Targeted cluster ablation of non-CTI-dependent atrial arrhythmias in congenital heart disease using ultrahigh-definition mapping.

BACKGROUND: Ablation of atrial arrhythmias in patients with congenital heart disease (CHD) has markedly improved with advanced mapping systems. However, recurrence rates remain high. The linear ablation strategy is not uncommonly practiced necessitating prolonged ablation times. We report the outcomes of adopting a strategy of minimal, cluster delivery of radiofrequency (RF) energy at critical substrates identified by ultrahigh-definition mapping for atrial arrhythmias in patients with CHD. METHODS: Non-cavotricuspid isthmus (non-CTI) atrial tachycardias were ablated with a targeted ablation cluster technique (TACT) using an ultrahigh-density mapping system combined with multielectrode monitoring and endpoint determination in preference to linear ablation. The arrhythmia substrates, RF times, and acute- and medium-term success rates were studied. RESULTS: Fifty-eight tachycardias were mapped and ablated in 42 procedures: 34 non-CTIs and 24 CTIs. A targeted ablation cluster was performed for non-CTI tachycardias, with a median ablation time of 3.1 min. In 53% of non-CTI tachycardias, arrhythmia termination was achieved with ≤2 RF applications. After a mean follow-up of 23.6 months, 27 (80%) patients were free of recurrent atrial arrhythmias. One of 34 targeted non-CTI tachycardia recurred, with a final success rate of 91%. Linear ablation was performed for CTI flutters with a median ablation time of 6.8 min (vs. non-CTIs, p = .006). Three of 21 tachycardias recurred due to reconnection of the ablation line but the final success rate was 100%. CONCLUSIONS: The TACT approach for non-CTI atrial arrhythmias in congenital patients as guided by the ultrahigh-density mapping is an effective method with short ablation times and excellent medium-term outcomes.

Standard care vs. TRIVEntricular pacing in Heart Failure (STRIVE HF): a prospective multicentre randomized controlled trial of triventricular pacing vs. conventional biventricular pacing in patients with heart failure and intermediate QRS left bundle branch block.

AIMS: To determine whether triventricular (TriV) pacing is feasible and improves CRT response compared to conventional biventricular (BiV) pacing in patients with left bundle branch block (LBBB) and intermediate QRS prolongation (120-150 ms). METHODS AND RESULTS: Between October 2015 and November 2019, 99 patients were recruited from 11 UK centres. Ninety-five patients were randomized 1:1 to receive TriV or BiV pacing systems. The primary endpoint was feasibility of TriV pacing. Secondary endpoints assessed symptomatic and remodelling response to CRT. Baseline characteristics were balanced between groups. In the TriV group, 43/46 (93.5%) patients underwent successful implantation vs. 47/49 (95.9%) in the BiV group. Feasibility of maintaining CRT at 6 months was similar in the TriV vs. BiV group (90.0% vs. 97.7%, P = 0.191). All-cause mortality was similar between TriV vs. BiV groups (4.3% vs. 8.2%, P = 0.678). There were no significant differences in echocardiographic LV volumes or clinical composite scores from baseline to 6-month follow-up between groups. CONCLUSION: Implantation of two LV leads to deliver and maintain TriV pacing at 6 months is feasible without significant complications in the majority of patients. There was no evidence that TriV pacing improves CRT response or provides additional clinical benefit to patients with LBBB and intermediate QRS prolongation and cannot be recommended in this patient group. CLINICAL TRIAL REGISTRATION NUMBER: Clinicaltrials.gov: NCT02529410.

First-Phase Ejection Fraction Predicts Response to Cardiac Resynchronization Therapy and Adverse Outcomes.

