Aim: To describe the performance and clinical outcomes of pts having a Medtronic Micra leadless pacemaker (LP) implanted at a single institution.

Introduction: The epicardium may contain the substrate underlying various arrhythmias. We describe the characteristics and outcomes of pts who have undergone percutaneous epicardial (EPI) access and mapping at our centre. Methods: Pts referred for catheter ablation between 2011 and 2017 were retrospectively reviewed. Demographic, procedural and outcome data were analysed. Results: 33 pts underwent EPI access. Access was successful in all cases. The indication was scar VT in 25/33 (76%), idiopathic VT in 4/33 (12%), SVT in 2/33 (6%), Brugada Syndrome in 1/33 (3%) and inappropriate sinus tachycardia in 1/33 (3%). Prior endocardial ablation had been attempted in 28/33 (85%) pts. Access was obtained using a 16F Tuohy needle in 25/33 (76%) cases and the remaining 8 cases utilised the ‘needle-in-needle’ technique. EPI radiofrequency ablation (RFA) was attempted in 20/33 (61%) cases, with acute procedural success occurring in 18 (90%) of these. EPI RFA was not performed in 9/12 (75%) cases due to minimal EPI substrate seen on mapping. Other limitations included coronary artery proximity (1 pt) and dense EPI adhesions (1 pt). 2 pts experienced complications (7%). Coronary artery occlusion requiring stenting occurred in one pt and RV perforation causing tamponade occurred in another. Conclusion: Percutaneous epicardial access can be considered in pts with various complex arrhythmias, especially if endocardial ablation attempts have failed or epicardial substrate is likely. EPI access is usually successful but complications are possible. In the majority of cases where EPI ablation is attempted, this contributes to acute procedural success.

Introduction: Implantable cardiac loop recorders (ILRs) are implanted to help establish a correlation between symptoms and cardiac arrhythmias in patients suffering from recurrent syncope of unknown aetiology. The Reveal LINQ ILR has increased remote monitoring capabilities and allows automatic transmissions for the detection of atrial fibrillation, bradycardia, tachycardia, and pauses of programmable rates/duration, as well as patient initiated transmissions. Methods: 33 patients (20 reveal LINQ: 13 Reveal DX/XT) are followed up via our remote monitoring service. We retrospectively analysed the total number of transmissions, including routine, patient initiated and episode initiated transmissions over a six-month period between June and December 2015. Transmissions were further analysed, and classified as being appropriate or inappropriate due to over sensing, under sensing or signal drop out. Results: Over the six-month period 294 remote transmissions were received for ILRs (275 LINQ: 19 Reveal DX/XT). The median number of transmissions per patient, per year was 37.3 for LINQ compared to 3.5 for Reveal DX/XT. Of the 275 LINQ transmissions, 216 were automatic transmissions, 59 were patient initiated. 46.5% of all transmissions and 59.6% of all automatic transmissions were deemed inappropriate. Inappropriate episodes were documented in 9 of the 20 LINQ patients. Conclusion: There is an increased transmission rate associated with LINQ when compared to Reveal DX/XT when followed up with remote monitoring. While there is improved availability of events with LINQ, a substantial portion of LINQ transmissions occur due to misdiagnosis of a rhythm by the device.

Introduction: Holter monitoring is commonly used in the assessment of pts with symptoms suggestive of cardiac arrhythmia. They can be applied for up to a week, with 24 hrs or 48 hrs being the most common duration. Our aim was to investigate additional benefit of 48 hr monitoring over the standard 24 hr monitor in the detection of cardiac arrhythmias or patient symptomatic events. Method: Between 12/2015 and 2/2016 our unit analysed 57, 48hr holter monitors. At the halfway point of each recording an analysis was performed investigating pt symptomatic events or significant cardiac arrhythmias (table 1). This was compared to the analysis performed at the end of the 48 hours of recording.Tabled 1Significant Cardiac Arrhythmia24 hour48 hourSustained VT or SVT00Atrial Fibillation/atrial flutter33AV block00Pause >3 seconds11Supraventricular ectopy burden >10%13Ventricular ectopy burden >10%33Patient symptomatic event1210 Open table in a new tab Results: Of the 57 holter monitors analysed, 16 (28%) recorded either a significant cardiac arrhythmia or had a pt symptomatic event. Of the recordings with significant arrhythmias, only two occurred in the second half of the recording that did not in the first half. There were no instances where a pt symptomatic event occurred in the second half of a recording that did not also occur in the first half. Conclusion: Holter monitoring has a reasonable diagnostic yield (28%) in detecting significant cardiac arrhythmias or pt symptomatic events, however a period of 48hr monitoring appeared to be of limited additional benefit when compared to a shorter 24hr monitoring period.

