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Introduction: Cardiac resynchronisation therapy is ineffective in 30–40% of patients with heart failure with reduced ejection fraction. Targeting non-scarred myocardium by selecting the site of latest mechanical activation using echocardiography has been suggested to improve outcomes but at the cost of increased resource utilisation. The interval between the beginning of the QRS complex and the local LV lead electrogram (QLV) might represent an alternative electrical marker. Aims: To determine whether the site of latest myocardial electrical and mechanical activation are concordant. Methods: This was a single-centre, prospective pilot study, enrolling patients between March 2019 and June 2021. Patients underwent speckle-tracking echocardiography (STE) prior to CRT implantation. Intra-procedural QLV measurement and R-wave amplitude were performed in a blinded fashion at all accessible coronary sinus branches. Pearson's correlation coefficient and Cohen's Kappa coefficient were utilised for the comparison of electrical and echocardiographic parameters. Results: A total of 20 subjects had complete data sets. In 15, there was a concordance at the optimal site between the electrically targeted region and the mechanically targeted region; in four, the regions were adjacent (within one segment). There was discordance (≥2 segments away) in only one case between the two methods of targeting. There was a statistically significant increase in procedure time and fluoroscopy duration using the intraprocedural QLV strategy. There was no statistical correlation between the quantitative electrical and echocardiographic data. Conclusions: A QLV-guided approach to targeting LV lead placement appears to be a potential alternative to the established echocardiographic-guided technique. However, it is associated with prolonged fluoroscopy and overall procedure time. [ABSTRACT FROM AUTHOR]

Introduction: Cardiac resynchronisation therapy is ineffective in 30–40% of patients with heart failure with reduced ejection fraction. Targeting non-scarred myocardium by selecting the site of latest mechanical activation using echocardiography has been suggested to improve outcomes but at the cost of increased resource utilisation. The interval between the beginning of the QRS complex and the local LV lead electrogram (QLV) might represent an alternative electrical marker. Aims: To determine whether the site of latest myocardial electrical and mechanical activation are concordant. Methods: This was a single-centre, prospective pilot study, enrolling patients between March 2019 and June 2021. Patients underwent speckle-tracking echocardiography (STE) prior to CRT implantation. Intra-procedural QLV measurement and R-wave amplitude were performed in a blinded fashion at all accessible coronary sinus branches. Pearson’s correlation coefficient and Cohen’s Kappa coefficient were utilised for the comparison of electrical and echocardiographic parameters. Results: A total of 20 subjects had complete data sets. In 15, there was a concordance at the optimal site between the electrically targeted region and the mechanically targeted region; in four, the regions were adjacent (within one segment). There was discordance (≥2 segments away) in only one case between the two methods of targeting. There was a statistically significant increase in procedure time and fluoroscopy duration using the intraprocedural QLV strategy. There was no statistical correlation between the quantitative electrical and echocardiographic data. Conclusions: A QLV-guided approach to targeting LV lead placement appears to be a potential alternative to the established echocardiographic-guided technique. However, it is associated with prolonged fluoroscopy and overall procedure time.

Background: For cardiac resynchronization therapy (CRT), image‐guided approaches targeting left ventricular (LV) lead placement at the site of latest mechanical activation had inconsistent outcomes. We examined evidence for improved CRT outcomes when LV lead placement concordant with latest mechanical activation occurred. Methods: A review of EMBASE and PubMed was performed for randomized controlled trials or prospective observational studies from October 2008 through October 2020 comparing outcomes with concordant versus discordant LV lead placement. Meta‐analyses were performed to assess the association between concordance and death, death or heart failure (HF) hospitalization, ≥ 15% reduction in LV end systolic volume (LVESV), and changes in LVESV or ejection fraction (LVEF). Results: From 5897 citations, nine publications (eight studies) with 1355 patients were selected; 975 with a concordant LV lead and 380 with a discordant lead. Mean age was 66–68 years, 82% were male, and 64% had ischemic cardiomyopathy. Meta‐analyses demonstrated a statistically significant reduction in death/HF hospitalization at 2 years (OR 0.38; 95% CI 0.16, 0.92) and LVESV at 6 months (mean difference [MD] ‐13.4%; 95% CI ‐6.7%, ‐20.0%), and an increase in LVEF (MD 4.03; 95% CI 0.77, 7.30) with the concordant LV lead. There were trends toward decreased death at 2 years (OR 0.49; 95% CI 0.19, 1.23) and ≥ 15% reduction in LVESV at 6 months (OR 3.81; 95% CI 0.24, 61.24) with concordant LV lead placement. Conclusion: A concordant LV lead was associated with better CRT outcomes. Further study of feasible methods to achieve LV lead concordance is needed. [ABSTRACT FROM AUTHOR]

