Left Ventricle Lead Research Articles

Multipoint pacing is associated with improved prognosis and cardiac resynchronization therapy response. MORE-CRT MPP randomized study secondary analyses.

Cardiac resynchronization therapy (CRT) via biventricular (BIV) pacing is indicated in patients with heart failure (HF), reduced ejection fraction and prolonged QRS duration. Quadripolar leads and MultiPoint Pacing (MPP) allow multiple left ventricle (LV) sites pacing. We aimed to assess clinical benefit of MPP in patients who do not respond to standard BIV pacing. Overall 3724 patients were treated with standard BIV pacing. After 6 months, 1639 patients were considered as CRT non-responders (echo-measured relative reduction in LV end-systolic volume (LVESV) < 15%) and randomized to MPP or BIV. We analysed 593 randomized patients (291 MPP, 302 BIV), who had BIV pacing >97% of time before randomization and complete 12-months clinical and echocardiographic data. The endpoint, composed by freedom from cardiac death and HF hospitalizations, and by LVESV relative reduction ≥15% between randomization and 12 months, occurred more frequently in MPP (96/291 (33.0%)) vs. BIV (71/302 (23.5%), p = 0.0103), also confirmed at multivariate analysis (hazard ratio = 1.55, 95% confidence interval = 1.02-2.34, p = 0.0402 vs. BIV). HF hospitalizations occurred less frequently in MPP (14/291 (4.81%)) vs. BIV (29/302 (9.60%), incidence rate ratio = 50%, p = 0.0245). Selecting patients with large (>30 ms) dispersion of interventricular electrical delay among the 4 LV lead dipoles, reverse remodeling was more frequent in MPP (18/51 (35.3%)) vs. BIV (11/62 (17.7%), p = 0.0335). In patients who do not respond to standard CRT, despite high BIV pacing percentage, MPP is associated with lower occurrence of HF hospitalizations and higher probability of reverse LV remodeling, compared with BIV pacing.

Visualization of Left Ventricular Endocardium Activation Time during Cardiac Conduction System Pacing

Introduction. Right ventricular myocardial pacing leads to asynchronous contraction of the left ventricle (LV) and can impair its contractility over time. Stimulation of the conduction system of the heart ensures physiological activation of the ventricles.&#x0D; The aim. To visualize the pattern of propagation of the electrical front on the activation map of the LV endocardium during conduction system pacing and during right ventricular myocardial pacing.&#x0D; Materials and methods. In two patients with the conduction system pacing, who were operated at the National Amosov Institute of Cardiovascular Surgery, invasive LV activation mapping was performed on various options of cardiac pacing using the EnSite Precision TM navigation system. One patient with complete atrioventricular block had nonselective His bundle pacing. The second patient had dilated cardiomyopathy and indications for cardiac resynchronization therapy and ablation of the atrioventricular junction due to chronic tachyform of atrial fibrillation. After an unsuccessful attempt to place LV lead in coronary sinus, a lead for left bundle branch pacing was implanted. Different activation maps of the LV endocardium were built in two patients with two types of cardiac pacing: right ventricular myocardial pacing and cardiac conduction system pacing.&#x0D; Results. The total LV endocardial activation time was significantly different in the two studied patients with different pacing options. In a patient with non-selective stimulation of His bundle, the total LV endocardial activation time was 43 ms (QRS width 126 ms, the interval from the stimulus to the peak of the R wave in lead V6 78 ms). After switching to right ventricular myocardial pacing with a decrease in the pacing amplitude, the total LV endocardial activation time prolonged to 90 ms (QRS width 165 ms, the interval from the stimulus to the peak of the R wave in lead V6 117 ms). In a patient with left bundle branch pacing, total LV endocardial activation time was 51 ms (QRS width 160 ms, the interval from the stimulus to the peak of the R wave in lead V6 66 ms). With switching exclusively to right ventricular pacing the total LV endocardial activation time prolonged to 93 ms (stimulated QRS width 180 ms). At the same time, the activation pattern of the LV endocardium was significantly different, since the right ventricular lead was located closer to the apex.&#x0D; Conclusions. Conduction system pacing provides rapid physiological LV activation and potentially avoids the negative consequences of asynchronous slow ventricular activation during right ventricular pacing.

Feasibility of Left Ventricle Lead Implantation in Cardiac Resynchronization Therapy Guided by Gated SPECT and Ventricular Remodeling.

Cardiac resynchronization therapy (CRT) may benefit patients with advanced heart failure (HF). Abnormal eccentricity index by gated SPECT is related to structural and functional alterations of the left ventricle (LV). The aim of this study is to evaluate the feasibility of LV lead implantation guided by phase analysis and its relationship to ventricular remodeling. Eighteen patients with indication for CRT underwent myocardial scintigraphy for implant orientation, and eccentricity and ventricular shape parameters were evaluated. P < 0.05 was adopted as statistical significance. At baseline, most patients were classified as NYHA 3 (n = 12). After CRT, 11 out of 18 patients were reclassified to a lower degree of functional limitation. In addition, patients' quality of life was improved post-CRT. Significant reductions were observed in QRS duration, PR interval, end-diastolic shape index, end-systolic shape index, stroke volume, and myocardial mass post-CRT. The CRT LV lead was positioned concordant, adjacent, and discordant in 11 (61.1%), 5 (27.8%), and 2 (11.1%) patients, respectively. End-systolic and end-diastolic eccentricity demonstrated reverse remodeling post-CRT. LV lead implantation in CRT guided by gated SPECT scintigraphy is feasible. The placement of the electrode concordant or adjacent to the last segment to contract was a determinant of reverse remodeling.

