Alligator Clips and a Non-sterile Ablation Catheter to Deliver Radiofrequency Energy Through a Brockenbrough Needle: A Simple, Low-cost Method to Facilitate Difficult Transseptal Puncture

DOI: 10.19102/icrm.2013.040704

GUY FURNISS, MB, ChB, EDWARD DAVIES, MB, ChB, PALASH BARMAN, MBBS, IAN LINES, DAVID R TOMLINSON, MD and GUY A HAYWOOD, MD

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The South West Cardiothoracic Centre, Derriford Hospital, Plymouth, UK

ABSTRACT.  Background: We describe our alligator clip method of using radiofrequency (RF) energy via a standard Brockenbrough needle to facilitate difficult transseptal puncture. Method: If standard transseptal puncture is unsuccessful RF energy is used via our alligator clip technique. A non-sterile ablation catheter is attached to the proximal end of the Brockenbrough needle using sterile alligator clips and using a standard generator in unipolar mode we deliver RF energy to the fossa ovalis. Initial cases were transesophageal echocardiography guided but most procedures used fluoroscopy alone. Results: Two-hundred and forty-four left atrial procedures were performed during the study period. RF-assisted transseptal puncture was used in 23 cases (17 males, 6 females, mean age 63±10 years). Redo transseptal puncture was significantly associated with difficult transseptal puncture, 20.4% (10/49) requiring RF compared with 6.66% (13/95) of first time cases (p = 0.0162). RF was successful after a median two bursts (maximum 4). There were no complications acutely or at follow-up (mean 10.4 months). Conclusion: RF is an effective tool to use in challenging transseptal puncture. Our simple, low-cost method is easy to institute and requires only the one-off cost of alligator clips and their sterilization between cases.

KEYWORDS. atrial fibrillation, catheter ablation, transseptal puncture.

The authors report no conflicts of interest for the published content.
Manuscript received April 28, 2013, final version accepted June 25, 2013.

Address correspondence to: Dr. Guy Furniss, MB, ChB, Wellington Regional Hospital, Department of Cardiology, Riddiford Street, Newtown, Wellington 6021. E-mail: guyfurniss@yahoo.co.uk

Introduction

Atrial septal puncture, for measurement of left atrial pressure, was first described in 1959;¹ however, the growth of electrophysiology and the advent of atrial fibrillation (AF) ablation have seen a dramatic increase in the number of transseptal punctures performed worldwide.² Recent reviews³ continue to endorse the basic method as described by Brockenbrough et al.⁴ in 1962.

The technique of using a specifically designed Brockenbrough needle to puncture the fossa ovalis under fluoroscopy guidance has a high success and low complication rate.^2,5 However, the number of transseptal punctures performed today increases the likelihood of encountering challenging anatomy such as a thickened or aneurysmal atrial septum. Repeat transseptal puncture, seen most commonly in patients requiring further left atrial ablation following an initial AF ablation, is associated with thickened intra-atrial septa, increased difficulty, and the potential for complications.

The Brockenbrough technique has evolved with novel needles^6,7 and guidewires^8,9 used to aid the operator in difficult cases. Radiofrequency (RF) energy has been used to aid transseptal puncture, either delivered through a standard needle^10–12 or recently via a specially developed RF transseptal needle.^6,7 We describe our technique and experience of RF-assisted transseptal puncture through a standard Brockenbrough needle with minimal add-on costs to the procedure.

Methods

At our tertiary center 244 consecutive left atrial ablation procedures requiring transseptal puncture were performed over a 3-year period by two experienced operators. A total of 195 cases were first-time procedures and 49 were redo procedures. Twenty-three patients of the total 244 (9.4%) had an unsuccessful initial transseptal puncture, and RF energy was then used to facilitate successful puncture. Of these, 10 patients were undergoing redo procedures. These 23 patients provide the study population. All provided written consent for the procedure (Table 1).

