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An unusual type of accessory pathway in tricuspid atresia
G Model
JCCASE-768; No. of Pages 4 Journal of Cardiology Cases xxx (2016) xxx–xxx
Contents lists available at ScienceDirect
Journal of Cardiology Cases journal homepage: www.elsevier.com/locate/jccase
Case Report
An unusual type of accessory pathway in tricuspid atresia Mukund A. Prabhu (MD, DM, PDF)*, Anjith Vupputuri (MD, DM), Saritha Shekar (MD, DNB), M.S. Harikrishnan (MD, DM), Praveen G. Pai (MD, DM), K.U. Natarajan (MD, DM) Department of Cardiology, Amrita Institute of Medical Sciences, Ponekkara, Kochi, Kerala, India
A R T I C L E I N F O
A B S T R A C T
Article history: Received 18 May 2016 Received in revised form 29 July 2016 Accepted 13 August 2016
The occurrence of pre-excitation in tricuspid atresia (TA) is slightly more common than that in normal children. The accessory pathway (AP), when it occurs in the setting of congenital atrioventricular valvar disease, is usually ipsilateral to the side of the abnormal valve. This report describes a patient with TA who had pre-excitation due to a left-sided AP that masked and modified the typical electrocardiographic features. The electrophysiological study confirmed an epicardial left posterior AP that was successfully ablated with radiofrequency energy, through the coronary sinus. Left-sided APs including epicardial ones may rarely be seen in TA and can potentially cause difficulties due to lack of vascular access to the heart after the Fontan surgery if arrhythmias occur. They are amenable to successful radiofrequency ablation and need to be dressed prior to Fontan surgery. ß 2016 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.
Keywords: Accessory pathway Electrocardiogram Epicardial Tricuspid atresia
Introduction The incidence of pre-excitation in tricuspid atresia (TA) is 0.29– 1.3% [1] which is slightly more common than in other children (0.05–0.31%). This is of paramount importance in these patients in whom Fontan type palliation is usually indicated. TA also has a characteristic electrocardiographic (ECG) pattern among various cyanotic congenital heart diseases (CHD). This case report underscores several atypical features about accessory pathway (AP) and ECG pattern in a patient with TA that has important clinical implications. Case report An 8-year-old girl with TA, non-restrictive ventricular septal defect, severe pulmonic stenosis, and normally related great vessels had undergone central aortopulmonary shunt surgery at 1 month of age. Subsequently, at the age of 9 months, she
* Corresponding author at: Department of Cardiology, Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham, Ponekkara PO, Kochi 682041, Kerala, India. Fax: +91 4842802020. E-mail address: [email protected] (M.A. Prabhu).
underwent division of the central shunt, bidirectional Glenn procedure (BDG), and atrial septectomy along with augmentation of the right pulmonary artery with a pericardial patch. ECG at that time was showing short PR interval and minimal pre-excitation (delta wave evident only in leads I and aVL). Two months’ post-BDG, she was found to have stenosis of the superior venacaval (SVC) anastomotic site with a mean gradient of 6 mm of mercury which was treated with balloon dilatation. During the same procedure, venovenous collateral from innominate vein was detected and coiled successfully. Subsequently, she remained asymptomatic with a saturation of 85–90% by pulse oximetry and has never had any palpitations. Recently she underwent a catheter study prior to the planned total cavopulmonary connection procedure (TCPC). Pulmonary pressures were normal and two major arteriovenous collaterals were identified and coiled. This time, however, her ECG showed short PR interval, delta wave, and deep S wave in lead V6 with no features of left ventricular (LV) dominance in precordial leads (Fig. 1A). As she was planned to undergo a TCPC, it was decided to undertake an electrophysiological study (EPS) before. Basal cycle length was 590 ms. Recording the His potential was difficult and unstable and HV interval was 20 ms. Incremental rate atrial pacing showed 1:1 pre-excited atrioventricular conduction up to 250 ms.
http://dx.doi.org/10.1016/j.jccase.2016.08.008 1878-5409/ß 2016 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: Prabhu MA, et al. An unusual type of accessory pathway in tricuspid atresia. J Cardiol Cases (2016), http://dx.doi.org/10.1016/j.jccase.2016.08.008
G Model
JCCASE-768; No. of Pages 4 M.A. Prabhu et al. / Journal of Cardiology Cases xxx (2016) xxx–xxx
2
Fig. 1.