OBJECTIVES: The aim of this study was to examine the value of first-phase ejection fraction (EF1), to predict response to cardiac resynchronization therapy (CRT) and clinical outcomes after CRT. BACKGROUND: CRT is an important treatment for patients with chronic heart failure. However, even in carefully selected cases, up to 40% of patients fail to respond. EF1, the ejection fraction up to the time of maximal ventricular contraction, is a novel sensitive echocardiographic measure of early systolic function and might relate to response to CRT. METHODS: An initial retrospective study was performed in 197 patients who underwent CRT between 2009 and 2018 and were followed to determine clinical outcomes at King's Health Partners in London. A validation study (n = 100) was performed in patients undergoing CRT at Barts Heart Centre in London. RESULTS: Volumetric response rate (reduction in end-systolic volume ≥15%) was 92.3% and 12.1% for those with EF1 in the highest and lowest tertiles (P < 0.001). A cutoff value of 11.9% for EF1 had >85% sensitivity and specificity for prediction of response to CRT; on multivariate binary logistic regression analysis incorporating previously defined predictors, EF1 was the strongest predictor of response (odds ratio [OR]: 1.56 per 1% change in EF1; 95% CI: 1.37-1.78; P < 0.001). EF1 was also the strongest predictor of improvement in clinical composite score (OR: 1.11; 95% CI: 1.04-1.19; P = 0.001). Improvement in EF1 at 6 months after CRT implantation (6.5% ± 5.8% vs 1.8% ± 4.3% in responders vs nonresponders; P < 0.001) was the best predictor of heart failure rehospitalization and death after median follow-up period of 20.3 months (HR: 0.81; 95% CI: 0.73-0.90; P < 0.001). In the validation cohort, EF1 was a similarly 1strong predictor of response (OR: 1.45; 95% CI: 1.23-1.70; P < 0.001) as in the original cohort. CONCLUSIONS: EF1 is a promising marker to identify patients likely to respond to CRT.

The physiological effects of cardiac resynchronization therapy on aortic and pulmonary flow and dynamic and static components of systemic impedance.

BACKGROUND: Patients who improve following cardiac resynchronization therapy (CRT) have left ventricular (LV) remodeling and improved cardiac output (CO). Effects on the systemic circulation are unknown. OBJECTIVE: To explore the effects of CRT on aortic and pulmonary blood flow and systemic afterload. METHODS: At CRT implant patients underwent a noninvasive assessment of central hemodynamics, including wave intensity analysis (n = 28). This was repeated at 6 months after CRT. A subsample (n = 11) underwent an invasive electrophysiological and hemodynamic assessment immediately following CRT. CRT response was defined as reduction in LV end-systolic volume ≥15% at 6 months. RESULTS: In CRT responders (75% of those in the noninvasive arm), there was a significant increase in CO (from 3 ± 2 L/min to 4 ± 2 L/min, P = .002) and LV dP/dtmax (from 846 ± 162 mm Hg/s to 958 ± 194 mm Hg/s, P = .001), immediately after CRT in those in the invasive arm. They demonstrated a significant increase in aortic forward compression wave (FCW) both acutely and at follow-up. The relative change in LV dP/dtmax strongly correlated with changes in the aortic FCW (R s 0.733, P = .025). CRT responders displayed a significant reduction in afterload, and a decrease in systemic vascular resistance and pulse wave velocity acutely; there was a significant decrease in acute pulmonary afterload measured by the pulmonary FCW and forward expansion wave. CONCLUSION: Improved cardiac function following CRT is attributable to a combination of changes in the cardiac and cardiovascular system. The relative importance of these 2 mechanisms may then be important for optimizing CRT.

Noninvasive electrocardiographic assessment of ventricular activation and remodeling response to cardiac resynchronization therapy.

