EP Lab Research Articles

RELATION OF THE LATE ACTIVATION ZONE WITH THE LEFT VENTRICLE MYOCARIDUM CHANGES IN CANDIDATES FOR RESYNCHRONIZING THERAPY

Aim. By non-invasive methods, to assess relations of the zone of late electrical activation with changes in the left ventricle (LV) myocardium structure in patients — candidates for cardiac resynchronizing therapy. Material and methods. Totally, 37 patients included, with III functional class of chronic heart failure (CHF). In all patients, there was complete His left bundle branch block (LBBB) with QRS width 205 (190; 215) ms. Non-invasive electrophysiological mapping (NEM) was done with the “Amycard01C EP LAB” (EP Solutions SA,Switzerland), and magnetic-resonance imaging (MRI). At the first step, multichannel electrocardiography (ECG) was done. At the second step, MRI was done (MAGNETOM Trio A Tim 3 T, Siemens AG,Germany) with intravenous contrast “Gadovist” load. Changes inLV myocardium structure (post-inflammatory fibrosis or scar tissue) were evaluated by segments, within the delayed MRI contrasting. At the third stage, individual models of ventricles were built up. Activation ofLV epicardium in LBBB was evaluated by NEM. Results. Most oftenly the zone of late activation by NEM was found in the basal region on the border of posterior and lateral LV segments — 17 patients (46%) and in basal lateral LV segment — 8 (21%). By MRI, only post inflammatory fibrosis was found in 21 patient, among them in 5 the area of fibrosis was located on LV epicardium and overlapped the zone of late activation by NEM. Among 12 patients with ischemic heart disease 2 had scar onLV epicardium overlapping with the late activation zone. No one of 4 patients with combination of post-inflammatory fibrosis and ischemic scar did not show overlap of structural changes on the epicardium with the late activation zone. Conclusion. Combination of NEM and MRI in pre-operational period of patients investigation make it to relate structural changes inLV myocardium with the zone of its late electrical activation.

136-12: Comparison of the Relative Radiation Reduction Assessed by Dosimetry of Radiation Pads and Collimation Used in the Electrophysiology Lab

Introduction: Use of x-ray is still prevalent although there is recognition that any radiation may be associated with cancer risk. Recent new technology allows real-time assessment of radiation dose exposure at a given location. The purpose of this study was to assess the relative value of two different radiation reduction methods in the EP lab (collimation and radiation pads) compared to an open configuration using real- time radiation dose monitoring. Methods: A phantom acrylic model was used in order to allow serial measurements using the same parameters with the x-ray system. Radiation real-time detectors (RaySafe™) were used to measure radiation dose around the phantom in three different configurations (open, collimation, and radiation pads) with three different camera angulations. The open configuration consisted of x-ray exposures without radiation reduction methods. Collimation tests were conducted by moving collimators to the border of the saline/contrast phantom. The radiation pad configuration used radiation pads placed along the operator side of the table extending from the acrylic block at the heart level to the block at groin level. Results: The parameters analyzed for radiation dose were measured in millirem by real-time radiation detectors. The parameters obtained from the x-ray system labeled patient measurements were total mGy and cGy-cm2. Collimation resulted in this phantom simulation in a significant decrease (p < 0.01) of approximately 50% in radiation exposure for the operator compared to the open configuration for all locations. A non-significant radiation reduction (6–11%) was observed for radiation pads compared to the open configuration. Collimation resulted in a significant reduction (p < 0.01) of 23–31% in the exit dose of radiation from the phantom, but a significant increase (p < 0.01) of 54% of the air kerma (AK) measured in mGy for all locations compared to the open configuration. Conclusion: This study showed a significant benefit of collimation compared to an open configuration or radiation pads to reduce radiation exposure. Despite the fact the AK measurement increases significantly with collimation compared to an open configuration, the radiation dose actually decreases as assessed by the dosimetry exit dose from the phantom.