Non-invasive three-dimensional electrical activation mapping to predict cardiac resynchronization therapy response: site of latest left ventricular activation relative to pacing site.

Pacing remote from the latest electrically activated site (LEAS) in the left ventricle (LV) may diminish response to cardiac resynchronization therapy (CRT). We tested whether proximity of LV pacing site (LVPS) to LEAS, determined by non-invasive three-dimensional electrical activation mapping [electrocardiographic Imaging (ECGI)], increased likelihood of CRT response. Consecutive CRT patients underwent ECGI and chest/heart computed tomography 6-24 months of post-implant. Latest electrically activated site and the distance to LVPS (dp) were assessed. Left ventricular end-systolic volume (LVESV) reduction of ≥15% at clinical follow-up defined response. Logistic regression probabilistically modelled non-response; variables included demographics, heart failure classification, left bundle branch block (LBBB), ischaemic heart disease (IHD), atrial fibrillation, QRS duration, baseline ejection fraction (EF) and LVESV, comorbidities, use of CRT optimization algorithm, angiotensin-converting enzyme inhibitor(ACE)/angiotensin-receptor blocker (ARB), beta-blocker, diuretics, and dp. Of 111 studied patients [64 ± 11 years, EF 28 ± 6%, implant duration 12 ± 5 months (mean ± SD), 98% had LBBB, 38% IHD], 67% responded at 10 ± 3 months post CRT-implant. Latest electrically activated sites were outside the mid-to-basal lateral segments in 35% of the patients. dp was 42 ± 23 mm [31 ± 14 mm for responders vs. 63 ± 24 mm non-responders (P < 0.001)]. Longer dp and the lack of use of CRT optimization algorithm were the only independent predictors of non-response [area under the curve (AUC) 0.906]. dp of 47 mm delineated responders and non-responders (AUC 0.931). The distance between LV pacing site and latest electrical activation is a strong independent predictor for CRT response. Non-invasive electrical evaluation to characterize intrinsic activation and guide LV lead deployment may improve CRT efficacy.

281 CARDIAC RESYNCHRONIZATION TERHAPY IN PERSISTENT LEFT SUPERIOR VENA CAVA WITH A BRIDGING INNOMINATE VEIN

Abstract Background The Persistent Left (PL) Superior Vena Cava (SVC) is a congenital malformation of the thoracic venous return that has an incidence of 0.2-3% in the general population and an incidence of about 0.5% in patients undergoing cardiac implantable electronic device. In this case, the placement of the leads, especially for the Right Ventricle (RV) and Left Ventricle (LV) through one of the branches could be challenging. Methods A 66-year-old man with hypertension, diabetes and dyslipidemia, in optimal pharmacologic therapy for congestive heart failure (NYHA II), hospitalized for recurrent syncopal episodes, with extreme sinus bradycardia, first-degree AV block and Left Bundle Branch Block, The patient had a LV hypertrophy and mild global systolic function (LV ejection fraction of 40%) for these we opted for a pacemaker CRT device implantation. Results Isolation of left cephalic vein was used as venous access for right atrium (RA) and RV leads while Seldinger technique via subclavian vein was used as venous access for LV lead. The guidewire through the subclavian vein pointed out the presence of PLSVC. Left subclavian venogram confirmed PLSVC and revealed a bridging innominate vein. To pass through the innominate vein and reach the SVC, a 0.035-inch hydrophilic guidewire was used. A 6Fr-sheath was advanced through the hydrophilic guidewire, subsequently a second metallic guidewire was advanced through the same introducer by removing the dilator. The RV and RA leads were placed respectively on low right interventricular septum and RA appendage passing through bridging innominate vein. Electrical parameters were normal. For the placement of the LV lead a 9.5Fr sheath introducer was advanced over the guidewire through the PLSVC. A venogram showed a lateral and a postero-lateral branch of the coronary sinus with acute angulation. With a 6Fr quadripolar Josephson catheter the postero-lateral branch was entered, eventually a 9Fr peelable outer guide catheter was advanced through the electrophysiology catheter becoming selective with the interested branch. A quadripolar S shaped lead was used, it was advanced into the targeted vein through a 0,014fr hydrophilic guidewire. Adequate electrical parameters and stability were achieved. Conclusion Lead implantation in patient with PLSVC is challenging. Placing the RA and RV leads through SVC ensure a better stability along time. The cannulation of CS is easily achieved by approach via PLSVC while selective vein cannulation can be difficult due to the modified acute angulation.

Non-invasive estimation of QLV from the standard 12-lead ECG in patients with left bundle branch block.

