A nurse-led implantable loop recorder service is safe and cost effective.

INTRODUCTION: Implantable loop recorders (ILR) are predominantly implanted by cardiologists in the catheter laboratory. We developed a nurse-delivered service for the implantation of LINQ (Medtronic; Minnesota) ILRs in the outpatient setting. This study compared the safety and cost-effectiveness of the introduction of this nurse-delivered ILR service with contemporaneous physician-led procedures. METHODS: Consecutive patients undergoing an ILR at our institution between 1st July 2016 and 4th June 2018 were included. Data were prospectively entered into a computerized database, which was retrospectively analyzed. RESULTS: A total of 475 patients underwent ILR implantation, 271 (57%) of these were implanted by physicians in the catheter laboratory and 204 (43%) by nurses in the outpatient setting. Six complications occurred in physician-implants and two in nurse-implants (P = .3). Procedural time for physician-implants (13.4 ± 8.0 minutes) and nurse-implants (14.2 ± 10.1 minutes) were comparable (P = .98). The procedural cost was estimated as £576.02 for physician-implants against £279.95 with nurse-implants, equating to a 57.3% cost reduction. In our center, the total cost of ILR implantation in the catheter laboratory by physicians was £10 513.13 p.a. vs £6661.55 p.a. with a nurse-delivered model. When overheads for running, cleaning, and maintaining were accounted for, we estimated a saving of £68 685.75 was performed by moving to a nurse-delivered model for ILR implants. Over 133 catheter laboratory and implanting physician hours were saved and utilized for other more complex procedures. CONCLUSION: ILR implantation in the outpatient setting by suitably trained nurses is safe and leads to significant financial savings.

Prolonged action potential duration and dynamic transmural action potential duration heterogeneity underlie vulnerability to ventricular tachycardia in patients undergoing ventricular tachycardia ablation.

AIMS: Differences of action potential duration (APD) in regions of myocardial scar and their borderzones are poorly defined in the intact human heart. Heterogeneities in APD may play an important role in the generation of ventricular tachycardia (VT) by creating regions of functional block. We aimed to investigate the transmural and planar differences of APD in patients admitted for VT ablation. METHODS AND RESULTS: Six patients (median age 53 years, five male); (median ejection fraction 35%), were studied. Endocardial (Endo) and epicardial (Epi) 3D electroanatomic mapping was performed. A bipolar voltage of <0.5 mV was defined as dense scar, 0.5-1.5 mV as scar borderzone, and >1.5 mV as normal. Decapolar catheters were positioned transmurally across the scar borderzone to assess differences of APD and repolarization time (RT) during restitution pacing from Endo and Epi. Epi APD was 173 ms in normal tissue vs. 187 ms at scar borderzone and 210 ms in dense scar (P < 0.001). Endocardial APD was 210 ms in normal tissue vs. 222 ms in the scar borderzone and 238 ms in dense scar (P < 0.01). This resulted in significant transmural RT dispersion (ΔRT 22 ms across dense transmural scar vs. 5 ms in normal transmural tissue, P < 0.001), dependent on the scar characteristics in the Endo and Epi, and the pacing site. CONCLUSION: Areas of myocardial scar have prolonged APD compared with normal tissue. Heterogeneity of regional transmural and planar APD result in localized dispersion of repolarization, which may play an important role in initiating VT.

A simple infection-control protocol to reduce serious cardiac device infections.

AIM: Device infection is a serious complication and is considered procedure-related if occurring within 12 months of an intervention. We analysed the effectiveness of a simple infection-control protocol (ICP) at reducing cardiac device infections (CDIs) in a tertiary referral centre. METHODS AND RESULTS: Prior to the introduction of a new ICP, we retrospectively analysed all simple and complex device implants, related procedures, and infections over a 3-year period. A new protocol was implemented from November 2007, including antibiotic prophylaxis determined by risk stratification, improved glycaemic control, specific skin preparation, and closure techniques, as well as different diathermy settings. Follow-up data for all patients were collected. Risk factors for infection were compared between pre- and post-intervention groups to ensure that the populations were comparable. A cost analysis of CDI and a review of the commonly identified micro-organisms were also undertaken. One thousand seven hundred and ninety-eight procedures were performed between November 2004 and November 2007 and 981 procedures between November 2007 and May 2009. There were no significant differences in the risk factors for infection between the two groups. Following the introduction of the ICP, there was a 54% reduction in the incidence of CDI from 1.3 to 0.6% (P < 0.03; CI 0.25, 1.36). Most patients with CDI had negative blood cultures or grew Staphylococcus sp. The average cost was £30 958.40 per infection incident and the cost of the new ICP was minimal. CONCLUSIONS: A significant reduction in CDI can be achieved with the introduction of a simple ICP with substantial cost savings.

