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Background: Cardiac resynchronization therapy (CRT) improves ventricular function, but a positive response to CRT is often limited due to left ventricular (LV) lead placement in a suboptimal position. Complex coronary venous anatomy can hinder the placement of an LV lead in the target vessel, leading to poor CRT response. Objective: To report experience with snare‐assisted LV lead delivery in CRT and compare outcomes with the conventional LV lead delivery. Methods: This is a single‐center retrospective case–control study of CRT implants between 2016 and 2021. Snare‐assisted lead delivery was performed in cases where conventional lead placement failed or when a preferred target vessel had anatomy amenable to the technique. Safety and outcomes were compared to conventional LV lead placement cases. Results: Among 180 CRT cases, 33 were snare‐assisted, and 147 were conventional LV lead placements. Median follow‐up was 924 days in the snare and 618.5 days in the control group. The lead placement was successful in 28/33 snare and 138/147 control cases. A mid‐vessel segment was attained in 89.3% of snare and 72.5% of control cases(p =.03). The apical position was more frequently observed in the control group (26.8% vs. 7.1%, p =.03). All‐cause mortality trended lower in the snare group (6.1%) compared to (17.1%) in the control group (p =.13). Conclusion: Snare‐assisted LV lead delivery is a safe and effective technique that can be utilized for overcoming complex venous anatomy. [ABSTRACT FROM AUTHOR]

Mengya Dong,1 Chenyuan Liang,1 Gong Cheng2 1Department of Cardiovascular Medicine, Shaanxi Provincial People’s Hospital, Xi’an, People’s Republic of China; 2Department of Cardiovascular Medicine, Honghui Hospital, Xi’an Jiaotong University, Xi’an, People’s Republic of ChinaCorrespondence: Gong Cheng, Department of Cardiovascular Medicine, Honghui Hospital, Xi’an Jiaotong University, 555 East Youyi Road, Xi’an, Shaanxi, 710054, People’s Republic of China, Tel +86– 18629529996, Email Xianchenggong@163.comObjective: A new approach called the loop technique has been proven safe and effective for repeated intraoperative transvenous left ventricular (LV) lead dislocations during cardiac resynchronization therapy (CRT) in a 3-year follow-up. This study aimed to report on the 5-year safety and effectiveness of the loop technique.Methods: This study was a prospective cohort study. Forty-four patients who underwent CRT device implantation at the Cardiology Department of Shaanxi Provincial People’s Hospital between January 2013 and June 2019 were included. Data on patient demographics, medical history, laboratory test results, and echocardiography images at admission were collected. The loop technique was performed with repeated intraoperative dislocations of the LV lead. The intraoperative CRT parameters were also recorded. All patients were followed for 5 years. Several auxiliary examinations were performed during follow-up.Results: The 44 patients were divided into the traditional operation group (n=36, 81.8%) and loop technique group (n=8, 18.2%). The baseline patient characteristics were almost balanced. During the 5-year follow-up, 8 (22.2%) patients in the traditional operation group and 2 (25.0%) patients in the loop technique group died. No lead dislocation or other complications related to CRT were observed. There were no significant differences in mortality rate (P=0.87), cardiac function (P=0.56), echocardiographic indices, threshold (P=0.58), or impedance (P=0.22) of the LV lead. There were no significant differences in the threshold and impedance between postoperative, 3-year, and 5-year follow-ups in the loop technique group (P=0.53).Conclusion: The loop technique is an ideal solution for repeated intraoperative LV lead dislocation during CRT implantation.Keywords: loop technique, new technique, cardiac resynchronization therapy, left ventricular lead, repeated intraoperative dislocations

Key Clinical Message: The newly‐proposed tandem approach, Wire ThRoUgh Snare Twice (Wire TRUST) is effective for grasping a lead with inaccessible ends. This case report shows that Wire TRUST can also enable successful extraction of a left ventricular lead by iteratively grasping and repositioning to the distal portion of the lead. [ABSTRACT FROM AUTHOR]