BACKGROUND: Cardiac resynchronization therapy (CRT) produces acute changes in electric resynchronization that can be measured noninvasively with electrocardiographic body surface mapping (ECGi). The relation between baseline acute electrophysiology metrics and their manipulation with CRT and reverse remodeling is unclear. OBJECTIVE: To test (ECGi) derived parameters of electrical activation as predictors of volumetric response to CRT. METHODS: ECGi was performed in 21 patients directly following CRT implant. Activation parameters (left ventricular total activation time [LVtat], global biventricular total activation time [VVtat], global left/right ventricular electrical synchrony [VVsync], and global left ventricular dispersion of activation times [LVdisp]) were measured at baseline and following echocardiographically optimized CRT. Remodeling response (>15% reduction left ventricular end-systolic volume) was assessed 6 months post CRT. RESULTS: Patients were aged 68.9 ± 12.1 years, 81% were male, and 57% were ischemic. Baseline measures of dyssynchrony were more pronounced in left bundle branch block (LBBB) vs non-LBBB. ECGi demonstrated a trend of greater interventricular dyssynchrony between responders and nonresponders that did not reach statistical significance (VVsync: -45.7 ± 22.4 ms vs -25.1 ± 29.3 ms, P = .227). Remaining activation parameters were similar between responders and nonresponders (VVtat 101 ± 22.0 ms vs 98.9 ± 23.4 ms, P = .838; LVtat 86.4 ± 17.1 ms vs 85.1 ± 27.7 ms, P = .904; LVdisp 28.2 ± 6.3 ms vs 27.0 ± 8.7 ms, P = .726). In volumetric responders activation parameters were significantly improved with CRT compared to nonresponders: VV sync (-45.67 ± 22.41 ms vs 2.33±18.87 ms, P = .001), VVtat (101 ± 22.04 ms vs 71 ± 14.01 ms, P = .002), LVtat (86.44 ± 17.15 ms vs 67.67 ± 11.31 ms, P = .006), and LVdisp (28.22 ± 6.3 ms vs 21.56 ± 4.45 ms, P = .008). CONCLUSION: Baseline ECGi activation times did not predict CRT volumetric response. Volumetric responders exhibited significant improvements in ECGi-derived metrics with CRT. ECGi does not select CRT candidates but may be a useful adjunct to guide left ventricle lead implants and to perform postimplant CRT optimization.

A multicenter prospective randomized controlled trial of cardiac resynchronization therapy guided by invasive dP/dt.

BACKGROUND: No periprocedural metric has demonstrated improved cardiac resynchronization therapy (CRT) outcomes in a multicenter setting. OBJECTIVE: We sought to determine if left ventricular (LV) lead placement targeted to the coronary sinus (CS) branch generating the best acute hemodynamic response (AHR) results in improved outcomes at 6 months. METHODS: In this multicenter randomized controlled trial, patients were randomized to guided CRT or conventional CRT. Patients in the guided arm had LV dP/dtmax measured during biventricular (BIV) pacing. Target CS branches were identified and the final LV lead position was the branch with the best AHR and acceptable threshold values. The primary endpoint was the proportion of patients with a reduction in LV end-systolic volume (LVESV) of ≥15% at 6 months. RESULTS: A total of 281 patients were recruited across 12 centers. Mean age was 70.8 ± 10.9 years and 54% had ischemic etiology. Seventy-three percent of patients in the guided arm demonstrated a reduction in LVESV of ≥15% at 6 months vs 60% in the conventional arm (P = .02). Patients with AHR ≥ 10% were more likely to demonstrate a reduction of ESV ≥ 15% (84% of patients with an AHR ≥10% vs 28% with an AHR <10%; P < 0.001). Procedure duration and fluoroscopy times were longer in the pressure wire-guided arm (104 ± 39 minutes vs 142 ± 39 minutes; P < .001 and 20 ±16 minutes vs 28 ± 15 minutes; P = .002). CONCLUSIONS: AHR determined by invasively measuring LV dP/dtmax during BIV pacing predicts reverse remodeling 6 months after CRT. Patients in whom LV dP/dtmax was used to guide LV lead placement demonstrated better rates of reverse remodeling.

Pacemaker-induced ventricular fibrillation during radiofrequency catheter ablation for ventricular tachycardia.

