Low voltage area as a predictor of recurrence after a single pulmonary vein isolation procedure: results of the WAVE-MAP AF study

Background/Introduction

Pulmonary vein isolation (PVI) is a recommended approach for atrial fibrillation (AF) ablation procedures. Substrate modification beyond PVI has mixed results but identifying and ablating low voltage zones and ablating those targets in addition to PVI may be beneficial. Electroanatomic mapping is critical to identify subjects that may require further substrate modification. Low voltage area may be predictive of optimal treatment approach.

Purpose

This was a prospective, multicenter, interventional study of a high-density grid-style mapping catheter (HD Grid) to characterize left atrial low voltage substrate during sinus rhythm (SR) and AF and identify associations with 12 month recurrence rates after a single de novo radiofrequency (RF) ablation using a PVI only approach.

Methods

This study (NCT03882021) enrolled 300 subjects at 18 centers in Europe and Israel. Subjects underwent de novo RF ablation for paroxysmal AF (PAF) (N=113), early persistent AF (PsAF; AF sustained 7 days to 3 months) (N=86) or non-early PsAF (AF sustained >3 months to 12 months) (N=101). High density voltage maps were collected with HD Grid. Two pre-ablation maps, in SR and AF, were created for each subject (N=196) followed by PVI only ablation. Low voltage area (using cutoffs of 0.1 mV to 1.5 mV) was investigated in SR and AF. Follow up visits were at 3, 6 and 12 months post-ablation, with a 24-hour Holter monitor at 12 months. A Cox proportional hazards model was used to identify associations between mapping data and 12 month AF/atrial flutter (AFL)/atrial tachycardia (AT) recurrence after a single PVI procedure.

Results

At 12 months, 75.5% of subjects were free from AF/AFL/AT recurrence. On average, PsAF subjects had more low voltage area than PAF subjects in SR and AF. However, while univariate analysis found no correlation between recurrence and PAF or PsAF diagnosis (p=0.1261), those with recurrence had a significantly larger percent left atrial low voltage area under 0.5 mV with simultaneous orthogonal bipole wave configuration (HDW) in both AF (p=0.0011) and SR (p=0.0210) than those without recurrence. Using HDW, low voltage area (identified as <0.5 mV) greater than 28% of the left atrium in SR (HR: 4.82, 95% CI: 2.08–11.18, p=0.0003) and greater than 72% in AF (HR: 5.66, 95% CI: 2.34–13.69, p=0.0001) were associated with a higher risk of AF/AFL/AT recurrence at one year.

Conclusion(s)

Using a standard cutoff of 0.5 mV, a larger percent low voltage area was associated with increased risk of recurrence in both SR and AF. Future analyses will explore optimal low voltage cutoffs and thresholds predictive of recurrence that may necessitate additional substrate modification beyond PVI.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Abbott

Assessment of fusion pacing on exercise capacity in patients with cardiac resynchronisation therapy devices

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): British Heart Foundation

Local Departmental Research Funding

Background

Cardiac resynchronisation therapy (CRT) using fusion pacing requires correct timing of left ventricular pacing to right ventricular activation. The SyncAV™ algorithm, achieves this by dynamic reassessment of intrinsic atrio-ventricular (AV) conduction to adjust the paced/sensed AV delay. However, it is unclear whether AV optimisation maintains resynchronisation during exercise, or whether loss of fusion could lead to decreased exercise capacity. Cardio-pulmonary exercise testing (CPET) is the gold standard method for assessing exercise performance and can provide prognostic information in the heart failure population.

Purpose

We therefore used CPET measures of exercise capacity to compare the SyncAV™ algorithm to conventional pacing with fixed AV delays, in a double blinded, randomised crossover study (NCT03768804).

Methods

Patients at least 6 months post-CRT implant performed 2 CPET tests at least 1 week apart, with randomisation to either SyncAV™ with fusion pacing or conventional biventricular pacing with a fixed AVD of 120ms. All other programming was optimised to produce the narrowest QRS duration possible at rest in each case.

Results

Twenty patients (11 male, age 71 [65-77] years, median [interquartile range]) were recruited, with both ischaemic and non-ischaemic aetiology of heart failure. All had clinical and/or echocardiographic response to CRT. Optimised Fixed AVD and SyncAV™programming resulted in similar narrowing of QRS duration (QRSd) from intrinsic rhythm at rest (131 [103-137] vs 134 [110-137] ms for fixed AVD and SyncAV™ groups respectively, p=0.85). Overall, there was no difference in peak oxygen consumption (V̇O2peak) between programming (14.91 [12.61-18.16] vs 15.61 [12.18-19.70] ml/kg/min, p=0.19), or oxygen consumption at anaerobic threshold (VT1) (7.36 [6.93-8.94] vs 7.87 [6.77-9.24] ml/kg/min, p=0.42), or in the time to reach either V̇O2PEAK (p=0.81) or VT1 (p=0.39). The BORG rating of perceived effort was also similar between groups. CPET performance was also analysed comparing whichever programming gave the narrowest QRSd at rest (119 [96-136] vs 134 [119-142] ms, p<0.01). Eight were narrower with fixed AVD, 8 with SyncAV™ and in 4 there was no difference. QRSd during exercise (p=0.03), peak O2 pulse (ml/beat, a surrogate of stroke volume, p=0.03) and cardiac efficiency (watts/ml/kg/min, p=0.04) were significantly improved when programmed to the narrowest QRS duration at rest.

Conclusion

There is no significant difference in exercise capacity or QRSd between the use of optimised fixed AVD or SyncAV™, lending reassurance to fusion pacing being adequately maintained on exercise. In addition, programming with whichever algorithm gives the narrowest QRSd at rest is associated with a narrower QRSd during exercise, higher peak stroke volume and improved cardiac efficiency. This supports the use of SyncAV™ in the 40% of patients where this gave the narrowest QRSd at rest.

High density wave mapping to characterize low voltage substrate in sinus rhythm and atrial fibrillation: acute results from the WAVE-MAP AF study

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Abbott

Background

Pulmonary vein isolation (PVI) is a recommended approach for all atrial fibrillation (AF) ablation procedures, but PVI alone does not cure all AF. Supplementary substrate modification beyond PVI has mixed results. Identifying low voltage zones and ablating those targets in addition to PVI may be beneficial. Electroanatomic mapping is critical to identify subjects that may require further substrate modification. The amount of low voltage area may be predictive of the optimal treatment approach.