This case highlights the importance of proper identification of congenital anomalies of the coronary sinus for the successful placement of left ventricular lead during cardiac resynchronization therapy device implantation. We discuss an alternate route for left ventricular lead placement via the vein of Marshall when the coronary sinus ostium in the right atrium was atretic and was facing difficulty initially in detecting the anomaly.

Aims: This study aims to investigate the long-term occurrence of the composite endpoint of heart failure (HF) hospitalization or all-cause death (primary endpoint) in patients randomized to cardiac resynchronization therapy (CRT) using individualized multimodality imaging-guided left ventricular (LV) lead placement compared with a routine fluoroscopic approach. Furthermore, this study aims to evaluate whether inter-lead electrical delay (IED) is associated with improved response rate of this endpoint.Methods and Results: We reviewed follow-up data until November 2020 for all 182 patients included in the ImagingCRT trial for the occurrence of HF hospitalization and all-cause death. During median (inter-quartile range) time to primary endpoint/censuring of 6.7 (3.3-7.9) years, the rate of the primary endpoint was 60% (n = 53) in the imaging group compared with 52% (n = 48) in the control group [hazard ratio (HR) 1.22, 95% confidence interval (CI) 0.83-1.81, P = 0.31]. Neither the risk of HF hospitalization (HR 1.11, 95% CI 0.62-1.99, P = 0.72) nor of all-cause death differed between treatment groups (HR 1.23, 95% CI 0.82-1.85, P = 0.32). The risk of the primary endpoint was significantly reduced among those with IED ≥100 ms when compared with those with IED <100 ms (HR 0.62, 95% CI 0.39-0.98, P = 0.04).Conclusions: In this study, an individualized multimodality imaging-guided strategy targeting LV lead placement towards the latest mechanically activated non-scarred myocardial segment during CRT implantation did not reduce HF hospitalization or all-cause death when compared with routine LV lead placement during long-term follow-up. Targeting the latest electrical activation should be studied as an alternative individualized strategy for optimizing LV lead placement in CRT recipients. [ABSTRACT FROM AUTHOR]

Background: Subselection inner catheters (Inner‐Cath) are used adjunctively with outer guiding catheters (Outer‐Cath) during cardiac resynchronization therapy (CRT) device implantation. This study aims to investigate the feasibility and efficacy of left ventricular lead placement (LV‐LP) guided by Inner‐Cath alone. Methods: A total of 74 patients undergoing de novo CRT implantation were investigated. LV‐LP was initially guided by Inner‐Cath in 42 patients (Inner‐Cath group) and Outer‐Cath in 32 patients (Outer‐Cath group). In the Inner‐Cath group, a 7Fr Inner‐Cath was advanced to the coronary sinus through a 7 Fr sheath inserted in a subclavian vein. In the Outer‐Cath group, 9Fr or 10Fr Outer‐Caths were used. Success rate of LV‐LP, additional use of inner or outer catheters and procedure‐related complications were compared between groups. Results: LV‐LP was successful in all patients in the Inner‐Cath group, while LV‐LP had to be abandoned in two patients (6.3%) of the Outer‐Cath group due to CS perforation caused by Outer‐Cath manipulation. Procedure time was significantly shorter in the Inner‐Cath group (148 vs. 168 min; p =.024). Deployment of both an inner and outer cath became necessary less frequently for the Inner‐Cath group (4.8% vs. 56.3%; p <.001). Mechanical CS injuries due to guiding catheter manipulation were only observed in the Outer‐Cath group (0% vs. 15.6%, p =.013). Conclusion: LV‐LP guided by Inner‐Cath alone was feasible in over 95% of the patients without severe complications. This methodology for LV‐LP may be preferable in CRT candidates with severe LV dysfunction in terms of shorter procedure time, smaller guiding sheath, and less procedure‐related complications. [ABSTRACT FROM AUTHOR]