Introduction: Leadless trans-catheter pacemaker systems have recently been developed to overcome the need for a pacemaker pocket and transvenous lead. It is hoped that this will reduce the long-term lead related problems and infections which are commonly seen with current transvenous pacing systems. Methods: To describe the early experience at The Prince Charles Hospital with the Micra Trans-catheter Leadless Pacemaker system Results: Between 12/2015 and 2/2016, 5 Male pts median age 74yrs (IQR74:79yrs) underwent implantation of a trans-catheter leadless pacemaker. All had symptomatic bradycardia and were in permanent atrial fibrillation. 2pts were on warfarin and 1pt was on Rivoraxiban at time of implant. The median in lab time was 70 mins (IQR 70:80mins) with median time from initial venous access to sheath removal of 31 min (IQR 28:31 min). The pacemaker was deployed successfully on the first attempt in 4 pts. The implant pacing performance and x-ray times are outlined in the following table. There were no femoral access site related haematomas although one pt required prolonged digital pressure because of skin ooze from the venous access skin edge. During a median follow up of 32 days there has been no procedural or device related complications. No pt has required re-intervention.Tabled 1R wave (mV)Threshold (V)@.24msImpedance (Ohms)X ray TimeDAP (uGy/m2)Median5.40.636107.5475IQR5.3:16.40.38:0:75580:7307.3-8377-764 Open table in a new tab Conclusions: In this early single centre experience, the trans-catheter leadless pacemaker appears to be able to be implanted safely with an acceptable procedural times and acute pacing performance. Longer-term follow up is clearly required but the early experience appears positive.

Introduction: Remote Monitoring is increasingly used for the follow up of Implantable Cardioverter Defibrillators (ICD), Permanent Pacemakers (PPM) and Implantable Loop Recorders (ILRs). In September 2015 Medicare re-imbursement became available for remote follow up of ICDs and PPMs. It is equivalent to approximately two in clinic ICD interrogations and one PPM interrogation per year. No re-imbursement was made available for the remote follow up ILRs. Methods: 349 pts (178 ICD: 139PPM: 32 ILR) were added to our remote monitoring service between 3/ 2008 and 12/ 2015. We retrospectively analysed the total number of ICD, PPM and ILR transmissions, including routine, patient initiated and alert initiated transmissions, which were received during this period. Results: A review of transmissions received showed, of the 178 pts with ICDs the median number of transmissions received per year was 2.26 over a median follow up of 3.4 years. Of the 139 PPM pts a median of 1.34 transmissions were received during a median follow up of 5.3 years. Of the 32 ILR pts a median of 4.1 transmissions were received per year during a median follow up of one year. Conclusion: The Medicare funding for the follow up of ICD and PPM using remote monitoring appears to be in line with the median number of transmissions received per year. ILR currently however are not reimbursed for remote follow up. They appear to have significantly more transmissions as compared to PPM and ICD pts per year. This has the potential to limit the use of remote monitoring in this patient group.

