Cardiovascular and Metabolic Science Clinical Case Vol. 31 No. 4 doi: 10.35366/97545 October-December2020 Pre-syncope and ablation of moderator band premature ventricular contraction

Pre-síncope y ablación de la contracción ventricular prematura con origen en la banda moderadora

William-Fernando Bautista-Vargas*

Keywords: Ventricular premature ABSTRACT RESUMEN complexes, syncope, catheter ablation. Introduction: Premature ventricular complex (PVC) is a Introducción: El complejo ventricular prematuro (CVP) es frequent diagnostic entity. The underlying cardiac condition is una entidad de diagnóstico frecuente. La condición cardiaca Palabras clave: important to establish a prognosis; in the majority of the cases subyacente es importante para establecer un pronóstico; en la Complejos prematuros with normal heart, PVCs have a good prognosis; nevertheless, mayoría de los casos con un corazón normal, los CVP tienen un ventriculares, síncope, there is a specific morphology of PVC related to serious car- buen pronóstico; sin embargo, existe una morfología específica ablación por catéter. diac issues. The moderator band (MB) PVCs are one of these, de éstos relacionada con problemas cardiacos graves. Los CVP described in a normal heart condition; however, MB- PVC can de la Banda Moderadora (MB) son uno de éstos, descritos en una lead to ventricular tachycardia, ventricular fibrillation, or even condición cardiaca normal; sin embargo, los CVP de la Banda sudden cardiac death. Material and methods: The case of a Moderadora pueden llevar a una taquicardia ventricular, fibri- 25-year-old female patient with very symptomatic, precordial lación ventricular o, incluso, muerte súbita cardiaca. Material palpitations is presented with a history of presyncope. The y métodos: Paciente de 25 años con palpitaciones precordiales workflow showed a normal transthoracic echocardiogram, muy sintomáticas se presenta con un historial de presincopía. normal cardiac MRI, and evidence of bigeminy cardiac El flujo de trabajo mostró un ecocardiograma transtorácico rhythm even an unstable ventricular tachycardia induction in normal, una resonancia magnética cardiaca normal y evidencia an electrophysiology study. She was taken to ablation therapy, de un ritmo cardiaco bigémico; incluso una inducción de taqui- PVCs from the moderator band were found with the highest cardia ventricular inestable en un estudio electrofisiológico. Se activation of -52 ms, the use of intracardiac echocardiogram, llevó a terapia de ablación, se encontraron CVP de la banda and successful ablation in an uncommon PVC location is moderadora con la activación más alta de -52ms, el uso de reported. Results: The radiofrequency ablation therapy with ecocardiograma intracardiaco, y se informa de una ablación 35 watts and 42 oC at the highest activation point on the lateral exitosa en un lugar poco común de CVP. Resultados: La tera- aspect of moderator band (MB) was successful therapy with pia de ablación por radiofrecuencia con 35 watts y 42°C en el the induction of ventricular tachycardia during the application punto de activación más alto en el aspecto lateral de la banda of radiofrequency as a result finish of PVCs. Conclusions: moderadora (BM) fue una terapia exitosa con la inducción de In patients with pre-syncopal, syncopal, and even aborted taquicardia ventricular durante la aplicación de la radiofrecuen- sudden cardiac death secondary to ventricular tachycardia cia como resultado del acabado de los CVP. Conclusiones: En or ventricular fibrillation premature ventricular complexes los pacientes con muerte cardiaca súbita pre-sincopal, sincopal should be addressed with an invasive strategy as RF abla- e incluso abortada secundaria a taquicardia ventricular o tion therapy with the aim of finish a trigger condition. The fibrilación ventricular, los complejos ventriculares prematuros moderator band is considered an arrhythmogenic structure, deben ser abordados con una estrategia invasiva como la terapia PVCs coming from a MB should be addressed as potential de ablación por radiofrecuencia, con el objetivo de terminar death risk and invasive therapy should be considered earlier con una condición desencadenante. La banda moderadora se * Head of Department than antiarrhythmic drugs. considera una estructura arritmogénica, los CVP provenientes of Electrophysiology. www.medigraphic.org.mxde una BM deben ser abordados como un riesgo potencial de St. Sophia Hospital. muerte y la terapia invasiva debe ser considerada antes que los Manizales, Caldas, medicamentos antiarrítmicos. Colombia.