An 8-year single-centre experience of cardiac resynchronisation therapy: procedural success, early and late complications, and left ventricular lead performance.

AIMS: Despite the increasing number of device implants worldwide, little is known about the early and late complications of cardiac resynchronisation therapy (CRT) or the incidence of these complications in patients with different heart failure aetiologies. We aim to determine procedural success and early and late complications in CRT patients. METHODS AND RESULTS: All early (<90 days) and late (>90 days) complications occurring over 490 consecutive CRT procedures in 402 patients, from a large single-centre registry between 2000 and 2009 were analysed. Mean follow-up duration was 1012 ± 610 days. In addition, procedural data and long-term left ventricular (LV) lead performance were examined. The mean age of patients was 65 ± 15 years, 31% were female. The majority of devices (70%) were CRT-defibrillators. Left ventricular lead implantation was achieved after one or more than one attempt in 96.7% of patients (first procedure was successful in 95.1%). The incidence of early and late complications was 9.4% and 6.1% respectively. Infection and lead displacement were the most common complications. Dilated cardiomyopathy (DCM) was associated with significantly more complications than ischaemic cardiomyopathy (P = 0.01) and these occurred later in the DCM population. Long-term LV lead performance was comparable with that of right atrial and ventricular leads. CONCLUSION: Transvenous implantation of the LV lead is safe and achievable for CRT with high procedural success rates. For the first time we describe the late complications from CRT in different heart failure populations. This group of patients must be kept under surveillance, not only for heart failure events but also for device-related issues. The reasons for higher complication rates in DCM patients require further evaluation.

Predictors of recurrence following radiofrequency ablation for persistent atrial fibrillation.

AIMS: To establish clinical factors affecting success in persistent atrial fibrillation (AF) ablation. METHODS AND RESULTS: Wide area circumferential ablation with linear and electrogram-based left atrial (LA) ablation was performed in 191 consecutive patients for persistent AF. After mean follow-up of 13.0 ± 8.9 months, overall success was 64% requiring a mean of 1.5 procedures. Single procedure success rate was 32%. Left atrial size was a univariate predictor of recurrence after a single procedure (P =0.04). Only LA size [hazard ratio (HR) 1.05/mm with 95% confidential interval (CI) 1.02-1.08] was an independent predictor of recurrence after a single procedure. Only LA size was a univariate predictor of recurrence after multiple procedures (P < 0.01). Left atrial size (HR 1.07/mm with 95% CI 1.02-1.11) and hypertrophic cardiomyopathy (HCM; HR 2.42 with 95% CI 1.06-5.55) were independent predictors of recurrence after multiple procedures. Ablation strategy did not affect success after a single procedure. Left atrial size of <43 mm predicted long-term success with a sensitivity of 92%, specificity 52%, positive predictive value 49%, and negative predictive value 93%. With LA size >43 mm, HCM (HR 3.09 with 95% CI 1.70-7.5) and AF duration (HR 1.07/year with 95% CI 1.00-1.13) were independent predictors of recurrence. CONCLUSION: Left atrial size is the major independent determinant of AF recurrence after ablation for persistent AF. This has important implications for patient selection for persistent AF ablation and the evaluation of AF ablation clinical trial results.

Management of atrial fibrillation after transcatheter aortic valve replacement: Challenges and therapeutic considerations.

Atrial Fibrillation (AF) is very common among patients with severe aortic stenosis. Moreover, new onset AF (NOAF) is a frequent finding after Transcatheter Aortic Valve Replacement (TAVR). There is a significant impact of AF on outcomes in patients undergoing TAVR including mortality, thrombo-embolic and bleeding events. There is lack of clear evidence about the optimal management of AF in TAVR patients. This review aims to summarize the epidemiology, predictors, prognosis, therapeutic considerations and challenges in the management of AF in patients undergoing TAVR.

Incidence of left atrial thrombus prior to atrial fibrillation ablation: is pre-procedural transoesophageal echocardiography mandatory?

