A conservative approach to performing transseptal punctures without the use of intracardiac echocardiography: stepwise approach with real-time video clips

Transseptal Access to the Left Atrium: Tips and Tricks to Keep it Safe Derived from Single Operator Experience and Review of the Literature

BACKGROUND

Transseptal puncture (TSP) remains a demanding procedural step in accessing the left atrium with inherent risks and safety concerns, mostly related to cardiac tamponade.

OBJECTIVE

Based on our own experience with 249 TSP procedures and in-depth literature review, we present our results and offer several tips and tricks that may render TSP successful and safe.

METHODS

This prospective study comprised 249 consecutive patients (146 men), aged 41.6±17.4 years, undergoing TSP by a single operator for ablation of a variety of arrhythmias, mostly related to left accessory pathways (n=145) or left atrial tachycardias (n=33) and more recently, atrial fibrillation (n=70). TSP was guided by fluoroscopy alone in all patients without the use of echocardiography imaging. In addition, an extensive literature review of TSP-related topics was carried out in PubMed, Scopus and Google Scholar.

RESULTS

Among 249 patients, 33 patients were children or young adolescents (aged 7-18 years); 14 patients were undergoing a repeat procedure. Patients with a manifest accessory pathway were the youngest (mean age 33.7±15.9) and patients with atrial fibrillation the oldest (mean age 56.0±10.8 years). A successful TSP was accomplished in 247 patients (99.2%). Two (0.8%) procedures were complicated by cardiac tamponade managed successfully with pericardiocentesis or surgical drainage. Review of the literature revealed no systematic reviews and meta-analyses of TSP studies; however, several patient series have documented that fluoroscopy-guided TSP, with various modifications in the technique employed in the present series, have been effective in 95-100% of the cases with a complication rate ranging from 0.0% to 6.7%, albeit with a mortality rate of 0.018%- 0.2%. Echo imaging techniques were employed in cases with difficult TSP.

CONCLUSION

Employing a standardized protocol with use of fluoroscopy alone minimized serious complications to 0.8% (2 patients) among 249 consecutive patients undergoing TSP for ablation of a variety of cardiac arrhythmias. Based on this single-operator experience and review of the literature, a list of practical tips and tricks is provided for a successful and safe procedure, reserving the more expensive and patient inconveniencing echo-imaging techniques for difficult or failed cases.

Wire- and needle potentials facilitating transseptal puncture

BACKGROUND

Transseptal puncture for left heart interventions became a routine procedure guided by fluoroscopy and echocardiography. The use of intracardiac potentials derived from the sheath-transseptal-needle/guidewire-combination may provide helpful information to increase safety of this procedure.

METHODS AND RESULTS

We recorded the intracardiac potentials from the sheath-transseptal-needle/guidewire-combination during the transseptal puncture procedure in 31 consecutive patients (mean age 67.2±8.2years; 21 in sinus rhythm, 10 in atrial fibrillation) designated for ablation of atrial fibrillation by the Cryo-balloon ® technique (Medtronic, Minnesota, USA). The EP-Navigator ® 3-D-image integration tool (Philips Healthcare, Hamburg, Germany) was used for visualization of the device position in relation to the cardiac structures. Typical and reproducible potentials could be derived in all patients for the different device localizations at transseptal puncture procedure. Especially the transition from the muscular interatrial septum into the fossa ovalis could be easily depicted by the changes of both morphology and magnitude of the atrial signal (6.1±2.3mV in sinus rhythm [SR]/3.5±0.9mV in atrial fibrillation [AF] at the muscular interatrial septum and 0.5±0.2mV in SR/0.5±0.1mV in AF in the fossa ovalis).

CONCLUSIONS

The crucial steps of a transseptal procedure can be verified by typical changes (morphology and amplitude) of the intracardiac signals derived from the sheath-transseptal-needle/guidewire-combination in patients with sinus rhythm as well as in atrial fibrillation.

Optimal management of the critically ill: anaesthesia, monitoring, data capture, and point-of-care technological practices in ovine models of critical care

Animal models of critical illness are vital in biomedical research. They provide possibilities for the investigation of pathophysiological processes that may not otherwise be possible in humans. In order to be clinically applicable, the model should simulate the critical care situation realistically, including anaesthesia, monitoring, sampling, utilising appropriate personnel skill mix, and therapeutic interventions. There are limited data documenting the constitution of ideal technologically advanced large animal critical care practices and all the processes of the animal model. In this paper, we describe the procedure of animal preparation, anaesthesia induction and maintenance, physiologic monitoring, data capture, point-of-care technology, and animal aftercare that has been successfully used to study several novel ovine models of critical illness. The relevant investigations are on respiratory failure due to smoke inhalation, transfusion related acute lung injury, endotoxin-induced proteogenomic alterations, haemorrhagic shock, septic shock, brain death, cerebral microcirculation, and artificial heart studies. We have demonstrated the functionality of monitoring practices during anaesthesia required to provide a platform for undertaking systematic investigations in complex ovine models of critical illness.