Received: 09/06/2020 Accepted: How to cite: Bautista-Vargas William-Fernando. Pre-syncope and ablation of moderator band premature ventricular contraction. 16/10/2020 Cardiovasc Metab Sci. 2020; 31 (4): 131-136. https://dx.doi.org/10.35366/97545

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Cardiovasc Metab Sci 2020; 31 (4): 131-136 @https://dx.. @ 132 Bautista-Vargas William-Fernando. Pre-syncope and ablation of moderator band premature

INTRODUCTION echocardiogram, and more recently the cardiac MRI are useful tools to clarify further conditions; he prevalence of premature ventricular even though the structural heart disease has a Tcomplex (PVC) is determinate by a diagnos- hard impact into the prognosis, there is on the tic method. Nowadays more people are been contrary PVC with normal heart related with using a cardiac monitoring wrist for sports or ventricular tachycardia (VT), Ventricular Fibril- lazy activities, and it is common to hear about lation (VF), even Sudden Cardiac Death (SCD).1 PVC in general populations, it seems that in The moderator band premature ventricular a few hours of using a monitoring device as complex is a potentially dangerous entity, even a rule almost everyone will have a PVC, not with a low PVC burden can lead to VT, VF, or specific data have been published regarding the SCD in which cases the prevalence is reported prevalence of wrist monitoring device.1 Other up to 2.5%;5,6 nonetheless, there are no data modalities are reported: in a study of 122,043 in the general population, further investigation subjects using a conventional electrocardiogram is needed to clarify the epidemiological data. (ECG) for about 48 seconds the prevalence of PVC was reported in 0.8%.2 In another study CASE PRESENTATION using a 2 minutes ECG monitoring in 13,456 subjects with no history of heart failure and no A 25-year-old lady presented to the emergency coronary disease, it is reported a prevalence room complained of precordial palpitations of 5.5% of PVC.3 skipped beats like; related to pre-syncopal feel- The symptoms, PVC burden (percentage in ing but nor loss of consciousness. Despite she a 24 hours Holter), and the presence of struc- was on metoprolol 50 mg bid and propafenone tural heart disease are important information 150 mg bid, her symptoms were uncontrolled. to consider to bring the right treatment.1 A In the last year, she was admitted several times broad symptom can be present from the skyped to the emergency room in a different institu- precordial chest palpitations to ventricular tion because of pre-syncope episodes, and tachycardia even ventricular fibrillation and even had an EP study that concludes unstable sudden cardiac death. As a handy approach, ventricular tachycardia which was not able to the PVC burden in a 24 hours Holter (10% or be ablated due to patient due to the instability more) can be used as an indication to proceed of the patient hemodynamic and was planned to further therapy with an invasive strategy if to implant an implantable loop recorder, and there is a cardiomyopathy risk or monitoring keep on medication. During the follow up she medication treatment if the PVC burden is not was transferred to our clinic and complained significant.4 There are different tools to figure of developing much more severe symptoms out if there is or not a normal heart; the ECG with ventricular bigeminy rhythm even with brings the information of underline diseases, the a short coupling interval, so it was planned to

Dl 1: VEGM AutoGain (8,7 mm/mV) A B 2: Marcadores Velocidad de barrido: 25 mm/s Dll Figure 1: Dlll A) A twelve aVR aVL ECG showing a B B aVF www.medigraphic.org.mx1582 1520 1586 clinical premature 22 s 23 s 24 s 25 s 26 s 27 s 28 s ventricular complex V1 V2 (red rectangle). Activador B) Implantable V3 cardiac monitor V4 Bradi trace showing a V5 B B B B 1504 1426 1559 1609 bigeminy rhythm. V6 29 s 30 s 31 s 32 s 33 s 34 s 35 s