AIMS: The exact role of transoesphageal echo (TOE) prior to atrial fibrillation (AF) ablation remains unclear. This study examines the incidence and predictors of left atrial (LA) thrombus in patients undergoing AF ablation. METHODS AND RESULTS: Patients were treated with warfarin for at least 4 weeks prior to ablation. This was substituted with therapeutic dalteparin 3 days before the procedure. All patients underwent TOE to exclude LA thrombus. Six clinical risk factors for thrombus were defined, known to be risk factors for stroke in AF: age>75, diabetes, hypertension, valve disease, prior stroke, or transient ischaemic attack and cardiomyopathy. A total of 635 procedures were performed. The incidence of thrombus was 12/635 (1.9%) despite therapeutic anti-coagulation. Patients with thrombus had larger LA diameter, mean 50.6+/-6.2 mm vs. 44.2+/-7.6 (P=0.006). In univariate analysis, persistent AF [odds ratio (OR)=10.4 with 95% CI 1.8-19.1], hypertension [OR=11.7 with 95% CI 2.5-54.1], age>75 (OR=4.5 with 95% CI 1.2-17.2), and cardiomyopathy (OR 5.9 with 95% CI 1.8-19.1) were significantly associated with thrombus. In multivariate analysis, hypertension (OR=14.2 with 95% CI 2.6-77.5), age>75 (OR=8.1, 95% CI 1.5-44.9), and cardiomyopathy (OR=10.5 with 95% CI 2.6-77.5) were independently associated with thrombus. There was no thrombus in patients without clinical risk factors. CONCLUSION: In patients presenting for AF ablation, LA thrombus is only seen in those with clinical risk factors. TOE is indicated in this group but may be unnecessary in patients without clinical risk factors.

Use of an angioplasty wire to perforate the interatrial septum for a difficult transseptal puncture.

With the expansion in catheter-based treatments for atrial fibrillation the number of transseptal punctures being performed by cardiac electrophysiologists has increased significantly. Although in general transseptal puncture is successful, in a small percentage of cases it cannot be achieved due to complex intraatrial anatomy. We report the case of a difficult transseptal puncture (TSP), performed where the conventional approach using a Brockenbrough needle sheath was unable to perforate the septum. TSP was only achieved using a novel technique assisted by an angioplasty wire.

The evolving landscape of oral anti-arrhythmic prescriptions for atrial fibrillation in England: 1998-2014.

AIMS: An important decision in the management of patients with atrial fibrillation is whether to adopt a rate or rhythm control strategy. Options for the latter include oral membrane-active anti-arrhythmic drugs (AADs) or catheter ablation. Recent prescription trends may have been affected by the introduction of dronedarone and an increasing number of reports suggesting increased mortality in those taking AADs. We describe the trend in oral AAD prescriptions in England in the period 1998-2014. METHODS AND RESULTS: We conducted a retrospective study using data from the Prescription Cost Analysis system, which holds information on every prescription dispensed in the community in England. We obtained data from 1998 to October 2014 for all Class Ia, Ic, and III AADs. Amiodarone and sotalol remain the most commonly prescribed AADs in England, though the use of both is decreasing. There has been a linear increase in the uptake of flecainide. Dronedarone prescriptions peaked in 2011, and our most recent data show that amiodarone prescriptions are 25-fold those of dronedarone. CONCLUSION: There is a decline in the use of amiodarone and sotalol consistent with the growing safety concerns with these drugs along with neutral results from landmark trials comparing rate and rhythm control. Dronedarone has failed to make an impact on AAD prescribing. In contrast, flecainide has seen an increase in use during the study period.

Is CRT pro-arrhythmic? A comparative analysis of the occurrence of ventricular arrhythmias between patients implanted with CRTs and ICDs.

UNLABELLED: Aim and Hypothesis: Despite the proven symptomatic and mortality benefit of cardiac resynchronization therapy (CRT), there is anecdotal evidence it may be pro-arrhythmic in some patients. We aimed to identify if there were significant differences in the incidence of ventricular arrhythmias (VAs) in patients undergoing CRT-D and implantable cardioverter-defibrillators (ICD) implantation for primary prevention indication. We hypothesized that CRT is unlikely to be pro-arrhythmic based on the positive mortality and morbidity data from large randomized trials. METHODS AND RESULTS: A retrospective analysis of device therapies for VA in a primary prevention device cohort was performed. Patients with ischemic (IHD) and non-ischemic (DCM) cardiomyopathy and ICD or CRT+ICD devices (CRT-D) implanted between 2005 and 2007 without prior history of sustained VA were included for analysis. VA episodes were identified from stored electrograms and defined as sustained (VT/VF) if therapy [anti-tachycardia pacing (ATP) or shocks] was delivered or non-sustained (NSVT) if not. Of a total of 180 patients, 117 (68% male) were in the CRT-D group, 42% IHD, ejection fraction (EF) 24.5 ± 8.2% and mean follow-up 23.9 ± 9.8 months. 63 patients (84% male) were in the ICD group, 60% IHD, EF 27.7 ± 7.2% and mean follow-up 24.6 ± 10.8 months. Overall, there was no significant difference in the incidence of VA (35.0 vs. 38.1%, p = 0.74), sustained VT (21.3 vs. 28.5%, p = 0.36) or NSVT (12.8 vs. 9.5%, p = 0.63) and no significant difference in type of therapy received for VT/VF: ATP (68 vs. 66.6%, p = 0.73) and shocks (32 vs. 33.3%, p = 0.71) between the CRT-D and ICD groups, respectively. CONCLUSION: In patients with cardiomyopathy receiving CRT-D and ICDs for primary prophylaxis, there was no significant difference in the incidence of VA. From this single center retrospective analysis, there is no evidence to support cardiac resynchronization causing pro-arrhythmia.