Purpose

This was a prospective, multicenter, interventional study of a high-density grid-style mapping catheter (HD Grid) to characterize left atrial (LA) low voltage substrate during sinus rhythm (SR) and AF in subjects undergoing de novo radiofrequency (RF) ablation for paroxysmal AF (PAF), early persistent AF (PsAF) (7 days-3 months) or non-early PsAF (>3 months-12 months) using a PVI only approach.

Methods

High-density voltage maps were collected with HD Grid during both SR and AF prior to ablation. Differences in low voltage area between (1) SR and AF and (2) simultaneous orthogonal bipole wave configuration (HDW) and standard along-the-spline linear electrode configuration (SD) were investigated.

Results

Three hundred subjects, enrolled at 18 centers in Europe and Israel, underwent PVI only RF ablation for PAF (N=113), early PsAF (N=79), and non-early PsAF (N=108). The average age was 62.0 ± 9.5 years and 70.3% (211/300) were male. SR maps and AF maps were available and evaluated in HDW and SD for 196 subjects (65.3%) (63 PAF, 65 early PsAF, 68 non-early PsAF). Mean LA surface area was 108.8 cm² and mean mapped surface area ranged from 83.2 to 89.5 cm².

HDW maps showed less low voltage area compared to SD in all subgroups, both in AF and in SR (Figure). For example, in AF with a low voltage cutoff of 0.5 mV, mean low voltage area was 49.8 cm² using SD and only 45.6 cm² using HDW (p<.0001). Similarly, in SR with a low voltage cutoff of 0.5 mV, mean low voltage area was 16.1 cm² using SD and only 12.6 cm² using HDW (p<.0001). HDW showed significantly less low voltage area than SD in SR for all measured voltage cutoffs from 0.1 mV to 1.5 mV.

On average, non-early PsAF subjects had a larger low voltage area than early PsAF subjects and PAF subjects in both SR and AF. In SR HDW, non-early PsAF subjects had 15.6 cm² under 0.5 mV, early PsAF subjects had 12.4 cm², and PAF subjects had 9.2 cm² (p=.0316). In AF HDW, non-early PsAF subjects had 56.6 cm² under 0.5 mV, early PsAF had 42.8 cm² and PAF subjects had 35.4 cm² (p<.0001).

Conclusion

Non-early PsAF subjects had the largest low voltage area on average compared to both early PsAF and PAF subjects in this study. Using HD grid, HDW provided better low voltage area characterization compared to SD in both SR and AF. The final results of this study will suggest whether an HDW substrate characterization of low voltage area can predict recurrences after a single PVI-only strategy procedure.

Improvement in electrical synchrony during bi-ventricular vs. left ventricular pacing with dynamic atrioventricular delays may be predicted by conduction times

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Abbott

Introduction

Automatic adjustment of atrioventricular delay (AVD) with SyncAV has been shown to improve electrical synchrony with either biventricular (BiV) or left ventricular (LV) only pacing. Selecting the optimal pacing mode may be guided by measuring conduction delays between the right atrium (RA), right ventricle (RV), and LV.

Purpose

Evaluate correlations between inter-chamber conduction delays and the QRS duration (QRSd) reduction achieved by BiV or LV-only pacing with SyncAV.

Methods

CRT implant patients (LBBB, QRSd ≥ 150 ms) were prospectively enrolled. Blinded QRSd was measured from 12-lead ECG during BiV and LV-only pacing, with SyncAV enabled and optimized to minimize QRSd. Conduction delays were measured by the device from unipolar electrograms during pacing and sensing (e.g. RAp-RVs). Correlations between each delay and which mode had the narrower QRSd was assessed by binomial regression.

Results

In total, 68 patients were evaluated (66.1 yr, 67.1% male, 32.5% ischemic, 26.3% EF, 165.1 ms intrinsic QRSd). BiV+SyncAV and LV+SyncAV reduced QRSd by 23.8% and 21.3% (P<0.001) vs. intrinsic conduction. Of all delays, RVs-LVs and LVp-RVs were significantly correlated with patient probability of BiV+SyncAV yielding a narrower QRSd than LV+SyncAV. BiV+SyncAV was favored in 70.6% (48/68) of all patients, but was favored in 92.3% (24/26) of patients with LVp-RVs < median (143 ms) (P=0.030 vs all).

Conclusion

When combined with SyncAV, BiV yielded a narrower QRSd than LV-only in the majority of patients, but was favored in a greater proportion who exhibit LVp-RVs delays below the median. Such conduction delay cut-offs can be used to facilitate pacing mode selection.

Assessment of the SyncAV fusion pacing algorithm on exercise capacity in patients with cardiac resynchronisation therapy device

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): British Heart Foundation (BHF) and Local Departmental Research Funding

Background

Fusion pacing as part of cardiac resynchronization therapy (CRT) requires correct timing of left ventricular pacing to right ventricular activation.  The SyncAV algorithm, available in Quadra Allure and Assura CRT devices, is designed to allow optimal fusion pacing by dynamic reassessment of intrinsic atrio-ventricular (AV) conduction to adjust the paced/sensed AV delay. However, it is unclear whether AV optimisation continues to maintain resynchronisation during exercise, or whether potential loss of fusion pacing with changes in intrinsic AV conduction could lead to decreased exercise capacity. Cardio-pulmonary exercise testing (CPET) is the gold standard method for assessing exercise performance.

Purpose

To assess exercise capacity using the SyncAV algorithm for fusion pacing, compared with conventional biventricular pacing with fixed AV delays (AVD) for CRT.

Methods

 Patients at least 6 months post-CRT implant were recruited in a prospective single-centre randomized single-blind crossover study.  Patients performed 2 CPET tests at least 1 week apart, with randomization to either SyncAV with fusion pacing or conventional biventricular pacing with a fixed AVD of 120ms. All other programming was optimised to produce the narrowest QRS duration possible at rest in each case.