Prior to ventricular tachycardia ablation, this patient's cardiac implantable electronic device (CIED) was temporarily programmed to backup pacing mode with tachycardia therapies disabled. During radiofrequency energy delivery, the patient developed ventricular fibrillation requiring emergent cardioversion. Electrogram interrogation showed that the CIED switched to noise reversion mode during ablation. The consequent asynchronous pacing resulted in a paced QRS landing on an intrinsic T wave, inducing ventricular fibrillation. This serves as an important reminder that asynchronous pacing consequent to CIED oversensing could occur in any procedure that could cause electromagnetic interference such as radiofrequency cathteter ablation.

Evaluation of [13N]ammonia positron emission tomography as a potential method for quantifying glutamine synthetase activity in the human brain.

PURPOSE: The conversion of synaptic glutamate to glutamine in astrocytes by glutamine synthetase (GS) is critical to maintaining healthy brain activity and may be disrupted in several brain disorders. As the GS catalysed conversion of glutamate to glutamine requires ammonia, we evaluated whether [13N]ammonia positron emission tomography (PET) could reliability quantify GS activity in humans. METHODS: In this test-retest study, eight healthy volunteers each received two dynamic [13N]ammonia PET scans on the morning and afternoon of the same day. Each [13N]ammonia scan was preceded by a [15O]water PET scan to account for effects of cerebral blood flow (CBF). RESULTS: Concentrations of radioactive metabolites in arterial blood were available for both sessions in five of the eight subjects. Our results demonstrated that kinetic modelling was unable to reliably distinguish estimates of the kinetic rate constant k3 (related to GS activity) from K1 (related to [13N]ammonia brain uptake), and indicated a non-negligible back-flux of [13N] to blood (k2). Model selection favoured a reversible one-tissue compartmental model, and [13N]ammonia K1 correlated reliably (r2 = 0.72-0.92) with [15O]water CBF. CONCLUSION: The [13N]ammonia PET method was unable to reliably estimate GS activity in the human brain but may provide an alternative index of CBF.

High mean entropy calculated from cardiac MRI texture analysis is associated with antitachycardia pacing failure.

BACKGROUND: Antitachycardia pacing (ATP), which may avoid unnecessary implantable cardioverter-defibrillator (ICD) shocks, does not always terminate ventricular arrhythmias (VAs). Mean entropy calculated using cardiac magnetic resonance texture analysis (CMR-TA) has been shown to predict appropriate ICD therapy. We examined whether scar heterogeneity, quantified by mean entropy, is associated with ATP failure and explore potential mechanisms using computer modeling. METHODS: A subanalysis of 114 patients undergoing CMR-TA where the primary endpoint was delivery of appropriate ICD therapy (ATP or shock therapy) was performed. Patients receiving appropriate ICD therapy (n = 33) were dichotomized into "successful ATP" versus "shock therapy" groups. In silico computer modeling was used to explore underlying mechanisms. RESULTS: A total of 16 of 33 (48.5%) patients had successful ATP to terminate VA, and 17 of 33 (51.5%) patients required shock therapy. Mean entropy was significantly higher in the shock versus successful ATP group (6.1 ± 0.5 vs 5.5 ± 0.7, P = .037). Analysis of patients receiving ATP (n = 22) showed significantly higher mean entropy in the six of 22 patients that failed ATP (followed by rescue ICD shock) compared to 16 of 22 that had successful ATP (6.3 ± 0.7 vs 5.5 ± 0.7, P = .048). Computer modeling suggested inability of the paced wavefront in ATP to successfully propagate from the electrode site through patchy fibrosis as a possible mechanism of failed ATP. CONCLUSIONS: Our findings suggest lower scar heterogeneity (mean entropy) is associated with successful ATP, whereas higher scar heterogeneity is associated with more aggressive VAs unresponsive to ATP requiring shock therapy that may be due to inability of the paced wavefront to propagate through scar and terminate the VA circuit.

Evidence of reverse electrical remodelling by non-invasive electrocardiographic imaging to assess acute and chronic changes in bulk ventricular activation following cardiac resynchronisation therapy.