(A) Twelve-lead electrocardiogram (ECG) showing short PR interval, delta wave and deep S waves in lead V6. The typical precordial pattern of tricuspid atresia is masked and the LV forces are inconspicuous. (B) Twelve-lead ECG after radiofrequency ablation shows a change in precordial pattern and LV forces typical of tricuspid atresia have been evident. ‘Memory T wave inversions’ are also to be seen.
Programmed stimulation showed antegrade effective refractory period (ERP) of the pathway to be 500–240 ms. Ventricular pacing showed eccentric non-decremental VA conduction with the earliest A in the coronary sinus (CS) 5, 6 electrodes. There was no inducible tachycardia. Mapping of the mitral annulus showed no areas where local V preceded the earliest delta wave. Mapping in the proximal CS (Fig. 2) showed a fusion of AV signal and local V preceded the earliest delta wave by 10 ms, suggesting a left posteroseptal epicardial AP (Fig. 3A). Radiofrequency ablation (RFA) was done here with 20 W power at 50 8C and resulted in local AV separation and loss of pre-excitation in 6 s (Fig. 3B). Ablation was continued in this region for a total duration of 120 s. There was no evidence of AP conduction at 30 min post-ablation. ECG after RFA showed LV dominance typical of TA, a slight reduction in the frontal QRS axis, and diffuse T wave inversions (Fig. 1B). There was ectopic atrial rhythm as evidenced by abnormal P wave axis and the AH interval was 50 ms. Discussion This case opens several interesting avenues for discussion. The implications of pre-excitation in TA, the occurrence of a mimicking pattern, its role in masking the typical ECG pattern, and the phenomenon of ‘memory T waves’ are all worth scrutiny. More important is the unusual occurrence of accessory pathways
contralateral to the atretic valve and its epicardial location. There are several reports of accessory atrioventricular pathways in patients with TA and previously surgical division of AP during Fontan procedure has been performed in these patients [2]. Currently, RFA is successfully performed in this scenario [3]. Pre-excitation in patients with TA has major connotations. Arrhythmias are a well-known cause of failure of the Fontan circulation. Atrial arrhythmias that can occur after Fontan can result in a fast ventricular rate in the presence of an AP. Endovascular access to the heart is hampered after Fontan procedure making mapping and ablation of the APs more complex. Puncture through the baffle is needed for this. The pre-excitation may become manifest for the first time only after the Fontan procedure, when there is a change in the conduction properties of atrial tissue, AV nodal tissue, and the sinus node function [4–6]. Our patient had no evidence of pre-excitation at the time of presentation, and it was noted only during evaluation prior to TCPC procedure. She never had any palpitations or documentation of tachycardia. An EPS was performed to find out the refractory period of the pathway, which is important in prognostication of asymptomatic pre-excitation. As the pathway had relatively short ERP, ablation was carried out even though there was no inducible tachycardia considering the difficulties of performing the same after TCPC procedure. It is noteworthy that this patient had only subtle features of pre-excitation in initial ECGs, and pre-excitation
Please cite this article in press as: Prabhu MA, et al. An unusual type of accessory pathway in tricuspid atresia. J Cardiol Cases (2016), http://dx.doi.org/10.1016/j.jccase.2016.08.008
G Model
JCCASE-768; No. of Pages 4 M.A. Prabhu et al. / Journal of Cardiology Cases xxx (2016) xxx–xxx
Fig. 2.
(A) The fluoroscopic left anterior oblique (458) view of the ablation catheter (white arrow head) at the site of successful ablation inside the coronary sinus (CS). (B) The corresponding right anterior oblique (308) view. The decapolar catheter is inside the CS.
more overt only at 8 years of age. This highlights the importance of frequent follow-up ECGs and invasive EPS in patients with TA prior to Fontan-type procedures. Some authors have postulated that the AP occurs on the side of the malformed valve in congenital heart disease [6]. In contrast, the present case had a left sided epicardial pathway. TA has a characteristic ECG pattern among congenital heart disease, with a preponderance of left ventricular forces, adult type of precordial R wave progression, and left-axis deviation of frontal QRS vector [7]. Interestingly, pre-excitation by an epicardial pathway has masked the LV preponderance and adult type of precordial progression and has exaggerated the leftward deviation of frontal QRS axis in our patient. This is reflected by the ECG after RFA which shows LV dominance, adult type progression, and a decrease in the
Fig. 3.