Objectives: To compare the clinical outcome of cardiac resynchronization therapy (CRT) in patients receiving a bipolar left ventricular (LV) lead with a side helix for active fixation to the outcome in patients receiving a quadripolar passive fixation LV lead. Design: Sixty-two patients (mean age 72 ± 11 years) were blindly and randomly assigned to the active fixation bipolar lead group (n = 31) or to the quadripolar lead group (n= 31). The LV leads were targeted to the basal LV segment in a vein concordant to the LV segment with the latest mechanical contraction chosen on the basis of preoperative radial strain (RS) echocardiography. Results: At the 6-month follow-up (FU), the reduction in LV end-systolic volume and LV reverse remodelling responder rate, defined as LV end-systolic volume reduction >15%, was 77% in the active fixation group and 83% in the quadripolar group, which was not significantly different. At the 12-month FU, the LV ejection fraction (LVEF) did not differ between the groups. There were no significant differences between the two groups in changes in New York Heart Association (NYHA) functional class or Minnesota Living with Heart Failure Questionnaire score. The occurrence of phrenic nerve stimulation (PNS) was 19% in the active fixation group versus 10% in the quadripolar group (p=.30), and all cases were resolved by reprogramming the device. All patients were alive at the 12-month FU. There was no device infection. Conclusions: There were no significant differences between the active fixation group of patients and the quadripolar group of patients concerning improvement in echocardiographic parameters or clinical symptoms. ClinicalTrials.gov number, NCT04632472 [ABSTRACT FROM AUTHOR]

Aims: To examine the feasibility and safety of a novel protocol for low fluoroscopy, electroanatomic mapping (EAM)-guided Cardiac resynchronization therapy with a defibrillator (CRT-D) implantation and using both EnSite NavX (St. Jude Medical, St. Paul, MN, USA) and Carto 3 (Biosense Webster, Irvine, CA, USA) mapping systems.Methods and Results: Twenty consecutive patients underwent CRT implantation using either a conventional fluoroscopic approach (CFA) or EAM-guided lead placement with Carto 3 and EnSite NavX mapping systems. We compared fluoroscopy and procedural times, radiopaque contrast dose, change in QRS duration pre- and post-procedure, and complications in all patients. Fluoroscopy time was 86% lower in the EAM group compared to the conventional group [mean 37.2 min (CFA) vs. 5.5 min (EAM), P = 0.00003]. There was no significant difference in total procedural time [mean 183 min (CFA) vs. 161 min (EAM), P = 0.33] but radiopaque contrast usage was lower in the EAM group [mean 16 mL (CFA) vs. 4 mL (EAM), P = 0.006]. Likewise, there was no significant change in QRS duration with BiV pacing between the groups [mean -13 (CFA) vs. -25 ms (EAM), P = 0.09].Conclusion: Electroanatomic mapping-guided lead placement using either Carto or ESI NavX mapping systems is a feasible alternative to conventional fluoroscopic methods for CRT-D implantation utilizing the protocol described in this study. [ABSTRACT FROM AUTHOR]