Standard transseptal puncture

All patients are anticoagulated with warfarin, aiming for an international normalization ratio of 2.5 for a minimum 4 weeks prior to the procedure. Procedures are performed either under conscious sedation or a general anesthetic dictated by comorbidity, patient preference, and predicted length of procedure. A 6-F quadripolar catheter is inserted into the coronary sinus via the right subclavian vein, right internal jugular vein, or right femoral vein. The TS sheath (SL1, St Jude, Minneapolis, MN) and dilator is flushed several times with heparinized saline outside the body, and the transseptal needle (BRK-1, St Jude Medical) is also flushed and passed up the dilator and sheath outside the body. The sheath is flushed again to protect against plastic shards from the sheath.

The sheath, dilator, and needle assembly is then placed into the superior vena cava over a guidewire introduced from the right femoral vein. Landmark guidance via a pigtail catheter in the aortic root or intracardiac echocardiography is not used as standard. Under fluoroscopy in the anterior–posterior view, the sheath and needle are angulated towards the atrial septum and withdrawn until the characteristic jump forward is seen, indicating the location of the fossa ovalis. Position is confirmed in the left anterior oblique and right anterior oblique views with contrast injection to visualize tenting and not staining of the fossa ovalis. The needle is then advanced across the atrial septum with continuous pressure monitoring and a second contrast injection confirming successful transseptal puncture. The needle and dilator are withdrawn and a guidewire placed in the left superior pulmonary vein.

Transseptal puncture using radiofrequency ablation

Transseptal puncture using our radiofrequency ablation technique is initially identical to our standard puncture technique. The sheath, dilator, and Brockenbrough needle assembly is placed in the fossa ovalis as described above. If the operators “usual” force fails to puncture the septum we move onto RF.

A non-sterile ablation catheter (Bard stinger, Biosense Webster, Diamond Bar, CA) in unipolar mode is attached to the proximal end of the Brockenbrough needle using sterile alligator clips. Care must be taken so that the tip of the alligator clip or the proximal end of the Brockenbrough needle does not touch the patient. The dilator and sheath insulates the inferior vena cava (Figure 1). The Brockenbrough needle is held in position in the fossa ovalis and checked with fluoroscopy in standard orthogonal views. We then deliver RF energy of up to 20 W for up to 10 s at a time. Transseptal puncture is confirmed as in the standard technique with operator feel, continuous pressure monitoring, contrast injection, and fluoroscopy.

Our initial cases used transesophageal echocardiography (TEE), in addition to standard fluoroscopy and pressure monitoring to confirm the needle tip is in the fossa ovalis prior to the puncture. However, the majority of cases were guided by fluoroscopy alone. Ablation was performed using color mapping and point-to-point ablation (Carto, Biosense Webster; Navex, St Jude Medical), cryoablation, or via the multi-electrode catheter PVAC/TVAC system (Ablation Frontiers, Medtronic Inc., St. Paul, MN).

Results

In a 36-month period 244 left atrial procedures were performed at our single center by two experienced operators. Of these, 49 were redo procedures where the patient had already undergone left atrial ablation and required repeat transseptal puncture. twenty-three patients had resistant atrial septa requiring RF to facilitate TSP, representing 9.4% of our total study population. Of these patients, 10 were undergoing a redo procedure for standard left atrial ablation, and one patient was undergoing a redo procedure following surgical AF ablation which had not involved TSP. In total 13 out of 195 (6.66%) of first time procedures had resistant atrial septa compared with 10 out of 49 (20.4%) of ablation procedures requiring redo TSP.

Overall, 9.4% of all cases and 20.4% of redo procedures required RF. No complications were seen acutely or at a mean follow-up of 10.4 months.

Of the 221 cases performed with standard TSP technique over the period of the study, there were no serious complications noted acutely or at follow-up.