INTRODUCTION: Cardiac resynchronisation therapy (CRT) corrects electrical dyssynchrony. However, the temporal changes in the electrical timing according to substrate are unclear. We used electrocardiographic imaging (ECGi) for serial non-invasive assessment of the underlying electrical substrate and its response to resynchronisation. MATERIAL AND METHODS: ECGi activation maps were constructed 1 day and 6 months post CRT implant. ECGi maps were analysed offline to determine the total ventricular activation time (TVaT) and the time for the bulk of ventricular activation (10th to 90th percentile activation; VaT10-90 Index). Statistical analysis was performed using repeated measures ANOVA with post-hoc pairwise comparisons using paired t-tests. The % relative change within each time point was also calculated and compared between the two time points. RESULTS: Eleven CRT patients were studied. Both total and bulk ventricular activation significantly decreased with CRT turned ON at day 1. Intrinsic (CRT OFF) TVaT and VaT10-90 Index at day 1 were 143 ± 23 and 84 ± 20 ms, respectively, and they significantly decreased post CRT to 115 ± 26 ms (P < 0.001) and 49 ± 17 ms (P < 0.05), respectively. The relative change at day 1 was also statistically significant for TVaT (19 ± 12%, P < 0.001) and VaT10-90 Index (39 ± 25%, P < 0.001). After 6 months, the relative decrease in TVaT with CRT ON remained stable (19% vs. 18% at day 1 and 6 months, respectively) whereas reduction the in VaT10-90 Index was decreased 39% vs. 26% at day 1 and 6 months, respectively. In non-ischaemic patients both total and bulk activation times reduced following CRT. Volumetric responders exhibited an electrical remodelling for bulk activation not apparent in Non-responders, after 6 months of CRT ON. CONCLUSIONS: Intrinsic bulk myocardium activation becomes more rapid and synchronous with CRT. The bulk activation time is more susceptible to improvement by CRT in ischaemic patients and volumetric responders. These observations are consistent with CRT causing reverse electrophysiological remodelling in the bulk myocardium, but not in late-activating ischaemic or fibrotic regions.

Ultra-High-Density Activation Mapping to Aid Isthmus Identification of Atrial Tachycardias in Congenital Heart Disease.

OBJECTIVES: A new electroanatomic mapping system (Rhythmia, Boston Scientific, Marlborough, Massachusetts) using a 64-electrode mapping basket is now available; we systematically assessed its use in complex congenital heart disease (CHD). BACKGROUND: The incidence of atrial arrhythmias post-surgery for CHD is high. Catheter ablation has emerged as an effective treatment, but is hampered by limitations in the mapping system's ability to accurately define the tachycardia circuit. METHODS: Mapping and ablation data of 61 patients with CHD (35 males, age 45 ± 14 years) from 8 tertiary centers were reviewed. RESULTS: Causes were as follows: Transposition of Great Arteries (atrial switch) (n = 7); univentricular physiology (Fontans) (n = 8); Tetralogy of Fallot (n = 10); atrial septal defect (ASD) repair (n = 15); tricuspid valve (TV) anomalies (n = 10); and other (n = 11). The total number of atrial arrhythmias was 86. Circuits were predominantly around the tricuspid valve (n = 37), atriotomy scar (n = 10), or ASD patch (n = 4). Although the majority of peri-tricuspid circuits were cavo-tricuspid-isthmus dependent (n = 30), they could follow a complex route between the annulus and septal resection, ASD patch, coronary sinus, or atriotomy. Immediate ablation success was achieved in all but 2 cases; with follow-up of 12 ± 8 months, 7 patients had recurrence. CONCLUSIONS: We demonstrate the feasibility of the basket catheter for mapping complex CHD arrhythmias, including with transbaffle and transhepatic access. Although the circuits often involve predictable anatomic landmarks, the precise critical isthmus is often difficult to predict empirically. Ultra-high-density mapping enables elucidation of circuits in this complex anatomy and allows successful treatment at the isthmus with a minimal lesion set.