Results

Nine patients (5 male, age 70 ± 10 years, mean ± standard deviation) were recruited, with both ischaemic and non-ischaemic aetiology of heart failure.  All had clinical or echocardiographic response to CRT.  There was no difference in peak oxygen consumption (V̇O2max) between programming (1.47 ± 0.57 vs 1.50 ± 0.65 l/min for fixed AVD and SyncAV groups respectively, p = 0.59), or oxygen consumption at anaerobic threshold (VT1) (0.72 ± 0.20 vs 0.74 ± 0.25 l/min, p = 0.57). There was no difference in oxygen pulse (V̇O2/heart rate - a surrogate of stroke volume) at peak (12.3 ± 3.8 vs 13 ± 5.0 ml/beat , p = 0.28) or VT1 (8.4 ± 2.2 vs 8.7 ± 2.1 ml/beat, p = 0.67) and also no change in time to V̇O2max (1400 ± 491 vs 1367 ± 543 seconds, p = 0.38) or VT1 (518 ± 211 vs 534 ± 200 seconds, p = 0.75).  Average heart rate at the median stage of exercise showed no difference between programming (96 ± 18 vs 93 ± 15 bpm respectively, p = 0.32).  There was no difference in BORG Rating of Perceived Exertion (BORG-RPE) score at either peak exercise (median 19 [interquartile range (IQR) 2] vs 17 [IQR 2], p = 0.23) or at the median stage of exercise (median 13 [IQR 1] vs 13 [IQR 2], p = 0.30). 

Conclusion

Fusion pacing using the SyncAV algorithm does not appear to improve exercise capacity compared to optimised conventional biventricular pacing with fixed AVD.

Impact of pacing configuration and right ventricular lead location on dynamic atrioventricular delay optimization

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Abbott

Introduction

Automatic adjustment of atrioventricular delay (AVD) with SyncAV has been shown to improve electrical synchronization. However, the effect of pacing configuration and right ventricular (RV) lead location on SyncAV programming is unknown.

Purpose

  Evaluate the effect of pacing configuration and lead location on SyncAV optimization during biventricular (BiV) and LV-only pacing, with and without MultiPoint Pacing (MPP).

Methods

  Patients with LBBB and QRS duration (QRSd) ≥ 150 ms scheduled for CRT-P/D device implantation with quadripolar LV lead were enrolled in this prospective study. RV lead location was classified at implant by the operator via  fluoroscopy. QRSd was measured post-implant from 12-lead surface ECG by blinded experts during the following pacing modes: intrinsic conduction, BiV (BiV = RV + LV1), MPP (MPP = RV + LV1 + LV2), LV-only single-site (LVSS = LV1 only), and LV-only MPP (LVMPP = LV1 + LV2). For each mode, SyncAV was enabled (e.g. BiV + SyncAV) with the patient-tailored SyncAV offset that minimized QRSd. For BiV and LVSS, LV1 was the latest activating LV cathode; for MPP and LVMPP, LV1 + LV2 were the two LV cathodes with the widest possible separation (≥30mm). All modes used minimal RV-LV and LV1-LV2 delays.

Results

  Fifty-three patients (68% male, 36% ischemic, 26% ejection fraction, 169 ms intrinsic QRSd) completed device implant and QRSd assessment. RV leads were implanted in either the septum (48%) or apex (52%), according to implanting physician preference. Relative to intrinsic conduction, BiV + SyncAV and MPP + SyncAV reduced QRSd by 23% and 27%, respectively (p < 0.01). LVSS + SyncAV reduced QRSd by 22% (p < 0.01 vs BiV + SyncAV), and LVMPP + SyncAV reduced QRSd by 25% (p < 0.05 vs MPP + SyncAV). RV apex or septum lead location did not have a significant impact on QRS reduction for each pacing configuration. As a percent of PR interval, optimal SyncAV offsets were similar for BiV + SyncAV and MPP + SyncAV (16% vs 13%, p = 0.05), and for LVSS + SyncAV and LVMPP + SyncAV (18% vs 21%, p = 0.46), but were significantly higher for LV-only settings vs. corresponding BiV/MPP settings (p < 0.05 for both pairs). For BiV + SyncAV, apical vs septal RV leads required greater SyncAV offsets (22% vs 11%, p < 0.05). SyncAV offsets also tended to be higher in apical vs septal RV leads for MPP (21% vs 11%), LVSS (20% vs 15%), and LVMPP (25% vs 16%), but without statistical significance.

Conclusion

SyncAV improves acute electrical synchronization in CRT patients with LBBB, particularly with patient-specific SyncAV programming. Pacing configuration (RV + LV or LV only, with or without MPP) and RV lead location (apex or septum) could potentially influence optimal SyncAV programming. Abstract Figure.

Application of recurrence plot analysis to characterise whole chamber propagation of atrial fibrillation

Funding Acknowledgements

Type of funding sources: Public hospital(s). Main funding source(s): Oxford Biomedical Research Centre

Introduction

Non-contact charge density mapping allows visualisation of whole chamber propagation during atrial fibrillation (AF). The identification of regions with repetitive or, conversely, more complex patterns of wavefront propagation may provide clues to mechanisms responsible for AF maintenance and lead to improved outcomes from catheter ablation. Our novel mapping approach based on signal recurrence plots has never been applied to whole chamber, bi-atrial recording of atrial fibrillation.

Purpose

To apply recurrence analysis to characterise whole chamber bi-atrial AF propagation.

Methods

Non-contact dipole signals from left and right atrial maps were obtained during simultaneous bi-atrial charge density mapping of AF. Signals were converted to phase and mean phase coherence calculated for the generation of recurrence distance matrices for the whole chamber and each anatomical region (6x LA and 4x RA) over the 30-second recording duration, where a value of 1 (purple, see figure panel A) represents uniform repetitive conduction, and 0 (red), irregular, non-repetitive activity. Whole chamber and regional mean recurrence values were calculated and correlated with the frequency of wavefronts of localised irregular activation patterns.

Results

Maps were obtained prior to ablation in 21 patients (5 paroxysmal (pAF), 16 persistent AF (persAF)) undergoing de-novo catheter ablation procedures. Whole chamber recurrence was higher in patients with pAF (0.40 ± 0.08) than persAF (0.34 ± 0.05), p < 0.0005. There was an inverse correlation between regional recurrence values and the number of localised irregular activations detected (-0.7021, p < 0.0005, figure panel B) with the lateral LA and anterior RA demonstrating the highest recurrence values in each chamber (figure panel C).

