Quadripolar Leads in Cardiac Resynchronization Therapy

Quadripolar left ventricle only single lead pacing in a patient with a tricuspid mechanical valve: A less invasive approach

In the presence of prosthetic tricuspid valve, the inaccessibility to the right ventricle makes permanent pacing challenging. The placement of a left ventricle (LV) single lead in the coronary sinus (CS) is a well-accepted alternative, with some limitations regarding sensing and threshold. We describe a clinical case of a patient who had a previous LV only lead in the CS due to the presence of a prosthetic tricuspid valve and, after a surgical valvular intervention, presented with recurrent syncope episodes due to lead malfunction with lack of pacing capture and significant ventricular pauses. A quadripolar lead was chosen to be placed in the CS connected to a cardiac resynchronization therapy pacemaker device, programmed at biventricular VVI and using a specific manufacturer T-wave protection algorithm to prevent pacemaker-induced arrhythmias and to use the patient's own rhythm. This approach prevented a fourth surgical intervention to place an epicardial lead and resulted in reasonable LV sensing and pacing threshold.

Learning objectives

This paper reports an alternative and atypical approach that could solve some of the limitations associated with ventricular pacing in patients with tricuspid prosthetic valves and multiple previous surgeries.

Programming Algorithms for Cardiac Resynchronization Therapy

Current cardiac resynchronization therapy (CRT) implant guidelines emphasize the presence of electrical dyssynchrony (left bundle branch block (LBBB) and QRS > 150 ms) yet have modest predictive value for response and have not reduced the 30% nonresponse rate. Optimized programming to optimize CRT delivery has promised much but to date has largely been ineffective. What is missing is the understanding of LV paced effects (which are unpredictable) and optimal paced AV interval (that can be conserved during physiologic variations) that then can be incorporated into an individualized programming prescription. Automatic device-based algorithms that deliver electrical optimization and maintain this during ambulatory fluctuations in AV interval are discussed.

Perioperative Sensor and Algorithm Programming in Patients with Implanted ICDs and Pacemakers for Cardiac Resynchronization Therapy

Background: ICDs and pacemakers for cardiac resynchronization therapy (CRT) are complex devices with different sensors and automatic algorithms implanted in patients with advanced cardiac diseases. Data on the perioperative management and outcome of CRT carriers undergoing surgery unrelated to the device are scarce. Methods: Data from 198 CRT device carriers (100 with active rate responsive sensor) were evaluated regarding perioperative adverse (device-related) events (A(D)E) and lead parameter changes. Results: Thirty-nine adverse observations were documented in 180 patients during preoperative interrogation, which were most often related to the left-ventricular lead and requiring intervention/reprogramming in 22 cases (12%). Anesthesia-related events occurred in 69 patients. There was no ADE for non-cardiac surgery and in pacemaker-dependent patients not programmed to an asynchronous pacing mode. Post-operative device interrogation showed significant lead parameter changes in 64/179 patients (36%) requiring reprogramming in 29 cases (16%). Conclusion: The left-ventricular pacing lead represents the most vulnerable system component. Comprehensive pre and post-interventional device interrogation is mandatory to ensure proper system function. The type of ICD function suspension has no impact on each patient’s outcome. Precautionary activity sensor deactivation is not required for non-cardiac interventions. Routine prophylactic device reprogramming to asynchronous pacing appears inessential. Most of the CRT pacemakers do not require surgery-related reprogramming.

Long-Term Performance Comparison of Bipolar Active vs. Quadripolar Passive Fixation Leads in Cardiac Resynchronisation Therapy

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.

Six months clinical outcome comparison between quadripolar and bipolar left ventricular leads in cardiac resynchronization therapy: A prospective, non-randomized, single-centre observational study

Background and objectives

Quadripolar left ventricular (LV) leads in cardiac resynchronization therapy (CRT) offer multi-vector pacing with different pacing configurations and hence enabling LV pacing at most suitable site with better lead stability. We aim to compare the outcomes between quadripolar and bipolar LV lead in patients receiving CRT.