The ABC of a Simple Method for Pulmonary Vein Angiography

Catheter-directed intervention to treat atrial fibrillation (AF) is becoming widely accepted procedure in current clinical practice. For assessment of pulmonary vein (PV) anatomy, angiography of left atrium (LA) and/or PV is often performed. We present a new, simple angiographic method for PVs and LA opacification using SL1 sheath. Total of 100 patients in our clinic underwent this procedure. In all of the cases good angiographic results were achieved. No immediate or late complications related to this procedure were observed.

Intracardiac echocardiography guided transeptal catheter injection of microspheres for assessment of cerebral microcirculation in experimental models

The use of microspheres for the determination of regional microvascular blood flow (RMBF) has previously used different approaches. This study presents for the first time the intracardiac injection of microspheres using transeptal puncture under intracardiac echocardiography guidance. Five Merino sheep were instrumented and cardiovascularly supported according to local guidelines. Two catheter sheaths into the internal jugular vein facilitated the introduction of an intracardiac probe and transeptal catheter, respectively. Five million colour coded microspheres were injected into the left atrium via this catheter. After euthanasia the brain was used as proof of principle and the endpoint for determination of microcirculation at different time points. Homogeneous allocation of microspheres to different regions of the brain was found over time. Alternate slices from both hemispheres showed the following flow ranges: for slice 02; 0.57–1.02 mL/min/g, slice 04; 0.45–1.42 mL/min/g, slice 06; 0.35–1.87 mL/min/g, slice 08; 0.46–1.77 mL/min/g, slice 10; 0.34–1.28 mL/min/g. A mixed effect regression model demonstrated that the confidence interval did include zero suggesting that the apparent variability intra- and intersubject was not statistically significant, supporting the stability and reproducibility of the injection technique. This study demonstrates the feasibility of the transeptal injection of microspheres, showing a homogeneous distribution of blood flow through the brain unchanged over time and has established a new interventional model for the measurement of RMBF in ovine models.

Use of a novel sharp-tip, J-shaped guidewire to facilitate transseptal catheterization

AIMS

Transseptal catheterization (TSP-C) is a demanding procedure and at the same time one of the key points of atrial fibrillation ablation, an increasingly diffused procedure. This study prospectively evaluates the usefulness of a novel sharp-tip, J-shaped 0.014'' transseptal guidewire (TSP-GW) to facilitate TSP-C in case of resistant atrial septum (AS).

METHODS AND RESULTS

Consecutive patients undergoing TSP-C for arrhythmia ablation in a single centre were considered for the study. TSP-C was performed according to a standardized technique. The criterion to use the TSP-GW was a resistant AS, defined as inability to perforate the fossa ovalis by applying moderate pressure to a standard Brockenbrough needle. The TSP-GW was inserted in the needle lumen and advanced to puncture the AS and enter the left atrium; subsequently, the transseptal assembly was advanced over the TSP-GW. Double transseptal puncture was routinely performed for ablation of atrial fibrillation. Eighty-one patients (54 males, 27 females; mean age 54 +/- 17 years, range 12-81) undergoing TSP-C were enrolled; 132 TSP-C procedures were planned and accomplished. Nineteen patients (23%) in 27 procedures showed a resistant AS. In all these procedures, the TSP-GW was safely and successfully used to accomplish the TSP-C. In patients with a resistant AS, only a significantly lower prevalence of structural heart disease was observed when compared with controls. No complication related to TSP-C was observed.

CONCLUSION

The TSP-GW facilitates TSP-C in 23% of the patients, in whom a resistant AS is encountered. In this population, there was no clinical predictor of such anatomy.

Novel trans-septal approach using a Safe Sept J-shaped guidewire in difficult left atrial access during atrial fibrillation ablation

Nowadays, trans-septal (TS) puncture is a relatively safe and straightforward procedure in experienced hands. However, in the presence of a thick, aneurysmatic or extremely elastic fossa ovalis crossing the septum might be challenging. We here describe the use of a novel guidewire that permits easy and safe 'over the wire' TS access during atrial fibrillation ablation.

Real-time MR imaging-guided laser atrial septal puncture in swine

PURPOSE

The authors performed this study to report their initial preclinical experience with real-time magnetic resonance (MR) imaging-guided atrial septal puncture by using a MR imaging-conspicuous blunt laser catheter that perforates only when energized.

MATERIALS AND METHODS

The authors customized a 0.9-mm clinical excimer laser catheter with a receiver coil to impart MR imaging visibility at 1.5 T. Seven swine underwent laser transseptal puncture under real-time MR imaging. MR imaging signal-to-noise ratio profiles of the device were obtained in vitro. Tissue traversal force was tested with a calibrated meter. Position was corroborated with pressure measurements, oximetry, angiography, and necropsy. Intentional non-target perforation simulated serious complication.