Left ventricular (LV) lead implantation is often the most challenging aspect of cardiac resynchronization therapy (CRT) procedures; early studies reported implant failure rates in ∼10% of cases. The purpose of this study was to define rates, reasons for, and factors independently associated with LV lead implant failure. We studied patients with left bundle branch block and ejection fraction ≤ 35% who underwent planned de novo transvenous CRT implantation (2010–2016) and were reported to the National Cardiovascular Data Registry ICD Registry. Independent predictors of LV lead implant failure were determined using logistic regression; age, sex, and variables with a univariable P value of <.15 were considered for inclusion in the model. Of the 111,802 patients who underwent a planned CRT procedure, 3.6% of patients (n = 3979) had LV lead implant failure. Reasons for implant failure included venous access (7.5%), coronary sinus access (64.3%), tributary vein access (13.5%), coronary sinus dissection (7.6%), unacceptable threshold (4.4%), and diaphragmatic stimulation (1.7%). Significant independent predictors of LV lead implant failure included younger age (odds ratio [OR] 1.01; 95% confidence interval [CI] 0.1.01–1.02), female sex (OR 1.38; 95% CI 1.29–1.47), black race (vs white, OR 1.44; 95% CI 1.32–1.57), Hispanic ethnicity (OR 1.23; 95% CI 1.08–1.40), QRS duration (OR 1.055 per 10 ms; 95% CI 1.038–1.072 per 10 ms), obstructive sleep apnea (OR 1.14; 95% CI 1.04–1.24), and implantation by a physician without specialized training (vs electrophysiology trained, OR 1.53; 95% CI 1.34–1.76). LV lead implant failure is uncommon in the current era and is most commonly due to coronary sinus access failure. Predictors of LV lead implant failure included younger age, female sex, black race, Hispanic ethnicity, increased QRS duration, sleep apnea, and absence of electrophysiology training. [ABSTRACT FROM AUTHOR]

Aims: to study the technical performance of epicardial left ventricular (LV) leads placed via video assisted thoracic surgery (VATS), compared to transvenously placed leads for cardiac resynchronization therapy (CRT). Methods: From 2001 until 2013, a total of 644 lead placement procedures were performed for CRT. In the case of unsuccessful transvenous LV lead placement, the patient received an epicardial LV lead. Study groups consist of 578 patients with a transvenous LV lead and 66 with an epicardial LV lead. The primary endpoint was LV-lead failure necessitating a replacement or deactivation. The secondary endpoint was energy consumption. Results: The mean follow up was 5.9 years (epicardial: 5.5 ± 3.1, transvenous: 5.9 ± 3.5). Transvenous leads failed significantly more frequently than epicardial leads with a total of 66 (11%) in the transvenous leads group vs. 2 (3%) in the epicardial lead group (p = 0.037). Lead energy consumption was not significantly different between groups. Conclusions: Epicardial lead placement is feasible, safe and shows excellent long-term performance compared to transvenous leads. Epicardial lead placement should be considered when primary transvenous lead placement fails or as a primary lead placement strategy in challenging cases. [ABSTRACT FROM AUTHOR]

Introduction: Left ventricular (LV) lead optimal positioning is one of the most important determinants of cardiac resynchronization therapy (CRT) success. LV quadripolar active fixation (QAF) leads have been designed to ensure stable LV pacing in the target area and reduce the likelihood of phrenic nerve stimulation (PNS). The aim of this analysis is to compare performances, safety, and clinical outcomes of QAF with those of quadripolar passive fixation leads (QPL) and bipolar active fixation (BAF) leads in a real‐world cohort of CRT patients. Methods and Results: This retrospective analysis compared the procedure and follow‐up data of 117 QAF included in the One Hospital ClinicalService project from nine Italian hospitals with two historical cohorts of 261 BAF and 124 QPL. QAF enabled basal pacing more frequently than QPL (24.1% vs. 6.5%, p <.001) but not differently from BAF (p =.981). At implant, mean QAF LV myocardial threshold (LVMT) was 1.21 ± 0.8 V at 0.4 ms, not different from that of BAF (p =.346) and QPL (p =.333). At a median follow‐up of 22 months, LVMT was 1.37 ± 0.90 V (p =.036 vs. implant). Acute LV lead dislodgment occurrence was low in all cohorts: 1 (0.9%) in QAF, 4 in BAF (1.5%), and none (0.0%) in QPL. During follow‐up, total LV‐related complication rate was lower in QAF (0.5/100 patient‐years) than in BAF (4.2/100 patient‐years, p =.014) and QPL (3.6/100 patient‐years, p =.055). QAF, BAF, and QPL annual rate of heart failure hospitalization were respectively 6.1/100 patient‐years, 2.5/100 patient‐years (p =.081), and 3.6/100 patient‐years (p =.346). CRT responders' rate in QAF was 69.9%, with no difference in comparison to BAF (p =.998) and QPL (p =.509). During follow‐up, mean left ventricular ejection fraction (LVEF) of QAF increased from 31.8 ± 10.1% to 40.3 ± 10.7% (p <.001). The average degree of echocardiographic response (ΔLVEF) did not differ between QAF and other cohorts; however, LVEF CRT responder's distribution of QAF differs from those of BAF (p =.003) and QPL (p =.022), due to a higher percentage of super‐responders. Conclusions: QAF with short interelectrode spacing resulted in non‐inferior clinical outcomes and CRT responders' rate in comparison to BAF and QPL, while reducing complication rate during follow‐up and increasing the possibilities of electronic repositioning to manage PNS or to optimize resynchronization therapy. [ABSTRACT FROM AUTHOR]