Methods

In this prospective, non-randomized, single-center observational study, we enrolled 93 patients receiving CRT with bipolar (BiP) (n = 31) and quadripolar (Quad) (n = 62) LV lead between August 2016 to August 2019. Patients were followed for six months, and outcomes were compared with respect to CRT response (defined as ≥5% absolute increase in left ventricle ejection fraction), electrocardiographic, echocardiographic parameters, NYHA functional class improvement, and incidence of LV lead-related complication.

Results

At the end of six months follow up, CRT with quadripolar lead was associated with better response rate as compared to bipolar pacing (85.48% vs 64.51%; p = 0.03), lesser heart failure (HF) hospitalization events (1.5 vs 2; p = 0.04) and better improvement in HF symptoms (patients with ≥1 NYHA improvement 87.09% vs 67.74%; p = 0.04). There were fewer deaths per 100 patient-year (6.45 vs 9.37; p = 0.04) and more narrowing of QRS duration (Δ12.56 ± 3.11 ms vs Δ7.29 ± 1.87 ms; p = 0.04) with quadripolar lead use. Lead related complications were significantly more with the use of bipolar lead (74.19% vs 41.94%; p = 0.02).

Conclusions

Our prospective, non-randomized, single-center observational study reveals that patients receiving CRT with quadripolar leads have a better response to therapy, lesser heart failure hospitalizations, lower all-cause mortality, and fewer lead-related complications, proving its superiority over the bipolar lead.

Exploring a New Systematic Route for Left Ventricular Pacing in Cardiac Resynchronization Therapy

BACKGROUND

Frequency and distribution of left ventricular (LV) venous collaterals were studied in vivo to evaluate the ease and feasibility of implanting a new ultra-thin LV quadripolar microlead for cardiac resynchronization therapy (CRT).Methods and Results:Evaluable venograms were analyzed to define the prevalence of venous collaterals (>0.5 mm diameter) between: (1) different LV segments; and (2) different major LV veins in: unselected patients who underwent CRT from 2008 to 2012 at Rouen Hospital, France (retrospective); and CRT patients from the Axone Acute pilot study in 2018 (prospective). In prospective patients with evaluable venograms, LV microlead implantation was attempted. Thirty-six (21/65 retrospective, 15/20 prospective) patients had evaluable venograms with ≥1 visible venous collaterals. Collaterals were found between LV veins in all CRT patients with evaluable venograms. Regionally, prevalence was highest between: the apical inferior and apical lateral (42%); and mid inferior and mid inferolateral (42%) segments. Collateral connections were most prevalent between: the inferior interventricular vein (IIV) and lateral vein (64% [23/36]); and IIV and infero-lateral vein (36% [13/36]). Cross-vein microlead implantation was possible in 18 patients (90%), and single-vein implantation was conducted in the other 2 patients (10%).

CONCLUSIONS

Venous collaterals were found in vivo between LV veins in all CRT patients with evaluable venograms, making this network an option for accessing multiple LV sites using a single LV microlead.

Second European Society of Cardiology Cardiac Resynchronization Therapy Survey: the Italian cohort

AIM

Adherence to guidelines was not homogeneous in Europe, according to the survey on cardiac resynchronization therapy conducted in 2008-2009. The aim of our study was to compare the results in the Italian and European cohorts of the Second European Cardiac Resynchronization Therapy Survey.

METHODS

Patients' characteristics, procedural data and follow-up were collected. Italian records were compared with European countries.