Aims: To test in a double-blinded, randomized trial whether the combination of electrically guided left ventricular (LV) lead placement and post-implant interventricular pacing delay (VVd) optimization results in superior increase in LV ejection fraction (LVEF) in cardiac resynchronization therapy (CRT) recipients.Methods and Results: Stratified according to presence of ischaemic heart disease, 122 patients were randomized 1:1 to LV lead placement targeted towards the latest electrically activated segment identified by systematic mapping of the coronary sinus tributaries during CRT implantation combined with post-implant VVd optimization (intervention group) or imaging-guided LV lead implantation by cardiac computed tomography venography, 82Rubidium myocardial perfusion imaging and speckle tracking echocardiography targeting the LV lead towards the latest mechanically activated non-scarred myocardial segment (control group). Follow-up was 6 months. Primary endpoint was absolute increase in LVEF. Additional outcome measures were changes in New York Heart Association class, 6-minute walk test, and quality of life, LV reverse remodelling, and device related complications. Analysis was intention-to-treat. A larger increase in LVEF was observed in the intervention group (11 ± 10 vs. 7 ± 11%; 95% confidence interval 0.4-7.9%, P = 0.03); when adjusting for pre-specified baseline covariates this difference did not maintain statistical significance (P = 0.09). Clinical response, LV reverse remodelling, and complication rates did not differ between treatment groups.Conclusion: Electrically guided CRT implantation appeared non-inferior to an imaging-guided strategy considering the outcomes of change in LVEF, LV reverse remodelling and clinical response. Larger long-term studies are warranted to investigate the effect of an electrically guided CRT strategy. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Failure to select the optimal left ventricular (LV) segment for lead implantation is one of the most important causes of unresponsiveness to the cardiac resynchronization therapy (CRT). In our study, we aimed to investigate the echocardiographic and clinical benefits of LV lead implantation guided by an intraoperative 12-lead surface electrocardiogram (ECG) in patients with multiple target veins. METHODS: We included 80 [42 (62.5%) male] heart failure patients who successfully underwent CRT defibrillator (CRT-D) implantation. Patients were divided into two groups. In group 1, LV lead was positioned at the site with the shortest biventricular-paced (BiV-paced) QRS duration (QRSd), as intraprocedurally measured using surface ECG. In group 2 (control), we included patients who underwent the standard unguided CRT. ECG, echocardiogram, and functional status were evaluated before and 6 months after CRT implantation in all patients. RESULTS: In group 1, BiV-paced QRSd measurements were successfully performed in 112 of 120 coronary sinus branches during CRT and an LV lead was successfully placed at the optimal site in all patients. Compared with group 2, group 1 had a significantly higher rate (85% vs. 50%, p=0.02) of response (>15% reduction in LV end-systolic volume) to CRT as well as a shorter QRSd (p<0.001) and a greater QRS shortening (ΔQRS) associated with CRT compared with baseline (p<0.001). The mean New York Heart Association functional class was significantly improved in both groups, and no significant differences were found in clinical response to CRT (85% vs. 70%, p=0.181). CONCLUSION: Surface ECG can be used to guide LV lead placement in patients with multiple target veins for improving response to CRT. Thus, it is a safe, feasible, and economic approach for CRT-D implantation. [ABSTRACT FROM AUTHOR]

Device Optimization for Acute and Chronic CRT Background Cardiac anatomy and function adapt in response to chronic cardiac resynchronization therapy (CRT). The effects of these changes on the optimal left ventricle (LV) lead location and timing delay settings have yet to be fully explored. Objective To predict the effects of chronic CRT on the optimal LV lead location and device timing settings over time. Methods Biophysical computational cardiac models were generated for 3 patients, immediately post-implant (ACUTE) and after at least 6 months of CRT (CHRONIC). Optimal LV pacing area and device settings were predicted by pacing the ACUTE and CHRONIC models across the LV epicardium (49 sites each) with a range of 9 pacing settings and simulating the acute hemodynamic response (AHR) of the heart. Results There were statistically significant differences between the distribution of the AHR in the ACUTE and CHRONIC models (P < 0.0005 in all cases). The site delivering the maximal AHR shifted location between the ACUTE and CHRONIC models but provided a negligible improvement (<2%). The majority of the acute optimal LV pacing regions (76-100%) and device settings (76-91%) remained optimal chronically. Conclusion Optimization of the LV pacing location and device settings were important at the time of implant, with a reduced benefit over time, where the majority of the acute optimal LV pacing region and device settings remained optimal with chronic CRT. [ABSTRACT FROM AUTHOR]