The snare technique can be used to overcome unsuitable cardiac venous anatomies for left ventricular (LV) lead implantation in cardiac resynchronization therapy (CRT) procedures. However, limited data exist regarding performance of the snare technique. We classified 262 patients undergoing CRT procedure into the snare (n = 20) or conventional group (n = 242) according to the LV lead implantation method. We compared the safety, efficacy, and composite outcome (all-cause death and heart failure readmission) at 3 years post-implant between the snare and conventional groups. In the snare group, all LV leads were implanted safely using orthodromic (n = 15) or antidromic (n = 5) techniques, and no immediate complications occurred including vessel perforation, tamponade, and lead dislodgement. During follow-up, LV lead threshold and impedance remained stable without requiring lead revision in the snare group. There were no significant between-group differences regarding LV ejection fraction increase (12 ± 13% vs. 12 ± 13%, p = 0.929) and LV end-systolic volume reduction (18 ± 48% vs. 28 ± 31%, p = 0.501). Both groups exhibited comparable CRT-response rates (62.5% vs. 60.6%, p = 1.000). The risk of primary outcome was not significantly different between the two groups (25.9% vs. 30.9%, p = 0.817). In patients who failed conventional LV lead implantation for CRT, the snare technique could be a safe and effective solution to overcome difficult coronary venous anatomy. [ABSTRACT FROM AUTHOR]

Abstract In this report, we present a case of successful advancement of a LV lead into tortuous vessels. This was achieved by deep engagement of the coronary sinus with a cannulation catheter by applying the anchor technique using the Medtronic Attain Stability Quad lead.

In this report, we present a case of successful advancement of a LV lead into tortuous vessels. This was achieved by deep engagement of the coronary sinus with a cannulation catheter by applying the anchor technique using the Medtronic Attain Stability Quad lead. [ABSTRACT FROM AUTHOR]

Background: Bipolar active fixation (BipolarAFL) and quadripolar passive fixation left-ventricular leads (QuadPFL) have been designed to reduce the risk of phrenic nerve stimulation (PNS), enable targeted left-ventricular pacing, and overcome problems of difficult coronary venous anatomy and lead dislodgment. This study sought to report the long-term safety and performance of a BipolarAFL, Medtronic Attain Stability 20066, compared to QuadPFL.Methods: We performed a single-operator retrospective analysis of 81 patients receiving cardiac resynchronization therapy (CRT) (36 BipolarAFL, 45 QuadPFL). Immediate implant data and electrical and clinical data during follow-up (FU) were analyzed.Results: BipolarAFL has been chosen in patients with significantly larger estimated vein diameter (at the lead tip: 7.2 ± 4.1 Fr vs. 4.1 ± 2.3 Fr, p < 0.001) without significant time difference until the final lead position was achieved (BipolarAFL: 20.9 ± 10.5 min, vs. QuadPFL: 18.9 ± 8.9 min, p = 0.35). At 12 month FU no difference in response rate to CRT was recorded between BipolarAFL and QuadPFL according to left ventricular end-systolic volume (61.1 vs. 60.0%, p = 0.82) and New York Heart Association (66.7 vs. 62.2%, p = 0.32). At median FU of 48 months (IQR: 44–54), no lead dislodgment occurred in both groups but a significantly higher proportion of PNS was recorded in QuadPFL (13 vs. 0%, p < 0.05). Electrical parameters were stable during FU in both groups without significant differences.Conclusion: BipolarAFL can be implanted with ease in challenging coronary venous anatomy, shows excellent electrical performance and no difference in clinical outcome compared to QuadPFL.

Background: Coronary sinus (CS) ostial atresia/abnormalities prevent access to the CS from the right atrium (RA) for left ventricular (LV) lead implantation. Some patients with CS ostial abnormalities also have a small persistent left superior vena cava (sPLSVC).Objective: The purpose of this study was to describe CS ostial abnormalities and sPLSVC as an opportunity for LV lead implantation and unrecognized source of stroke.Methods: Twenty patients with CS ostial abnormalities and sPLSVC were identified. Clinical information, imaging methods, LV lead implantation techniques, and complications were summarized.Results: Forty percent had at least 1 previously unsuccessful LV lead placement. In 70%, sPLSVC was identified by catheter manipulation and contrast injection in the left brachiocephalic vein, and in 30% by levophase CS venography. In 30%, sPLSVC was associated with drainage from the CS into the left atrium (LA). When associated with CS ostial abnormalities, the sPLSVC diameter averaged 5.6 ± 3 mm. sPLSVC was used for successful LV lead implantation in 90% of cases. In 80%, the LV lead was implanted down sPLSVC, and in 20%, sPLSVC was used to access the CS from the RA. Presumably because of unrecognized drainage from the CS to the LA, 1 patient had a stroke during implantation via sPLSVC.Conclusion: When CS ostial abnormalities prevent access to the CS from the RA, sPLSVC can be used to successfully implant LV leads. In some, the CS partially drains into the LA and stroke can occur spontaneously or during lead intervention. It is important to distinguish sPLSVC associated with CS ostial abnormalities from isolated PLSVC. [ABSTRACT FROM AUTHOR]

Abstract Suboptimal biventricular pacing has deleterious effects on patients with cardiac resynchronization therapy. We describe a unique case of suboptimal biventricular pacing and our approach to overcome it.