Introduction: Catheter ablation for scar-related VT in NICM is challenging. We review the characteristics and outcomes of such pts undergoing VT ablation at our centre Methods: Pts referred for VT ablation between 2011 and 2015 were reviewed Results: 35/138 (25%) pts referred for VT ablation had a NICM substrate. These pts underwent a total of 45 ablation procedures. Characteristics are outlined below.Tabled 1Variable (n = 35)Age58 ± 13 yearsLVEF36 ± 15%NYHA ClassI (58%), II (39%), III (4%)Specific AetiologySarcoidosis (17%), ARVC (6%)Pre-existing ICD/CRT22/27 (79%)Anti-arrhythmic agentsAmiodarone (63%), mexiletine (19%), sotalol (19%)Presenting symptomsRecurrent ICD shocks (91%)ComorbiditiesHTN (20%), DM (18%), AF (11%)SedationGA (22%), conscious sedation (78%)Procedure characteristicsIABP (24%), ICE (16%), epicardial mapping (33%) Open table in a new tab Of those tested 18/36 (50%) were non-inducible for VT at the end of the case. Of 32 pts with follow up data, 23 pts (72%) were free of VT requiring ICD therapy at a median follow up of 16 months (IQR 10 – 27). Conclusion: Arrhythmia-free survival following catheter ablation can be achieved in a significant proportion of NICM patients with scar-related VT.

Introduction: The left ventricular (LV) summit is a recognised site of origin of ventricular arrhythmias (VA). We review the characteristics and outcomes of pts who underwent LV summit VA ablation at our centre. Methods: Pts referred for ablation between 2011 and 2015 were reviewed. Results: Of 80 pts with idiopathic VA, 23 (29%) originated from the LV summit.Tabled 1VariableAge54 ± 13.4 yearsGender13/23 (57%) maleLVEF50.0 ± 15.2%PVC burden (pre/post ablation)38.0 ± 24.1%/6.6 ± 11.8%V1 R wave duration112.1 ± 43.8 msMaximal deflection index0.49 ± 0.10Earliest electrogram timing pre-QRS30.1 ± 16.6 ms Open table in a new tab Attempted ablation via the anterior interventricular vein (AIV) or great cardiac vein (GCV) was possible in 7 pts. Of these, 6 (86%) had a successful outcome. Ablation via the AIV/GCV was unsuccessful in the remainder due to coronary artery proximity (7 pts), coronary venous access issues (3 pts), high impedance during ablation (3 pts) and summit sites remote from coronary venous vessels (3 pts). Of these, 8/16 (50%) had ablation performed successfully from adjacent sites. 3 pts had pericardial access obtained, but none were successfully ablated from the epicardium. Conclusion: Ablation of LV summit VA is challenging. Outcomes are best when ablation can be performed via the AIV/GCV.

Background: Involvement of the right ventricle (RV) during inferior AMI has been defined as a strong predictor of major complications and in-hospital mortality. This study aims to describe long-term outcomes in patients with acute ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI) to a right coronary artery (RCA) or dominant left circumflex artery (LCx). Methods: Retrospective review of patients presenting with acute STEMI, treated with primary PCI to the RCA or dominant LCx, from January 2011 until January 2013. Patient outcomes were reviewed for 24-months from indexed admission. RV dysfunction was categorised as absent, mild, moderate or severe from transthoracic echocardiography performed within 30 days of indexed event. Composite primary end point was: all-cause mortality, reinfarction and heart failure hospitalisation. Results: 204 patients were identified, 156 (76%) males and 48 (24%) females. Mean age: 62 years. 37(19%) had RV dysfunction, 13 (6.4%) had LVEF<40%. 68 (33%) patients reached the composite primary end-point. 10 (4.9%) died in the follow-up period, 4 (2%) were in-hospital deaths. 38 (19%) represented with reinfarction and 20 (9.8%) represented with heart failure. Any RV dysfunction was associated with a higher risk of the composite primary endpoint than those with a normal RV (OR, 2.2; 95% CI, 1.0 to 4.7; p<0.05). Conclusion: A significant proportion of acute STEMI with PCI to the RCA or dominant LCx is associated with RV dysfunction. These patients are at an increased risk of representation with reinfarction or heart failure within a 24 month period.