Background: Placing the left ventricular (LV) lead at a site of late electrical activation remote from scar is desired to improve cardiac resynchronization therapy (CRT) response.Objective: The purpose of this study was to integrate coronary venous electroanatomic mapping (EAM) with delayed enhancement cardiac magnetic resonance (DE-CMR) enabling LV lead guidance to the latest activated vein remote from scar.Methods: Eighteen CRT candidates with focal scar on DE-CMR were prospectively included. DE-CMR images were semi-automatically analyzed. Coronary venous EAM was performed intraprocedurally and integrated with DE-CMR to guide LV lead placement in real time. Image integration accuracy and electrogram parameters were evaluated offline.Results: Integration of EAM and DE-CMR was achieved using 8.9 ± 2.8 anatomic landmarks and with accuracy of 4.7 ± 1.1 mm (mean ± SD). Maximal electrical delay ranged between 72 and 197ms (57%-113% of QRS duration) and was heterogeneously located among individuals. In 12 patients, the latest activated vein was located outside scar, and placing the LV lead in the latest activated vein remote from scar was accomplished in 10 patients and prohibited in 2 patients. In the other 6 patients, the latest activated vein was located in scar, and targeting alternative veins was considered. Unipolar voltages were on average lower in scar compared to nonscar (6.71 ± 3.45 mV vs 8.18 ± 4.02 mV [median ± interquartile range), P <.001) but correlated weakly with DE-CMR scar extent (R -0.161, P <.001) and varied widely among individual patients.Conclusion: Integration of coronary venous EAM with DE-CMR can be used during CRT implantation to guide LV lead placement to the latest activated vein remote from scar, possibly improving CRT. [ABSTRACT FROM AUTHOR]

Aim: Left ventricular (LV) lead position at the latest mechanically activated non-scarred myocardial LV region confers improved response to cardiac resynchronization therapy (CRT). We conducted a double-blind, randomized controlled trial to evaluate the clinical benefit of multimodality imaging-guided LV lead placement in CRT.Methods and Results: Patients were allocated (1:1) to imaging-guided LV lead placement using cardiac computed tomography (CT) venography, 99m Technetium myocardial perfusion imaging, and speckle-tracking echocardiography radial strain to target the optimal coronary sinus (CS) branch closest to the non-scarred myocardial segment with latest mechanical activation (imaging group, n = 89) or to routine LV lead implantation in a posterolateral region with late electrical activation (control group, n = 93). The primary endpoint was clinical non-response to CRT [≥1 of the following after 6 months: (1) death, (2) heart failure hospitalization, or (3) no improvement in New York Heart Association class and <10% increase in 6-min walk distance]. Secondary outcomes included LV remodelling and the combination of all-cause mortality and hospitalization owing to heart failure during 1.8 ± 0.9 years. Analysis was intention-to-treat. In the imaging group, fewer patients reached the primary endpoint (26% vs. 42%, P = 0.02). More patients in the imaging group had the LV lead placed in the optimal CS branch (83% vs. 65%, P = 0.01). There were no between-group differences in reverse LV remodelling or the combined endpoint of death or hospitalizations for heart failure.Conclusions: Multimodality imaging-guided LV lead placement towards the CS branch closest to latest mechanically activated non-scarred myocardial LV segment reduces the proportion of clinical non-responders to CRT. Larger long-term multicentre studies are needed. [ABSTRACT FROM AUTHOR]

Aims: Suboptimal placement, phrenic nerve stimulation, and dislodgements of left-ventricular (LV) leads are main challenges in cardiac resynchronization therapy. We investigated the handling, performance, safety, and stability for a novel 4Fr LV lead with a small side helix located proximal to the ring electrode for active fixation of the LV lead.Methods and Results: The novel LV lead was successfully implanted in 103 of 106 patients. Patients with dislodged LV leads and with demanding coronary vein anatomies were included. The lead body was rotated clockwise to engage the active fixation side helix in the vein wall. The stimulating electrode was located in basal LV segment and middle LV segment in 54 and 46% of the patients, respectively. The lead was targeted to a vein concordant to the LV segment with latest mechanical activation. Concordant LV lead placement was achieved in 73% of the patients and in adjacent segment in 24%. The average pacing capture threshold (PCT) at implantation was 1.04 ± 0.6 V (n = 103) and at an average follow-up at 7 months, the PCT remained low and no dislodgements have been observed. During follow-up, four leads have been explanted without complications.Conclusion: Active fixation of this 4Fr LV lead by using a side helix, offers flexibility to place the lead precisely in targeted vein segments over a wide range of vein anatomies. The average LV pacing threshold was low at implantation and follow-ups. The lead seems to be extractable and no late dislodgements have been observed. [ABSTRACT FROM AUTHOR]