Background: Left ventricular (LV) lead placement is the most challenging aspect of cardiac resynchronization therapy (CRT) device implantation, with a failure rate of up to 10% due to complex coronary anatomies. We describe a modified snare technique for LV lead placement and evaluate its safety and efficacy in cases when standard methods fail. Methods and Results: A prospective study was conducted of patients indicated for a CRT implant. When LV lead delivery to the target vessel failed using standard techniques, a modified snare technique was employed. Patients were evaluated every 6 months. From 2015 to 2019, 566 CRTs were implanted (26.1% female, 72 ± 10.2 years old, follow‐up duration 18.9 ± 15.8 months). The standard LV implant technique failed in 94 cases (16.6%), of which the modified snare technique was successful in 92 (97.9%). There were no differences between the modified snare and standard techniques in the rates of 30‐day postimplant CRT all‐cause mortality (3.2% vs. 1.7%, p =.33), 4‐year all‐cause mortality (15.9% vs. 15.5%, p =.49), or major acute complications (7.4% vs. 3.8%, p =.12). However, the 4‐year procedural reintervention rate was lower with the modified snare technique (3.2% vs. 10.2%, p <.05), specifically LV implant failure or dislodgement rates (0% vs. 5.3%, p <.05), improving the response rate (71.8% vs. 55.1%, p <.05). Conclusions: For challenging coronary sinus anatomies that preclude LV lead placement by standard methods, this modified snare alternative was safe and effective, with comparable mortality and complications, but significantly lower procedural reintervention and higher response rates. [ABSTRACT FROM AUTHOR]

Introduction: Studies have shown an association between the outcome in cardiac resynchronization therapy (CRT) and longer interventricular delay at the site of the left ventricular (LV) lead. Targeted LV lead placement at the latest electrically activated segment increases LV function further as compared with standard treatment. We aimed to determine reproducibility and repeatability of identifying the latest electrically activated segment during mapping of all available coronary sinus (CS) branches in patients receiving CRT. Methods: We included 35 patients who underwent CRT implantation with protocolled mapping guided LV lead implantation aiming for the site of the latest electrical activation. Three different doctors experienced in electrophysiology and implantation of CRT devices independently measured time interval from the local bipolar right ventricular (RV) electrogram (EGM) to the local unipolar LV EGM at all mapped sites (RV–LV). The segment with the latest electrical activation was defined as the target segment (TS) and the CS tributary containing TS was defined as the target vein (TV). Weighted κ statistics with 95% confidence intervals were computed to assess intra‐ and interobserver agreement for TS and TV. Results: We mapped 258 segments within 131 veins. Weighted κ values for repeatability were 0.85 (0.81–0.89) for TS and 0.92 (0.89–0.93) for TV, and weighted κ values of interobserver agreement ranged from 0.70 (0.61–0.73) to 0.80 (0.76–0.83) for TS and 0.73 (0.64–0.78) to 0.86 (0.83–0.89) for TV among all three observers. Conclusion: The reproducibility and repeatability of identifying the latest electrically activated segment during mapping of all available CS branches in patients receiving CRT range from good to very good. [ABSTRACT FROM AUTHOR]

Background In cardiac resynchronization therapy, left ventricular (LV) lead placement at the desired position may be difficult due to abnormal coronary sinus (CS) and lateral vein anatomy. We present a case with difficult anatomy in which we used 'an indigenous snare' made from hardware used for coronary angioplasty procedures, which is available in any cardiac catheterization laboratory. Case summary A 52-year-old man presented with dyspnoea due to chronic heart failure was evaluated for cardiac resynchronization therapy. The LV lead was difficult to advance into the only target lateral branch of the CS due to a combination of angulation and proximal stenosis. Balloon dilation was tried first, but we failed to track the LV lead. We formed a venovenous loop, advancing the coronary guidewire 0.014″ into the posterolateral vein; subsequently into the middle cardiac vein via a collateral. The wire was advanced into the CS and then to superior vena cava. The guidewire then snared through the same left subclavian vein and exteriorized by using indigenous snare. Over this loop, the LV lead of the cardiac resynchronization therapy with defibrillator device was implanted successfully. Discussion We have used the snare technique, with the use of a snare prepared from a coronary guidewire. Use of such an indigenous snare has not been described before in the literature. The hardware used in this case is routinely used for coronary angioplasty procedures in all catheterization labs. The importance of our case is that no special hardware like dedicated snare was required to negotiate the LV lead at its desired location. [ABSTRACT FROM AUTHOR]