Conclusion

Use of recurrence distance matrices characterises global AF propagation phenotypes. Regional values are inversely correlated with the frequency of localised irregular activation patterns identified demonstrating an anatomic dependence in the level of AF propagation complexity, greatest in the anterior LA and septal RA. Comparison of strategies targeting regions with maximal vs. minimal values during catheter ablation may define an optimal approach to treatment of persistent AF. Abstract Figure. Recurrence abstract figure

Initial and long-term antithrombotic therapy after left atrial appendage closure with the WATCHMAN

Background

Evidence regarding post-procedural antithrombotic regimes other than used in randomized trials assessing percutaneous left atrial appendage (LAA) closure is limited.

Purpose

The present work aimed to compare different antithrombotic strategies applied in the real-world EWOLUTION study.

Methods

A total of 998 patients with successful WATCHMAN implantation at 47 centers were available for the present analysis. The composite ischemic endpoint of stroke, TIA, systemic embolism and device thrombus as well as the bleeding endpoint defined as at least major bleeding according to BARC were assessed during an initial period (from implant until first medication change) and long-term period (from first change until up to 2 years).

Results

The antithrombotic medication chosen in the initial phase was dual antiplatelet therapy (DAPT) in 60%, oral anticoagulation (OAC) in 27%, single antiplatelet therapy (SAPT) in 7% and no medication in 6%. In the long-term phase SAPT was used in 65%, DAPT in 23%, no therapy in 8% and OAC in 4%. No significant differences were found between the groups regarding the ischemic endpoint both in the initial period (Kaplan-Meier estimated rate 2.9% for DAPT vs. 4.3% for OAC vs. 3.9% for SAPT or no therapy; p=0.97) and in the second period (4.2% for SAPT vs. 1.8% for DAPT vs. 3.5% for no therapy; p=0.36). With respect to bleeding events the only difference was found in the initial phase with a higher incidence in patients under SAPT or no therapy (1.0% for DAPT vs. 0.8% for OAC vs. 7.4% for SAPT or no therapy; p=0.01). No differences in bleeding complications were observed during the second period (2.6% for SAPT vs. 2.9% for DAPT vs. 2.2% for no therapy; p=0.88).

Conclusions

Tailored antithrombotic treatment using even very reduced strategies such as SAPT or no therapy showed no significant differences regarding ischemic complications after LAA closure.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Boston Scientific

863Leadless endocardial pacing improves symptoms in patients with failed conventional CRT implant in long term follow up

Funding Acknowledgements

EBR Systems, Inc

OnBehalf

WiSE-CRT and LV-SELECT study and POST-M REGISTRY

Background

The WiSE-CRT (Wireless stimulation endocardial) system has advantages over conventional epicardial CRT. Whenever conventional CRT failed to implant or failed to echocardiographic response, the WiSE-CRT was implanted as part of the WiSE CRT study (N = 13), as part of the LV-SELECT study (N = 35) or as part of the POST-M REGISTRY (N = 117) over the last 8 years. All these studies have reported high rates of clinical and echocardiographic response compared to conventional CRT.

Objectives

The purpose of this analysis was to determine the safety and clinical response in the largest available number of implanted patients (pts) with long term follow up of 2 years and the first, second and third generation of WiSE-CRT devices.

Method

All pts undergoing a WiSE-CRT implantation as part of the WiSE CRT study (N = 13), as part of the LV-SELECT study (N = 35) or as part of the POST-M REGISTRY (N = 117) were analysed (N = 165). Pts were followed-up for 24 months and considered CRT responders if an improvement in NYHA ≥ 1 class from baseline (pre-implant) was achieved.

Results

In total, 165 pts were implanted, demographics include: 68.2 ± 9.6 year’s old, 81.8% male, 49.7% with history of AFib and 54.5% non-ischaemic aetiology. The mean intrinsic QRS duration was 165.0 ± 32.3 msec (28 pts pace-maker dependent). 161 pts had the system successfully implanted with no major complications, 3 (1.8%) pts developed a pericardial effusion and 1 (0.6%) electrode was lost during implantation and recovered surgically. During the 24-month follow-up period, 20 (12.1%) pts died from any cause, 4 (2.4%) pts developed TIA or Stroke and 15 (9.1%) pts had pocket or transmitter infection. There was a significant improvement in NYHA functional class in 63.6% pts and an average improvement of -26.1 (-45.1, -7.1) msec in QRS duration.

Conclusion

Despite a history of failed conventional CRT implantation, pts undergoing CRT upgrades with a WiSE-CRT have a high success rate and a complication rate similar to previously described. In addition endocardial LV pacing led to symptomatic improvements in 64% of patients reaching the 24 month of follow up.

Abstract Figure 1: Forest Plot NYHA Responder Rat

P1389Periodicity and Spatial Stability of Complex Propagation Patterns in Atrial Fibrillation

Introduction

Non-contact charge density mapping identifies complex wavefront propagation including localised rotational activation (LRA), localised irregular activation (LIA) and focal firing (FF). However, the duration of mapping required to reveal underlying patterns and their temporal stability is unknown.

Purpose

We sought to evaluate the variability in propagation patterns over increasing durations of recordings up to 30 seconds and examine the stability of these patterns between 2 separate maps with the aim of identifying the minimum duration required to reveal underlying patterns and how they represent the stable arrhythmia substrate.

Methods

Patients undergoing first time AcQMap guided catheter ablation were studied. 30s recordings of left atrial propagation were analysed. LIA, LRA, and FF were quantified for frequency, percentage time present and percentage surface area affected (for FF only frequency was assessed) at increasing durations up to 30s in 1s increments. At each incremental recording duration the percentage change in each variable was calculated. For occurrence frequency the results for every possible combination of maps of increasing duration within the 30s recording were compared whilst for occurrence time and surface area a 5s moving average at 1s increments was calculated. The point at which variability was seen to plateau represents the minimum optimal mapping duration. Spatial stability was assessed by correlating the frequency of patterns at each vertex of the anatomy over 2 separate 30s recordings. Stability of regions with the most repetitive patterns were compared using Cohen’s kappa statistic.