Discussion

The number of left atrial procedures undertaken worldwide is increasing due to the rapid expansion of AF ablation.² Of these, many require reintervention due to recurrence of AF or the development of atrial arrhythmias. The consequent increase in the number of patients requiring repeated TSP means operators will increasingly encounter cases where standard TSP is challenging. Studies by Marcus et al.¹³ and Tomlinson et al.⁵ have shown repeat TSP is more likely to be difficult with a potentially greater risk of complication. Greater force imparted to puncture a tough intra-atrial septum may make a sudden jump of the needle tip more likely with the potential to puncture the atrial wall. Therefore, new techniques such as RF ablation^6,10–12 or the use of nitinol tipped wires (Safe Sept, Pressure Products Inc., Warminster, PA)^8,9 allow operators an alternative to just greater manual force, a technique which intuitively can be thought associated with greater risk of complications.

Several techniques using RF to facilitate TSP have been described and demonstrated to be safe and effective.^11,12 Techniques described previously to deliver RF through a standard Brockenbrough needle have used either direct contact of a sterile ablation catheter,¹¹ or an electrocautery device, to the Brockenbrough needle. Our technique utilizes sterile alligator clips to connect a non-sterile ablation catheter to the proximal end of the needle. The advantage of this is that they alone are the only additional piece of equipment required in a standard electrophysiology laboratory and only the clips require sterilization after the procedure as opposed to an ablation catheter. Electrocautery devices also require sterilization or disposal with each case; however, not all laboratories have electrocautery available for standard electrophysiology cases. Using direct contact with the proximal end of the Brockenbrough needle and the ablation catheter to be used for the procedure has the disadvantage of limiting the ablation technique used. Using a non-sterile ablation catheter and sterile alligator clips ensures compatibility with all AF ablation techniques.

The development of a TSP needle (Radiofrequency Transseptal System, Baylis, Medical, Montreal, Canada) with built in RF gives another option available in difficult cases.^6,7 Experience with these needles has demonstrated their feasibility and safety, with one study by Winkle et al.⁶ showing a significant reduction in tamponade compared with conventional TSP. However, the needle is a single-use ablation catheter and there is an additional cost to be considered, especially if it is adopted for all cases requiring TSP. Additional options for the difficult TSPs include using nitinol-tipped wires, which have been shown to be safe and effective.^8,9

This series illustrates an easily instituted, low cost additional technique for delivering RF to assist TSP. The resistant atrial septum is increasingly encountered, and our series confirms this is especially true with redo TSP. It is therefore important that operators have alternative tools to facilitate puncture. These should be safe and easy to incorporate in standard TSP techniques at limited extra cost. Our technique and other similar series have demonstrated that RF delivery via a standard transseptal needle is feasible and safe.

The majority of our cases were performed without TEE guidance. This was used in previous series, as was intracardiac echocardiography (ICE). Our practice of using fluoroscopy alone is more straightforward, requiring fewer staff, and being more suitable for procedures performed under sedation only. It must be emphasized that the operator needs to be confident the needle tip is in the fossa ovalis; in cases of uncertainty or unusual anatomy, alternative imaging such as TEE or ICE may be indicated to ensure that the needle tip is in the correct position prior to applying force or RF.

Our series, as with other similar studies, is on a small number of patients, and further randomized studies are required. Further work is also required to refine our technique, optimizing time and energy delivery at the intra-atrial septum with the energy used for RF varying between 10 W and 20 W. One study in pig models¹⁴ has demonstrated that the tissue lesion at the fossa ovalis showed no significant difference between conventional TSP and RF facilitated puncture. We did not perform follow-up imaging to look for residual septal defects in our patients, but no problems have been seen during follow-up.

Limitations

The decision to use RF in our cases was determined by failure to achieve successful TSP with a conventional Brockenbrough needle following “usual” operator force. This is subjective, and having RF available to us may increase the number of cases classified as difficult.

Conclusion

RF energy delivered through a standard needle to facilitate TSP is a safe and effective technique. The use of alligator clips to connect a non-sterile ablation catheter to the needle is simple, inexpensive, safe, and an important additional tool to use in challenging TSP.

Reference

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