Background Cardiac resynchronization therapy (CRT) could be an effective therapy for patients suffering from severe heart failure (HF) despite optimal medical therapy. However, it has been reported that about 30% of patients receive ineffective results even if CRT has been performed. In a recent study, four-dimensional computed tomography (4DCT) was shown to be useful for pre-operative planning in transcatheter aortic valve intervention. The 4DCT is reconstructed with 10% increments over the cardiac cycle so that the displacement of the myocardium can be evaluated over time. From the above, we considered that the most delayed site where we would implant the left ventricular (LV) lead could be recognized by 4DCT. Case summary A 55-year-old man with a recurrent admission for HF indicated for CRT was referred to our hospital. In this patient, the 12-lead electrocardiogram (ECG) showed a relatively narrow QRS complex with a left bundle branch block pattern. An echocardiography demonstrated severe LV dysfunction. Although no dyssynchrony was detected, the LV lead was inserted into the most delayed site based on the 4DCT. Three-month later, the ejection fraction increased and the cardiothoracic ratio obviously shortened. Discussion We experienced a case in which we could evaluate the effective implantation site for the LV lead based on the 4DCT even though the effective site was not detected by echocardiography, and we could implant the LV lead at that effective site. The 4DCT may be useful for implanting LV leads in effective sites. [ABSTRACT FROM AUTHOR]

Background: There are limited data on cardiac implantable electronic device implantation (CIED) in patients with persistent left superior vena cava (PLSVC). Objective: To describe the outcomes of implanting CIEDs with a focus on cardiac resynchronization therapy (CRT) in patients with PLSVC. Methods: We identified all patients with a PLSVC that underwent CIED implantation from December 2008 until February 2019 at our institution by querying the electronic medical record (n = 34). We then identified controls in a 3:1 fashion (n = 102) by matching on device type (CRT vs non‐CRT). Procedure success, complications, fluoroscopy and procedural time were recorded. Outcomes were compared using a two‐way analysis of variance test and conditional regression modeling for continuous and categorical variables, respectively. Results: A total of 34 patients with PLSVC underwent 38 procedures. Four patients underwent dual chamber system implantation followed by a subsequent upgrade to CRT. Thirteen patients underwent CRT implantation: one was implanted via the right subclavian while the rest were implanted via the PLSVC. Left ventricular (P =.06). Procedure and fluoroscopy times were significantly higher in the PLSVC as compared with the control group (97.7 vs 66.1 minute, P <.001 and 18.1 minute vs 8.7 minutes, P =.005, respectively). Conclusion: CIED implant in patients with PLSVC is feasible but technically more challenging and appears to be associated with higher risk of right ventricular lead dislodgment. [ABSTRACT FROM AUTHOR]

Abstract Background We retrospectively assessed two types of sutureless screw-in left ventricular (LV) leads (steroid eluting vs. non-steroid eluting) in cardiac resynchronization therapy (CRT) implantation with regards to their electrical performance. Methods Between March 2008 and May 2014 an epicardial LV lead was implanted in 32 patients after failed transvenous LV lead placement using a left-sided lateral minithoracotomy or video-assisted thoracoscopy (mean age 64 ± 9 years). Patients were divided into two groups according to the type of implanted lead. Steroid eluting (SE) group: 21 patients (Myodex™ 1084 T; St. Jude Medical) and non-steroid eluting (NSE) group: 11 patients (MyoPore® 511,212; Greatbatch Medical). Results All epicardial leads could be placed successfully, without any intraoperative complications or mortality. With regard to the implanted lead following results were observed: sensing (mV): SE 8.8 ± 6.1 vs. NSE 10.1 ± 5.3 (p = 0.380); pacing threshold (V@0.5 ms): SE 1.0 ± 0.5 vs. NSE 0.9 ± 0.5 (p = 0.668); impedance (ohms): SE 687 ± 236 vs. NSE 790 ± 331 (p = 0.162). At the follow-up (2.6 ± 1.9 years) the following results were seen: sensing (mV): SE 8.7 ± 5.0 vs. NSE 11.2 ± 6.6 (p = 0.241), pacing threshold (V@0.5 ms): SE 1.4 ± 0.5 vs. NSE 1.0 ± 0.3 (p = 0.035), impedance (ohms): SE 381 ± 95 vs. NSE 434 ± 88 (p = 0.129). Conclusions Based on the results no strong differences have been found between the both types of epicardial LV leads (steroid eluting vs. non-steroid eluting) in CRT implantation in short- and midterm.