Background: Cardiac resynchronization therapy (CRT) is a treatment for patients with heart failure and electrical dyssynchrony, i.e., left bundle branch block (LBBB) ECG pattern. CRT resynchronizes ventricular contraction with a right ventricle (RV) and a left ventricle (LV) pacemaker lead. Positioning the LV lead in the latest electrically activated region (measured from Q wave onset in the ECG to LV sensing by the left pacemaker electrode [QLV]) is associated with favorable outcome. However, optimal LV lead placement is limited by coronary venous anatomy and the inability to measure QLV non-invasively before implantation. We propose a novel non-invasive method for estimating QLV in sinus-rhythm from the standard 12-lead ECG. Methods: We obtained 12-lead ECG, LV electrograms and LV lead position in a standard LV 17-segment model from procedural recordings from 135 standard CRT recipients. QLV duration was measured post-operatively. Using a generic heart geometry and corresponding forward model for ECG computation, the electrical activation pattern of the heart was fitted to best match the 12-lead ECG in an iterative optimization procedure. This procedure initialized six activation sites associated with the His-Purkinje system. The initial timing of each site was based on the directions of the vectorcardiogram (VCG). Timing and position of the sites were then changed iteratively to improve the match between simulated and measured ECG. Noninvasive estimation of QLV was done by calculating the time difference between Q-onset on the computed ECG and the activation time corresponding to centroidal epicardial activation time of the segment where the LV electrode is positioned. The estimated QLV was compared to the measured QLV. Further, the distance between the actual LV position and the estimated LV position was computed from the generic ventricular model. Results: On average there was no difference between QLV measured from procedural recordings and non-invasive estimation of QLV (). Median distance between actual LV pacing site and the estimated pacing site was 18.6 mm (IQR 17.3 mm). Conclusion: Using the standard 12-lead ECG and a generic heart model it is possible to accurately estimate QLV. This method may potentially be used to support patient selection, optimize implant procedures, and to simulate optimal stimulation parameters prior to pacemaker implantation.

Determinants of the time-to-peak left ventricular dP/dt (Td) and QRS duration with different fusion strategies in cardiac resynchronization therapy.

BackgroundCardiac resynchronization therapy (CRT) is helpful in selected patients; however, responder rates rarely exceed 70%. Optimization of CRT may therefore benefit a large number of patients. Time-to-peak dP/dt (Td) is a novel marker of myocardial synergy that reflects the degree of myocardial dyssynchrony with the potential to guide and optimize treatment with CRT. Optimal electrical activation is a prerequisite for CRT to be effective. Electrical activation can be altered by changing the electrical wave-front fusion resulting from pacing to optimize resynchronization. We designed this study to understand the acute effects of different electrical wave-front fusion strategies and LV pre-/postexcitation on Td and QRS duration (QRSd). A better understanding of measuring and optimizing resynchronization can help improve the benefits of CRT.MethodsTd and QRSd were measured in 19 patients undergoing a CRT implantation. Two biventricular pacing groups were compared: pacing the left ventricle (LV) with fusion with intrinsic right ventricular activation (FUSION group) and pacing the LV and right ventricle (RV) at short atrioventricular delay (STANDARD group) to avoid fusion with intrinsic RV activation. A quadripolar LV lead enabled pacing from widely separated electrodes; distal (DIST), proximal (PROX) and both electrodes combined (multipoint pacing, MPP). The LV was stimulated relative in time to RV activation (either RV pace-onset or QRS-onset), with the LV stimulated prior to (PRE), simultaneous with (SIM) or after (POST) RV activation. In addition, we analyzed the interactions of the two groups (FUSION/STANDARD) with three different electrode configurations (DIST, PROX, MPP), each paced with three different degrees of LV pre-/postexcitation (PRE, SIM, POST) in a statistical model.ResultsWe found that FUSION provided shorter Td and QRSd than STANDARD, MPP provided shorter Td and QRSd than DIST and PROX, and SIM provided both the shortest QRSd and Td compared to PRE and POST. The interaction analysis revealed that pacing MPP with fusion with intrinsic RV activation simultaneous with the onset of the QRS complex (MPP*FUSION*SIM) shortened QRSd and Td the most compared to all other modes and configurations. The difference in QRSd and Td from their respective references were significantly correlated (β = 1, R = 0.9, p < 0.01).ConclusionPacing modes and electrode configurations designed to optimize electrical wave-front fusion (intrinsic RV activation, LV multipoint pacing and simultaneous RV and LV activation) shorten QRSd and Td the most. As demonstrated in this study, electrical and mechanical measures of resynchronization are highly correlated. Therefore, Td can potentially serve as a marker for CRT optimization.

Targeting the latest site of left ventricular mechanical activation is associated with improved long-term outcomes for recipients of cardiac resynchronization therapy.