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10 mV A B

Figure 2:

MB A) Intracardiac RV echocardiogram (ICE) of the right 5 mV ventricle (RV) showing a moderator band (MB). B) Voltage map scale (0.5-1.5 mv) Voltage Map showing a normal ICE voltage map. 0 mV

hospitalize the patient since the medication is apply consolidation points of ablation on that not effective. area, with a good outcome. At the end of the The electrocardiogram showed ventricular procedure, the patient was on sinus rhythm bigeminy, with narrow ventricular premature and the implantable loop recorder interroga- contractions that are negative in DII, DIII, aVF, tion during the follow-up did not show any aVR, positive in aVL, DI, and V1 with a late pre- ventricular premature contractions (Figure 3). cordial transition at V6 (Figure 1). She also had a normal transthoracic echocardiogram, there DISCUSSION was no late enhancement in the cardiac MRI, even a normal coronary angiogram. Finally, the The moderator band first described as a patient was taken for an electrophysiology study structure to protects the right ventricular from since she was symptomatic and there was no distention,7 goes from the lateral free walk to improvement of her condition on medication. the septum, it is a muscle structure that courses All medications were discontinued five half- inferiorly from the right ventricular septum to lives, and on the day of the procedure she was the base of the anterior papillary muscle of the in a fasting state, she was taken to Electrophysi- tricuspid valve,8,9 and it is histologically com- ology Laboratory with a bigeminy rhythm. Bi- posed by a complex sheaths structure as well lateral femoral groin accesses were performed, as myocardium and more density of specialized then a coronary sinus catheter was advanced, Purkinje cells, than the rest of the right ventri- an intracardiac echocardiogram probe was cle,10 considered as an important structure be- used and a bidirectional irrigated catheter, D-F cause contains a right atrioventricular bundle. catheter, and Duo-Decapolar catheter were Loukas and col. in a morphological study have used too. During intracardiac echocardiogram been classified into five different types form a visualization, it was noted a hyper-refringent on very thick muscular structure to the absence of the moderator band, then the 3D mapping us- the moderator band, they described a mean ing the Ensite system (St. Jude Medical, St. Paul, of the thickness of 4.5 ± 1.8 mm and mean of Mn, USA) was performed. During the voltage length of 16.23 ± 2.3 mm.11 The arterial irriga- map, there was no scar related noted (Figure tion of the moderator band is from branches of 2) and duringwww.medigraphic.org.mx the activation map we found the left coronary system can be found from the a -52 ms activation at the inferior part of the second anterior septal artery up to 72% of the moderator band, then ablation was performed cases, 18% from the first anterior septal artery, with 35 watts and 42 oC lead to a rapid, stable and 7% from the third anterior septal artery.8 ventricular tachycardia that was terminated im- The moderator band is considered as a mediately during ablation and disappearance source of potentially fatal arrhythmias as ven- of the PVCs, and as a result, we decided to tricular tachycardia or ventricular fibrillation.12

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The right band moderator PVC is a rare entity, echocardiogram are used not only as helping the prevalence is estimated at 2.5%; however, tools to ensure a good definition and contact could be more because the patients who died between catheters and tissue but also to im- as a result of this arrhythmia are not counted in prove ablation lesion and effectiveness and the clinical studies; the concern of this kind of safeness of therapy.6 arrhythmia is that can lead to ventricular fibril- Mapping PVC from MB could be an issue, lation and eventually death if there is a delay therefore some strategies should be considered in the treatment.6 to increase the chance of success as medication The PVC from MB has a LBBB morphology drips used during mapping a PVC as isoproter- with a left superior axis, and late transition typi- enol or dobutamine iv, pacing during mapping cally from V4 and forward; moreover it can be to induce PVC, pace mapping approaches, different if the heart anatomy has congenital even using multipolar catheters as Pentaray variations as it was described by Yasumoto in (Biosense Webster, Diamond Bar, California), a patient with corrected transposition of great to collect as many activation points as you can arteries, where the morphology of PVC was on one touch.17 RBBB like.13,14 The moderator band contains Purkinje Treatment of moderator band PVC could be system cells is consider a potentially arrhyth- tricky, typically the antiarrhythmic drugs do not mogenic structure, PVC from this structure can work very well because high doses are required lead to a ventricular fibrillation; ablation can and the chance of secondary effects are more be a real challenge to a electrophysiologist;18 likely to be present,15 with no guarantee of total even though, there are several aspects to con- PVC suppression, as a result, invasive strategy sider: first the best target is difficult to achieve with catheter ablation could be considered as described as the identification of preceding a first option.16 Purkinje potential, pre ventricular activation, The ablation is an effective strategy to concordant morphology with pace mapping; treat a moderator band premature ventricle second: stability is difficult to achieve in this contractions, the 3D mapping and intracardiac structure, some strategies are been proposed:

A RA B 400 ms C

TV 200 ms AC ILR OT ICE Ablation 0 ms Catheter MB 200 ms

400 ms RAO ICE Activation Map Name: ID Male 35+ years sep 1, 2018 5:21 AM 78 bpm 10 mm/mV 10 mm/mV I10 mm/mV 25 mm/s Filter 150 Hz H60 d 10 mm/mV aVR V1 V4 D

II aVL V2 V5

www.medigraphic.org.mxaVF V3 V6 III

Figure 3: A) Right anterior oblique fluoroscopic projection (RAO), showing ablation catheter (AC) at the moderator band (MB). B) Intracardiac echocardiogram (ICE) showing the ablation catheter. C) Activation map showing the point with the highest precocity -54 ms. D) First day ECG with sinus rhythm without premature ventricular contractions (PVC) ILR: implantable loop recorder (ICE), right atrium (RA), tricuspid valve (TV), outflow tract (OT).

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using a tridimensional mapping, intracardiac premature complexes to heart failure (from the Ath- echocardiogram, even cryo catheters to freeze erosclerosis Risk In Communities [ARIC] Study). Am J 19 Cardiol. 2012; 109 (1): 105-109. de area, or a strategy who includes: a 3D 4. Bogun F. Premature ventricular complexes and pre- mapping, ICE, radiofrequency and 23 mm bal- mature ventricular complex induced cardiomyopathy. loon to cryoablation (freezing up to 4 minutes Curr Probl Cardiol. 2015; 40 (9): 379-422. up to -47 oC) has been reported in the setting 5. Li YQ, Wang YX, Que DD, Shao J, Song XD, Yang PZ. Successful ablation of moderator band-originated of a patient with already two failed procedures ventricular tachycardia at its ventricle insertion sites. 20 with successful results, at last but not less the Chin Med J (Engl). 2018; 131 (11): 1371-1372. ablation with RF or Cryo could be trigger VF or 6. Russo AM. PVCs arising from the moderator band: VT, as a destruction of conduction cells during An under-recognized trigger for idiopathic VF? Heart applications.19 Rhythm. 2015; 12 (1): 76-77. 7. Power JH. Anatomy of the arteries of the human body. The percentages of the patients who might Philadelphia: J.B. Lippincott and Co.; 1862. pp. 37-41. need a second procedure have been reported 8. Reig J, Albertí N, Petit M. Arterial vascularization of the up to 60%; and the possible reasons to explain human moderator band: An analysis of this structure’s failed procedures or turn an early successful role as a collateral circulation route. Clin Anat. 2000; 13 (4): 244-250. ablation into a fail therapy with increasing of 9. Galea N, Carbone I, Cannata D, Cannavale G, Conti B, PVC burden are: poor tissue contact with abla- Galea R et al. Right ventricular cardiovascular magnetic tion catheter, lack of stability, insufficient deep resonance imaging: normal anatomy and spectrum of lesions during ablation, and change of PVC exit pathological findings. Insights Imaging. 2013; 4 (2): 213-223. (as a result of ablation points); though, a failed 10. De Almeida MC, Stephenson RS, Anderson RH, Ben- procedure can be dangerous to the patient if venuti LA, Loukas M, Aiello VD. Human subpulmonary the clinic is syncope or even ventricular tachy- infundibulum has an endocardial network of special- cardia or ventricular fibrillation.6 ized conducting cardiomyocytes. Heart Rhythm. 2020; 17 (1): 123-130. 