мира». С. 48.

2. Markides V, et al. Characterization of Left Atrial Activation in the Intact Human Heart // Circulation, 2003. 107(5): p. 733-739.

3. Platonov P.G. P-Wave Morphology: Underlying Mechanisms and Clinical Implications // Annals of Noninvasive Electrocardiology, 2012. 17(3): p. 161-169.

4. David M., Harrild C.H. A Computer Model of Normal Conduction in the Human Atria // Circulation Research, 2000. 87(7): p. e25-e36.

5. Bachmann G. The inter-auricular time interval // American Journal of Physiology -- Legacy Content, 1916. 41(3): p. 309-320.

6. Prakash A., et al. Regional right and left atrial activation patterns during single- and dual-site atrial pacing in patients with atrial fibrillation // The American journal of cardiology, 1998. 82(10): p. 1197-1204.

7. Bailin S.J., Adler S., and Giudici M. Prevention of Chronic Atrial Fibrillation by Pacing in the Region of Bachmann’s Bundle: Results of a Multicenter Randomized Trial // Journal of Cardiovascular Electrophysiology, 2001. 12(8): p. 912-917.

8. Ho S.Y., Anderson R.H., Sanchez-Quintana D.N. Atrial structure and fibres: morphologic bases of atrial conduction // Cardiovascular Research, 2002. 54(2): p. 325-336.