BackgroundPrevious studies have suggested that targeting the site of latest mechanical activation of the left ventricle (LV) results in improved cardiac resynchronization therapy (CRT) outcomes. It is not known whether these benefits are sustained over medium-term follow-up.ObjectiveTo assess the clinical outcome of imaging-guided LV lead position.MethodsWe sought to assess the medium-term clinical outcome by performing a patient-level meta-analysis of 2 previously published randomized controlled trials (the “STARTER” trial and the “CRT Clinic” trial). These 2 trials compared imaging-guided LV lead placement in the latest activated scar-free segment (intervention group) to standard of care (control). Mortality and heart failure hospitalization outcomes over extended follow-up were gathered from the medical records and merged. Results were stratified for native electrocardiogram (ECG) morphology.ResultsA total of 289 patients were followed for a median of 6.3 years. Seven years post implant, 47 (28%) in the intervention group had died, vs 47 (38%) in the control group (P = .13); 49 (30%) vs 53 (42%) had been hospitalized for heart failure (P = .035); and 47% vs 59% (P = .057) had reached the combined endpoint. In Kaplan-Meier analysis, patients in the intervention group had better survival free of heart failure hospitalization (P = .045) and lower risk of heart failure hospitalization (P = .019).ConclusionTargeting the latest mechanically activated segment in CRT results in better medium-term clinical outcome, mainly driven by a reduced risk of hospitalization for heart failure. The effect was seen regardless of native ECG morphology.

Quadripolar leads are associated with better results according to bipolar leads in cardiac resynchronization therapy in one-year follow-up: Multicenter, retrospective study

Aim: In this study, we compared patients who were performed cardiac resynchronization therapy with quadripolar left ventricle lead or bipolar left ventricle lead in one-year follow-up. We investigated the relationship between the improvements of New York Heart Association classification, electrocardiography and echocardiography parameters according to lead type at one-year follow-up after CRT treatment. Materials and Methods: In this study, 91 patients were enrolled respectively as bipolar left ventricle lead and quadripolar left ventricle lead. 40 patients are quadripolar left ventricle lead and 51 patients are bipolar left ventricle lead. Results: After cardiac resynchronization therapy treatment in one year follow-up, patients with ≥1 NYHA improvement was 80% vs 56.8%, p=0.006 and left ventricular ejection fraction ≥5% was 77.5% vs 54.9%, p=0.031 and QRS duration 140.4±11.7 vs 151.7±19.4 ms, p=0.018 in quadripolar and bipolar left ventricle lead respectively. The univariable regression analysis revealed that left ventricular ejection fraction (OR:1.082 95%CI [1.005–1.165], p=0.037), QRS duration (OR:0.980 95%CI [0.961–0.999], p=0.038), NYHA class (OR:1.107 95%CI [0.075–0.682], p=0.008) and left ventricular ejection fraction improvement (OR:2.959 95%CI [1.083–8.086], p=0.034) were better response cardiac resynchronization therapy with quadripolar left ventricle rather than bipolar left ventricle lead. Conclusion: Qdp LVL can be considered instead of BiP LVL to shorten QRS duration and better improve LVEF and NYHA in patients undergoing CRT in long-term follow-up

JCS/JHRS 2021 guideline focused update on non-pharmacotherapy of cardiac arrhythmias.

JCS/JHRS 2021 guideline focused update on non-pharmacotherapy of cardiac arrhythmias.

557 His bundle pacing: how to troubleshoot the implantation of a ventricular back-up lead

Abstract Aims Interest in permanent His bundle pacing (HBP) as a means of both preventing pacing-induced cardiomyopathy and providing physiological resynchronization by normalization of His-Purkinje activation is constantly growing. Current devices are not specifically designed for HBP, which gives rise to programming challenges. To evaluate the critical troubleshooting HBP options in patients with permanent atrial fibrillation (AF) and variable degree of atrio-ventricular block (AVB) who receive HBP through a lead connected to the atrial port, and an additional ventricular ‘backup’. Methods and results Between December 2018 and July 2021, 156 consecutive patients with indication for pacing underwent HBP. Among these, 37 had permanent AF with documented symptomatic pauses. Fourteen of them received a dual-chamber device which was used to place a backup right ventricle (RV) lead; in this scenario, the His lead is implanted in the right atrial (RA) port, the RV lead in the RV port. Depending on the presence of an additional left ventricle (LV) lead, either a dual-chamber and a CRT device can be used. In this context, the events marked as atrial sensed (As) or paced (Ap) are indeed ventricular, so that sensing is more complex. A clinical scenario is atrial activity oversensed on the His channel (As) leading to RV dyssynchronous pacing in the ventricular safety pacing (VSP) window. A second one is intrinsic QRS undersensing causing inappropriate His pacing. The interplay of intrinsic ventricular activity (rate, signal amplitude, and slew rate on both the His and the ventricular channel) and of the HV interval may be of key importance to troubleshoot As–Vp (atrial sensed–ventricular paced) (Figure 1A) as well as Vs–Ab (ventricular sensed–atrial blanking period) sequences (Figure 1B). Changing sensitivity and sensing configuration may help to fix these issues. DVI(R) mode programming may indeed prove safer than DDD(R) in the setting of preserved intrinsic activity or in the event of intermittent His capture loss. Paced AV delay should be programmed slightly longer than H-V+QRS duration to avoid unnecessary RV pacing with pseudo-fusion (too short) (Figure 2A) and possibly R/T events (too long). Stability of H-V interval and of QRS duration must be verified at each device follow-up by decremental His pacing to ensure consistent sensitivity of the ventricular signal beyond stable His capture, that may be challenged by infra-Hisian block (Figure 2B). Conclusions Owing to the absence of HBP-specific devices, HBP shall be made safe and effective by careful troubleshooting, consisting of sensitivity setting, paced AV interval and mode programming. 557 Figure