Results

15 patients were analysed (age 63 ± 9, 10 male, BMI 30 ± 5, CHA2DS2Vasc 1 ± 1.3, ejection fraction 54 ± 12%, left atrial diameter 46 ± 7mm, paroxysmal 1, persistent 14) with 11 included in the spatial stability analysis due to availability of recordings of sufficient duration. LRA demonstrated most variability followed by LIA and FF. Variability in LIA, LRA and FF decrease at increasing durations. LIA and FF variability plateau by 13 and 17s respectively. LRA plateaus at 23s. Variability of <10% is reached in all parameters at 18s.

LIA demonstrated the greatest stability with average R2 of 0.76 ± 0.14 (figure). Average R2 for LRA and FF were 0.45 ± 0.16 and 0.47 ± 0.12.  Low frequency focal firings were widely distributed across the atrial surface. For FF occurring at a frequency ≥10 over the 30s, average R2 value was 0.65 ± 0.14. Cohen kappa statistic was 0.70 for LIA and 0.45 for LRA.

Conclusion

Mapping durations of ≥23s are required to identify all temporally variable propagation patterns although shorter durations will identify less variable LIA and FF. 

LIA demonstrates high spatiotemporal stability and may best reflect disrupted conduction caused by the underlying atrial substrate and tissue architecture. Regions of high frequency FF are temporally stable and may represent important targets for ablation.

Abstract Figure 1

862Syncav with multipoint pacing improves acute left ventricular hemodynamics

Funding Acknowledgements

Abbott

Introduction

SyncAV has been shown to improve electrical synchronization by automatically adjusting atrioventricular delay (AVD) according to the intrinsic atrioventricular conduction time. Additional incremental electrical synchronization may be gained by the addition of second left ventricular (LV) pulse with MultiPoint Pacing (MPP). While the electrical synchronization benefits of SyncAV have been previously explored, there has been no assessment of the acute hemodynamic impact of SyncAV with or without MPP.

Objective

 Evaluate the acute LV hemodynamic impact of SyncAV with and without MPP.

Methods

Heart failure patients with LBBB and QRS duration (QRSd) > 140 ms undergoing CRT-P/D implant with a quadripolar LV lead were enrolled in this prospective study. A guidewire or catheter with pressure transducer was placed in the LV chamber and the maximum pressure change (dP/dtmax) was recorded during the following pacing modes:  intrinsic conduction, conventional biventricular pacing with SyncAV (BiV + SyncAV), and MPP with SyncAV (MPP + SyncAV). Twelve-lead surface ECG was used to determine the patient-tailored SyncAV offset that minimized QRSd.

Results

Twenty-seven patients (67% male, 44% ischemic, 30 ± 7% ejection fraction) completed the acute recordings. Relative to the intrinsic QRSd of 163 ms, BiV + SyncAV reduced QRSd by 21.5% to 124 ms (p < 0.001 vs. intrinsic) and MPP + SyncAV reduced QRSd by 26.6% to 120 ms (p < 0.05 vs. BiV + SyncAV). Beyond electrical synchronization, SyncAV significantly improved acute hemodynamics. Relative to the intrinsic dP/dtmax of 842 mmHg/s, BiV + SyncAV elevated dP/dtmax by 6.3% to 900 mmHg/s (p < 0.001 vs. intrinsic) and MPP + SyncAV elevated dP/dtmax by 8.8% to 926 mmHg/s (p < 0.005 vs. BiV + SyncAV). Despite both QRSd and dP/dtmax improvement with SyncAV and MPP, correlation between electrical and hemodynamic measurements was poor (R2 = 0.0 for BiV + SyncAV, R2 = 0.1 for MPP + SyncAV).

Conclusion

SyncAV may significantly improve acute LV hemodynamics in addition to electrical synchrony in LBBB patients. Further incremental improvement was achieved by combining SyncAV with MPP.

Abstract Figure.

43Dynamic atrioventricular delay achieves superior electrical synchrony when pacing both ventricles rather than left ventricle alone

Funding Acknowledgements

Abbott

Introduction

Automatic adjustment of atrioventricular delay (AVD) with SyncAV has been shown to improve electrical synchronization when pacing one or two sites in the left ventricle together with the right ventricle. However, it is unknown if the same benefit can be gained by using SyncAV while pacing only the left ventricle without right ventricular pacing.

Purpose

  Evaluate the acute improvement in electrical synchrony provided by SyncAV with and without MultiPoint Pacing (MPP) during biventricular (BiV) and LV only pacing.

Methods

  Patients with LBBB and QRS duration (QRSd) ≥ 150 ms scheduled for CRT-P/D device implantation with quadripolar LV lead were enrolled in this prospective study. QRSd was measured post-implant from 12-lead surface electrograms by blinded experts during the following pacing configurations: intrinsic conduction, conventional BiV (BiV = RV + LV1), MPP (MPP = RV + LV1 + LV2), LV-only single-site (LVSS = LV1 only), and LV-only MPP (LVMPP = LV1 + LV2). For each pacing mode, SyncAV was enabled (e.g. BiV + SyncAV) with the patient-tailored SyncAV offset that minimized QRSd. As an additional reference, QRSd during BiV was also measured using the nominal static AVD (paced/sensed AVD = 140/110 ms). BiV and LVSS pacing used the latest activating LV cathode, whereas MPP and LVMPP used the two LV cathodes with the widest possible separation (>30mm). All configurations used the minimum programmable RV-LV and LV1-LV2 delays.

Results

  Thirty-five patients (78% male, 33% ischemic, 26% ejection fraction, 165 ms intrinsic QRSd) completed device implant and QRSd assessment. Relative to intrinsic conduction, BiV with nominal AVD reduced the QRSd by 17.5% (p < 0.001 vs intrinsic). Enabling SyncAV with a patient-optimized offset significantly improved QRSd reduction. BiV + SyncAV reduced QRSd by 25.2% (p < 0.001 vs. BiV). The greatest QRSd reduction of 28.9% was achieved by MPP + SyncAV (p < 0.01 vs. BiV + SyncAV). Single- and multi-site LV-only pacing reduced QRSd significantly less than corresponding biventricular modes. LVSS + SyncAV reduced QRSd by 22.5% (p < 0.05 vs. BiV + SyncAV), and LVMPP + SyncAV reduced QRSd by 24.3% (p < 0.05 vs. MPP + SyncAV). As a percent of PR interval, optimal SyncAV offsets were similar for BiV + SyncAV (median: 13%, mean: 17%) vs. MPP + SyncAV (median: 13%, mean 16%, p = 0.35 vs. BiV + SyncAV), and similar for LVSS + SyncAV (median: 20%, mean: 28%) and LVMPP + SyncAV (median: 23%, mean: 26%, p = 0.35 vs. LVSS + SyncAV), but were significantly higher for LV-only settings vs. corresponding BiV/MPP settings (p < 0.01 for both pairs). Conclusion: Greater improvement in electrical synchrony using SyncAV was observed when right ventricular pacing was included with left ventricular pacing. Additional benefit was gained by the addition of a second left ventricular pacing site with MPP in combination with SyncAV in both biventricular and LV only pacing modes.