RESULTS

Italian hospitals enrolled 526 patients. The italian cohort was older (71.6 ± 9.5 vs. 68.4 ± 10.8; P < 0.00001), had less severe NYHA class (>II 47.2 vs. 59.6%; P < 0.00001), higher ejection fraction (30.3 ± 7.4 vs. 28.4 ± 8.2%; P < 0.00001), and less atrial fibrillation prevalence (34.4 vs. 41.2%; P = 0.00197) than the European cohort. Italian patients were more frequently hospitalized for heart failure in the previous year (51.9 vs. 46.2%; P = 0.01118) and had lower mean QRS duration (151 ± 26 vs. 157 ± 27 ms; P < 0.0001). CRT-D were more often implanted in Italian patients (79.3 vs. 69.3%; P < 0.00001). The complication rate was similar (4.6% vs. 5.6%; ns). The rate of use of ACEi/ARBs in Italy was lower than in Europe (77.2 vs. 86.9%; P < 0.00001). Patients were followed up in the implantation centre (92.1 vs. 86%; P = 0.00014), but rarely with remote monitoring (25.9 vs. 30%; P = 0.04792).

CONCLUSION

The survey demonstrates important similarities as well as substantial differences regarding most of the aspects evaluated. Efforts to implement adherence to guidelines will be endorsed in Italy.

Performance of a novel active fixation quadripolar left ventricular lead for cardiac resynchronization therapy: Attain Stability Quad Clinical Study results

INTRODUCTION

The Medtronic Attain Stability Quad lead is a quadripolar left ventricular (LV) lead with an active fixation helix assembly designed to fixate the lead within the coronary sinus and pace nonapical regions of the LV. The primary objective of this study was to determine the safety and effectiveness of this novel active fixation quadripolar LV lead.

METHODS

Patients with standard indications for cardiac resynchronization therapy (CRT) were enrolled. All patients were followed at 3 and 6 months post-implant and every 6 months thereafter until study closure. Pacing capture thresholds (PCTs) were measured at implant and each follow-up and adverse events (AEs) were recorded upon occurrence.

RESULTS

Of the 440 patients who underwent implant procedures, placement of the Attain Stability Quad lead was successful in 426 (96.8%). LV lead-related complications occurred in 10 patients (2.3%), including LV lead dislodgement in three patients (0.7%). The percentage of patients with at least one LV pacing vector with a PCT ≤2.5 V at a 6-month follow-up was 96.3%. The LV lead was successfully fixated to the prespecified pacing location in 97.4% of cases.

CONCLUSIONS

This large, multinational study of the Attain Stability Quad lead demonstrated a high rate of implant success with a low complication rate. The active fixation mechanism allowed precise placement of the pacing electrodes at the desired target region with good PCTs and a very low dislodgement rate.

Contrast-induced nephropathy after cardiac resynchronization therapy implant impairs the recovery of ejection fraction in responders

Aims

Data regarding contrast‐induced nephropathy (CIN) after cardiac resynchronization therapy (CRT) implant are limited. We aimed to investigate the incidence and determinants of CIN and its impact on CRT response and outcomes.

Methods and results

Patients who underwent CRT implant were retrospectively analysed, and CIN was defined as an increase of serum creatinine ≥0.3 mg/dL or ≥1.5 times the baseline value. Response to CRT was defined as a reduction of left ventricle end‐systolic volume (LVESV) of 15% or the increase of five percentage points in ejection fraction (EF) as assessed by echocardiography at 6 months. Follow‐up visits were scheduled at 3, 6, and 12 months.

Contrast‐induced nephropathy occurred in 13/107 patients (12%). Among baseline clinical, echocardiographic, and laboratory characteristics, only a high baseline serum creatinine was associated with the occurrence of CIN. Symptoms, EF, and LVESV at 6 months improved in both CIN and non‐CIN patients, and the rate of responders to CRT was similar. Among responders, at 6 months, those with CIN had significantly lower EF (28.5% vs. 35.7% P = 0.003).

At a median follow‐up of 112 weeks, 43% of patients experienced a clinical event with similar incidence in CIN and non‐CIN patients, and likewise survival was similar. Non‐responders to CRT had worse survival while among responders those with CIN had worse survival than non‐CIN patients (71% vs. 90%, P = 0.0035).

Conclusions

The incidence of CIN is rather high. Although CIN does not influence response to CRT overall, however among responders impairs the recovery of EF and survival.