AV nodal reentrant tachycardia. Diagnosis and therapy

The AV nodal reentrant tachycardia (AVNRT) is one of the most common arrhythmias encountered in clinical practice. It is characterized by a constant heart rate and an on/off phenomenon. The clinical symptoms may include palpitations, anxiety, polyuria, and dyspnea. Typically, tachycardia may be disrupted by vagal maneuvers in many patients. First-line treatment of symptomatic AVNRT is radiofrequency ablation. The present article deals with the characteristics, differential diagnosis and treatment of AVNRT in the EP lab. It is the second part of a series of manuscripts which may facilitate further education in the specific field of electrophysiology.

Abstract 14355: Sinus Rhythm Prior to Catheter Ablation Positively Impacts Ablation Outcome in Non-Paroxysmal Atrial Fibrillation Patients

Background: Catheter ablation of non-paroxysmal atrial fibrillation (NPAF) is associated with longer procedure times and lower long-term success rates than that of paroxysmal AF. We tested the hypothesis that NPAF patients entering the EP laboratory (lab) with sinus rhythm (SR) have shorter procedure time and better ablation-outcome than those with AF as the entry-rhythm. Methods: Total of 804 consecutive NPAF patients undergoing radiofrequency catheter ablation at our center were included in this prospective analysis. Based on the presenting rhythm in the EP lab, patients were classified into two groups; patients on SR (group 1, n=236, age 63±10 years, male 71%, LVEF 55.2±8.4, LA size 4.5±0.9 cm), patients in AF (group 2, n=568, age 64±10 years, male 69%, LVEF 54.4±11.4, LA size 4.6±0.6 cm). All patients were followed up for 38±6 months for arrhythmia recurrence by event recorder, ECG and Holter monitoring. Results: The baseline characteristics were not different between the groups. When comparing the procedural parameters between the groups, patients presenting with SR required significantly shorter radiofrequency time (64.1±30.7 min vs. 82.3±29.4 min in AF group, p&lt;0.0001) and procedure times (143.9±91.2 min vs. 162.3±62.2 min in AF group, p=0.019). At the end of follow-up, significantly higher recurrence rate was noted in those presenting with AF compared to patients on SR at the procedure; 264 of 568 (47%) vs. 80 of 236 (34%) respectively, log-rank p=0.002 (unadjusted hazard ratio 1.55 [1.17 - 2.05]) (figure). After adjusting for AF type, age, gender, LA size, and LVEF in multivariable Cox model, patients presenting with AF at procedure were twice more likely to fail compared to those on SR (hazard ratio 1.91 (95% CI 1.19 to 4.15), p=0.001). Conclusion: Sinus rhythm prior to catheter ablation for non-paroxysmal AF decreases the duration of ablation and increases the long-term efficacy of the procedure. Figure: Kaplan-Meier curve showing recurrence by study groups

Abstract 18237: Non-invasive Three Dimensional Imaging of Ventricular Arrhythmias: In-procedure Simultaneous Mapping of Ventricular Tachycardia and Premature Ventricular Complexes

Introduction: Noninvasive activation imaging and the identification of initiation sites or reentrant circuits are highly desirable for aiding catheter ablative treatment of ventricular arrhythmia. While approaches are being developed to image epicardial potential, Cardiac Electrical Sparse Imaging (CESI), a 3-dimensional noninvasive activation imaging technique offers insight into intramural activation. In this study, we report the first clinical study of the CESI technique with in-procedure simultaneous mapping of Ventricular Tachycardia (VT) and Premature Ventricular Complexes (PVCs). Methods: Body surface potential maps (BSPMs) were recorded using 170±9 electrodes in 4 patients (2 males, 2 females, age 53±5) with VT and/or PVC in the EP lab simultaneously with CARTO mapping and ablation. CT or MRI images were obtained for individualized volume conductor modeling. Activation sequences were estimated using CESI upon the 40 isolated PVC or VT beats induced by programmed stimulation or isoproterenol infusion. Imaging results were compared with CARTO map and ablation sites/outcomes. Results: Good concordance was observed between the imaged results and the EP study. A Correlation Coefficient of 0.76±0.04 and Relative Error of 0.22±0.05 were found between the imaged activation sequences and the Local Activation Time maps from CARTO. The imaged initiation sites well co-localized with the ablation outcomes with Localization Error of 8±1.3mm from the last ablation site and 3.3±1.7mm from the nearest ablation site. Conclusions: We demonstrate for the first time that the beat-to-beat 3D activation imaging technique CESI can be applied clinically with simultaneous mapping in the EP lab. The noninvasive imaging results are in good agreement with the EP study and catheter ablation outcome. The promising results suggest CESI warrants further investigation and has the potential to become a clinically useful technology guiding ablation procedures in patients.

