Pacing Optimized by Left Ventricular dP/dtmax

Left ventricular (LV) dP/dt_max provides a sensitive measure of the acute hemodynamic response to cardiac resynchronization therapy (CRT) and can predict reverse remodeling on echocardiography. Its use to guide LV lead placement has been shown to improve outcomes in a multicenter randomized trial. Given the invasive protocol required for measurement, it is unlikely to be universally beneficial for patients undergoing CRT but may be useful for patients who do not respond to conventional CRT, or in those who have borderline indications or risk factors for non-response. In such cases, LV dP/dt_max may help guide LV lead placement, optimize device programming, and select the best alternative method of delivering CRT, such endocardial LV pacing or conduction system pacing.

Multisite Left Ventricular Pacing in Cardiac Resynchronization Therapy

Cardiac resynchronization therapy (CRT) is an established treatment of patients with heart failure with reduced ejection fraction and prolonged ventricular depolarization on surface electrocardiogram. Although patients' characteristics, such as their type of cardiomyopathy and the morphology and width of their baseline QRS complex, have been associated with CRT response, these features are not modifiable. Left ventricular multisite pacing has been proposed and tested as a tool to improve response to CRT and positively impact patient outcomes. This article reviews the published literature on left ventricular multisite pacing, with focus on the results of recently presented or published clinical trials.

Potential efficacy of multipoint pacing in the reduction of mitral regurgitation volume: a case report

A 70‐year‐old woman who had cardiac sarcoidosis and severe tethering mitral regurgitation (MR) and had been implanted with a biventricular pacemaker experienced recurrent hospitalisation due to decompensated heart failure (HF). Application of MultiPoint™ pacing reduced the MR volume and maintained the symptoms under control; however, the predicted longevity of the device significantly decreased because of the very high threshold of the added pacing site. Transcatheter mitral valve repair (TMVR) using MitraClip® was performed to further diminish the severe MR, thereby enabling the switch from highly consumptive multipoint pacing (MPP) to energy‐saving single‐point pacing. MPP could further reduce MR compared to the conventional single‐point pacing, and this could be a bridging therapy to TMVR in some patients implanted with a biventricular pacemaker. This is the first case to report that switching from conventional single‐point pacing to MPP decreased the MR, to some extent, resulting in the improvement of HF symptoms.

Impact of anatomical reverse remodelling in the design of optimal quadripolar pacing leads: A computational study

Lead position is an important factor in determining response to Cardiac Resynchronization Therapy (CRT) in dyssynchronous heart failure (HF) patients. Multipoint pacing (MPP) enables pacing from multiple electrodes within the same lead, improving the potential outcome for patients. Virtual quadripolar lead designs were evaluated by simulating pacing from all combinations of 1 and 2 electrodes along the lead in each virtual patient from cohorts of HF (n = 24) and simulated reverse remodelled (RR, n = 20) patients. Electrical synchrony was assessed by the time 90% of the ventricular myocardium is activated (AT090). Optimal 1 and 2 electrode pacing configurations for AT090 were combined to identify the 4-electrode lead design that maximised benefits across all patients. LV pacing in the HF cohort in all possible single and double electrode locations reduced AT090 by 14.48 ± 5.01 ms (11.92 ± 3.51%). The major determinant of reduction in activation time was patient anatomy. Pacing with a single optimal lead design reduced AT090 more in the HF cohort than the RR cohort (12.68 ± 3.29% vs 10.81 ± 2.34%). Pacing with a single combined HF and RR population-optimised lead design achieves electrical resynchronization with near equivalence to personalised lead designs both in HF and RR anatomies. These findings suggest that although lead configurations have to be tailored to each patient, a single optimal lead design is sufficient to obtain near-optimal results across most patients. This study shows the potential of virtual clinical trials as tools to compare existing and explore new lead designs.

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 (dPdt_max); systolic arterial pressure (P_sys); 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 dPdt_max and P_sys, respectively. Focusing on in silico parameters, with respect to RVS, S-BS exhibited a significant increase of SV, dPdt_max and P_sys. 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.