Introduction: Percutaneous epicardial catheter mapping and ablation can lead to a significant inflammatory and fibrotic response. Intrapericardial glucocorticoid administration attenuates this response in animal models and clinical series with minimal systemic effects are described. We assessed white blood cell (WBC) and neutrophil response following epicardial mapping procedures to index systemic absorption of intrapericardial triamcinolone acetate (IPTA). Methods: Eight pts that underwent scar related epicardial ablation for ventricular tachycardia (VT) since 2011 were included. They all received 2 mg/kg IPTA. Fourteen pts that underwent scar related endocardial-only VT ablation and 12 pts who underwent pericardiocentesis were included as controls. Total WBC and neutrophil counts were compared pre and post procedure. Results: The median ejection fractions were 37%, 30% and 60% for the epicardial, endocardial and pericardiocentesis groups respectively. Both neutrophil and WBC counts increased post-procedurally in the epicardial group with no increase seen in the other groups despite more RF lesion delivery (30 vs 64) in the endocardial–only ablation group. No associated local or systemic complications of IPTA were seen.Tabled 1Group (n)WBC (pre)WBC (post)p valueNeutrophil (pre)Neutrophil (post)p valueEpicardial (8)8. 113.30.0434.711.70.018Endocardial (14)7.78.20.7784.66.00.594Pericardiocentesis (12)8.07.90.4105.65.60.937 Open table in a new tab Conclusions: An increase in WBC count was seen after epicardial ablation with the use of IPTA suggesting significant systemic absorption of the drug. Further studies are warranted to optimise the dosage, safety and efficacy of this practice.

The St Jude Medical Riata ICD lead is subject to a hazard alert because of a high failure rate of the silicone insulation. Optimal management of this lead is not well defined. Lead integrity alerts (LIA) and remote monitoring (RM) have been proposed as potential ways to provide early warning of lead failure and possibly prevent inappropriate shocks. Methods: We evaluated the outcomes of 103 patients undergoing generator change with normally functioning Riata leads. All leads were assessed for normal function at time of generator change by a combination of visual inspection (103/103), DFT testing (94/103) or lead screening (68/103). Results: Thirty-nine patients were placed on RM and 61 patients had an LIA enabled device implanted. During a median follow up of 17 months, 8% (8/103) failed. The median time to failure was 19.5 months. Early detection of lead failure was seen in four patients triggered by LIA (2) or RM (2). Of the four patients who did not receive early warning, one patient had LIA inadvertently off, one patient didn't satisfy LIA criteria, and two patients had devices without LIA or RM. Two patients received an inappropriate shock for noise. No patient with LIA turned on or RM received an inappropriate shock. No deaths occurred during follow up that could be attributed to lead malfunction. Conclusions: Despite a normally functioning Riata lead at generator change, 8% of leads failed at a median of 17 months post generator change. LIA and RM appear to be helpful in preventing inappropriate shocks.

Introduction: Majority of idiopathic ventricular tachycardias (VT) arise from the infundibulum of the right ventricle (RV). Non-infundibular idiopathic VTs are known to arise from multiple sites in both ventricles. We aimed to examine the outcomes of ablation in this group. Methods: We retrospectively assessed the outcomes following ablation of non-infundibular VT at The Prince Charles Hospital since February 2011. Results: A total of 32 patients with idiopathic VT underwent ablation of whom 18 had non-infundibular VT/ventricular ectopy. A total of 22 procedures were performed. Seventy-two percent were male with a mean age of 49.4 yrs. Palpitations were the commonest clinical symptom. The mean ejection fraction was 58%. Sustained VT was demonstrated in 10 patients. The common sites of origin were papillary muscles (27%), the anterior interventricular vein (11%), aortic cusps (11%), LV apex (6%) and mitral annulus (6%). Electroanatomic mapping was used for all patients and intracardiac echo was required in 13/22 procedures. Percutaneous pericardial access was needed in one patient. Twenty (91%) procedures were either successful or partially successful (partially successful defined as suppression of the dominant clinical morphology). Four patients underwent a repeat procedure. One patient had a groin haematoma. There were no other acute or long-term complications at median clinical follow up of 4.5 months (2–12). Ten patients (55%) remained asymptomatic and five (28%) had reduced symptom frequency. Conclusions: Catheter ablation of non-infundibular idiopathic VTs results in favourable clinical outcomes with low complication rates.