IT IS POSSIBLE TO REDUCE EXPOSURE TO IONIZING RADIATION BY > 90% DURING CARDIAC RESYNCHRONIZATION THERAPY IMPLANT PROCEDURES IN THE EP LAB: THE MONTRÉAL HEART INSTITUTE EXPERIENCE WITH LOW-DOSE FLUOROSCOPY SETTINGS AND MEDIGUIDE

All cardiologists working with ionizing radiations (IR) should apply the ALARA (As Low As Reasonably Achievable) principles. Among all procedures, implantation of cardiac resynchronization devices (CRT) result in the highest IR exposure, to the patients, staff and implanter with average IR doses (Dose-Area-Product: DAP) in the range of 2,500 μGray.cm2. These doses can easily double in difficult procedures (longer fluoroscopic times and higher DAP/min generated by fluoroscopic tube angulations, LAO projection being the worst). Our objective is to report on our recent experience to reduce IR exposure with the new 3-D navigation system (MediGuide, MDG, St Jude Inc.) and low-dose fluoroscopy settings during CRT implant procedures. Since January 2013, we’ve collected for all CRT implantations the procedure duration and fluoroscopy exposure (time in minutes, DAP in μGy.cm2 and DAP/min). In June 2013, MDG was installed in one (of 3) EP lab where CRT are implanted and in December 2014, we changed the fluoroscopy settings in all labs to lower-dose parameters (power and frame rate), sacrificing image quality in favor of lower IR exposure. 283 procedures are included in the data base (table). With lower fluoroscopy settings, DAP non-significantly decreased by 33% (P=0.386) compared to normal settings (non-MDG cases). The benefits of lower DAP/min were offset by longer fluoroscopy times. Usage of MDG (normal settings) resulted in 75% reduction of DAP (P<0.001), mainly due to a 72% reduction in fluoro duration (P<0.001). The most striking effects were noted when low-dose fluoroscopy settings were used in combination with MDG: 94% reduction in DAP (vs. NON-MDG), due both to shorter fluoroscopy duration and reduction of DAP/min (all P<0.001). Of note, these beneficial effects were not obtained at the cost of longer procedure duration (expected with lower image quality). It is possible (and desirable) to reduce by >90% ionization radiation exposure during CRT implantation procedures. Adopting low-dose fluoroscopy settings, failed to reduce IR exposure, the benefits from lower DAP/min being offset by longer fluoroscopy usage times. However, using low-fluoroscopy settings with a 3-D navigating system (MediGuide) during the difficult steps (CS cannulation and LV lead placement) significantly reduced exposure to ionizing radiation by 94% (with benefits coming from both lower fluoroscopy time and IR dose/minute).

Abstract 358: Patient Satisfaction and Preference Assessment Post Outpatient Electrophysiology Procedures: Same Day versus Next Day Discharge