3
amount of leftward axis deviation. Posteroseptal APs that can be ablated inside CS have typical features such as a deep S wave in lead V6, a positive delta wave in aVR and a negative delta wave in lead II. The deep S wave in lead V6 was responsible for the masking of expected LV dominance which became manifest after RFA in this patient. The diffuse T wave change seen after RFA is a vivifying example for the well-known phenomenon of ‘memory T waves’ [8]. These are repolarization abnormalities that occur after loss of pre-excitation from the ablation of accessory pathway and are more common after ablation of postero-septal pathways. These usually normalize in a few weeks. This case underscores several important issues in patients with TA. Firstly, pre-excitation may become manifest during follow-up even if minimal at initial presentation. Secondly, APs may occur on the left side of the heart,
(A) The tracings show the electrograms obtained during the electrophysiological study. The first three channels correspond to the standard surface electrocardiographic leads – lead I, aVF, and the V1 respectively. HiSd and HiSp represent the recordings from distal and proximal bipoles of a His-bundle catheter respectively, whereas CS represents recordings from the five bipoles of the decapolar catheter placed in the coronary sinus. ABLd and ABLp represent signals from distal and proximal bipoles of the ablation catheter. The arrow-head highlights the short AV interval and fusion of A and V in the CS 5,6 electrode. The arrow represents the signal from the ablation catheter at the site of successful ablation, with good AV fusion. (B) The tracings labeled are the same as described in (A). The straight arrow marks the signal at the ablation site, which shows AV fusion. The curved arrow denotes the AV separation at the site during delivery of radiofrequency energy. There is evident change in the QRS morphology in the electrocardiogram leads. The first three complexes are pre-excited whereas the next three show loss of pre-excitation. There are artifacts seen in the ABLd tracing, which are due to the energy delivery.
Please cite this article in press as: Prabhu MA, et al. An unusual type of accessory pathway in tricuspid atresia. J Cardiol Cases (2016), http://dx.doi.org/10.1016/j.jccase.2016.08.008
G Model
JCCASE-768; No. of Pages 4 M.A. Prabhu et al. / Journal of Cardiology Cases xxx (2016) xxx–xxx
4
in contrast to the usual notion that APs occur ipsilateral to the side of the abnormal valve. Thirdly, EPS may be useful prior to Fontantype procedures as this helps in identifying APs not manifest in ECG, and to prognosticate those in whom pre-excitation is manifest so that RFA can be performed prior to Fontan procedure. Conflicts of interest The authors declare that there is no conflict of interest. Source of funding None. References [1] Dick M, Fyler DC, Nadas AS. Tricuspid atresia: clinical course in 101 patients. Am J Cardiol 1975;36:327–37.
[2] Dick 2nd M, Behrendt DM, Byrum CJ, Sealy WC, Stern AM, Hees P, Rosenthal A. Tricuspid atresia and the Wolff–Parkinson–White syndrome: evaluation methodology and successful surgical treatment of the combined disorders. Am Heart J 1981;101(4):496–500. [3] Dalili M, Rao JY, Brugada P. Radiofrequency ablation of accessory pathways in children with complex congenital cardiac lesions: a report of three cases. J Tehran Univ Heart Cent 2013;8(2):111–5. [4] Peinado R, Gnoatto M, Merino JL, Oliver JM. Catheter ablation of multiple, surgically created, atrioventricular connections following Fontan Bjork procedure. Europace 2007;9(9):848–50 [Internet]. Available from: http://europace. oxfordjournals.org/cgi/doi/10.1093/europace/eum077. [5] Porter CJ, Driscoll David JE. Pseudo-preexcitation in tricuspid. Tex Heart Inst J 1991;18:124–6. [6] Hager A, Zrenner B, Brodherr-Heberlein S, Steinbauer-Rosenthal I, Schreieck J, Hess J. Congenital and surgically acquired Wolff–Parkinson–White syndrome in patients with tricuspid atresia. J Thorac Cardiovasc Surg 2005;130(1):48–53 [Internet]. Available from: http://www.ncbi.nlm.nih.gov/pubmed/15999040. [7] Davachi F, Lucas Jr RV, Moller JHE. The electrocardiogram and ventorcardiogram in tricuspid atresia. Correlation with pathologic anatomy. Am J Cardiol 1970;25(1):18–27. [8] Wood MA, DiMarco JP, Haines DEE. Electrocardiographic abnormalities after radiofrequency catheter ablation of accessory bypass tracts in the Wolff– Parkinson–White syndrome. Am J Cardiol 1992;70(2):200–4.