Background: The introduction of quadripolar (QP) cardiac resynchronization therapy (CRT) leads aimed to improve procedural and clinical outcomes.Objective: The National Cardiovascular Data Registry was analyzed to characterize the use as well as the procedural and clinical outcomes of QP leads in comparison with unipolar and bipolar (BP) leads.Methods: We evaluated data on 175,684 procedures reported between September 1, 2010, and December 31, 2015. Clinical outcomes were analyzed using Centers for Medicare & Medicaid Services claims data.Results: Among all CRT device implants, there was a drop in reported lead placement failure from 6.04% to 5.21% (P < .0001 for trend) and a drop in the reported diaphragmatic stimulation rates from 0.07% to 0.01% (P < .007 for trend) between the last quarters of 2010 and 2015. No significant difference in procedural complication rates between QP and BP leads occurred (1.34% and 1.39%, respectively; P = .50). Among patients linked to Centers for Medicare & Medicaid Services claims data, no statistically significant difference in the combined primary outcome of death, congestive heart failure admission, device malfunction, and reoperation between BP and QP leads was observed (34.15 and 34.19 events per 100 patient-years, respectively; P = .89).Conclusion: Since the introduction of QP leads, there was a reduction in CRT lead placement failure rates and a reduction in diaphragmatic stimulation rates. However, no statistically significant difference in long-term clinical outcomes between BP and QP leads was observed in elderly patients undergoing CRT implantation. [ABSTRACT FROM AUTHOR]

Background: Few data are available regarding lead preferences of electrophysiologists during cardiac implantable electronic devices (CIEDs) implantation. Aim of this survey is to evaluate the leads used, and the reasons behind these choices, in a large population of implanters. Methods: A questionnaire was sent to all 314 Italian centers with experience in CIED implantation. Results: 103 operators from 100 centers (32% of centers) responded. For atrium, passive leads represented first choice for pacemakers and defibrillators (71% and 64% of physicians, respectively), mainly for safety. For right ventricle, active fixation was preferred (61% and 93% operators in pacemaker and defibrillator patients), for higher versatility in positioning and lower dislodgement risk. For left ventricular stimulation, quadripolar leads were preferred by more than 80% of respondents, for better phrenic nerve and myocardial threshold management; active-fixation leads represent a second choice, in order to prevent or manage dislodgement (78% and 17% of respondents, respectively), but 44% of operators considered them dangerous. Conclusions: The choice of leads is heterogeneous. Trends are toward active-fixation right ventricular leads and passive-fixation atrial leads (particularly in pacemaker patients, considered frailer). For left ventricular stimulation, operators' majority want to disposition all kind of leads, although quadripolar leads are the favorites. [ABSTRACT FROM AUTHOR]

Introduction: Some cardiac resynchronization therapy (CRT) device manufacturers (Biotronik, Germany; Boston Scientific, United States) have implemented left ventricular (LV) sensing functionality to prevent pacing into the vulnerable phase. Physicians are only partially aware of programming pitfalls related to LV sensing and general programming advice is lacking. Methods and Results: We provide an illustrative case–series‐based review of the variety of potential problems with LV sensing. LV sensing may inappropriately impair CRT delivery due to LV‐sensing issues or improper device programming. This can cause beat‐wise loss of resynchronization but also ongoing desynchronization. On the other hand, LV sensing provides additional diagnostic information, which may reveal intermittent problems of the LV lead such as capture loss. We summarize the available evidence to provide manufacturer‐specific recommendations on device programming and troubleshooting for daily clinical practice. Conclusion: CRT devices with LV sensing may suffer from impaired resynchronization due to programming pitfalls. If LV sensing is active (nominal setting in Biotronik and Boston Scientific devices), careful lookout for related problems and resynchronization percentage is required. Optimization is mandatory and even deactivation of LV sensing may have to be considered. [ABSTRACT FROM AUTHOR]

Aims: An appropriate left ventricular (LV) lead position is a pre-requisite for response to cardiac resynchronization therapy (CRT) and is highly patient-specific. The purpose of this study was to develop a non-invasive pre-procedural CRT-roadmap to guide LV lead placement to a coronary vein in late-activated myocardium remote from scar.Methods and Results: Sixteen CRT candidates were prospectively included. Electrocardiographic imaging (ECGI), computed tomography angiography (CTA), and delayed enhancement cardiac magnetic resonance imaging (DE-CMR) were integrated into a 3D cardiac model (CRT-roadmap) using anatomic landmarks from CTA and DE-CMR. Electrocardiographic imaging was performed using 184 electrodes and a CT-based heart-torso geometry. Coronary venous anatomy was visualized using a designated CTA protocol. Focal scar was assessed from DE-CMR. Cardiac resynchronization therapy-roadmaps were constructed for all 16 patients [left bundle branch block: n = 6; intraventricular conduction disturbance: n = 8; narrow-QRS (ablate and pace strategy); n = 1; right bundle branch block: n = 1]. The number of coronary veins ranged between 3 and 4 per patient. The CRT-roadmaps showed no (n = 5), 1 (n = 6), or 2 (n = 5) veins per patient located outside scar in late-activated myocardium [≥50% QRS duration (QRSd)]. Final LV lead position was outside scar in late-activated myocardium in 11 out of 14 implanted patients, while a LV lead in scar was unavoidable in the remaining three patients.Conclusion: A non-invasive pre-implantation CRT-roadmap was feasible to develop in a case series by integration of coronary venous anatomy, myocardial-scar localization, and epicardial electrical activation patterns, anticipating on clinically relevant features. [ABSTRACT FROM AUTHOR]