Evaluation of relationship between interlead electrical delay time and reverse remodeling of left ventricle in patients with quadripolar cardiac resynchronization therapy for long-term follow-up

Abstract Background Cardiac resynchronization therapy (CRT) has undoubtedly shown a high role in the treatment of advanced heart failure (HF). The effectiveness of CRT is individual and variable in each case. It is associated with the functional and structural features of heart as well as the dynamics of these features over time. Despite the quadripolar left ventricle (LV) lead widespread use, the problem of low response to CRT in the early and long-term remains actual. The search for predictors of the CRT response is an important scientific and practical issue. Purpose To determine the relationship between the interlead electrical delay time and the CRT response during 24 month postoperative period. Materials and methods We evaluated the clinical status, the quality of life and echocardiographic response of 37 patients with HF treated for 2 years with quadripolar LV lead CRT devices implanted according to guidelines: 25 males/12 females with age 62±10 years, 25 pts with history of ischemic cardiac disease, LVEF 26±7%; QRS duration 184±31 ms. The response to CRT was defined as 15% decrease of LV end-systolic volume (ESV). Interlead electrical delay time (EDT) was calculated automatically during CRT implantation, and subsequent 3–6-12–18–24 month follow-up. Results The dynamic changes EDT and ESV were assessed for 24 months after CRT. There was a significantly higher average percentage of decrease of ESV in patients (n=18), in whom the stimulation of the LV lead was carried out from a pole having a maximum EDT, in 3 months (12±8% versus 10±6% p=0.021) and in 6 months (23±9% versus 18±9% p=0.003) after CRT. That was the dynamic of reverse remodeling is significantly higher in such patients for the first 6 months. Using logistic regression, it was shown that the relative decrease EDT in the first 3 months after CRT can be a predictor of outcomes in18 and 24 months after CRT with an accuracy of 71% and 77%, respectively. The greater the relative decrease EDT between 0 and 3 months, the greater the probability of a respond in 18 and 24 months after CRT. The cut-off threshold for determining the outcomes in 18 months was 18% on the balance of specificity and sensitivity equal to 80% and in 24 months was 15% on the balance of specificity and sensitivity equal to 90%. There were no differences between the HF etiology (ischemic/ non-ischemic) and baseline rhythm. Conclusion The relationship between EDT and LV reverse remodeling have been investigated for 24 months. The rate of reverse remodeling is higher in patients in whom the stimulation of the LV lead was carried out from a pole having a maximum EDT. Relative decrease EDT in early period after CRT may be a predictor of the CRT outcomes in longtime period. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Russian Science Foundation

Prognostic effect of the electrocardiographic pattern following cardiac resincronization

Abstract Introduction Following cardiac resincronization therapy (CRT), QRS duration is the most important prognostic factor in the 12-lead electrocardiogram (ECG). However, there is little evidence regarding if the electrocardiographic pattern following CRT has impact on morbidity and mortality. Purpose In this historical cohort study we analysed if a certain pattern in three leads of the ECG (Rs in V1, Qr in aVL or rS in I) is associated with lower incidence of adverse outcomes in a population of CRT patients within 1 year of implant. Other variables previously associated with success or failure of CRT were analysed. Methods Patients with CRT devices (pacemaker or defibrillator) with left ventricle lead in the coronary sinus were included from January 2012 to April 2019. One year clinical follow-up was performed. The primary endpoint was a composite of death of any cause and heart failure hospitalization. Differences in categorical data were reported as frequencies then compared using χ2 tests. Continuous variables were reported as means ± standard deviation with differences between groups tested using independent samples t-tests. Survival analysis was performed using Kaplan-Meier test, comparing survival graphics through Log-Rank test. For multivariate analysis, Cox regression was performed. Variables that showed significance in the univariate analysis were included. Results 111 patients were included. Sample was divided into 2 groups according to the presence of the pattern in any of the three ECG leads. Two patients (1.8%) presented Rs in V1 and Qr in aVL simultanously and two patients (1.8%) presented Rs in V1 and rS in I. None of the patients presented all three patterns simultaneously. Baseline characteristics are reported in Table 1. Presence of any of the three patterns was independently associated with a lower incidence of the primary endpoint (2.3% vs. 17.6%, hazard ratio 0.1, 95% confidence interval 0.013–0.774, p=0.016). Previous atrial fibrillation was also independently associated with a higher incidence of the primary endpoint. QRS duration postimplantation did not showed prognostic value. Conclusion The presence of the patterns Rs in V1, Qr in aVL or rS in I is an independent predictor of good prognosis in patients with CRT. Funding Acknowledgement Type of funding sources: None. Baseline characteristicsKaplan Meier survival curves