Transvenous lead extraction procedures in women based on ESC-EHRA EORP European Lead Extraction ConTRolled ELECTRa registry: is female sex a predictor of complications?

AIMS: Female sex is considered an independent risk factor of transvenous leads extraction (TLE) procedure. The aim of the study was to evaluate the effectiveness of TLE in women compared with men. METHODS AND RESULTS: A post hoc analysis of risk factors and effectiveness of TLE in women and men included in the ESC-EHRA EORP ELECTRa registry was conducted. The rate of major complications was 1.96% in women vs. 0.71% in men; P = 0.0025. The number of leads was higher in men (mean 1.89 vs. 1.71; P < 0.0001) with higher number of abandoned leads in women (46.04% vs. 34.82%; P < 0.0001). Risk factors of TLE differed between the sexes, of which the major were: signs and symptoms of venous occlusion [odds ratio (OR) 3.730, confidence interval (CI) 1.401-9.934; P = 0.0084], cumulative leads dwell time (OR 1.044, CI 1.024-1.065; P < 0.001), number of generator replacements (OR 1.029, CI 1.005-1.054; P = 0.0184) in females and the number of leads (OR 6.053, CI 2.422-15.129; P = 0.0001), use of powered sheaths (OR 2.742, CI 1.404-5.355; P = 0.0031), and white blood cell count (OR 1.138, CI 1.069-1.212; P < 0.001) in males. Individual radiological and clinical success of TLE was 96.29% and 98.14% in women compared with 98.03% and 99.21% in men (P = 0.0046 and 0.0098). CONCLUSION: The efficacy of TLE was lower in females than males, with a higher rate of periprocedural major complications. The reasons for this difference are probably related to disparities in risk factors in women, including more pronounced leads adherence to the walls of the veins and myocardium. Lead management may be key to the effectiveness of TLE in females.

Erratum to "Comparison of Echocardiographic and Electrocardiographic Mapping for Cardiac Resynchronisation Therapy Optimisation".

[This corrects the article DOI: 10.1155/2019/4351693.].

Emerging role of cardiac computed tomography in heart failure.

Despite medical advancements, the prognosis of patients with heart failure remains poor. While echocardiography and cardiac magnetic resonance imaging remain at the forefront of diagnosing and monitoring patients with heart failure, cardiac computed tomography (CT) has largely been considered to have a limited role. With the advancements in scanner design, technology, and computer processing power, cardiac CT is now emerging as a valuable adjunct to clinicians managing patients with heart failure. In the current manuscript, we review the current applications of cardiac CT to patients with heart failure and also the emerging areas of research where its clinical utility is likely to extend into the realm of treatment, procedural planning, and advanced heart failure therapy implementation.

Optimization of CRT programming using non-invasive electrocardiographic imaging to assess the acute electrical effects of multipoint pacing.

AIM: Quadripolar lead technology and multi-point pacing (MPP) are important clinical adjuncts in cardiac resynchronization therapy (CRT) pacing aimed at reducing the rate of non-response to therapy. Mixed results have been achieved using MPP and it is critical to identify which patients require this approach and how to configure their MPP stimulation, in order to achieve optimal electrical resynchronization. METHODS & RESULTS: We sought to investigate whether electrocardiographic imaging (ECGi), using the CARDIOINSIGHT ™ inverse ECG mapping system, could identify alterations in electrical resynchronization during different methods of device optimization. In no patient did a single form of programming optimization provide the best electrical response. The effects of utilizing MPP were idiosyncratic and highly patient specific. ECGi activation maps were clearly able to discern changes in bulk LV activation during differing MPP programming. In two of the five subjects, MPP resulted in more rapid activation of the left ventricle compared to standard CRT; however, in the remaining three patients, the use of MPP did not appear to acutely improve electrical resynchronization. Crucially, this cohort showed evidence of extensive LV scarring which was well visualized using both CMR and ECGi voltage mapping. CONCLUSIONS: Our work suggests a potential role for ECGi in the optimization of non-responders to CRT, as it allows the fusion of activation maps and scar analysis above and beyond interrogation of the 12 lead ECG.