11. Loukas M, Klaassen Z, Tubbs RS, Derderian T, Paling CONCLUSIONS DAN, Chow D et al. Anatomical observations of the moderator band. Clin Anat. 2010; 23 (4): 443-450. Nowadays the diagnosis of a premature ventric- 12. Sadek MM, Benhayon D, Sureddi R, Chik W, San- tangeli P, Supple GE et al. Idiopathic ventricular ular complex is more common; even though, arrhythmias originating from the moderator band: some specific PVC morphologies should have Electrocardiographic characteristics and treatment by a more careful follow-up, because of the di- catheter ablation. Heart Rhythm. 2015; 12 (1): 67-75. rect association with ventricular tachycardia, 13. Sadek MM, Marchlinski FE. Ablation of ventricular ventricular fibrillation, or even sudden cardiac arrhythmias. Trends Cardiovasc Med. 2014; 24 (7): 296-304. death, especially the majority of these PVCs are 14. Yasumoto K, Egami Y, Nakamura H, Matsuhiro Y, not even symptomatic. The moderator band Yasumura K, Tanaka A et al. Successful ablation for PVCs are a potentially risky entity and typically premature ventricular contraction originating from presented in a normal heart; moreover, further moderator band of morphologic right ventricle in congenitally corrected transposition of great arteries. evaluation is always needed. Ablation therapy J Electrocardiol. 2019; 56: 106-108. should be considered as a first therapy even 15. Anter E, Buxton AE, Silverstein JR, Josephson ME. though there is not a significant PVC burden in Idiopathic ventricular fibrillation originating from the patients with a history of pre-syncope, syncope, moderator band. J Cardiovasc Electrophysiol. 2013; 24 (1): 97-100. or severe symptomatic episodes not controlled 16. Cronin EM, Bogun FM, Maury P, Peichl P, Chen M, Nam- with antiarrhythmic drugs. boodiri N et al. 2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular REFERENCES arrhythmias. Heart Rhythm. 2020; 17 (1): e2-154. www.medigraphic.org.mx17. Ho RT, Frisch DR, Greenspon AJ. Idiopathic ventricular fibrillation ablation facilitated by PENTARAY mapping 1. Marcus GM. Evaluation and management of premature of the moderator band. JACC Clin Electrophysiol. ventricular complexes. Circulation. 2020; 141 (17): 2017; 3 (3): 313-314. 1404-1418. 18. Singh P, Noheria A. Ablation approaches for ventricular 2. Hiss RG, Lamb LE. Electrocardiographic findings in fibrillation. Curr Treat Options Cardiovasc Med. 2018; 122,043 individuals. Circulation. 1962; 25: 947-961. 20 (3): 21. 3. Agarwal SK, Simpson RJ Jr, Rautaharju P, Alonso A, 19. Barber M, Chinitz J, John R. Arrhythmias from the right Shahar E, Massing M et al. Relation of ventricular ventricular moderator band: diagnosis and manage-

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ment. Arrhythmia Electrophysiol Rev. 2020; 8 (4): Correspondence to: 294-299. William-Fernando Bautista-Vargas 20. Chinitz JS, Sedaghat D, Harding M, Darge A, Epstein Carrera 23 #65ª-41 Consultorio 904, LM, John R. Adjuvant use of a cryoballoon to facilitate ZIP code: 170003, Manizales, ablation of premature ventricular contraction-triggered Caldas, Colombia. ventricular fibrillation originating from the moderator Phone: +573125315075 band. HeartRhythm Case Rep. 2019; 5 (12): 578-581. E-mail: [email protected]

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