Abstract Figure.

Characteristics of non-vitreoretinal ocular injury in child maltreatment: a systematic review

PurposeTo identify the spectrum of non-vitreoretinal ocular injury due to child maltreatment.MethodsAll language search of MEDLINE, PsychINFO, EMBASE, AMED, Web of Science, and CINAHL databases, 1950-2015, was conducted.

INCLUSION CRITERIA

explicit confirmation of injury aetiology, age <18 years, examination conducted by an ophthalmologist. Exclusion: post-mortem data, organic diseases, review articles. Standardised critical appraisal and narrative synthesis was conducted of included publications by two independent reviewers.ResultsOf 1492 studies identified, 153 full texts were assessed, 49 underwent full review, resulting in five included studies: three case series and two case reports. The 26 included cases describe a wide variety of ocular, facial and skeletal injuries occurring as a consequence of child maltreatment. Ocular signs included periorbital oedema, chemosis, injection, abrasion, hyphaema, and cataract. Of interest all children that had suffered physical abuse with ocular injury had subconjunctival haemorrhages. Children presenting with abusive ocular injuries had a mean age of 13.9 months (range 1-68), while those who suffered violent corporal punishment were considerably older (mean 96 months). All cases, apart from severe corporal punishment, underwent screening for occult fractures, but neuroimaging only apparent in 2/5 eligible cases.ConclusionAlthough, the face is the most common site of abusive injury, there is a paucity of high-quality data on non-vitreoretinal ocular abusive injury. Thus, while subconjunctival haemorrhages are a potential sentinel injury of maltreatment, and may warrant further evaluation, the lack of large-scale published data limits our ability to highlight further specific characteristics of non-vitreoretinal ocular injury indicative of child abuse.

Evaluation of body weight as a predictive factor for transvenous ventricular defibrillation characteristics

AIMS

To investigate the correlation between body weight and defibrillation threshold (DFT) for transvenous lead systems using a porcine model.

METHODS AND RESULTS

Twenty-eight pigs were anaesthetised and DFTs assessed in single and dual coil configurations using a four-reversal binary search method. DFT was correlated with body weight in the RV --> Can and RV --> SVC + Can configurations. A Pearson correlation coefficient and a two-sided p-value were calculated. A positive correlation exists between body weight and DFT in RV --> Can (r=0.66, p<0.000) and RV --> SVC + Can (r=0.44, p=0.018).

CONCLUSION

There is a significant correlation between body weight and DFT in swine. This tends to be greater in the two-electrode than in the three-electrode configuration. With these and previous human observations, one may predict a higher DFT in heavy individuals and make appropriate procedural adjustments.

The cost of everything and the value of nothing

A series of three nursing case histories related to epilepsy care are presented to demonstrate the range of clinical nursing activity in an epilepsy clinic and to pose the question whether any of these activities, deemed essential by both clinician and nurse, would be thought appropriate if cost effectiveness of nursing care was merely measured by a significant reduction in seizure frequency. The conclusion drawn is that a specialist epilepsy nurse in an epilepsy clinic is an invaluable member of the team, who frees the medical member of the team to concentrate on those duties which need medical input: but, using currently applied outcome criteria, it would be difficult to justify the nurse's cost effectiveness. Measures that do this accurately and fairly must be developed.

The epilepsy nurse specialist--expendable handmaiden or essential colleague?

The benefits of a specialist epilepsy nurse in the management of people with epilepsy are still in question. Evidence from controlled clinical trials suggests that patients supported by a nurse specialist are well informed and have a high degree of satisfaction. However, no significant effect on health status or the number of seizures has been yet demonstrated, although this is not the primary function of most epilepsy specialist nurses. The recent International League Against Epilepsy (ILAE) British Branch meeting in Liverpool (April 2001) dedicated a one-day symposium to epilepsy nursing including a debate on the effectiveness of the epilepsy specialist nursewarm fuzzy feeling or evidence based?'. Although it was agreed that evidence-based research is limited, the case studies and data presented, throughout the symposium, highlighted the varying role of the epilepsy specialist nurse in supporting both the specialist physician in epilepsy care, the non-specialist physician and the primary care physician in patient communication. This paper provides an overview of the presentations given at the symposium, including those on nursing research and publishing.

Epilepsy and the ovary (cutting out the hysteria)

This review touches on the historical links between epilepsy, seizures and the uterus and ovaries which have fascinated and misled physicians since Greco-Roman times. It then examines present knowledge of ovarian function and its effect on epileptic activity and vice versa before exploring the modern controversy about polycystic ovaries and the polycystic ovary syndrome, epilepsy and anticonvulsant medication. Based on present evidence, women with epilepsy are more prone to develop polycystic (polyfollicular) ovaries than other women due to the epilepsy itself. But women with epilepsy related polycystic (polyfollicular) ovaries are vulnerable to the effects of sodium valproate (possibly particularly during adolescence) and may develop the polycystic ovary syndrome: this is reversible if the valproate is withdrawn. Lamotrigine and carbamazepine seem to prevent the development of the syndrome.

Epilepsy--doctor's dilemma, lawyer's delight? Medico-legal consequences of practising in the field of epilepsy report of an International League Against Epilepsy British Branch meeting--Edinburgh, April 2000

Six cases are described where the medical management of a person's epilepsy was brought under legal scrutiny. Lessons learnt from this educational exercise include improving doctor patient communication, the function of a Coroner's Court, when is misdiagnosis negligent, the vagaries of expert witnesses, should failure to diagnose a tumour be blamed on the physician or the service when facilities are inadequate, is failure to recognise a rare drug interaction, failure to warn against an interaction, or failure to take a proper history, negligent? The conference also examined the legal ramifications of the nurse/doctor relationship in epilepsy care, the place of epilepsy guidelines and, due to its interactive nature, reflected on the audience's epilepsy knowledge, which, in places seemed significantly deficient. It was a gripping educational exercise.