Objectives: Multiple studies have reported the safety of same day discharge (SDD) post-electrophysiology (EP) procedures, while patient satisfaction associated with this approach has not been well- studied. We sought to evaluate whether SDD would be associated with a comparable patient satisfaction rate compared with next day discharge (NDD) in various EP procedures. Furthermore, we aimed to assess patient preferences regarding discharge timing. Methods: A cohort of patients was identified using our institutional record of all outpatient EP lab procedures from August 2013 to November 2014. From this list, 6 groups were created based on discharge timing “SDD/NDD” and procedure “Ablation (A)/Pacemaker (P)/ICD (I)”. All operators offered SDD and were included. We excluded generator change and lead extraction procedures. Patients who stayed more than one night were also excluded. Post-discharge phone surveys were conducted starting from the most recent procedure until the target number was reached. The research team gathering surveys was blind to patient characteristics. The survey was composed of 24 questions, 10 of which were for Post-Discharge Coping Difficulty Scale (PDCDS). Results: We surveyed 132 patients, 53F/79M, 66 SDD/66 NDD with mean age (SD) of 63 (15). We had 29 patients in each A group, 17 in each I group, and 20 in each P group. Patients’ rating of overall satisfaction and readiness for discharge, as well as, calculated PDCDS outcomes were not significantly different in SDD vs. NDD for all procedures, I+A only, and A only ( p &gt;.05). Patient characteristics and procedural complications between groups did not differ significantly, though different operators did differ in numbers of SDD or NDD procedures. No significant interactions were found between various covariates and study outcomes including age, gender, BMI, number of home medications, operator, and type of procedure. Approximately1/3 of patients (43/132) were given the choice of the two discharge strategies by the operator. The majority of them (93%; 40/43) opted for SDD and rated “the opportunity for this choice” with a mean of 9.1 (1-10 scale, 10 excellent) in comparison to a mean of 6.7 for those who were not given the choice ( p &lt;. 0001). Only 12% (8/66) of SDD patients wished they had the alternative discharge strategy (P &lt; .0001), in comparison to 38% of NDD patients (25/66) ( p &lt;. 07). Overall, 51% (67/132) of all patients preferred SDD if they were to undergo similar procedure in the future. Conclusions: SDD strategy resulted in similar patient satisfaction to NDD strategy across different EP procedures and operators. Patients significantly appreciated the choice of SDD. The SDD group was more willing to repeat their discharge experience. This further supports following SDD strategy, whenever possible, to improve quality of care; in addition to the cost savings and increased efficiency associated with this approach.

Significant reduction in radiation exposure with a newer x-ray imaging system in the EP lab

Significant reduction in radiation exposure with a newer x-ray imaging system in the EP lab

MediGuide-impact on catheter ablation techniques and workflow.

Since the introduction of percutaneous intervention in modern medical science, specifically cardiovascular medicine fluoroscopy has remained the gold standard for navigation inside the cardiac structures. As the complexity of the procedures continue to increase with advances in interventional electrophysiology, the procedural times and fluoroscopy times have proportionately increased and the risks of radiation exposure both to the patients as well as the operator continue to rise. 3D electroanatomic mapping systems have to some extent complemented fluoroscopic imaging in improving catheter navigation and forming a solid platform for exploring the electroanatomic details of the target substrate. The 3D mapping systems are still limited as they continue to be static representations of a dynamic heart without being completely integrated with fluoroscopy. The field needed a technological solution that could add a dynamic positioning system that can be successfully incorporated into fluoroscopic imaging as well as electroanatomic imaging modalities. MediGuide is one such innovative technology that exploits the geo-positioning system principles. It employs a transmitter mounted on the X-ray panel that emits an electromagnetic field within which sensor-equipped diagnostic and ablation catheters are tracked within prerecorded fluoroscopic images. MediGuide is also integrated with NavX mapping system and helps in developing better 3D images by field scaling-a process that reduces field distortions that occur from impedance mapping alone. In this review, we discuss about the principle of MediGuide technology, the catheter ablation techniques, and the workflow in the EP lab for different procedures.

Mapping and ablation of ventricular fibrillation—how and for whom?

The involvement of the Purkinje system in a subset of patients with idiopathic ventricular fibrillation or polymorphic VT/VF related to structural heart disease was first demonstrated in the pioneering work of Michel Haissaguerre and co-workers (Circulation 106:962-967, 2002 and Lancet 359:677-678, 2002). It is very important to identify these patients with recurrent episodes of ventricular fibrillation and/or ICD shocks with regard to the presence of triggering premature ventricular contractions (PVC), which may be amenable to mapping and catheter ablation by screening Holter and ICD recordings. The practical problem, which is frequently encountered, is the absence of these PVCs when the patients are brought to the EP lab. However, catheter ablation is an important adjunctive tool to antiarrhythmic drug treatment, beta blocker therapy, and general anesthesia in this setting. Local electrogram criteria related to this phenomenon have been identified guiding mapping and ablation (e.g., low amplitude, high-frequency Purkinje potentials preceding a closely coupled ventricular signal (Fig.1a)). The favorable long-term follow-up after catheter ablation has been demonstrated in the setting of right and left ventricular Purkinje-related PVCs leading to polymorphic VT/VF (Leenhardt et al., Circulation 89:206-215, 1994) and also following myocardial infarction (Baensch et al., Circulation 108:3011-3016, 2003) and right ventricular outflow tract-associated VF (Noda et al., Journal of the American College of Cardiology 46:1288-1294, 2005). Most recently, epicardial ablation strategies leading to suppression of polymorphic VT/VF episodes related to the Brugada syndrome have been described irrespective to the presence of premature ventricular beats (Nademanee et al., Circulation 123:1270-1279, 2011).