A multi-purpose spiral high-density mapping catheter: initial clinical experience in complex atrial arrhythmias.

PURPOSE: There is an increasing need for catheter ablation procedures to treat complex atrial tachycardias (AT) and atrial fibrillation (AF), often requiring detailed endocardial mapping. The sequential point-to-point contact mapping of complex arrhythmias is time-consuming and may not always be feasible. We assessed the utility of a novel spiral duo-decapolar high-density (HD) mapping catheter to delineate complex arrhythmia substrates for ablation. METHODS: The patients underwent HD mapping using a spiral catheter (AFocusII) and the EnSite NavX system, during catheter ablation procedures, to treat atrial arrhythmias. RESULTS: In 26 patients, a total of 32 atrial arrhythmias were mapped and ablated, comprising of five focal AT, eight macroreentrant AT, 11 persistent AF and eight paroxysmal AF. The HD catheter was used to acquire endocardial surface geometries in all cases and to map the pulmonary veins in patients undergoing AF ablation. In persistent AF, HD catheter mapping permitted the creation of highly detailed complex fractionated electrogram maps (left atrium 449 ± 128 points in 7.2 ± 2.6 min; right atrium 411 ± 113 points in 6.7 ± 1.6 min). In AT, activation mapping was performed with the acquisition of 305 ± 158 timing points in 7.3 ± 2.6 min, guiding successful ablation in all cases. During the follow-up of 7.0 ± 2.6 months, all AT patients remained free of significant arrhythmia. CONCLUSIONS: High-density contact mapping with a novel spiral multipolar catheter allows rapid assessment of focal and macroreentrant AT, and complex fractionated electrical activity in the atria. It has further multi-functional capabilities as a pulmonary vein mapping catheter and for accurate geometry creation when used with a 3D mapping system.

First report of phrenic nerve injury during pulmonary vein isolation using the Ablation Frontiers pulmonary vein ablation catheter.

In an attempt to improve procedural outcomes and reduce time and complications, there has been particular interest in alternative technologies specifically designed for atrial fibrillation (AF) ablation. One novel technique is isolation of the pulmonary veins using an over-the-wire multielectrode catheter delivering duty-cycled bipolar and unipolar radiofrequency energy. Phrenic nerve injury is a rare but significant complication of AF ablation. This is the first report of phrenic nerve injury following catheter ablation for AF using the Pulmonary Vein Ablation Catheter (Medtronic, Minneapolis, MN, USA).

Wound management and restrictive arm movement following cardiac device implantation - evidence for practice?

BACKGROUND: The rate of cardiac device implantation has risen significantly secondary to an increase in the number of indications. Wound infection and lead displacement are two common and potentially life-threatening complications. No national/international guidelines address postoperative care and controversy exists regarding wound management and arm movement following cardiac device implantation. AIMS: We aimed to explore and review the evidence behind current practice but found that certain aspects of established practice. METHODS: An electronic search of the databases EMBASE, British Nursing Index, CINAHL, Cochrane and PubMed to identify evidence regarding wound management and lead displacement. FINDINGS: We found that certain aspects of established practice are based on tradition rather than evidence. Recent guidelines on wound management published by The National Institute for Health and Clinical Excellence in the UK recommend covering the wound postoperatively for 48 h with a low-adherent transparent dressing and letting patients shower thereafter. Since specific guidelines for cardiac device patients are lacking, we suggest that further research address whether or not the NICE guidelines can be extrapolated to this area. Studies showed that early mobilisation and allowing a full range of arm movements following device implantation is safe. Further research must validate these findings. CONCLUSION: We discuss the reasons behind these gaps in the evidence base and support the idea that nursing education has not placed enough emphasis on how to critically appraise research. This accounts for the very small proportion of nurses that get involved in conducting research and generating guidelines. Additionally, we argue that nurses can play a key role in identifying and addressing research questions that lead to improved patient outcome. Thus, we support proposals to enhance nurses' opportunities to pursue academic careers to achieve adequate research skills.