A multifilamented electrode in the middle cardiac vein reduces energy requirements for defibrillation in the pig

OBJECTIVE

To compare the defibrillation efficacy of a novel lead system placed in the middle cardiac vein with a conventional non-thoracotomy lead system.

METHODS

In eight pigs (weighing 35-71 kg), an electrode was advanced transvenously to the right ventricular apex (RV), with the proximal electrode in the superior caval vein (SCV). Middle cardiac vein (MCV) angiography was used to delineate the anatomy before a three electrode system (length 2 x 25 mm + 1 x 50 mm) was positioned in the vein. An active housing (AH) electrode was implanted in the left pectoral region. Ventricular fibrillation was induced and biphasic shocks were delivered by an external defibrillator. The defibrillation threshold was measured and the electrode configurations randomised to: RV-->AH, RV+MCV-->AH, MCV-->AH, and RV-->SCV+AH.

RESULTS

For these configurations, mean (SD) defibrillation thresholds were 27.3 (9.6) J, 11.9 (2.9) J, 15.2 (4.3) J, and 21.8 (9.3) J, respectively. Both electrode configurations incorporating the MCV had defibrillation thresholds that were significantly less than those observed with the RV-->AH (p < 0.001) and RV-->SCV+AH (p < 0.05) configurations. Necropsy dissection showed that the MCV drained into the coronary sinus at a location close to its orifice (mean distance = 2.7 (2.2) mm). The MCV bifurcated into two main branches that drained the right and left ventricles, the left branch being the dominant vessel in the majority (6/7) of cases.

CONCLUSIONS

Placement of specialised defibrillation electrodes within the middle cardiac vein provides more effective defibrillation than a conventional tight ventricular lead.

Reduction in defibrillation threshold using an auxiliary shock delivered in the middle cardiac vein

Defibrillation in the middle cardiac vein (MCV) has been shown to reduce ventricular defibrillation thresholds (DFTs). Low amplitude auxiliary shock (AS) from an electrode sutured to the left ventricle at thoracotomy have also been shown to reduce DFT if delivered immediately prior to a biphasic shock (between the ventricular RV and superior vena caval (SVC) electrodes). This study investigates the impact on DFT of an AS shock from a transvenously placed MCV lead system. A standard defibrillation electrode was positioned in the RV in eight anesthetized pigs (35-43 kg). A 50 x 1.8-mm electrode was inserted in the MCV through an 8 Fr angioplasty guide catheter. A 150-V (leading edge) monophasic AS was delivered (95 microF capacitor) from the MCV-->Can with three different pulse widths (3, 5, 7 ms). A primary biphasic shock (PS) (95 microF capacitor, phase 1: 44% tilt, 1.6-ms extension and phase 2: 2.5-ms fixed duration) was delivered from the RV-->Can +/- AS. The four configurations were randomized and DFTs (PS + AS) assessed using a modified binary search. Ventricular fibrillation (VF) was induced with 60 Hz AC followed 10 seconds later by the test shock. The DFTs were compared using repeated measures analysis of variance (ANOVA). All configurations incorporating AS produced significant (P < 0.05) reduction in the DFT compared to no AS (13.8 +/- 7.4 J). There was no difference in the efficacy of differing pulse widths (P > 0.05); 3 ms (11.0 +/- 5.4 J), 5 ms (11.5 +/- 6.0), and 7 ms (10.6 +/- 5.3 J). In conclusion, delivering an AS from a transvenous lead system deployed in the MCV reduces the DFT by 23% compared to a conventional RV-->Can shock alone.

Psychiatric symptoms after therapy with new antiepileptic drugs: psychopathological and seizure related variables

The purpose of this paper is to understand the association between antiepileptic drugs (AEDs), patient characteristics, changes in seizure pattern and emergent psychiatric disorder, i.e. psychosis or affective disorder. To this end we carried out a retrospective casenote study on 89 patients who developed psychiatric symptoms during treatment with topiramate, vigabatrin or tiagabine. The psychiatric problem was either an affective or a psychotic disorder (not including affective psychoses). It was discovered that 99% of the patients suffered from complex partial seizures with or without secondary generalization. More than half were on polytherapy with two or more other AEDs. Nearly two-thirds had a previous psychiatric history. There was a strong association between the type of previous psychiatric illness and the type of emerging psychiatric problem, both for psychoses and for affective disorders. Patients on vigabatrin had an earlier onset of epilepsy and more neurological abnormalities than those on topiramate. Those patients on lower doses had a shorter interval between the start of the AED therapy and the onset of the psychiatric problem. A seizure-free period was observed in more than half of the patients before they developed the psychiatric symptoms, and of these more were likely to develop a psychosis rather than an affective disorder. There seemed to be an association of suppression of right-sided seizures and the onset of the psychiatric problem. The conclusions drawn were that patients with a previous history of psychosis or affective disorder tended to develop the same psychiatric problem with new AEDs. Those with a seizure-free period before the onset of the psychiatric problem were more likely to develop a psychosis than an affective disorder.

Increased defibrillation threshold with right-sided active pectoral can

The aim of this study was to identify the optimal position on the chest wall to place an implant able cardioverter defibrillator in a two-electrode system, consisting of a right ventricular electrode and active can.

METHODS AND RESULTS

Defibrillation thresholds (DFT) were measured in 10 anaesthetised pigs (weight 33-45 kg). An Angeflextrade mark lead was introduced transvenously to the right ventricular apex. The test-can (43 cc) was implanted submuscularly in each of four locations: left pectoral (LP), right pectoral (RP), left lateral (LL) and apex (A). The sequence in which the four locations were tested was randomized. Ventricular fibrillation (VF) was induced using 60 Hz alternating current. Rectangular biphasic shocks were delivered 10 seconds after VF induction. The DFT was measured using a modified four-reversal binary search. The results of the four configurations were: LP, 14.6+/- 4.0 J; RP, 18.8+/- 4.2 J; LL, 14.7+/- 4.1 J; A, 14.9+/- 3.1 J. Repeated measures analysis of variance showed that the DFT of RP was significantly higher than LP, LL and A (p < 0.05).