Non-response to Cardiac Resynchronization Therapy

PURPOSE OF REVIEW

Cardiac resynchronization therapy (CRT) is an effective treatment option for therapy-refractory mild to severe heart failure (HF) patients with reduced ejection fraction and left ventricular (LV) conduction delay. Multiple clinical trials have shown that CRT improves cardiac function and overall quality of life, as well as reduces HF hospitalizations, health care costs, and mortality.

RECENT FINDINGS

Despite its effectiveness, the "non-response" rate to CRT is around 30%, remaining a major challenge that faces electrophysiologists and researchers. It has been recently suggested that the etiology of CRT non-response is multifactorial, and it requires a multifaceted approach to address it. In this focused review, we will summarize the definitions of CRT non-response, identify key factors for CRT non-response, and offer a simplified framework to address CRT non-response with the main goal of improving CRT outcomes.

Efficacy, Safety, and Performance of Isolated Left vs. Right Ventricular Pacing in Patients with Bradyarrhythmias: A Randomized Controlled Trial

Background

Considering the potential deleterious effects of right ventricular (RV) pacing, the hypothesis of this study is that isolated left ventricular (LV) pacing through the coronary sinus is safe and may provide better clinical and echocardiographic benefits to patients with bradyarrhythmias and normal ventricular function requiring heart rate correction alone.

Objective

To assess the safety, efficacy, and effects of LV pacing using an active-fixation coronary sinus lead in comparison with RV pacing, in patients eligible for conventional pacemaker (PM) implantation.

Methods

Randomized, controlled, and single-blinded clinical trial in adult patients submitted to PM implantation due to bradyarrhythmias and systolic ventricular function ≥ 0.40. Randomization (RV vs. LV) occurred before PM implantation. The main results of the study were procedural success, safety, and efficacy. Secondary results were clinical and echocardiographic changes. Chi-squared test, Fisher's exact test and Student's t-test were used, considering a significance level of 5%.

Results

From June 2012 to January 2014, 91 patients were included, 36 in the RV Group and 55 in the LV Group. Baseline characteristics of patients in both groups were similar. PM implantation was performed successfully and without any complications in all patients in the RV group. Of the 55 patients initially allocated into the LV group, active-fixation coronary sinus lead implantation was not possible in 20 (36.4%) patients. The most frequent complication was phrenic nerve stimulation, detected in 9 (25.7%) patients in the LV group. During the follow-up period, there were no hospitalizations due to heart failure. Reductions of more than 10% in left ventricular ejection fraction were observed in 23.5% of patients in the RV group and 20.6% of those in the LV group (p = 0.767). Tissue Doppler analysis showed that 91.2% of subjects in the RV group and 68.8% of those in the LV group had interventricular dyssynchrony (p = 0.022).

Conclusion

The procedural success rate of LV implant was low, and the safety of the procedure was influenced mainly by the high rate of phrenic nerve stimulation in the postoperative period.

Alternative left ventricular pacing approaches for optimal cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) improves mortality, morbidity, and quality of life in selected heart failure patients with severe left ventricular (LV) ejection fraction impairment. However, between 20% and 40% of device recipients do not benefit clinically from CRT. Indeed, some anatomic and technical difficulties are related to the coronary venous implantation site via the coronary sinus (CS). Additionally, electrical constraints have been described, and CS does not always correspond to the optimal LV lead position. In the last decade, engineers and physicians have worked together to overcome the challenging LV lead implantation, and various biventricular pacing alternatives have been developed to improve CRT response. In this review, we discuss the evolution from CS pacing to wireless LV stimulation and His-bundle pacing.

A comparison of the different features of quadripolar left ventricular pacing leads to deliver cardiac resynchronization therapy

INTRODUCTION

Cardiac Resynchronization therapy (CRT) improves the quality of life and reduces morbidity and mortality of certain patients with heart failure. However, not all patients respond positively after CRT and about one third of cases do not experience benefit. Suboptimal biventricular pacing may account for this and quadripolar left ventricular (LV) leads have emerged in the last years to address issues relating to inadequate delivery of CRT.