DIRECT HIS-BUNDLE PERMANENT PACING AS AN ALTERNATIVE TO CONVENTIONAL RIGHT VENTRICULAR APICAL PACING: A PILOT STUDY IN ZAGAZIG UNIVERSITY CARDIAC ELECTROPHYSIOLOGY LABORATORY

Aim: was to evaluate the feasibility of direct his bundle pacing (DHBP) as one of the physiological pacing approaches in our EP lab. Methods: All suitable patients admitted for permanent pacemaker implantation, between January and June 2013, were given a trial for DHBP. Using his bundle (HB) recording through a quadripolar catheter as an electrical and radiological guidance, custom shape stylet was used to direct an active fixation lead to the target position; a pacing protocol was applied to insure pure HB capture. A matching group of patients with apical right ventricular pacing (ARVP) were used as control, to assess the feasibility of DHBP technique. Results: Pure DHBP was successful in 12 out of 32 patients 38%.The DHBP procedure was costly when compared to ARVP in total procedure time (94.7±30.4 vs. 43.2±17.4 minutes), fluoroscopy time(35.2±10.9 vs. 10.1±3.6 minutes), patient x-ray exposure (34.1±7.8 vs. 11.9±4.9 Gy Cm2)and acute pacing threshold (2.1±0.6 vs.0.6±0.4 V). But in the other hand it was better in paced QRS width (76.8±14.8 vs. 193.9±35.8 ms.), patients’ exercise capacity as percentage of achieved METS from Max METS for age (75.5±8.7 vs.54.9±8.7%). the DHBP procedure time was progressively shorter indicating a steep learning curve. Conclusion: Although DHBP has many technical difficulties, it can be achieved with a reasonable coast in our EP lab with a demonstrable benefit, and a steep learning curve. Keywords: direct his bundle pacing, apical right ventricular pacing, physiological pacing, pacemaker, paced QRS duration, and active fixation lead.

Differentiation between atrioventricular reentrant tachycardia (AVRT) and AV nodal reentrant tachycardia (AVNRT)

Differentiation between atrioventricular reentrant tachycardia (AVRT) and AV nodal reentrant tachycardia (AVNRT) can be sometimes challenging in the EP lab. RV pacing during SVT produces progressive QRS fusion before QRS morphology becomes stable. This fusion zone (FZ) may differentiate AVRT from AVNRT independent of entrainment success. PPI-TCL during RV entrainment can help in differentiation; however it has some fallacies and limitations. We thought to compare the accuracy of atrial preexcitation (AP) & Stimulus to atrial (S-A) interval fixation in relation to fusion zone in identifying the mechanism of SVT. We studied retrospectively and prospectively the effect of properly timed RVP on atrial timing during FZ. 118 SVT patients had RVP within 40 ms shorter than tachycardia cycle length (TCL). S–A interval and atrial CL were measured during FZ and with each QRS complex thereafter. A fixed S–A interval was defined as variation 9 patients were excluded due to cycle length oscillation > 10 ms before the onset of RVP and 6 patients had atrial tachycardia (VA dissociation with RVP) and were excluded. In the remaining 103 patients, PPI-TCL was significantly longer in AVNRT patients but postpacing response couldn’t be assessed in 12 patients who showed consistent termination of tachycardia during RVP entrainments; 3 AVNRT patients (5%) & 9 AVRT patients (22%). And when assessed it was not diagnostic in additional 4 (6%) patients with AVNRT ( We can conclude that during RVP within 40 ms of the tachycardia cycle length, fixed S–A interval and AP in relation to FZ were superior to PPI-TCL measurement in identifying the mechanism of SVT.