Optimal his bundle pacing programming in patients with permanent atrial fibrillation

Abstract Background Interest in permanent His bundle pacing (HBP) as a means of both preventing pacing-induced cardiomyopathy and providing physiological resynchronization by normalization of His-Purkinje activation is constantly growing. Current devices are not specifically designed for HBP, which gives rise to programming challenges. Purpose To evaluate the critical troubleshooting HBP options in patients with permanent atrial fibrillation (AF) and variable degree of atrio-ventricular block (AVB) who receive HBP through a lead connected to the atrial port, and an additional ventricular “backup”. Methods Between December 2018 and March 2021, 136 consecutive patients with indication for pacing underwent HBP. Among these, 24 had permanent AF with documented symptomatic pauses. Seven of them received a dual-chamber device which was used to place a backup right ventricle (RV) lead; in this scenario, the His lead is implanted in the right atrial (RA) port, the RV lead in the RV port. Depending on the presence of an additional left ventricle (LV) lead, either a dual-chamber and a CRT device can be used. Results In this context, the events marked as atrial sensed (As) or paced (Ap) are indeed ventricular, so that sensing is more complex. A clinical scenario is atrial activity oversensed on the His channel (As) leading to RV dyssynchronous pacing in the ventricular safety pacing (VSP) window. A second one is intrinsic QRS undersensing causing inappropriate His pacing with possible delivery of the RV pulse depending on capture of the His pulse. The interplay of intrinsic ventricular activity (rate, signal amplitude and slew rate on both the His and the ventricular channel) and of the HV interval may be of key importance to troubleshoot As-Vp (atrial sensed – ventricular paced) [Fig. 1A] as well as Vs-Ab (ventricular sensed – atrial blanking period) sequences [Fig. 1B]. Changing sensitivity and sensing configuration may help or fail to fix these issues depending on the abovementioned aspects, making it mandatory to check that the paced AV delay is appropriately set as to avoid inappropriate RV pacing on the T wave of an undersensed intrinsic event at the His channel. DVI(R) mode programming may indeed prove safer than DDD(R) in the setting of preserved intrinsic activity or in the event of intermittent His capture loss. Paced AV delay should be programmed slightly longer than H-V+QRS duration to avoid unnecessary RV pacing with pseudo-fusion (too short) and possibly R/T events (too long). Stability of H-V interval and of QRS duration must be verified at each device follow-up by decremental His pacing to ensure consistent sensitivity of the ventricular signal beyond stable His capture, that may be challenged by infra-hisian block. Conclusions Owing to the absence of HBP-specific devices, HBP shall be made safe and effective by careful troubleshooting, consisting of sensitivity setting, paced AV interval and mode programming. Funding Acknowledgement Type of funding sources: None. Different sensitivity settings for HBP

Ventricular activation patterns during intrinsic conduction and right ventricular pacing in cardiac resynchronization therapy patients.

Cardiac resynchronization therapy (CRT) involves stimulation of both right ventricle (RV) and left ventricle (LV). LV pacing from the sites of delayed electrical activation improves CRT response. The RV-LV conduction is typically measured in intrinsic rhythm. The differences in RV-LV conduction patterns and timing between intrinsic rhythm and during paced RV activation, these differences are not fully understood. Enrolled patients were implanted with a de novo CRT device and quadripolar LV lead, with lead implant locations at the implanting physician's discretion. QRS duration and conduction delay between the RV lead and each of the four LV electrodes (D1, M2, M3, and P4) were measured during intrinsic conduction and RV pacing. Conduction measurements were collected from 275 patients across 14 international centers (68 ± 13 years of age, 73% male, 45% ischemic, 158 ± 22ms QRS duration). Mean RV-LV conduction time was shorter during intrinsic conduction versus RV pacing by 59.6ms (106.5 ± 36.5versus 166.1 ± 32.1ms, p<0.001). The intra-LV activation delay between the latest and earliest activating LV electrode was also shorter during intrinsic conduction versus RV pacing by 6.6ms (20.6 ± 13.1vs. 27.2 ± 21.2ms, p<0.001). Intrinsic conduction and RV pacing resulted in a different activation order in 72.7% of patients, and the same LV activation order in 27.3%. Differences in RV-LV conduction time, intra-LV conduction time, and activation pattern were observed between intrinsic conduction and RV pacing. These findings highlight the importance of evaluating intrinsic versus paced ventricular activation to guide LV pacing site selection in CRT patients.