Non-invasive hemodynamic determination of patient-specific optimal pacing mode in cardiac resynchronization therapy

PURPOSE

Cardiac resynchronization therapy (CRT) devices have multiple programmable pacing parameters. The purpose of this study was to determine the best pacing mode, i.e., associated with the greatest acute hemodynamic response, in each patient.

METHODS

Patients in sinus rhythm and intact atrioventricular conduction were included within 3 months of implantation of devices featuring SyncAV and multipoint pacing (MPP) algorithms. The effect of nominal biventricular pacing using the latest activated electrode (BiV-Late), optimized atrioventricular delay (AVD), nominal and optimized SyncAV, and anatomical MPP was determined by non-invasive measurement of systolic blood pressure (SBP). CRT response was defined as SBP increase > 10% relative to baseline.

RESULTS

Thirty patients with left bundle branch block (LBBB) were included. BiV-Late increased SBP compared to intrinsic rhythm (128 ± 21 mmHg vs. 121 ± 22 mmHg, p = 0.0002). The best pacing mode further increased SBP to 140 ± 19 mmHg (p < 0.0001 vs. BiV-Late). The proportion of CRT responders increased from 40% with BiV-Late to 80% with the best pacing mode (p = 0.0005). Compared to BiV-Late, optimized AVD and optimized SyncAV increased SBP (to 134 ± 21 mmHg, p = 0.004, and 133 ± 20 mmHg, p = 0.0003, respectively), but nominal SyncAV and MPP did not. The best pacing mode was variable between patients and was different from nominal BiV-Late in 28 (93%) patients. Optimized AVD was the most frequent best mode, in 14 (47%) patients.

CONCLUSION

In patients with LBBB, the best pacing mode was patient-specific and doubled the magnitude of acute hemodynamic response and the proportion of acute CRT responders compared to nominal BiV-Late pacing.

TRIAL REGISTRATION

ClinicalTrials.gov : NCT03779802.

Cardiac resynchronization therapy in heart failure patients: tough road but clear future

Cardiac resynchronization therapy (CRT) based on biventricular pacing (BVP) is an invaluable intervention currently used in heart failure (HF) patients. The therapy involves electromechanical dyssynchrony, which can not only improve heart function and quality of life but also reduce hospitalization and mortality rates. However, approximately 30% to 40% of patients remain unresponsive to conventional BVP in clinical practice. In the recent years, extensive research has been employed to find a more physiological approach to cardiac resynchronization. The His-Purkinje system pacing (HPSP) including His bundle pacing (HBP) and left bundle branch area pacing (LBBaP) may potentially be the future of CRT. These technologies present various advantages including offering an almost real physiological pacing, less complicated procedures, and economic feasibility. Additionally, other methods, such as isolated left-ventricular pacing and multipoint pacing, may in the future be important but non-mainstream alternatives to CRT because currently, there is no strong evidence to support their effectiveness. This article reviews the current situation and latest progress in CRT, explores the existing technology, and highlights future prospects in the development of CRT.

Evaluating multisite pacing strategies in cardiac resynchronization therapy in the preclinical setting

Background

Multisite pacing strategies that improve response to cardiac resynchronization therapy (CRT) have been proposed. Current available options are pacing 2 electrodes in a multipolar lead in a single vein (multipoint pacing [MPP]) and pacing using 2 leads in separate veins (multizone pacing [MZP]).

Objective

The purpose of this study was to compare in a systematic manner the acute hemodynamic response (AHR) and electrophysiological effects of MPP and MZP and compare them with conventional biventricular pacing (BiVP).

Methods

Hemodynamic and electrophysiological effects were evaluated in a porcine model of acute left bundle branch block (LBBB) (n = 8). AHR was assessed as LVdP/dtmax. Activation times were measured using >100 electrodes around the epicardium, measuring total activation time (TAT) and left ventricular activation time (LVAT).