New Computer Program for Detecting 12-Lead ECG Misplacement in the EP Lab Using a 3D Kinect Camera

The accurate electrode positions are required by our cardiac isochrones positioning system. Therefore we developed a KINECT camera based system to localize the electrodes. The KINECT camera was used to take 3D images of the torso of five male subjects with ECG electrodes attached. Our software transformed the 3D quantitative image into a subject specific electrode torso model. These torso models were scaled to obtain an objective standard for electrode misplacement. New KINECT camera computer software automatically and rapidly detected misplacement of 12-lead ECGs electrodes. An increased database is needed to calculate the sensitivity and specificity of distances and angles to determine accurately misplaced leads.

Ventricular premature beat terminating SVT

The following tracings were obtained in the EP lab during a SVT study. Fig. 1 shows a 12 lead recording of ECG of a patient showing termination of supraventricular tachycardia (SVT). The first 8 beats are narrow QRS short RP tachycardia e with the differential diagnosis of AVNRT or AVRT or less commonly atrial tachycardia. This train is followed by a single ventricular premature beat (VPB) delivered from a catheter in right ventricle, which terminates the tachycardia. On the 12 lead ECG, the single paced beat is seen as a fusion beat as it has some resemblance to a paced ventricular beat and some to the SVT beat. The fusion can result only if both the paced and SVT beats have excited the HisePurkinje system and confirms that the paced beat is His refractory. Fig. 2 shows the corresponding intracardiac recordings of the same event. The first 3 complexes are the SVT beats, where the atrial activation of distal coronary sinus appears to precede that of theHis andproximal coronary sinus suggesting possible involvement of a left sided accessory pathway. The single VPB (4th beat) is delivered during the SVT coinciding with the His deflection on the His catheter and this terminates the tachycardia. Subsequent 2 beats are sinus. Delivering of a His synchronous or

Imaging the PM/AICD patient; fancy or fanatical?

Background Imaging patients with a pacemaker or AICD has always been taboo in the MRI environment. However, with current improvements in pacemaker lead and generator development along with very vigilant and knowledgeable personnel in pacemaker safety, MRI procedures can be implemented successfully. However, safe performance, not withstanding the risks, leads one to question if the results from the scans provide additional valuable clinical information to warrant the risk. Hypothesis: We propose that MRI imaging patients with a pacemaker can be crucial to establish clinical diagnosis. Methods A total of 25 patients were imaged on a GE CV/i Excite Version 12, 1.5 T system (GE, Milwaukee, WI). Three patients had an AICD, 4 patients had an AICD/Pacemaker, 2 patients had a single pacemaker lead and the remaining 16 patients had a complete pacemaker implantation. Each patient was performed in the dedicated Cardiac MRI Imaging Suite under the strict supervision of the Cardiologist. EP Lab personnel were present and reconfigured the pacemaker into an appropriate asynchronous mode under the guidance of the Cardiologist. The MRI scan sequences were selected such that the SAR level was lower or equal to 2.0 W/kg. to reduce additional heating to the device. Results All patients completed the procedure with no adverse events and the pacemaker was interrogated after the procedure by EP Lab and reprogrammed under the direction of the Cardiologist. Impedance, thresholds, amplitudes and shock impedances were unchanged pre to post scanning. The average MRI scan time was 20±55min. Regarding the population, of the 25 patients imaged, 17 (68%) were neurology cases and 8(32%) were cardiac cases. After reviewing the results from the 17 neurology cases and comparing the results from prior studies (CT, angio and/or myelogram) 14 (82%) out of the 17 patients benefited from having this procedure. 12 (70%) out of the 17 patients altered the diagnosis for a better outcome in patient care. The remaining 3(18%) patients did not show additional information that enhanced the diagnosis. The 8 cardiac cases were also compared to prior studies (heart cath, TEE, TTE and stress) and the outcome of all patients’ diagnosis was shown to be enhanced by the MRI imaging. In 4(50%) of the 8 patients CMR altered the prevailing clinical diagnosis. Thus, a total of 22 patients (88%) benefited by enhancement or alteration of the original diagnosis while 3(12%) patients did not provide any additional information. Conclusions The use of PM/AICD imaging in MRI remains controversial but as the lead/generator technology has improved, increased confidence in its use is found. Herein, we show that MRI procedures on carefully selected patients with pacemakers/AICD’s are beneficial and substantially enhance or alter patient diagnosis. We propose that not only are Pacemakers/AICD’s no longer taboo in the MRI environment but they can be markedly efficient with lifealtering and life-saving consequences. Funding None.