Background: Left ventricular (LV) lead placement at the late activation site (LAS) has been proposed as an optimal LV pacing site (ie, Q-LV interval). However, LAS may be relevant to local electrical conduction, measured as an interval from LV pacing stimulation to QRS onset (S-QRS interval).Objective: The purpose of this study was to evaluate the prognostic value of S-QRS for reverse remodeling and the impact of S-QRS on pacing QRS configuration in patients undergoing cardiac resynchronization therapy (CRT).Methods: Sixty consecutive heart failure patients with a wide QRS complex underwent CRT. A site with Q-LV ≥95 ms was targeted for LV lead placement. A responder was defined as one with >15% reduction in LV end-systolic volume 6 months after CRT.Results: LV lead placement with Q-LV ≥95 ms was achieved in 52 of 60 patients (86.7%). Thirty-two of 52 patients (61.5%) were responders. S-QRS was significantly shorter in responders than nonresponders (P <.01), whereas Q-LV was not significantly different. A cutoff value of 37 ms for S-QRS had sensitivity and specificity of 81% and 90%, respectively. Shorter S-QRS (<37 ms) showed significantly narrower LV pacing QRS width and biventricular pacing QRS width compared to longer S-QRS. After multivariate analysis, PQ interval (odds ratio 0.97; P = .01) and long S-QRS ≥ 37ms (odds ratio 0.014; P <.01) were independent predictors of response to CRT.Conclusion: In addition to a sufficient Q-LV, S-QRS can be a useful indicator of optimal LV lead position to achieve reverse remodeling. S-QRS contributes to the pacing QRS configuration associated with CRT response. [ABSTRACT FROM AUTHOR]

Cardiac resynchronization therapy (CRT) has become the gold standard for patients with systolic left ventricular function, left ventricular ejection fraction less than or equal to 35%, wide complex QRS, and symptomatic heart failure. Annual implantation volume has steadily increased because of expanding indications for CRT. Improved survival resulted in many of these patients having their CRT devices for many years and eventually requiring an increased number of device-related procedures, including coronary sinus lead revisions and replacements following a coronary sinus lead extraction. [ABSTRACT FROM AUTHOR]

Background: Quadripolar left ventricular (LV) leads are capable of pacing from four different electrodes which allows for easier and more stable intra-operative lead positioning with optimal pacing parameters. We therefore investigated the rate of combined intra-operative and post-operative LV lead related events in quadripolar vs. bipolar LV lead cardiac resynchronization therapy (CRT) recipients in the real world setting. Methods: We retrospectively collected data for N = 1441 patients at our institution implanted with quadripolar (n = 292) or bipolar (n = 1149) LV leads from 2012 to 2014 and followed them to the primary end-point of composite lead outcome defined as intra-operative lead implant failure or post-operative lead dislodgement or deactivations. Results: Patients implanted with a quadripolar lead were younger (70.6 ± 11.4 vs 72.5 ± 11.6, p = 0.014) and had higher incidence of diabetes (41.8% vs 32.8%, p = 0.004) compared to those with bipolar leads. All other baseline characteristics were comparable. Patients implanted with a quadripolar were significantly less likely to reach the primary endpoint in the first 12 months after LV lead implantation (Hazard Ratio 0.22, 95% Confidence Interval 0.08–0.60, p = 0.001). There were no differences between the two groups in rates of hospitalization for any cause or in mortality. Conclusion: In this real world study, quadripolar LV leads have significantly lower rates of implantation failure and post-operative lead dislodgement or deactivation. These results have important clinical implications to CRT recipients.

