Atrioventricular accessory pathways in 89 dogs: Clinical features and outcome after radiofrequency catheter ablation

Figures

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  Figure 1. A 30° left anterior oblique fluoroscopic view of multielectrode catheter positioning for the initial EP study. HRA, high right atrium; HB, His bundle region; CS, coronary sinus; RVA, right ventricular apex. All multielectrode catheter poles are labeled by convention in numerical order starting at the distal (tip) electrode

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  Figure 2. A, Left anterior oblique fluoroscopic view of a right posteroseptal accessory pathway ablation. ABL: ablation catheter at the ninth electrode of the CS catheter, which was located at the coronary sinus os. All multielectrode catheter poles are labeled by convention in numerical order starting at the distal (tip) electrode. CS, coronary sinus decapolar catheter; His, decapolar catheter with the tip electrodes located at the His bundle region. RV, quadripolar catheter located in the right ventricle. B, Left anterior oblique fluoroscopic view of a left anterior accessory pathway ablation. ABL, ablation catheter that has been prolapsed retrograde across the aortic valve and is deflected under the septal mitral valve leaflet. CS, coronary sinus decapolar catheter. His, decapolar catheter with the tip electrodes originally located at the His bundle region; however, it had flipped away from the septum at the time of this image. RV, quadripolar catheter located in the right ventricle

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  Figure 3. A, Surface ECG leads and intracardiac electrograms demonstrating retrograde accessory pathway activation during orthodromic atrioventricular reciprocating tachycardia. The figure on the left displays 9 of the 12 ECG leads recorded in the awake state just prior to electrophysiologic study. A narrow complex tachycardia at a cycle length of 221 ms is present. Arrows point to representative retrograde P′ waves visible within the early ST segment following each QRS complex. Paper speed 50 mm/s, calibration 10 mm/mV. The figure on the right is at the time of electrophysiologic study. Three surface ECG leads and eight intracardiac dipole recordings are shown. Orthodromic atrioventricular tachycardia is present. Electrograms are labeled as follows: A′, retrograde atrial depolarization over the accessory pathway; V, ventricular depolarization; H, His bundle activation. The earliest retrograde atrial activation is seen in the proximal coronary sinus for this right posterolateral free wall accessory pathway. Sweep speed is 100 mm/s. B, Surface ECG leads and intracardiac electrograms demonstrating intermittent retrograde accessory pathway conduction during sinus rhythm. The figure on the…

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  Figure 4. Diagram corresponding to a left anterior oblique fluoroscopic view showing the mitral and tricuspid valve annuli (11, 24). The number of accessory pathways found in this group of 89 dogs at each location is marked. RPS, right posteroparaseptal; LPS, left posteroparaseptal; SPS, superoparaseptal or anteroparaseptal; AV, atrioventricular. The location of the AV node is marked by the symbol **

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  Figure 5. Three surface ECG leads and eight intracardiac dipoles are displayed during radiofrequency catheter ablation (sweep speed 100 mm/s). The first 5 complexes represent orthodromic atrioventricular reciprocating tachycardia with retrograde atrial activation (labeled as A′ in the fifth complex) over a right posteroparaseptal accessory pathway. Earliest retrograde atrial activation in these standard leads occurs in the CS 9, 10 dipole. With the sixth complex, the accessory pathway is successfully ablated, as ventricular activation (V) is not followed by retrograde atrial activation. In this dog, OAVRT terminates 3.4 s after the onset of radiofrequency energy (RF onset is not shown in this figure), and sinus rhythm resumes after a ventricular complex. Small His bundle electrograms are marked with H. Sinus nodal activation of the atria is labeled A