A clinical-in silico study on the effectiveness of multipoint bicathodic and cathodic-anodal pacing in cardiac resynchronization therapy

Up to one-third of patients undergoing cardiac resynchronization therapy (CRT) are nonresponders. Multipoint bicathodic and cathodic-anodal left ventricle (LV) stimulations could overcome this clinical challenge, but their effectiveness remains controversial. Here we evaluate the performance of such stimulations through both in vivo and in silico experiments, the latter based on computer electromechanical modeling. Seven patients, all candidates for CRT, received a quadripolar LV lead. Four stimulations were tested: right ventricular (RVS); conventional single point biventricular (S-BS); multipoint biventricular bicathodic (CC-BS) and multipoint biventricular cathodic-anodal (CA-BS). The following parameters were processed: QRS duration; maximal time derivative of arterial pressure (dPdtmax); systolic arterial pressure (Psys); and stroke volume (SV). Echocardiographic data of each patient were then obtained to create an LV geometric model. Numerical simulations were based on a strongly coupled Bidomain electromechanical coupling model.Considering the in vivo parameters, when comparing S-BS to RVS, there was no significant decrease in SV (from 45 ± 11 to 44 ± 20 ml) and 6% and 4% increases of dPdtmax and Psys, respectively. Focusing on in silico parameters, with respect to RVS, S-BS exhibited a significant increase of SV, dPdtmax and Psys. Neither the in vivo nor in silico results showed any significant hemodynamic and electrical difference among S-BS, CC-BS and CA-BS configurations.These results show that CC-BS and CA-BS yield a comparable CRT performance, but they do not always yield improvement in terms of hemodynamic parameters with respect to S-BS. The computational results confirmed the in vivo observations, thus providing theoretical support to the clinical experiments.

Electrocardiographic pattern in V1, aVL and I as predictor of events in heart failure following cardiac resincronization

Abstract Funding Acknowledgements Type of funding sources: None. Introduction following cardiac resincronization therapy (CRT), QRS duration is the most important prognostic factor in the 12-lead electrocardiogram (ECG). However, there is little evidence regarding if the electrocardiographic pattern following CRT has impact on morbidity and mortality. Purpose In this historical cohort study we analysed if a certain pattern in three leads of the ECG (Rs in V1, Qr in aVL or rS in I) is associated with lower incidence of adverse outcomes in a population of CRT patients within 1 year of implant. Other variables previously associated with success or failure of CRT were analysed. Methods patients with CRT devices with left ventricle lead in the coronary sinus were included from January 2012 to April 2019. The primary endpoint was a composite of death of any cause and heart failure hospitalization at 1 year. Survival analysis was performed using Kaplan-Meier test, comparing survival graphics through Log-Rank test. For multivariate analysis, Cox regression was performed. Results 111 patients were included. Sample was divided into 2 groups according to the presence of the pattern in any of the three ECG leads. Baseline characteristics are reported in Table 1. Presence of any of the three patterns was independently associated with a lower incidence of the primary endpoint (2.3% vs. 17.6%, hazard ratio 0.1, 95% confidence interval 0.013-0.774, p = 0.016). Previous atrial fibrillation was also independently associated with a higher incidence of the primary endpoint. QRS duration postimplantation did not showed prognostic value. Conclusion the presence of the patterns Rs in V1, Qr in aVL or rS in I is an independent predictor of good prognosis in patients with CRT. Baseline characteristicsPattern Rs-V1/Qr-aVL/rS-INo patternp-valueAge (years)69 ± 1767 ± 210.257Women8 (18.6)17 (25)0.432Atrial fibrillation18 (41.9)22 (32.4)0.309- Ischemic cardiomyopathy- Non ischemic cardiomyopathy18 (41.9)25 (58.1)26 (38.8)41 (61.2)0.75Indication- HFrEF + NYHA II-IV + wide QRS- rEF + indication of cardiac stimulation- LV dysfunction secondary to stimulation 35 (81.4)7 (16.3)1 (2.3) 58 (85.3)9 (13.2)1 (1.5) 0.5870.6560.741Preimplantation LVEF (%)28 ± 1328 ± 150.882Up-titrated treatment17 (39.5)26 (38.2)0.891- LBBB- RBBB36 (83.7)5 (11.6)61 (89.7)6 (8.8)0.3550.63QRS duration postimplantation (ms)144 ± 35142 ± 500.657HFrEFheart failure with reduced ejection fraction; NYHA: New York Heart Association; rEF: reduced ejection fraction; LV: left ventricle; LVEF: left ventricle ejection fraction; LBBB: left bundle branch block; RBBB: right bundle branch block.Abstract Figure. Kaplan Meier survival curves

Impact of synchronous atrioventricular delay optimization on left ventricle flow force angle evaluated by echocardiographic particle image velocimetry.