Background: There have been many advances in the area of cardiovascular electrophysiology and radiofrequency ablation (RF) in the past 10 years. One of the biggest changes is the introduction and use of three-dimensional mapping technology to treat arrhythmias that previously have been difficult, if not impossible, to treat. This study aims to review the trends in ablation over a period of 15 years at single tertiary referral site. Methods: Data was extracted from the hospital electrophysiology database for all ablations performed from 1998 to 2012. The data was grouped into a three-year period 1998–2001 and four-year periods there after until 2012. Data analysed included procedure time, X-ray time and ablation sites. Ablation procedures were grouped into complex ablation [atrial fibrillation (AF), ventricular tachycardia (VT) and atrial tachycardia (AT)] and simple ablation [AV nodal re-entry tachycardia (AVNRT), bypass tracts (BT), atrial flutter (AFL) and AV node (AV)]. Results: A total of 2640 procedures were performed over the period analysed. During the period complex ablation increased from 13 to 34% of the workload (Fig. 1). During this time period there been an increase in procedure time (Fig. 2). Conclusions: This analysis shows complex ablations have increased in frequency over the time period and are associated with a two-hour longer procedure time on average. This is placing significant pressure on limited hospital resources.

Background: Recent changes to the CRT guidelines recommend BVICDs should be implanted in patients with less advanced heart failure. The cost effectiveness of CRT depends very much on battery longevity. In patients with less advanced heart failure and an overall better prognosis, battery longevity will become increasingly important in maintaining cost effectiveness. Aim: To compare battery longevity between two major manufacturers Methods: The time to elective replacement of BVICDs implanted at a single institution from 2004 was reviewed Results: 301 BVICDs were implanted in 264 patients. The median age was 66 years. The median EF was 25%. 142 Guidant and 159 Medtronic devices were implanted during the period. All devices included in this analysis had a functioning LV lead implanted and programmed to pace both ventricles. The estimated mean time to ERI for all devices was 2089 days. The estimated mean time to replacement for Guidant devices was 2170 days compared to Medtronic 1840 days (see Fig. 1). This difference was significant (p = 0.024). The median LV pacing threshold of all leads was 1 [email protected] ms. 30 LV (10%) leads had a high pacing (>2.5 V) thresholds. There was no difference between manufacturers. During a median follow up of 987 days, 36 patients died. Conclusions: The estimated median time to device replacement was a modest 2089 days. A significant difference between manufactures was observed. Further advances in battery technology that allow greater longevity is urgently required if cost effectiveness of CRT is to be maintained as we move to a lower risk patient group.

Background: The oral direct thrombin inhibitor dabigatran has been shown to be effective for prevention of thromboembolism in patients with atrial fibrillation. No effective antidote for dabigatran exists and current periprocedural guidelines suggest withholding Dabigatran for up to five days prior to elective procedures. We report an early experience with pacemaker and ablation procedures performed without interruption of dabigatran therapy. Methods: Consecutive patients undergoing pacemaker and ablation procedures were studied. Demographic and procedural data was collected. Dabigatran dosage was recorded, in addition to use of other anticoagulants. Results: Eleven patients underwent a total of twelve procedures. There were seven male patients (64%), mean age 74 years and median CHADS2 score was 2. Two patients were also on Aspirin. Mean creatinine clearance was 70 mL/min/1.73 m2. Procedures included permanent pacemaker implantation (6), implantable cardioverter-defibrillator implantation (1), pacemaker generator change (2), atrial flutter ablation (2) and AV node ablation (1). Venous access was via subclavian, axillary, cephalic or femoral vein. The mean time between the last dose of dabigatran and procedure start time was 10 h. Mean procedure time was 64 min. No bleeding complications were recorded. Pneumothorax occurred in one device patient; dabigatran was withheld and an intercostal catheter was placed without further complication. Conclusion: In this early series, no bleeding or thrombotic complications following pacemaker and catheter ablation procedures were noted in patients on dabigatran whose anticoagulation was not interrupted periprocedurally. Further study will be required to define the safety and efficacy of this approach.