Aim Current targeted left ventricular ( LV) lead placement strategy is directed at the latest activated region during intrinsic activation. However, cardiac resynchronization therapy ( CRT) is most commonly applied by simultaneous LV and right ventricular ( RV) pacing without contribution from intrinsic conduction. Therefore, targeting the LV lead to the latest activated region during RV pacing might be more appropriate. We investigated the difference in LV electrical activation sequence between left bundle-branch block ( LBBB) and RV apex ( RVA) pacing using coronary venous electro-anatomic mapping ( EAM). Methods and results Twenty consecutive CRT candidates with LBBB underwent intra-procedural coronary venous EAM during intrinsic activation and RVA pacing using EnSite NavX. Left ventricular lead placement was aimed at the latest activated region during LBBB according to current recommendations. In all patients, LBBB was associated with a circumferential LV activation pattern, whereas RVA pacing resulted in activation from the apex of the heart to the base. In 10 of 20 patients, RVA pacing shifted the latest activated region relative to LBBB. In 18 of 20 patients, the LV lead was successfully positioned in the latest activated region during LBBB. For the whole study population, LV lead electrical delay, expressed as percentage of QRS duration, was significantly shorter during RVA pacing than during LBBB (72 ± 13 vs. 82 ± 5%, P = 0.035). Conclusion Right ventricular apex pacing alters LV electrical activation pattern in CRT patients with LBBB, and shifts the latest activated region in a significant proportion of these patients. These findings warrant reconsideration of the current practice of LV lead targeting for CRT. [ABSTRACT FROM AUTHOR]

Cardiac resynchronization therapy (CRT) requires permanent left ventricular (LV) pacing. Coronary sinus (CS) lead placement is the first line clinical approach but can be difficult or impossible; may suffer from a high LV pacing threshold, phrenic nerve stimulation, and dislodgement; and produces epicardial LV pacing, which is less physiological and hemodynamically effective and potentially more proarrhythmic than endocardial LV pacing. CS leads can usually be extracted with direct traction but may require use of extraction sheaths. Half of CS side branches previously used for lead placement may be unusable for the same purpose after successful lead extraction, and 30% of CS lead reimplantation attempts may fail due to exhaustion of side branches. Surgical epicardial LV lead placement is the more invasive second line approach, produces epicardial LV pacing, and has a lead failure rate of ≈15% in 5 years. Transseptal endocardial LV lead placement is the third line approach, can be difficult to achieve, but produces endocardial LV pacing. The major concern with transseptal endocardial LV leads is systemic thromboembolism, but the risk is unknown and oral anticoagulation is advised. Among the new CRT recipients in the United States and Western Europe between 2003 and 2007, 22,798 patients may require CS lead revisions, 9,119 patients may have no usable side branches for CS lead replacement, and 1,800 patients may require surgical epicardial LV lead revision in the next 5 years. The CRT community should actively explore and develop alternative approaches to LV pacing to meet this anticipated clinical demand. [ABSTRACT FROM AUTHOR]

Aims: Recent studies suggest differences in coronary venous anatomy between patients with ischaemic (I) and non-ischaemic (N) cardiomyopathy. We hypothesize that these differences may affect the potential for left ventricular (LV) lead targeting in patients undergoing cardiac resynchronization therapy. [ABSTRACT FROM PUBLISHER]