Results

Compared to LBBB, BiVP, MZP, and MPP reduced TAT by 26% ± 10%, 32% ± 13%, and 32% ± 14%, respectively (P = NS between modes) and LVAT by 4% ± 5%, 11% ± 5%, and 12% ± 5%, respectively (P <.05 BiVP vs MPP and MZP). On average, BiVP increased LVdP/dtmax by 8% ± 4%, and optimal BiVP increased LVdP/dtmax by 13% ± 4%. The additional improvement in LVdP/dtmax by MZP and MPP was significant only when its increase during BiVP and decrease in TAT were poor (lower 25% of all sites in 1 subject). The increase in LVdP/dtmax was larger when large interelectrode distances (>5 cm vs <2.2 cm) were used.

Conclusion

In this animal model of acute LBBB, MPP and MZP create similar degrees of electrical resynchronization and hemodynamic effect, which are larger if interelectrode distance is large. MPP and MZP increase the benefit of CRT only if the left ventricular lead used for BiVP provides poor response.

Delay optimization of multipoint pacing increases the cardiac index and narrows the QRS width

INTRODUCTION

The benefits of MPP delay optimization on hemodynamics and ventricular contraction synchronicity can be quantified with cardiac index (CI) and QRS width. A delay with the maximum CI and minimum QRS width may be the optimized settings for multipoint pacing (MPP).

METHODS

Twelve patients with advanced heart failure who received cardiac resynchronization therapy defibrillation with MPP at the Third People's Hospital of Chengdu from March 2016 to April 2019 were included. Interventricular and intraventricular delays were optimized through noninvasive cardiac output monitoring and a 12 lead ECG.

RESULTS

According to CI, the optimized left ventricular- left ventricular - right ventricular delay setting was mainly 25 ms-25 ms and 40 ms-40 ms. And the delay with the minimum QRS width was mainly in 5 ms-5 ms, 25 ms-25 ms, and 40 ms-25 ms. The optimal MPP configuration increased CI compared to the MPP setting that produced the minimum CI (4.5 ± 1.3 vs. 2.8 ± 1.0 L/min/m2, P < 0.001). The QRS width of the optimized MPP was narrower than the MPP setting that produced the maximum QRS width (127 ± 20 vs. 160 ± 29 ms, P < 0.001).

CONCLUSION

Delay optimization improves hemodynamic response and ventricular contraction synchronicity. The delay of 25 ms-25 ms may be the optimal setting for most MPP patients.

Clinical outcome of left ventricular multipoint pacing versus conventional biventricular pacing in cardiac resynchronization therapy: a systematic review and meta-analysis

Cardiac resynchronization therapy (CRT) is an effective treatment for selected patients with systolic heart failure. Unlike conventional biventricular pacing (BIP), the left ventricular multipoint pacing (MPP) can increase the number of left ventricular pacing sites via a quadripolar lead positioned in the coronary sinus. This synthetic study was conducted to integratively and quantitatively evaluate the clinical outcome of MPP in comparison with BIP. We systematically searched the databases of EMBASE, Ovid medline, and Cochrane Library through May 2018 for studies comparing the clinical outcome of MPP with BIP in the patients who accepted CRT. Hospitalization for reason of heart failure, left ventricular eject fraction (LVEF), CRT response, all-cause morbidity, and cardiovascular death rate was collected for meta-analysis. A total of 11 studies with 29,606 participants were included in this meta-analysis. Compared with BIP group, MPP decreased heart failure hospitalization (OR, 0.41; 95% CI, 0.33 to 0.50; P < 0.00001), improved LVEF (mean difference, 4.97; 95% CI, 3.11 to 6.83; P < 0.00001), increased CRT response (OR, 3.64; 95% CI, 1.68 to 7.87; P = 0.001), and decreased all-cause morbidity (OR, 0.41; 95% CI, 0.26-0.66; P = 0.0002) and cardiovascular death rate (OR, 0.21; 95% CI, 0.11-0.40; P < 0.00001). The published literature demonstrates that MPP was more effective than BIP in the heart failure patients who accepted cardiac resynchronization therapy.

Multisite pacing via a quadripolar lead for cardiac resynchronization therapy

Cardiac resynchronization therapy is challenging. Up to 40% of patients are non-responder. Multisite pacing via a quadripolar lead, also called multipoint/multipole pacing (MPP), is a debated alternative. In this review, we summarize evidence in the literature, tips and pitfalls related to MPP programming, and the different algorithms of MPP in different manufacturers.

