Europace Advance Access published online on June 16, 2008
Europace, doi:10.1093/europace/eun170
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SHORT COMMUNICATION
Persistent left superior vena cava in patients treated with His-bundle pacing: trouble or help?
1 Heart Rythm Management Center, UZ Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101, Brussel 1090, Belgium; 2 Department of Cardiology, Hospital of Portogruaro, Via Zappetti 35, 30029, Italy
Manuscript submitted 25 April 2008. Accepted after revision 27 May 2008.
* Corresponding author. Tel: +32 2 4776010; fax: +32 2 4776011. E-mail address: ga.pap{at}libero.it
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Abstract |
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We describe a case of a 50-year-old man with advanced atrioventricular block treated successfully with His-bundle pacing via a persistent left superior vena cava draining into the coronary sinus.
Key Words: Persistent left superior vena cava, His-bundle pacing, Coronary sinus
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Introduction |
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Persistent left superior vena cava (LSVC) is a congenital abnormality due to an aberrant development of the sinus venous in the early stages of foetal life. Left superior vena cava typically drains into the right atrium via the coronary sinus (CS), which becomes enlarged due to volume overload. In few patients with LSVC, drainage occurs in the left atrium because of failure of CS formation.1
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Case report |
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A 50-year-old man came to our attention after two syncopal episodes preceded by vagal prodromes. The patient presented no other significant cardiac history. The baseline ECG showed complete right bundle branch block (RBBB). No structural cardiac disease was observed on the echocardiogram. No arrhythmias were observed on the ECG Holter recording. The patient underwent a head-up tilt testing that resulted positive for a vasodepressive response (type 3).
Two years later, he attended the Emergency Room complaining of pre-syncopal symptoms. The ECG showed high-degree atrioventricular (AV) block with a mean ventricular heart rate of 29 bpm (Figure 1A). The patient was referred for DDD PM implantation. Suspecting future pacemaker dependence, we decided to choose an alternative site of pacing close to the His-bundle, in order to avoid potentially damaging haemodynamic effects associated with chronic RV apical pacing (RVAP). Mapping of the His-bundle was achieved by placing a Cournand diagnostic catheter using right femoral venous access. The EP study confirmed infra-hisian block. Subsequently, the left subclavian vein was punctured permitting the insertion of two wires, which followed an uncommon course descending down the left side of cardiac silhouette. Thus, we suspected a persistent LSVC and we decided to attempt His-bundle pacing via LSVC. The natural course of the RV lead, which curved back towards the septum just after the exit from the CS, facilitated the placement of the lead tip close to the Cournand catheter. The position of the RV lead was checked in right and left anterior oblique projections. The surface ECG confirmed His-bundle pacing, showing narrow QRS complexes (Figure 1B). Therefore, we proceeded to screw the lead's tip in this position obtaining the following parameters: R wave 12 mV; threshold 2.3 mV; impedance 540 ohm. Next, we placed the atrial lead in the lateral free wall where we observed the best stability and pacing and sensing parameters (Figure 2). The leads were then connected to the pulse generator (Medtronic SDR303, Minneapolis, MN, USA). At the end of the procedure, an angiogram confirmed the presence of an LSVC. The patient was asymptomatic during 24 months of follow-up. Sensing and pacing parameters did not show significant variations.
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Discussion |
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Left superior vena cava is a congenital anomaly rarely diagnosed before PM implant. The most important clinical implication of a persistent LSVC is its association with disturbances of genesis and conduction of cardiac impulse. The embryologic development of sinus node, AV node, and His-bundle are strongly influenced by the regression of the left cardinal vein. A persistent LSVC seems to alter histological arrangement of the conduction system, predisposing patients to bradyarrhythmias.2
An LSVC limits lead handling during the implantation procedure. The main technical problem is the difficulty to put the lead in the RV, because the electrode tip points away from the tricuspid annulus.
Right ventricular apical pacing has been previously recommended as the first choice to place an endocardial lead. However, it has been demonstrated that this pacing site induces a left ventricular activation pattern similar to that observed in spontaneous left bundle branch block. This activation pattern provokes ventricular dyssynchrony, which may cause a detrimental effect on cardiac function.3 Recently, Occhetta et al.4 have shown that when compared with conventional RVAP, para-Hisian pacing improves ventricular asynchrony providing haemodynamic benefits during long-term follow-up. In our young patient, we expected to require long-term ventricular pacing. Thus, we decided for para-Hisian pacing to preserve the ‘physiological’ ventricular activation and to avoid the long-term detrimental effects deriving from RVAP even in patients with normal LV function.3 In our case, we found that the presence of an LSVC did not impede the placement of RV lead close to the His-bundle region. The pacing threshold >2 mV and the surface ECG equivalence between native and paced QRS seemed to suggest that we achieved Hisian pacing.4 In our validation criteria for His-bundle pacing, we did not consider QRS duration because at baseline, the patient displayed a wide QRS due to RBBB. Our experience is similar to a case report described by Foo and Lim,5 and it would confirm that His-bundle pacing is feasible even in patients with an LSVC.
Conflict of interest: none declared.
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References |
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[1] Nsah EN, Moore GW, Hutchins GM. Pathogenesis of persistent left superior vena cava with a coronary sinus collection. Pediatr Pathol (1991) 11:261–9.[CrossRef][Medline]
[2] James TN, Marshall TK, Edwards JE. Cardiac electrical instability in the presence of a left superior vena cava. Circulation (1976) 54:689–97.
[3] Thambo JB, Bordachar P, Garrigue S, Lafitte S, Sanders P, Reuter S, Girardot R, Crepin D, Reant P, Roudaut R, Jais P, Haissaguerre M, Clementy J, Jimenez M. Detrimental ventricular remodelling in patients with congenital complete heart block and chronic right ventricular apical pacing. Circulation (2004) 110:3766–72.
[4] Occhetta E, Bortnik M, Magnani A, Francalacci G, Piccinino C, Plebani L, Marino P. Prevention of ventricular desynchronization by permanent para-Hisian pacing after atrioventricular node ablation in chronic atrial fibrillation: a crossover, blinded, randomised study versus apical right ventricular pacing. J Am Coll Cardiol (2006) 47:1938–45.
[5] Foo D, Lim J. His-bundle pacing in a patient with persistent left superior vena cava. PACE (2005) 28:588–90.[Medline]
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