Aims: This study aims to investigate the long-term occurrence of the composite endpoint of heart failure (HF) hospitalization or all-cause death (primary endpoint) in patients randomized to cardiac resynchronization therapy (CRT) using individualized multimodality imaging-guided left ventricular (LV) lead placement compared with a routine fluoroscopic approach. Furthermore, this study aims to evaluate whether inter-lead electrical delay (IED) is associated with improved response rate of this endpoint., Methods and Results: We reviewed follow-up data until November 2020 for all 182 patients included in the ImagingCRT trial for the occurrence of HF hospitalization and all-cause death. During median (inter-quartile range) time to primary endpoint/censuring of 6.7 (3.3-7.9) years, the rate of the primary endpoint was 60% (n = 53) in the imaging group compared with 52% (n = 48) in the control group [hazard ratio (HR) 1.22, 95% confidence interval (CI) 0.83-1.81, P = 0.31]. Neither the risk of HF hospitalization (HR 1.11, 95% CI 0.62-1.99, P = 0.72) nor of all-cause death differed between treatment groups (HR 1.23, 95% CI 0.82-1.85, P = 0.32). The risk of the primary endpoint was significantly reduced among those with IED ≥100 ms when compared with those with IED <100 ms (HR 0.62, 95% CI 0.39-0.98, P = 0.04)., Conclusions: In this study, an individualized multimodality imaging-guided strategy targeting LV lead placement towards the latest mechanically activated non-scarred myocardial segment during CRT implantation did not reduce HF hospitalization or all-cause death when compared with routine LV lead placement during long-term follow-up. Targeting the latest electrical activation should be studied as an alternative individualized strategy for optimizing LV lead placement in CRT recipients., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2022. For permissions, please email: journals.permissions@oup.com.)

Cardiac resynchronization therapy (CRT) improves symptoms and reduces morbidity and mortality in select heart failure patients but remains challenging to deploy widely because of difficult or unsuccessful coronary sinus (CS) access in up to 10% to 15% of patients. This report describes the radiological and anatomical aspects for improving CS catheterization and left ventricular (LV) lead positioning, focusing on the radioscopic and anatomical aspects, based on phlebography, to identify demanding cases in patients with dilated cardiomyopathy referred for CRT implantation. Anatomical and radiological aspects were explored in the anteroposterior, 30° left anterior oblique, and 30° right anterior oblique (RAO) views. In total, 117 phlebographies were performed in 39 consecutive procedures (one reintervention). Access to the CS was successful 37 times (94.9%). The most difficult cases were complicated by issues related to the altered spatial orientation of the CS ostium toward the tricuspid annular plane (TAP), which was best perceived in the 30° RAO projection and occurred in 37% of patients. One of two catheterization failures that occurred was caused by anomalous coronary venous drainage into the left atrium. Final LV lead positioning was successful in 36 (92.3%) of 39 procedures. More severe heart failure and worse LV ejection fraction did not translate into greater difficulty in LV lead implantation. As such, understanding anatomical and radiological relationships is the key to successful LV lead positioning. RAO projection can be particularly useful in the assessment of demanding CRT implant cases, especially when the CS ostium pointed to the TAP., Competing Interests: The authors report no conflicts of interest for the published content., (Copyright: © 2020 Innovations in Cardiac Rhythm Management.)

Aims: To examine the feasibility and safety of a novel protocol for low fluoroscopy, electroanatomic mapping (EAM)-guided Cardiac resynchronization therapy with a defibrillator (CRT-D) implantation and using both EnSite NavX (St. Jude Medical, St. Paul, MN, USA) and Carto 3 (Biosense Webster, Irvine, CA, USA) mapping systems., Methods and Results: Twenty consecutive patients underwent CRT implantation using either a conventional fluoroscopic approach (CFA) or EAM-guided lead placement with Carto 3 and EnSite NavX mapping systems. We compared fluoroscopy and procedural times, radiopaque contrast dose, change in QRS duration pre- and post-procedure, and complications in all patients. Fluoroscopy time was 86% lower in the EAM group compared to the conventional group [mean 37.2 min (CFA) vs. 5.5 min (EAM), P = 0.00003]. There was no significant difference in total procedural time [mean 183 min (CFA) vs. 161 min (EAM), P = 0.33] but radiopaque contrast usage was lower in the EAM group [mean 16 mL (CFA) vs. 4 mL (EAM), P = 0.006]. Likewise, there was no significant change in QRS duration with BiV pacing between the groups [mean -13 (CFA) vs. -25 ms (EAM), P = 0.09]., Conclusion: Electroanatomic mapping-guided lead placement using either Carto or ESI NavX mapping systems is a feasible alternative to conventional fluoroscopic methods for CRT-D implantation utilizing the protocol described in this study., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2019. For permissions, please email: journals.permissions@oup.com.)