Please cite this article in press as: Prabhu MA, et al. An unusual type of accessory pathway in tricuspid atresia. J Cardiol Cases (2016), http://dx.doi.org/10.1016/j.jccase.2016.08.008
JCCASE-768; No. of Pages 4 Journal of Cardiology Cases xxx (2016) xxx–xxx
Contents lists available at ScienceDirect
Journal of Cardiology Cases journal homepage: www.elsevier.com/locate/jccase
Case Report
An unusual type of accessory pathway in tricuspid atresia Mukund A. Prabhu (MD, DM, PDF)*, Anjith Vupputuri (MD, DM), Saritha Shekar (MD, DNB), M.S. Harikrishnan (MD, DM), Praveen G. Pai (MD, DM), K.U. Natarajan (MD, DM) Department of Cardiology, Amrita Institute of Medical Sciences, Ponekkara, Kochi, Kerala, India
A R T I C L E I N F O
A B S T R A C T
Article history: Received 18 May 2016 Received in revised form 29 July 2016 Accepted 13 August 2016
The occurrence of pre-excitation in tricuspid atresia (TA) is slightly more common than that in normal children. The accessory pathway (AP), when it occurs in the setting of congenital atrioventricular valvar disease, is usually ipsilateral to the side of the abnormal valve. This report describes a patient with TA who had pre-excitation due to a left-sided AP that masked and modified the typical electrocardiographic features. The electrophysiological study confirmed an epicardial left posterior AP that was successfully ablated with radiofrequency energy, through the coronary sinus. Left-sided APs including epicardial ones may rarely be seen in TA and can potentially cause difficulties due to lack of vascular access to the heart after the Fontan surgery if arrhythmias occur. They are amenable to successful radiofrequency ablation and need to be dressed prior to Fontan surgery.
Keywords: Accessory pathway Electrocardiogram Epicardial Tricuspid atresia
Introduction The incidence of pre-excitation in tricuspid atresia (TA) is 0.29– 1.3% [1] which is slightly more common than in other children (0.05–0.31%). This is of paramount importance in these patients in whom Fontan type palliation is usually indicated. TA also has a characteristic electrocardiographic (ECG) pattern among various cyanotic congenital heart diseases (CHD). This case report underscores several atypical features about accessory pathway (AP) and ECG pattern in a patient with TA that has important clinical implications. Case report An 8-year-old girl with TA, non-restrictive ventricular septal defect, severe pulmonic stenosis, and normally related great vessels had undergone central aortopulmonary shunt surgery at 1 month of age. Subsequently, at the age of 9 months, she
* Corresponding author at: Department of Cardiology, Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham, Ponekkara PO, Kochi 682041, Kerala, India. Fax: +91 4842802020. E-mail address: [email protected] (M.A. Prabhu).
underwent division of the central shunt, bidirectional Glenn procedure (BDG), and atrial septectomy along with augmentation of the right pulmonary artery with a pericardial patch. ECG at that time was showing short PR interval and minimal pre-excitation (delta wave evident only in leads I and aVL). Two months’ post-BDG, she was found to have stenosis of the superior venacaval (SVC) anastomotic site with a mean gradient of 6 mm of mercury which was treated with balloon dilatation. During the same procedure, venovenous collateral from innominate vein was detected and coiled successfully. Subsequently, she remained asymptomatic with a saturation of 85–90% by pulse oximetry and has never had any palpitations. Recently she underwent a catheter study prior to the planned total cavopulmonary connection procedure (TCPC). Pulmonary pressures were normal and two major arteriovenous collaterals were identified and coiled. This time, however, her ECG showed short PR interval, delta wave, and deep S wave in lead V6 with no features of left ventricular (LV) dominance in precordial leads (Fig. 1A). As she was planned to undergo a TCPC, it was decided to undertake an electrophysiological study (EPS) before. Basal cycle length was 590 ms. Recording the His potential was difficult and unstable and HV interval was 20 ms. Incremental rate atrial pacing showed 1:1 pre-excited atrioventricular conduction up to 250 ms.
http://dx.doi.org/10.1016/j.jccase.2016.08.008 1878-5409/ß 2016 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: Prabhu MA, et al. An unusual type of accessory pathway in tricuspid atresia. J Cardiol Cases (2016), http://dx.doi.org/10.1016/j.jccase.2016.08.008
G Model
JCCASE-768; No. of Pages 4 M.A. Prabhu et al. / Journal of Cardiology Cases xxx (2016) xxx–xxx
2
Fig. 1.