Mean entropy predicts implantable cardioverter-defibrillator therapy using cardiac magnetic resonance texture analysis of scar heterogeneity.

BACKGROUND: Risk stratification of ventricular arrhythmia remains complex in patients with ischemic and nonischemic cardiomyopathy. OBJECTIVE: The purpose of this study was to determine whether scar heterogeneity, quantified by mean entropy, predicts appropriate implantable cardioverter-defibrillator (ICD) therapy. We hypothesized that higher mean entropy calculated from cardiac magnetic resonance texture analysis (CMR-TA) will predict appropriate ICD therapy. METHODS: Consecutive patients underwent CMR imaging before ICD implantation. Short-axis left ventricular scar was manually segmented. CMR-TA was performed using a Laplacian filter to extract and augment image features to create a scar texture from which histogram analysis of pixel intensity was used to calculate mean entropy. The primary end point was appropriate ICD therapy. RESULTS: A total of 114 patients underwent CMR-TA (ischemic cardiomyopathy [ICM]: n = 70; nonischemic cardiomyopathy [NICM]: n = 44) with a median follow-up of 955 days (interquartile range 691-1185 days). Mean entropy was significantly higher in the ICM group (5.7 ± 0.7 vs 5.5 ± 0.7; P= .045). Overall, 33 patients received appropriate ICD therapy. Using optimized cutoff values from receiver operating characteristic curves, Kaplan-Meier survival analysis demonstrated time until first appropriate therapy was significantly shorter in the high mean entropy group (P = .003). Multivariable analysis showed that mean entropy was the sole predictor of appropriate ICD therapy (hazard ratio 1.882; 95% confidence interval 1.083-3.271; P = .025). In the ICM group, mean entropy remained an independent predictor of appropriate ICD therapy, whereas in the NICM group, precontrast T1 values were the sole predictor. CONCLUSION: Scar heterogeneity, quantified by mean entropy using CMR-TA, was an independent predictor of appropriate ICD therapy in the mixed cardiomyopathy cohort and ICM-only group, suggesting a potential role for CMR-TA in predicting ventricular arrhythmia and risk-stratifying patients for ICD implantation.

Comparison of Echocardiographic and Electrocardiographic Mapping for Cardiac Resynchronisation Therapy Optimisation.

STUDY HYPOTHESIS: We sought to investigate the association between echocardiographic optimisation and ventricular activation time in cardiac resynchronisation therapy (CRT) patients, obtained through the use of electrocardiographic mapping (ECM). We hypothesised that echocardiographic optimisation of the pacing delay between the atrial and ventricular leads-atrioventricular delay (AVD)-and the delay between ventricular leads-interventricular pacing interval (VVD)-would correlate with reductions in ventricular activation time. BACKGROUND: Optimisation of AVD and VVD may improve CRT patient outcome. Optimal delays are currently set based on echocardiographic indices; however, acute studies have found that reductions in bulk ventricular activation time correlate with improvements in acute haemodynamic performance. MATERIALS AND METHODS: Twenty-one patients with established CRT criteria were recruited. After implantation, patients underwent echo-guided optimisation of the AVD and VVD. During this procedure, the participants also underwent noninvasive ECM. ECM maps were constructed for each AVD and VVD. ECM maps were analysed offline. Total ventricular activation time (TVaT) and a ventricular activation time index (VaT10-90) were calculated to identify the optimal AVD and VVD timings that gave the minimal TVaT and VaT10-90 values. We correlated cardiac output with these electrical timings. RESULTS: Echocardiographic programming optimisation was not associated with the greatest reductions in biventricular activation time (VaT10-90 and TVaT). Instead, bulk activation times were reduced by a further 20% when optimised with ECM. A significant inverse correlation was identified between reductions in bulk ventricular activation time and improvements in LVOT VTI (p < 0.001), suggesting that improved ventricular haemodynamics are a sequelae of more rapid ventricular activation. CONCLUSIONS: EAM-guided programming optimisation may achieve superior fusion of activation wave fronts leading to improvements in CRT response.