Aims: To test in a double-blinded, randomized trial whether the combination of electrically guided left ventricular (LV) lead placement and post-implant interventricular pacing delay (VVd) optimization results in superior increase in LV ejection fraction (LVEF) in cardiac resynchronization therapy (CRT) recipients., Methods and Results: Stratified according to presence of ischaemic heart disease, 122 patients were randomized 1:1 to LV lead placement targeted towards the latest electrically activated segment identified by systematic mapping of the coronary sinus tributaries during CRT implantation combined with post-implant VVd optimization (intervention group) or imaging-guided LV lead implantation by cardiac computed tomography venography, 82Rubidium myocardial perfusion imaging and speckle tracking echocardiography targeting the LV lead towards the latest mechanically activated non-scarred myocardial segment (control group). Follow-up was 6 months. Primary endpoint was absolute increase in LVEF. Additional outcome measures were changes in New York Heart Association class, 6-minute walk test, and quality of life, LV reverse remodelling, and device related complications. Analysis was intention-to-treat. A larger increase in LVEF was observed in the intervention group (11 ± 10 vs. 7 ± 11%; 95% confidence interval 0.4-7.9%, P = 0.03); when adjusting for pre-specified baseline covariates this difference did not maintain statistical significance (P = 0.09). Clinical response, LV reverse remodelling, and complication rates did not differ between treatment groups., Conclusion: Electrically guided CRT implantation appeared non-inferior to an imaging-guided strategy considering the outcomes of change in LVEF, LV reverse remodelling and clinical response. Larger long-term studies are warranted to investigate the effect of an electrically guided CRT strategy., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2019. For permissions, please email: journals.permissions@oup.com.)

Aims: Suboptimal placement, phrenic nerve stimulation, and dislodgements of left-ventricular (LV) leads are main challenges in cardiac resynchronization therapy. We investigated the handling, performance, safety, and stability for a novel 4Fr LV lead with a small side helix located proximal to the ring electrode for active fixation of the LV lead., Methods and Results: The novel LV lead was successfully implanted in 103 of 106 patients. Patients with dislodged LV leads and with demanding coronary vein anatomies were included. The lead body was rotated clockwise to engage the active fixation side helix in the vein wall. The stimulating electrode was located in basal LV segment and middle LV segment in 54 and 46% of the patients, respectively. The lead was targeted to a vein concordant to the LV segment with latest mechanical activation. Concordant LV lead placement was achieved in 73% of the patients and in adjacent segment in 24%. The average pacing capture threshold (PCT) at implantation was 1.04 ± 0.6 V (n = 103) and at an average follow-up at 7 months, the PCT remained low and no dislodgements have been observed. During follow-up, four leads have been explanted without complications., Conclusion: Active fixation of this 4Fr LV lead by using a side helix, offers flexibility to place the lead precisely in targeted vein segments over a wide range of vein anatomies. The average LV pacing threshold was low at implantation and follow-ups. The lead seems to be extractable and no late dislodgements have been observed., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.)

Aim: Left ventricular (LV) lead placement in the latest activated region is an important determinant of response to cardiac resynchronization therapy (CRT). We investigated the feasibility of coronary venous electroanatomic mapping (EAM) to guide LV lead placement to the latest activated region., Methods and Results: Twenty-five consecutive CRT candidates with left bundle-branch block underwent intra-procedural coronary venous EAM using EnSite NavX. A guidewire was used to map the coronary veins during intrinsic activation, and to test for phrenic nerve stimulation (PNS). The latest activated region, defined as the region with an electrical delay >75% of total QRS duration, was located anterolaterally in 18 (basal, n = 10; mid, n = 8) and inferolaterally in 6 (basal, n = 3; mid, n = 3). In one patient, identification of the latest activated region was impeded by limited coronary venous anatomy. In patients with >1 target vein (n = 12), the anatomically targeted inferolateral vein was rarely the vein with maximal electrical delay (n = 3). A concordant LV lead position was achieved in 18 of 25 patients. In six patients, this was hampered by PNS (n = 4), lead instability (n = 1), and coronary vein stenosis (n = 1)., Conclusion: Coronary venous EAM can be used intraprocedurally to guide LV lead placement to the latest activated region free of PNS. This approach especially contributes to optimization of LV lead electrical delay in patients with multiple target veins. Conventional anatomical LV lead placement strategy does not target the vein with maximal electrical delay in many of these patients., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.)