Sinus Rhythm Conduction Properties across Bachmann’s Bundle: Impact of Underlying Heart Disease and Atrial Fibrillation

Figures

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  Figure 1. Mapping procedure of Bachmann’s bundle. (Upper panel) 192-unipolar electrode mapping array including measurements of length, inter-electrode distance and electrode diameter. The mapping array is subsequently positioned at Bachmann’s bundle, by placing the array behind the aorta with the tip against the left atrial appendage. (Middle panel) unipolar electrogram with steep atrial deflection (A) and far-field ventricular signal (V). After marking all atrial deflections, a color-coded activation map is constructed. The arrows depict direction of wavefront propagation. The striped star illustrates an area of simultaneous excitation/focal wave. In the current example, the mid-entry corresponds to location of the interatrial septum and transition of BB to left atrial roof (posterior). (Lower panel) Schematic overview of 192-unipolar electrode mapping array. Entry sites are denoted with R (right), M (middle) and L (left). IAS = interatrial septum; LAA = left atrial appendage; RA = right atrium.

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  Figure 2. Entry sites and patterns of activation at Bachmann’s bundle. (Upper panel) Frequency pie illustrating all different entry sites in the entire study population including right entry site only (green) and other entry sites (red). (Middle panel) Frequency pies demonstrating the number of patients without a mid-entry site (blue) and with a mid-entry site (yellow) of wavefronts. The left panels illustrate the difference for underlying heart disease, the right panels for patients with/without a history of AF. (Lower panel) Examples of color-coded activation maps of BB during SR demonstrating different activation patterns; entry site only from the right (left upper map), right and middle (right upper map), right and left (left lower map) and right, middle and left (right lower map). Arrows indicate the main propagation direction of wavefronts, stars an area of simultaneous excitation/focal wave. AF = atrial fibrillation; IHD = ischemic heart disease; (I)VHD = (ischemic) valvular heart disease; L = left entry; M = mid entry; R = right entry.

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  Figure 3. Incidence and extensiveness of conduction disorders. (Upper panels) Frequency histograms depicting the longest measured line of conduction delay (green), block (purple) and connected conduction delay and block (red) per patient. (Lower panels) Frequency histogram illustrating the percentage of conduction delay (green), block (purple) and combined (red) per patient. CB = conduction block; CD = conduction delay; CDCB (mm) = length of connected conduction delay and block; CDCB (%) = sum of conduction delay and block.

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  Figure 4. Relation between underlying heart disease, atrial fibrillation and conduction disorders Differences in the amount of conduction delay (green), block (yellow) and combined (red) between patients with ischemic heart disease (upper panels) and valvular heart disease (lower panels). In addition, difference in conduction disorders are shown between patients without atrial fibrillation (left panels) and with a history of atrial fibrillation (right panels). AF = atrial fibrillation; CB = conduction block; CD = conduction delay; CDCB = sum of conduction delay and block.

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  Figure 5. Predictive value of entry-site and conduction disorders. (Upper panels) Predictive value of the length of conduction disorders for previous AF episodes. The left panel depicts a ROC curve for length of lines of conduction disorders, The right panel cut-off values of the length of conduction disorders and previous AF episodes. (Lower panel) Flowchart demonstrating the predictive value of mid-entry site and a line of conduction block or CDCB of 12mm or more. Table shows sensitivity and specificity. AF = atrial fibrillation; CB = conduction block; CDCB = connected conduction delay and block; Sens = sensitivity; Spec = specificity.