Deep sedation and atrioventricular nodal reentry tachycardia ablation.

Cardiac ablation is an invasive procedure requiring conscious and deep sedation for immobility and analgesia. AVNRT ablation generates acute pain during the radiofrequency application. Although the success rate is high, the procedure is uncomfortable for patients who must remain motionless. Sedation in EP lab is needed for several purposes such as providing anaesthesia and airway management for cardio version during EP study and induction of atrial fibrillation, pain management, and haemodynamic monitoring. The best anaesthetic agent should not alter Electrophysiological properties including SA node, AV node functions, conduction velocities, and refractoriness. Most anaesthetic agents have not been studied in the context of EPS and most of our data were based on animal and laboratory experiments. A few investigators reported that anesthetic agents have no significant clinical effects on conduction system (1, 2). There are some reports concerning non-inducibility of AVNRT after intravenous sedation in pediatrics (3). Fazelifar et al. investigated inducibility of AVNRT and electrophysiological properties after deep sedation (4). Anesthesia with benzodiazepines and opiates used in a repeated bolus fashion can easily be provided without influencing accurate EP testing and/or arrhythmia induction. There are no known specific side-effects of benzodiazepines on cardiac conduction (1). Propofol and benzodiazepine may change heart rate via baroreflex regulatory mechanisms (5, 6). The authors demonstrated that AVNRT induction is not related to anesthetic agents and it could be performed safely in all patients who undergo slow pathway induction. Induction and ablation of reentrant arrhythmias such as AVNRT can be performed safely after deep sedation. Ablation after sedation in other supra-ventricular tachy-arrhythmias requires another well-designed randomized trial.

Imaging the PM/AICD patient; a neuro-cardiac efficacy study

Background Imaging patients with a pacemaker (PM) or AICD has been mostly taboo in the MRI environment. However, with current improvements in PMlead and generator development along with very vigilant and knowledgeable personnel in pacemaker safety, MRI procedures can be implemented successfully. However, safe performance, not withstanding the risks, leads one to question if the results from the scans provide additional valuable clinical information to warrant such risk. Hypothesis: We propose that MRI imaging patients with a pacemaker can be crucial to establish clinical diagnosis. Methods A total of 25 patients were imaged on a GE CV/i Excite Version 12, 1.5 T system (GE, Milwaukee, WI). Three patients had an AICD, 4 patients had an AICD/PM 2 pts had a single PM lead and the remaining 16 pts had a dualchamber PM implantation. Each pt was performed in the dedicated Cardiac MRI Imaging Suite under the strict supervision of the Cardiologist. EP Lab personnel were present and reconfigured the PMor AICD into an appropriate asynchronous mode and/or with therapies under the guidance of the Cardiologist. The MRI scan sequences were selected such that the SAR level <2.0 W/kg. Results All patients completed the procedure with no adverse events and the pacemaker was interrogated after the procedure by EP Lab. Impedance, thresholds, amplitudes and shock impedances were unchanged pre to post scanning. The average MRI scan time was 20±55min. Regarding the population, of the 25 patients imaged, 17 (68%) were neurology cases and 8(32%) were cardiac cases. After reviewing the results from the 17 neurology cases and comparing the results from prior studies (CT, angio and/ or myelogram) 14/17 (82%) pts benefited from having this procedure. Additionally, 12/17(70%) patients altered the diagnosis resulting in improved outcome in patient care. The remaining 3(18%) pts MRI did not provide additional information that enhanced the diagnosis. The 8 cardiac cases were also compared to prior studies (heart cath, TEE, TTE and stress) and the outcome of 8/8 (100%) pts’ diagnosis was shown to be enhanced by the CMR imaging. In 4/8(50%) of the 8 pts, CMR altered the prevailing clinical diagnosis while dramatically improving pt care. Thus, a total of 22 patients (88%) benefited by enhancement or alteration of the original diagnosis while 3(12%) patients did not provide any additional information. Conclusions The use of PM/AICD imaging in MRI remains controversial but as the lead/generator technology has improved, increased confidence in its use is found. Herein, we show that MRI/CMR procedures on carefully selected patients with pacemakers/AICD’s are beneficial and substantially enhance or alter patient diagnosis and downstream therapy. We propose that not only are PM/AICD’s no longer taboo in the MRI environment but in the proper setting they can be markedly efficient with life-altering and lifesaving consequences. Funding None.