CONCLUSIONS

Implanting an active can in the RP position increases the DFT by 29% compared to LP, LL and A sites. The can position on the left thorax does not appear to have a significant influence on DFT.

A multicentre, double-blind, randomized, parallel group study to evaluate the tolerability and efficacy of two oral doses of levetiracetam, 2000 mg daily and 4000 mg daily, without titration in patients with refractory epilepsy

The aim of this study was to determine the tolerability and efficacy of two oral regimens of levetiracetam, 1000 mg and 2000 mg twice daily, as add-on treatment without titration in patients with refractory epilepsy. After a 1- to 4-week baseline, 119 patients were randomized to receive levetiracetam 2000 mg daily, 4000 mg daily, or placebo for a 24-week double-blind period, then levetiracetam 4000 mg daily in a 24-week open-label phase. Somnolence was the most common reason for discontinuation, and along with asthenia, occurred more frequently with levetiracetam than placebo. Responder rates were higher with levetiracetam 2000 mg and 4000 mg daily (48.1% [P < 0.05] and 28.6% [NS], respectively) than placebo (16.1%). In the open-label phase, the overall responder rate was 43.0%. Switching from placebo to levetiracetam increased the overall responder rate from 16.7% to 44.0%. No such increase was observed with patients initiated on levetiracetam 2000 mg daily. Levetiracetam initiated at doses of 2000 mg or 4000 mg daily without titration is well-tolerated and effective as add-on therapy in patients with partial and/or generalized seizures. The higher dose may be related to an increased incidence of somnolence and is not necessarily more effective than the lower dose.

How much risk does a woman with active epilepsy pose to her newborn child in the puerperium? A pilot study

Much attention in the literature has recently been paid to women's issues in epilepsy but most of the literature stops in the delivery room or at the first moment of suckling. Although it is commonly supposed that a woman who continues to have active epilepsy during the puerperium will pose a risk to her child, little assessment of how great a risk this is has been carried out. We present an audit of the puerperal experiences of 187 women with epilepsy counselled before birth in our women's clinic and contrast this with a number of women with epilepsy seen for the first time in the puerperium (and therefore uncounselled). The audit suggests that in counselled women the risk is very low (women with Juvenile Myoclonic Epilepsy may be particularly at risk, as may women with tonic-clonic seizures that occur without warning, plus those with automatisms or who have prolonged post-ictal confusion). Some women with controlled epilepsy prior to conception may lose that control during the puerperium so even women with well controlled epilepsy should adopt precautions in the puerperium. The only baby to die (or be seriously injured) in the puerperium born to a woman with epilepsy was killed in the mother's first seizure.

Proactive pre-conception counselling for women with epilepsy-is it effective?

We describe the development of a proactive pre-conception counselling service for women with epilepsy based on complete re-investigation of the woman's epilepsy, a policy of withdrawing antiepileptic drugs (AEDs) thought to carry an increased risk of foetal abnormality (and substitution, where indicated, of AEDs thought to carry a lesser risk) and the exhibition of folic acid 5 mg daily plus fulfilment of the woman's educational needs and exploration of her and her partner's wishes. The outcome of the assessment of 90 such women is compared with the outcome of 59 women presenting to our service already pregnant. An audit of the outcomes in the two groups suggests that re-investigation of women pre-conceptually is worthwhile (some women turn out not to have epilepsy or have cerebral lesions best managed before pregnancy) and that foetal morbidity may be reduced by judicious rationalization of medication: folic acid taken before conception may also be protective for the foetus. Proactive pre-conception counselling, however, only works if the woman is prepared to wait (sometimes up to a year) for necessary drug changes to be instituted and is using reliable contraception.

Best practice guidelines for the management of women with epilepsy. The Women with Epilepsy Guidelines Development Group

Clinical guidelines for the treatment of epilepsy have been published. A statement on management issues for women with epilepsy has recently been produced by the American Academy of Neurology which has raised awareness of the issues facing women with epilepsy. The communication presented here aims to review current literature on specific issues relating to women with epilepsy, and proposes graded recommendations for its management within a UK health care framework.

Epilepsy needs revisited: a revised epilepsy needs document for the UK

We revisit epilepsy needs in the United Kingdom, and update our previous publication to take into account new epidemiological data, changes in investigation and treatment and trends in the organization of health and other caring agencies. This document attempts to define and quantify the scope, content and standards of services required, from primary care settings to specialized centres. Reference is also made to the role of other agencies.

A note on a phrase in Shakespeare's play King Lear: 'a plague upon your epileptic visage'

In Shakespeare's play King Lear the word 'epileptic' appears (used in a derogatory manner). This is held to be the first appearance of the word in the English language (although we have found earlier English references to the word which Shakespeare may have read). Textual analysis of the lines following the use of 'epileptic' suggests that it is actually a reference to the pock-marks of syphilis, endemic in Elizabethan England, and is not actually a reference to epilepsy itself.

John Hall and his epileptic patients--epilepsy management in early 17th century England

John Hall, a physician, practised in Stratford in the early 17th century and was the son-in-law of William Shakespeare. During his career he kept records of his patients (in Latin) which he may have been preparing for publication when he died. Despite his instruction for them to be destroyed some were later translated into English and published by another physician. The case records were popular and have recently been reprinted with a commentaryl. We have searched the case records for descriptions of epilepsy and examined the treatments offered (and the attitudes to) this condition in early 17th century England. Treatment consisted of standard remedies ('fumes' of hartshorn and extracts of peony) related to the Galenic system of medicine, plus individual remedies. Interestingly, there is no evidence that the condition was stigmatized.

Learning disability and epilepsy. 2, a review of available outcome measures and position statement on development priorities

People with epilepsy plus learning disabilities pose a challenge in terms of clinical management and research investigation, and, to date, the measurement of outcomes in this population has been limited. There have been uncertainties concerning both the 'what' and the 'how' of assessment. This paper presents a comprehensive review of available outcome measures across nine domains, i.e. relating to seizures, drugs, cognitive function, behaviour, social functioning, carer functioning, attitudes, motivation and 'quality of life'. This last domain reflects more global measures designed to encompass several assessment strands. The uses and limitations of each scale is discussed and, where data are available, psychometric properties are also presented. The paper concludes with suggestions for the further development of outcome measures in this population.