AREAS COVERED

This review article concisely summarizes the main technical characteristics of the quadripolar LV leads either currently available in the market today or under final stages of development. Focus is given in recent advancements in the area and challenging aspects and controversies, future implications as well as opportunities for further development.

EXPERT COMMENTARY

Quadripolar LV pacing leads have now become the standard of care in CRT. Currently a multitude of lead options is available to the clinician. The selection process of the most appropriate lead is far from the 'one size fits all' concept. Further development of quadripolar LV leads is currently ongoing and it is anticipated to contribute towards the release of more technologically advantageous leads which will enable the delivery of optimal CRT therapy with the lowest rate of complications.

Using three-dimensional echocardiography to guide left ventricle lead position in cardiac resynchronization therapy: does it make any difference

BACKGROUND

Cardiac resynchronization therapy (CRT) is an effective treatment for patients with advanced heart failure. Nearly 30% of candidates are inadequate responders. Proper patient selection, left ventricle (LV) lead placement optimization, and optimization of the programming of the CRT device are important approaches to improve outcome of CRT. We examined the role of three-dimensional (3D) echocardiography in determining the optimal LV lead position as a method of optimizing CRT response.

METHODS

Forty-seven patients with a mean age of 60.2 ± 11.1 years including five (10.6%) females, all having advanced CHF (EF <35%, LBBB >120 mesc, or non-LBBB >150 msec, with NYHA II-III or ambulatory class IV) were enrolled. Detailed history (NYHA class, Minnesota living with heart failure questionnaire), clinical examination, 6-min walk test, and standard 2D echocardiography were done in all cases. 3D echo detailed analysis of the LV 16 segments was done to determine the latest wall to reach the minimal systolic volume. Multisite pacing was done blind to the 3D echo data achieving a stable LV lead position in mid LV segment. This exact fluoroscopic site was determined (in two orthogonal views) and correlated with 3D most delayed area using a resized 16-segment schema. Patients were classified retrospectively into group A with concordance between the delayed LV area and LV lead position and group B with discordance between both. Patients were followed up after 3-6 (5.1 ± 1.8) months. Patients with reduction of 2D LV end-systolic volume of ≥10% at follow-up were termed volumetric responders. Poorly echogenic patients and those with decompensated NYHA class IV, sustained atrial arrhythmias, and rheumatic or congenital heart diseases were excluded.

RESULTS

LV lead placement was concordant in 22 (46.8%) cases. After the follow-up period, 31 (65.9%) of the study population were considered volumetric responders with no significant difference among both groups (14 (63.3%) in group A vs 17 (68%) in group B, p > 0.05). CRT insertion resulted in significant improvement of NYHA class in 36 (76.5%) cases, 6-min walk test (447.2 ± 127.0 vs 369.6 ± 87.5 m, p < 0.01), MLHFQ (58.1 ± 19.7 vs 69.6 ± 13.5, p < 0.01), QRS duration (131.2 ± 13.8 vs 149.4 ± 16 msec, p < 0.01), 2D LV EF 33.0 ± 9.5 vs 25.3 ± 6.5, p < 0.001), LVESV (156.0 ± 82.9 vs177.6 ± 92.7 ml, p < 0.05), and 3D LVEF (29.1 ± 9.0 vs 23.6 ± 5.9, p < 0.001) irrespective of the etiology of heart failure. However, there were no significant differences between both groups regarding the same parameters (6-min walk test 470.8 ± 128.7 vs 428.3 ± 126.8 m, MLHFQ 56.8 ± 20.0 vs 58.11 ± 19.0, QRS duration 129.9 ± 12.4 vs 132.1 ± 15.1 msec, 2D LVEF 30.9 ± 8.3 vs 34.58 ± 10.9, LVESV 173.0 ± 110.0 vs 143.0 ± 67.9, 3D LVEF 26 ± 8 vs 31 ± 9, for groups A and B, respectively, p < 0.05).

CONCLUSIONS

Standard anatomical LV lead placement remains a simple, practical, and effective method in patients undergoing CRT. 3D echocardiography-guided LV lead placement added no clinical benefit compared to standard techniques.