Procedural outcomes associated with transvenous lead extraction in patients with abandoned leads: an ESC-EHRA ELECTRa (European Lead Extraction ConTRolled) Registry Sub-Analysis.

AIMS: The decision to abandon or extract superfluous leads remains controversial. We sought to compare procedural outcome of patients with and without abandoned leads undergoing transvenous lead extraction (TLE). METHODS AND RESULTS: An analysis of the ESC-EHRA European Lead Extraction ConTRolled ELECTRa registry was conducted. Patients were stratified into two groups based on the presence (Group 1) or absence (Group 2) of abandoned leads at the time for extraction. Out of 3508 TLE procedures, 422 patients (12.0%) had abandoned leads (Group 1). Group 1 patients were older and more likely to have implantable cardioverter-defibrillator devices, infection indication (78.8% vs. 49.8%), and vegetations (24.6% vs. 15.3%). Oldest lead dwelling time was longer in Group 1 (10.9 vs. 6.3 years) as was the number of extracted leads per patient (3.2 vs. 1.7). Manual traction failure (94.5% vs. 78.8%), powered sheath use (50.7% vs. 28.4%), and femoral approach were higher in Group 1 (P < 0.0001). Procedural success rate and clinical success (89.8% vs. 96.6%, P < 0.0001) were lower in Group 1. Major complication including deaths (5.5% vs. 2.3%, P = 0.0007) and procedure related major complications (3.3% vs. 1.4%, P = 0.0123) were higher in Group 1. The presence of abandoned leads at the time of TLE was an independent predictor of clinical failure [odds ratio (OR) 2.31, confidence interval (CI) 1.57-3.40] and complications [OR 1.69, CI 1.22-2.35]. receiver-operating characteristic curve analysis showed a dwell time threshold of 9 years for radiological failure and major complications. CONCLUSIONS: Previously abandoned leads at the time of TLE were associated with increased procedural complexity, clinical failure, and major complication, which may have important implications for future studies regarding managing of lead failures.

Left ventricular activation-recovery interval variability predicts spontaneous ventricular tachyarrhythmia in patients with heart failure.

BACKGROUND: Enhanced beat-to-beat variability of repolarization is strongly linked to arrhythmogenesis and is largely due to variation in ventricular action potential duration (APD). Previous studies in humans have relied on QT interval measurements; however, a direct relationship between beat-to-beat variability of APD and arrhythmogenesis in humans has yet to be demonstrated. OBJECTIVE: This study aimed to explore the beat-to-beat repolarization dynamics in patients with heart failure at the level of ventricular APD. METHODS: Forty-three patients with heart failure and implanted cardiac resynchronization therapy - defibrillator devices were studied. Activation-recovery intervals as a surrogate for APD were recorded from the left ventricular epicardial lead while pacing from the right ventricular lead to maintain a constant cycle length. RESULTS: During a mean follow-up of 23.6±13.6 months, 11 patients sustained ventricular fibrillation/ventricular tachycardia (VT/VF) and received appropriate implantable cardioverter-defibrillator therapies (antitachycardia pacing or shock therapy). Activation-recovery interval variability (ARIV) was significantly greater in patients with subsequent VT/VF than in those without VT/VF (3.55±1.3 ms vs 2.77±1.09 ms; P=.047). Receiver operating characteristic curve analysis (area under the curve 0.71; P=.046) suggested high- and low-risk ARIV groups for VT/VF. Kaplan-Meier survival analysis demonstrated that the time until first appropriate therapy for VT/VF was significantly shorter in the high-risk ARIV group (P=.028). ARIV was a predictor for VT/VF in the multivariate Cox model (hazard ratio 1.623; 95% confidence interval 1.1-2.393; P=.015). CONCLUSION: Increased left ventricular ARIV is associated with an increased risk of VT/VF in patients with heart failure.