Identifying non-inducible ventricular tachycardia origin utilizing defibrillator electrograms

Developing an ablation strategy when the clinical arrhythmia cannot be induced is a challenge. A 72-year-old man is transferred to our facility for ventricular tachycardia (VT) storm. Endocardial and epicardial voltage mapping was normal and program stimulation failed to induce any arrhythmias. Implantable cardioverter-defibrillators (ICD) electrograms (EGMs) were recorded while pacing and compared to the stored clinical events. Ablation lesions were delivered across a narrow area of matching ICD EGM pace maps. The patient has remained arrhythmia free for 11 months. ICD EGMs may be useful in facilitating successful VT ablation when the clinical arrhythmia cannot be induced in the EP lab.

060 The practice and perception of transvenous lead extraction in the UK: lessons from a nationwide survey

IntroductionThe rate of cardiac implantable electronic device (CIED) implantation in the UK has been rising consistently and this trend is likely to continue. We sought to establish the nature of...

Laser sheath for tunneled dialysis catheters extraction

The number of patients with acute renal failure and end-stage renal disease undergoing hemodialysis (HD) has increased during the past years, and the management of vascular access is pivotal. Among tunneled dialysis catheters (TDC), Tesio twin-catheter system (Medcomp, Harleysville, PA, USA) provides good long-term survival with acceptably high blood flow and low complication rates [1, 2]. Unfortunately, catheter infection is still a serious and common complication related to temporary HD vascular access. When catheter infection and/or dysfunction occur, extraction is mandatory [3]. Although the development of a fibro-epithelial sheath is a common occurrence, TDC extraction is usually easily performed by traction or cut down technique [3, 4]. However, when the catheters are tethered or attached to central veins and/or to right atrium, these techniques could lead to their rupture and retention and could increase the risk of vascular or atrial wall avulsion. Laser extraction technique is usually adopted for pacing leads, but it can also be helpful in TDC extraction to avoid the previous mentioned complications. A circumferential Excimer laser beam applied at the tip of a specialized telescopic sheath is passed over the lead. The energy source comes from a xenon chloride laser with an output wave length of 308 nm. It is a cool cutting laser (50 C) with a very limited absorption depth; twothirds of the energy are absorbed within 0.06 mm from the tip of the sheath by proteins and lipids instead of water. These technical characteristics allow the ablation of the fibro-epithelial sheath surrounding TDC without damaging the endothelial wall and the catheter itself [5]. According to these assumptions, our laboratory has decided to adopt this technique to extract tethered TDCs. A woman of 57 years, affected by endstage renal disease, was admitted to our Department for a Tesio twin-catheter system-associated bacteraemia. A transesophageal echocardiographic evaluation showed a thrombus occluding the apex of the right atrial appendage. A valvular involvement was excluded. After 2 months of oral anticoagulation therapy, she underwent TDC extraction performed using an Excimer Laser system emitting energy at the tip of a flexible, fiber-optic 12F-sheath (Spectranetics Inc., Colorado Springs, CO, USA). The procedure was performed under assistant sedation with i.v. midazolam. First, the TDC was isolated. Then, an A. Curnis L. Bontempi M. Cerini F. Vassanelli A. Lipari N. Ashofair C. Pagnoni L. Dei Cas Division of Cardiology, EP Lab, Post Graduate School of Cardiology, Spedali Civili, University of Brescia, Brescia, Italy