RESULTS

Embedded MR imaging antennae accurately reflected the position of the laser catheter tip and profile in vitro and in vivo. Despite having an increased profile from the microcoil, the 0.9-mm laser catheter traversed in vitro targets with similar force (0.22 N +/- 0.03) compared with the unmodified laser. Laser puncture of the atrial septum was successful and accurate in all animals. The laser was activated an average of 3.8 seconds +/- 0.4 before traversal. There were no sequelae after 6 hours of observation. Necropsy revealed 0.9-mm holes in the fossa ovalis in all animals. Intentional perforation of the aorta and atrial free wall was evident immediately.

CONCLUSIONS

MR imaging-guided laser puncture of the interatrial septum is feasible in swine and offers controlled delivery of perforation energy by using an otherwise blunt catheter. Instantaneous soft tissue imaging provides immediate feedback on safety.

Fossa ovalis radiofrequency perforation in a difficult case of conventional transseptal puncture for atrial fibrillation ablation

A 65-year-old man was referred for atrial fibrillation ablation to our center. Routine pre-procedure transthoracic and transoesophageal echocardiography and cardiac computed tomography examinations showed a normal interatrial septum and fossa ovalis anatomy. Access to left atrium was initially planned using a conventional transseptal needle puncture. During the procedure, several consecutive attempts in conjunction with intracardiac echocardiography support, failed to cross the septum. The procedure was then successfully carried out using a specifically designed radiofrequency transseptal catheter.

Blunt atrial transseptal puncture using excimer laser in swine

OBJECTIVES

We describe a new approach that may enhance safety of atrial transseptal puncture using a commercially available laser catheter that is capable of perforation only when energized. We test this approach in swine.

BACKGROUND

Despite wide application, conventional needle transseptal puncture continues to risk inadvertent nontarget perforation and its consequences.

METHODS

We used a commercial excimer laser catheter (0.9-mm Clirpath, Spectranetics). Perforation force was compared in vitro with a conventional Brockenbrough needle. Eight swine underwent laser transseptal puncture under X-ray fluoroscopy steered using a variety of delivery catheters.

RESULTS

The 0.9-mm laser catheter traversed in vitro targets with reduced force compared with a Brockenbrough needle. In vitro, the laser catheter created holes that were 25-30% larger than the Brockenbrough needle. Laser puncture of the atrial septum was successful and accurate in all animals, evidenced by oximetry, pressure, angiography, and necropsy. The laser catheter was steered effectively using a modified Mullins introducer sheath and using two different deflectable guiding catheters. The mean procedure time was 15 +/- 6 min, with an average 3.0 +/- 0.8 sec of laser activation. There were no adverse sequelae after prolonged observation. Necropsy revealed discrete 0.9-mm holes in all septae.

CONCLUSION

Laser puncture of the interatrial septum is feasible and safe in swine, using a blunt laser catheter that perforates tissues in a controlled fashion.

Impact of Heart Rhythm Status on Registration Accuracy of the Left Atrium for Catheter Ablation of Atrial Fibrillation

INTRODUCTION

Registration accuracy is of crucial importance to the successful use of image integration technique to facilitate atrial fibrillation (AF) ablation. It is well known that a patient's heart rhythm can switch from sinus rhythm (SR) to AF or vice versa during an AF ablation procedure. However, the impact of the heart rhythm change on the accuracy of left atrium (LA) registration has not been studied.

METHODS

This study included 10 patients who underwent AF ablation. Prior to the ablation procedure, the patients had contrast-enhanced cardiac CT scan obtained during SR (n = 7) or AF (n = 3). Using an image integration system (CartoMerge, Biosense Webster Inc.), LA CT surface reconstruction was registered to the real-time mapping space represented by the LA electroanatomic map. To determine the effect of rhythm change on registration accuracy, LA registration was performed during both SR and AF in each study subject. The distance between the surface of the registered LA CT reconstruction and multiple real-time LA electroanatomic map points (surface-to-point distance) was used as an index for LA registration error. The position error after rhythm change was defined as the surface-to-point distance between the surface of the LA CT reconstruction registered in the initial rhythm and the LA electroanatomic map points sampled during the second rhythm.

RESULTS

A total of 90 +/- 12 and 92 +/- 9.5 LA electroanatomic map points were sampled for registration during SR and AF, respectively. No significant difference was found in surface-to-point distance when comparing SR with AF as the underlying rhythm during registration (1.91 +/- 0.24 vs 1.84 +/- 0.38 mm, P = 0.60). The position error after rhythm change was not different from the surface-to-point distance of LA registration conducted during the initial rhythm (2.05 +/- 0.39 vs 1.96 +/- 0.29 mm, P = 0.4). The surface-to-point distance did not differ when comparing LA registration conducted during the same versus different rhythm from that during CT imaging (1.96 +/- 0.29 vs 1.79 +/- 0.32 mm, P = 0.13).

CONCLUSIONS

Registration error did not differ between LA registrations conducted during the same versus different rhythm as was present during CT imaging. Rhythm changes between SR and AF did not introduce significant error to the LA registration process for catheter ablation of AF. These findings are reassuring and suggest that reregistration is not needed if a patient's rhythm changes from SR to AF or vice versa during an ablation procedure.