(A) Twelve-lead electrocardiogram (ECG) showing short PR interval, delta wave and deep S waves in lead V6. The typical precordial pattern of tricuspid atresia is masked and the LV forces are inconspicuous. (B) Twelve-lead ECG after radiofrequency ablation shows a change in precordial pattern and LV forces typical of tricuspid atresia have been evident. ‘Memory T wave inversions’ are also to be seen.
Programmed stimulation showed antegrade effective refractory period (ERP) of the pathway to be 500–240 ms. Ventricular pacing showed eccentric non-decremental VA conduction with the earliest A in the coronary sinus (CS) 5, 6 electrodes. There was no inducible tachycardia. Mapping of the mitral annulus showed no areas where local V preceded the earliest delta wave. Mapping in the proximal CS (Fig. 2) showed a fusion of AV signal and local V preceded the earliest delta wave by 10 ms, suggesting a left posteroseptal epicardial AP (Fig. 3A). Radiofrequency ablation (RFA) was done here with 20 W power at 50 8C and resulted in local AV separation and loss of pre-excitation in 6 s (Fig. 3B). Ablation was continued in this region for a total duration of 120 s. There was no evidence of AP conduction at 30 min post-ablation. ECG after RFA showed LV dominance typical of TA, a slight reduction in the frontal QRS axis, and diffuse T wave inversions (Fig. 1B). There was ectopic atrial rhythm as evidenced by abnormal P wave axis and the AH interval was 50 ms. Discussion This case opens several interesting avenues for discussion. The implications of pre-excitation in TA, the occurrence of a mimicking pattern, its role in masking the typical ECG pattern, and the phenomenon of ‘memory T waves’ are all worth scrutiny. More important is the unusual occurrence of accessory pathways
contralateral to the atretic valve and its epicardial location. There are several reports of accessory atrioventricular pathways in patients with TA and previously surgical division of AP during Fontan procedure has been performed in these patients [2]. Currently, RFA is successfully performed in this scenario [3]. Pre-excitation in patients with TA has major connotations. Arrhythmias are a well-known cause of failure of the Fontan circulation. Atrial arrhythmias that can occur after Fontan can result in a fast ventricular rate in the presence of an AP. Endovascular access to the heart is hampered after Fontan procedure making mapping and ablation of the APs more complex. Puncture through the baffle is needed for this. The pre-excitation may become manifest for the first time only after the Fontan procedure, when there is a change in the conduction properties of atrial tissue, AV nodal tissue, and the sinus node function [4–6]. Our patient had no evidence of pre-excitation at the time of presentation, and it was noted only during evaluation prior to TCPC procedure. She never had any palpitations or documentation of tachycardia. An EPS was performed to find out the refractory period of the pathway, which is important in prognostication of asymptomatic pre-excitation. As the pathway had relatively short ERP, ablation was carried out even though there was no inducible tachycardia considering the difficulties of performing the same after TCPC procedure. It is noteworthy that this patient had only subtle features of pre-excitation in initial ECGs, and pre-excitation
Please cite this article in press as: Prabhu MA, et al. An unusual type of accessory pathway in tricuspid atresia. J Cardiol Cases (2016), http://dx.doi.org/10.1016/j.jccase.2016.08.008
G Model
JCCASE-768; No. of Pages 4 M.A. Prabhu et al. / Journal of Cardiology Cases xxx (2016) xxx–xxx
Fig. 2.
(A) The fluoroscopic left anterior oblique (458) view of the ablation catheter (white arrow head) at the site of successful ablation inside the coronary sinus (CS). (B) The corresponding right anterior oblique (308) view. The decapolar catheter is inside the CS.
more overt only at 8 years of age. This highlights the importance of frequent follow-up ECGs and invasive EPS in patients with TA prior to Fontan-type procedures. Some authors have postulated that the AP occurs on the side of the malformed valve in congenital heart disease [6]. In contrast, the present case had a left sided epicardial pathway. TA has a characteristic ECG pattern among congenital heart disease, with a preponderance of left ventricular forces, adult type of precordial R wave progression, and left-axis deviation of frontal QRS vector [7]. Interestingly, pre-excitation by an epicardial pathway has masked the LV preponderance and adult type of precordial progression and has exaggerated the leftward deviation of frontal QRS axis in our patient. This is reflected by the ECG after RFA which shows LV dominance, adult type progression, and a decrease in the
Fig. 3.