Background: Laser powered sheaths have become the preferred tool to achieve high success rate during lead extraction, however initial and ongoing costs are significant. Methods: To review the outcomes of successive patients undergoing lead removal at a tertiary referral institution. Results: During a 10 y period to 2011, 300 pts, median age 68 y (6–99) underwent lead extraction. A total of 518 leads were removed, including 374 pacemaker (PM), 101 high voltage (HV), and 43 LV leads. A mean of 1.75 leads (1–5) were removed per pt. A superior approach was used in 99% of cases. The indication for lead removal was infection 169, malfunctioning leads 82, abandoned leads 24, venous obstruction/growth 11 and other 10. The median implant duration was 68 mths (6–312 mths). Simple traction was used in 52% (273/518), non-powered dilator sheaths 16% (83/518) and electrosurgical sheaths 32% (162/518). 98.7% (511/518) of the leads in 293 pts were completely removed. In 1.1% (6/518) partially removal was achieved (5 PM and 1 HV lead). In 0.2% (1/512) the procedure was unsuccessful due to PM lead fragmentation and this was removed surgically. Four serious adverse events occurred (1.3%): two pericardial effusions requiring percutaneous drainage, one haemopneumothorax and one tricuspid value injury requiring subsequent surgical intervention. No emergency surgical intervention was needed, with no procedure-related in hospital mortality. Conclusions: PM and HV leads can be removed safely with a high success rate without laser powered sheaths. The outcomes in this single centre experience compare favourably with reported large multicenter laser lead extraction series.

Introduction: Many parahisian focal atrial tachycardias (FAT) can be successfully ablated from the non-coronary cusp (NCC) of the aortic root. We identified clues that could obviate the need for intracardiac mapping of both sides of the interatrial septum prior to targeting the NCC. Methods: We reviewed clinical and electrophysiologic data from a single-centre series of patients with FAT that underwent radiofrequency ablation (RFA) from the NCC. Results: Five patients were included, three female, aged 43–78 years. One patient had LV systolic dysfunction but the remainder had no structural disease. FAT was induced by programmed stimulation in three patients (incessant in two), cycle length 400–540 ms, P wave morphology variable but narrow (70–89 ms) in all with biphasic V1. The atrial electrogram on the His catheter preceded the P wave by 15–30 ms. When this was seen, the NCC was directly targeted next. Here, with a far-field His recording, atrial activation was seen 35–46 ms pre-P wave and 4 mm tip RFA (30–50 W) was immediately successful in 4 pts within 2.1–6.0 s after acceleration. In the other pt, NCC catheter pressure suppressed FAT and RFA there rendered it noninducible. No AV block was seen. No recurrence has occurred over a follow up of 2–10 months. Conclusions: Parahisian FAT can be successfully ablated from the NCC of the aortic root. The presence of a His A electrogram that precedes the surface P wave by ≥15 ms may represent a marker that precludes the need for intracardiac mapping and allows direct targeting of the NCC for RFA.

Introduction: Developments in implantable cardioverter-defibrillator (ICD) lead technology have facilitated wider acceptance of ICDs as an essential component of primary prevention of sudden cardiac death and treatment of ventricular tachyarrhythmias. Nowadays ICD implantation is a safer procedure, but complications still do occur. Our study evaluates the incidence, mechanism and management of ICD lead complications. Methods and results: A single-centre ICD database review yielded 1627 patients (1309 male) who received 1751 transvenous ICD leads between January 1988 and September 2010. Mean age at implant was 58.96 years (range, 11 months to 90 years). Implant indication was primary prevention in 756 patients. Mean follow-up time was 42.5 months. There were 245 deaths at study conclusion. In total, 159 lead complications occurred, including 100 lead failures (5.71%), 56 infected systems (3.2%), two cardiac tamponades, and one death during defibrillation threshold testing. Mean lead survival time was 175.84 months (165.24–186.44 months, 95% CI). Cumulative event-free lead survival was 96.9% at one year, 86.9% at five years, and 66.6% at 10 years. Most common lead faults noted were a raised pacing threshold (36%) and noise (20%). Adverse events necessitated surgical intervention in 138 cases (107 leads explanted, 31 abandoned). Conclusion: The risk of adverse events rises as leads age. This concern is more pressing now that ICD recipients are living, and being followed up, longer. Research must be undertaken into ways to improve long-term reliability of ICD leads, and to more rigorously monitor patients with older leads.

Background: Implantable Cardiac Defibrillators (ICDs) are an important life saving therapy associated with considerable cost to the health care sector. We investigated the number of ICD generator changes required for this patient population at one tertiary referral centre prior to death.