Background The efficacy of cardiac resynchronization therapy may be reduced in the event of pacing within myocardial fibrosis. We aimed to develop a method to determine the anatomical relationships between the left ventricular (LV) lead and myocardial fibrosis. Methods and Results In consecutive patients indicated for cardiac resynchronization therapy, cardiovascular magnetic resonance imaging with late gadolinium enhancement assessment was performed before implantation. After implantation, an injected computed tomography scanner (CT scan) was performed. The 2 imaging techniques were fused to assess the LV lead position relative to myocardial scar. A total of 68 patients were included. Myocardial scar was found in 29 (43%) and was localized in lateral segments in 14 (21%). Scar was significantly associated with male sex, ischemic cardiomyopathy, a Selvester score adapted to left bundle branch block (LBBB Selvester), and Selvester criteria for localizing lateral fibrosis (V2 S/S′ ratio). Image fusion was feasible in all patients. Position within myocardial scar was confirmed for 6 electrodes in 3 patients. Prolonged QRS duration during LV pacing ≥139% predicted electrode positioning within scar tissue (sensitivity, 83%; specificity, 91%; P=0.002). Conclusions In cardiac resynchronization therapy patients, fusion between preimplantation cardiovascular magnetic resonance and a postimplantation injected computed tomography scan is a feasible technique. Prolongation of the QRS duration during LV pacing predicts pacing within myocardial scar. Accurate location of LV lead pacing electrodes on the epicardial surface relative to myocardial scar, either by imaging or ECG analyses, may help improve cardiac resynchronization therapy response in selected patients.

Objectives: The purpose of this study is to use ECG-gated SPECT MPI to detect the latest contracting viable left ventricular (LV) segments to help guide the LV probe placement used in CRT therapy and to validate segment selection against the visual integration method by experts.Methods: For each patient, the resting ECG-gated SPECT MPI short-axis images were sampled in 3D to generate a polar map of the perfusion distribution used to determine LV myocardial viability, and to measure LV synchronicity using our phase analysis tool. In the visual integration method, two experts visually interpreted the LV viability and mechanical dyssynchrony from the short-axis images and polar maps of viability and phase, to determine the latest contracting viable segments using the 17-segment model. In the automatic method, the apical segments, septal segments, and segments with more than 50% scar were excluded as these are not candidates for CRT LV probe placement. Amongst the remaining viable segments, the segments, whose phase angles were within 10° of the latest phase angle (the most delayed contracting segment), were identified for potential CRT LV probe placement and ranked based on the phase angles of the segments. Both methods were tested in 36 pre-CRT patients who underwent ECG-gated SPECT MPI. The accuracy was determined as the percent agreement between the visual integration and automatic methods. The automatic method was performed by a second independent operator to evaluate the inter-operator processing reproducibility.Results: In all the 36 patients, the LV lead positions of the 1st choices recommended by the automatic and visual integration methods were in the same segments in 35 patients, which achieved an agreement rate of 97.2%. In the inter-operator reproducibility test, the LV lead positions of the 1st choices recommended by the two operators were in the same segments in 25 patients, and were in the adjacent segments in 7 patients, which achieved an overall agreement of 88.8%.Conclusions: An automatic method has been developed to detect the latest contracting viable LV segments to help guide the LV probe placement used in CRT therapy. The retrospective clinical study with 36 patients suggests that this method has high agreement against the visual integration method by experts and good inter-operator reproducibility. Consequently, this method is promising to be a clinical tool to recommend the CRT LV lead positions. [ABSTRACT FROM AUTHOR]

Objective To compare the electrocardiographic patterns recorded after left ventricular pacing from different coronary veins. MethodsWe selected 43 patients treated by cardiac resynchronization therapy(CRT). According to the target vessel of coronary vein in the implantation of left ventricular electrode, they were divided into five groups: lateral vein group(7 patients), posterior vein group(8 patients), posterolateral vein group(13 patients), great(anterior) vein group(8 patients) and middle cardiac vein group(7 patients). The uni-left-ventricular pacing mode was set by programming controller after CRT. We recorded 12-lead electrocardiograms(ECGs) during uni-left-ventricular pacing, and measured and compared the ECG patterns among the five groups.Results Among the 43 patients, right axis deviation was observed in 26(60.47%); 4 cases of left axis deviation were only found in middle cardiac vein group of which the axis distribution significantly varied from other groups. The incidences of Q wave in the initial segment of lead I, R/S≤1 in lead I and R/S≥1 in lead V1 were 79.07%, 83.72% and 67.44%, respectively while in middle cardiac vein group the incidences were only 42.86%, 42.86% and 28.57%, respectively. In posterolateral vein group, the incidence of R/S≤1 in lead I was significantly higher than that in middle cardiac vein group(P=0.007). The QRS morphology patterns in inferior wall leads and lead V5，V6 did not vary significantly among different groups.ConclusionDifferent electrocardiographic patterns of left ventricular pacing correspond to different target vessels in the implantation of left ventricular electrode. The ECG patterns of left ventricular pacing from lateral vein, posterior vein, posterolateral vein and great(anterior) vein are similar, but the pattern of pacing from middle cardiac vein is quite different from those from other veins. The implantation site of left ventricular electrode should be paid extra attention in the diagnosis of left ventricular pacing. [ABSTRACT FROM AUTHOR]