To evaluate the improvement in electrical synchrony and left ventricle (LV) hemodynamics provided by combining the dynamic atrioventricular delay (AVD) of SyncAVTM CRT and the multiple LV pacing sites of MultiPoint pacing (MPP). Patients with LBBB and QRS duration (QRSd) > 140 ms implanted with a CRT-D or CRT-P device and quadripolar LV lead were enrolled in this prospective study. During a post-implant follow-up visit, QRSd was measured from 12-lead surface electrograms by experts blinded to pacing configurations. QRSd reduction relative to intrinsic rhythm was evaluated during biventricular pacing (BiV) and MPP for two AVDs: nominal (140/110 ms paced/sensed) and SyncAV (patient-optimized SyncAV offset [10-60 ms] minimizing QRSd). Echocardiography particle imaging velocimetry (Echo-PIV) analysis was performed for each configuration. The resulting hemodynamic force LV flow angle (φ) was analyzed, which ranges from 0o (predominantly base-apex forces) to 90o (predominantly transverse forces). Higher angles indicate more energy dissipation at lateral walls due to transverse flow; lower angles indicate healthier flow aligned with the longitudinal base-apex path of the pressure gradient. Twelve patients (58% male, 17% ischemic, 32±7% ejection fraction, 165 ± 18 ms intrinsic QRSd) completed QRSd and Echo-PIV assessment. Relative to intrinsic rhythm, BiV and MPP with nominal AVD reduced QRSd by 10 ± 9% and 12 ± 9%, respectively. BiV+SyncAV and MPP+SyncAV further reduced QRSd by 19 ± 8%, (p < 0.05 vs. BiV with nominal AVD) and 23 ± 9% (p < 0.05 vs BiV+SyncAV), respectively. Echo-PIV showed similar sequential hemodynamic improvements. LV flow angular orientation during intrinsic activation (46 ± 3o) reduced with BiV+SyncAV (37 ± 4o, p < 0.05 vs intrinsic) and further with MPP+SyncAV (34 ± 4o, p < 0.05 vs BiV+SyncAV). These results suggest that SyncAV may improve electrical synchrony and influence LV flow patterns in patients suffering from heart failure compared to conventional CRT with a fixed AVD, with further improvement observed by combining with MPP.

Advanced Heart Failure Exacerbated by Discreet Left Ventricular Lead Non-Capture

This case report illustrates a challenging case of worsening heart failure in a previously well-compensated patient with unclear etiology. Further workup revealed the patient’s cardiac resynchronization therapy-defibrillator (CRT-D) left ventricle (LV) lead was losing capture during positional changes. This case demonstrates the importance of device optimization, as well as electrocardiogram (ECG) monitoring to elucidate possible causes of acute systolic heart failure.

Cathodic-anodal left ventricular stimulation during cardiac resynchronization therapy: haemodynamic evaluation and electrocardiographic analysis

Abstract Background Cardiac resynchronization therapy (CRT) is an established treatment for heart failure with reduced ejection fraction (HFrEF). However, one third of patients are “non responders”. Cathodic-anodal (CA) left ventricle (LV) capture is a multisite pacing occurring during CRT using both bipolar and quadripolar LV lead. It allows depolarization to arise simultaneously from the cathode and the anode of the bipole located on the LV epicardium, activating a larger volume of myocardium than cathodal pacing alone, thus potentially improving electromechanical synchrony (figure 1). We have previously proven that CA-LV stimulation is feasible and similar to bicathodic multipoint pacing (MPP) in terms of QRS wavefront activation. Purpose We aimed to evaluate both the acute intraprocedural haemodynamic and electrical effects of CA biventricular stimulation (CA-BS), comparing it with right-ventricle only pacing (Right Ventricle-Stimulation: RV-S), single-point CRT (Single Point-Biventricular Stimulation: SP-BS) and multipoint bicathodic biventricular stimulation (Multi Point-Biventricular Stimulation:MP-BS) in de novo CRT implants. Methods Ten patients candidates to CRT (LV ejection fraction ≤35% and left bundle branch block) received a quadripolar LV lead. Four pacing configurations were tested: RV-S, SP-BS, MP-BS and CA-BS, where cathode and the anode were the same electrodes used as cathodes in MP-BS. QRS duration by 12-lead ECG was defined as the time from the earliest ventricular deflection until the return to the isoelectric line. Haemodynamic assessment by radial artery catheterization using Pressure Recording Analytical Method processed the following parameters: dP/dT max (mmHg/msec), systolic arterial pressure (aPsys, mmHg), diastolic arterial pressure (aPdia, mmHg), mean arterial pressure (aPmean, mmHg), Cardiac Index (CI, l/min/m2), Stroke Volume Index (SVI, ml/min/m2). Results dP/dT max and aPmean increased significantly from RV-S to SP-BS (mean dP/dT max 0,82±0,28 versus 0,87±0,29 mmHg/msec, p=0,02; mean aPmean 89±19 versus 93±20 mmHg, p=0,01), but not from RV-S to MP-BS. Comparing RV-S to CA-BS, only aPmean exhibited a significant increase (mean aPmean 89±19 versus 92±20 mmHg, p=0,01). There were no haemodynamic differences between SP-BS, MP-BS and CA-BS. QRS duration reduced significantly from RV-S (167±10 msec) to each biventricular stimulation (135±14 msec, p=0,0002 for SP-BS; 130±17 msec, p=0,0001 for MP-BS; 129±18 msec, p=0,0002 for CA-BS) and from SP-BS to MP-BS and CA-BS (p=0,03 for both), whereas there were no difference comparing MP-BS and CA-BS. Conclusions CA-LV stimulation is not superior to single-point CRT in terms of acute haemodynamic performance, whereas it reduces the duration of ventricular electrical activation, showing an electrohaemodynamic mismatch. Long-term studies are needed to evaluate if acute electrical benefits of CA stimulation can predict chronic benefits, in terms of reverse cardiac remodelling. Cathodic-anodal left ventricular capture Funding Acknowledgement Type of funding source: None