3
amount of leftward axis deviation. Posteroseptal APs that can be ablated inside CS have typical features such as a deep S wave in lead V6, a positive delta wave in aVR and a negative delta wave in lead II. The deep S wave in lead V6 was responsible for the masking of expected LV dominance which became manifest after RFA in this patient. The diffuse T wave change seen after RFA is a vivifying example for the well-known phenomenon of ‘memory T waves’ [8]. These are repolarization abnormalities that occur after loss of pre-excitation from the ablation of accessory pathway and are more common after ablation of postero-septal pathways. These usually normalize in a few weeks. This case underscores several important issues in patients with TA. Firstly, pre-excitation may become manifest during follow-up even if minimal at initial presentation. Secondly, APs may occur on the left side of the heart,
(A) The tracings show the electrograms obtained during the electrophysiological study. The first three channels correspond to the standard surface electrocardiographic leads – lead I, aVF, and the V1 respectively. HiSd and HiSp represent the recordings from distal and proximal bipoles of a His-bundle catheter respectively, whereas CS represents recordings from the five bipoles of the decapolar catheter placed in the coronary sinus. ABLd and ABLp represent signals from distal and proximal bipoles of the ablation catheter. The arrow-head highlights the short AV interval and fusion of A and V in the CS 5,6 electrode. The arrow represents the signal from the ablation catheter at the site of successful ablation, with good AV fusion. (B) The tracings labeled are the same as described in (A). The straight arrow marks the signal at the ablation site, which shows AV fusion. The curved arrow denotes the AV separation at the site during delivery of radiofrequency energy. There is evident change in the QRS morphology in the electrocardiogram leads. The first three complexes are pre-excited whereas the next three show loss of pre-excitation. There are artifacts seen in the ABLd tracing, which are due to the energy delivery.
Please cite this article in press as: Prabhu MA, et al. An unusual type of accessory pathway in tricuspid atresia. J Cardiol Cases (2016), http://dx.doi.org/10.1016/j.jccase.2016.08.008
G Model
JCCASE-768; No. of Pages 4 M.A. Prabhu et al. / Journal of Cardiology Cases xxx (2016) xxx–xxx
4
in contrast to the usual notion that APs occur ipsilateral to the side of the abnormal valve. Thirdly, EPS may be useful prior to Fontantype procedures as this helps in identifying APs not manifest in ECG, and to prognosticate those in whom pre-excitation is manifest so that RFA can be performed prior to Fontan procedure. Conflicts of interest The authors declare that there is no conflict of interest. Source of funding None. References [1] Dick M, Fyler DC, Nadas AS. Tricuspid atresia: clinical course in 101 patients. Am J Cardiol 1975;36:327–37.
[2] Dick 2nd M, Behrendt DM, Byrum CJ, Sealy WC, Stern AM, Hees P, Rosenthal A. Tricuspid atresia and the Wolff–Parkinson–White syndrome: evaluation methodology and successful surgical treatment of the combined disorders. Am Heart J 1981;101(4):496–500. [3] Dalili M, Rao JY, Brugada P. Radiofrequency ablation of accessory pathways in children with complex congenital cardiac lesions: a report of three cases. J Tehran Univ Heart Cent 2013;8(2):111–5. [4] Peinado R, Gnoatto M, Merino JL, Oliver JM. Catheter ablation of multiple, surgically created, atrioventricular connections following Fontan Bjork procedure. Europace 2007;9(9):848–50 [Internet]. Available from: http://europace. oxfordjournals.org/cgi/doi/10.1093/europace/eum077. [5] Porter CJ, Driscoll David JE. Pseudo-preexcitation in tricuspid. Tex Heart Inst J 1991;18:124–6. [6] Hager A, Zrenner B, Brodherr-Heberlein S, Steinbauer-Rosenthal I, Schreieck J, Hess J. Congenital and surgically acquired Wolff–Parkinson–White syndrome in patients with tricuspid atresia. J Thorac Cardiovasc Surg 2005;130(1):48–53 [Internet]. Available from: http://www.ncbi.nlm.nih.gov/pubmed/15999040. [7] Davachi F, Lucas Jr RV, Moller JHE. The electrocardiogram and ventorcardiogram in tricuspid atresia. Correlation with pathologic anatomy. Am J Cardiol 1970;25(1):18–27. [8] Wood MA, DiMarco JP, Haines DEE. Electrocardiographic abnormalities after radiofrequency catheter ablation of accessory bypass tracts in the Wolff– Parkinson–White syndrome. Am J Cardiol 1992;70(2):200–4.
Please cite this article in press as: Prabhu MA, et al. An unusual type of accessory pathway in tricuspid atresia. J Cardiol Cases (2016), http://dx.doi.org/10.1016/j.jccase.2016.08.008