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International Journal of Arrhythmia 2012;13(3): 35-40.
Surgical Ablation of
a Manifest Right Free Wall
Accessory Pathway

Jae-Sun Uhm, MD1, Moon-Hyoung Lee, MD1, Byung-Chul Chang, MD2, Sung Soon Kim, MD3
1Division of Cardiology, 2Division of Cardiovascular Surgery, Severance Cardiovascular Hospital, Yonsei University College of Medicine 3Department of Cardiology, Armed Forces Capital Hospital


   Catheter ablation of an accessory pathway at the right free wall is sometimes challenging because it is difficult to maintain stable tissue contact with the catheter and because the anatomy of this region is complex. Here, we report the case of a patient with Wolff-Parkinson-White (WPW) syndrome due to a manifest right free wall accessory pathway that was surgically ablated.


   A 20-year-old male patient with abrupt-onset palpitations and dyspnea while running was referred to our hospital after being admitted to the emergency room, 1 week ago. The patient had a single episode of syncope several years before. Electrocardiogram (ECG) showed wide QRS tachycardia, irregularly irregular RR interval, and multiple QRS morphology (Figure 1A). ECG was compatible with atrial fibrillation in a patient with WPW syndrome. Flecainide was administrated intravenously for chemical cardioversion, after atrial fibrillation converted to a normal sinus rhythm, delta waves were apparent (Figure 1B). Because the polarity of the delta wave in lead V1 was negative, it was possible that the manifest accessory pathway was located at the tricuspid annulus. Physical examination, chest X-ray, and echocardiography did not show any abnormal findings.

   An electrophysiology study was performed with 3 quadripolar catheters placed in the lateral wall of the high right atrium (HRA), His bundle area, and right ventricular (RV) apex via the left femoral vein. In addition, a decapolar catheter was threaded into the coronary sinus via the right internal jugular vein. Sinus rhythm was evident with AH and HV intervals of 55 and 20 msec, respectively. During ventricular pacing, eccentric retrograde atrial activation was observed, with the earliest atrial signal located at HRA electrodes 3,4. When single ventricular premature extrastimuli were delivered, ventriculoatrial (VA) conduction did not have any decremental property. During atrial pacing, delta waves and ventricular preexcitation were augmented. When single atrial premature extrastimuli were delivered, atrioventricular (AV) conduction did not have any decrement. Narrow QRS tachycardia was induced spontaneously with a cycle length of 352 msec. The RP interval was shorter than the PR interval, and the VA interval was 105 msec in duration. Intracardiac electrogram showed eccentric retrograde right atrial activation with the earliest atrial activation at the HRA electrode pair 3,4 (Figure 2). This was compatible with orthodromic atrioventricular reentrant tachycardia resulting from a right free wall accessory pathway. Meticulous retrograde and antegrade mapping around the right free wall/ tricuspid annulus was performed with an ablation catheter (EP Technologies, Natick, MA, USA). The narrowest VA conduction signals and accessory pathway signal were found at the 8-o'clock position on the tricuspid annulus. We determined this was the location of the accessory pathway, and radiofrequency energy of up to 50 Watts and 50℃ was delivered to the site with the ablation catheter in a Mullin sheath(Figure 3). After 30 ablation attempts, the accessory pathway persisted, although ECG and intracardiac electrogram showed transient loss of delta waves during radiofrequency energy delivery. We presumed the accessory pathway was located deep within the tricuspid annulus and decided upon surgical ablation as the best course of action.

   The next day the patient was transferred to the operating room for surgical ablation. The ablation of right free wall and right posterior accessory pathway was approached via median sternotomy and right atriotomy under the total cardiopulmonary bypass. Atrial side of the right free wall, 4-5 mm from the tricuspid annulus was incised and dissected to the epicardial reflection of the right ventricle after cardioplegia (Figure 4). At the end of the incision adjacent to the AV node, endocardium was incised and dissected under beating heart to prevent AV node injury. Finally, cryolesion was made at the AV nodal area after release of aorta cross clamping and the endocardial incision was sutured continuously. After surgical ablation and weaning of the cardiopulmonary bypass pump, ECG showed no delta wave (Figure 5). Before closing the sternum, 2 pacing wires were implanted on the right atrial and RV free wall in case of postoperative AV block. Atrial pacing was performed postoperatively with the pacing wire, and no delta waves were observed. The patient was discharged without complication, and a follow-up visit to the outpatient clinic did not show any evidence of recurrence.


   In 1968, Rosenbaum and his colleagues described Catheter ablation of right-sided accessory pathways is sometimes challenging because of catheter instability and anatomical complexities of the tricuspid annulus.1 A Schwartz right or Mullin sheath can be useful for right free wall ablations. It aids approach by making a large loop around the tricuspid annulus with the ablation catheter. Recent reports have noted that three-dimensional electroanatomical mapping systems and remote robotic systems can also be used successfully for catheter ablation of right-sided accessory pathways.2,3

In the present case, because of anatomical complexities and because the accessory pathway was located deep within the tricuspid annulus, catheter ablation could not be succeed. Although surgical ablation is less prevalent now because of recent developments in catheter ablation techniques and equipment, it remains a useful tool in cases like those described here.


  1. Jackman WM, Wang X, Friday KJ, Roman CA, Moulton KP, Beckman KM, McClelland JH, Twidale N, Hazlitt HA, Prior MI, Margolis PD, Calame JD, Overholt ED, Lazzara R. Catheter ablation of accessory atrioventricular pathways (Wolff-Parkinson- White syndrome) by radiofrequency current. N Engl J Med. 1991;324:1605-1611.
  2. Long DY, Dong JZ, Liu XP, Tang RB, Ming M, Gao LY, Yu RH, Fang DP, Jiang CX, Yuan YQ, Sang CH, Yin XD, Chen G, Zhang XY, Liang C, Ma CS. Ablation of right-sided accessory pathways with atrial insertion far from the tricuspid annulus using an electroanatomical mapping system. J Cardiovasc Electrophysiol. 2011;22:499-505.
  3. Steinwender C, Honig S, Leisch F, Hofmann R. Ablation of a right-sided accessory pathway with the Hansen robotic system. Europace. 2011;13:755-756.
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