How to maximize QRS narrowing

BACKGROUND

Cardiac resynchronization therapy (CRT) resulting in maximal QRS narrowing may be associated with improved outcomes.

METHODS

Various atrioventricular (AV) delay settings, including the new SyncAV™ algorithm (St. Jude Medical/Abbott, St. Paul, MN, USA), aimed at maximal QRS narrowing were tested in an 81-year old CRT recipient.

RESULTS

Maximal QRS narrowing from 160 to 100 ms was achieved with a manually programmed value of SyncAV™ -30 ms. At 2 months, the patient proved to be a CRT super-responder.

CONCLUSION

SyncAV™ algorithm is a new way for effective QRS narrowing with potentially improved outcomes.

Benefits of Multisite/Multipoint Pacing to Improve Cardiac Resynchronization Therapy Response

This article provides a general overview of the underlying mechanisms that support pacing from more discrete points and/or a wider vector (multisite and multipoint pacing) to improve left ventricular resynchronization. We performed a critical overview of the current literature and to identify some remaining knowledge gaps to spur further research. It was not our goal to provide a systematic review with a comprehensive bibliography, but rather to focus on selected publications that, in our opinion, have either expertly reviewed a specific aspect of cardiac resynchronization therapy or have been landmark studies in the field.

Cardiac resynchronization therapy by multipoint pacing improves response of left ventricular mechanics and fluid dynamics: a three-dimensional and particle image velocimetry echo study

Aims

To characterize the effect of multipoint pacing (MPP) compared to biventricular pacing (BiV) on left ventricle (LV) mechanics and intraventricular fluid dynamics by three-dimensional echocardiography (3DE) and echocardiographic particle imaging velocimetry (Echo-PIV).

Methods and results

In 11 consecutive patients [8 men; median age 65 years (57-75)] receiving cardiac resynchronization therapy (CRT) with a quadripolar LV lead (Quartet,St.Jude Medical,Inc.), 3DE and Echo-PIV data were collected for each pacing configuration (CRT-OFF, BiV, and MPP) at follow-up after 6 months. 3DE data included LV volumes, LV ejection fraction (LVEF), strain, and systolic dyssynchrony index (SDI). Echo-PIV was used to evaluate the directional distribution of global blood flow momentum, ranging from zero, when flow force is predominantly along the base-apex direction, up to 90° when it becomes transversal. MPP resulted in significant reduction in end-diastolic and end-systolic volumes compared with both CRT-OFF (P = 0.02; P = 0.008, respectively) and BiV (P = 0.04; P = 0.03, respectively). LVEF and cardiac output were significant superior in MPP compared with CRT-OFF, but similar between MPP and BiV. Statistical significant differences when comparing global longitudinal and circumferential strain and SDI with MPP vs. CRT-OFF were observed (P = 0.008; P = 0.008; P = 0.01, respectively). There was also a trend towards improvement in strain between BiV and MPP that did not reach statistical significance. MPP reflected into a significant reduction of the deviation of global blood flow momentum compared with both CRT-OFF and BiV (P = 0.002) indicating a systematic increase of longitudinal alignment from the base-apex orientation of the haemodynamic forces.

Conclusion

These preliminary results suggest that MPP resulted in significant improvement of LV mechanics and fluid dynamics compared with BiV. However, larger studies are needed to confirm this hypothesis.

Multipoint pacing via a quadripolar left-ventricular lead: preliminary results from the Italian registry on multipoint left-ventricular pacing in cardiac resynchronization therapy (IRON-MPP)

Aims

This registry was created to describe the experience of 76 Italian centres with a large cohort of recipients of multipoint pacing (MPP) capable cardiac resynchronization therapy (CRT) devices.

Methods and results

A total of 507 patients in whom these devices had been successfully implanted were enrolled between August 2013 and May 2015. We analysed: (i) current clinical practices for the management of such patients, and (ii) the impact of MPP on heart failure clinical composite response and on the absolute change in ejection fraction (EF) at 6 months. Multipoint pacing was programmed to ‘ON’ in 46% of patients before discharge. Methods of optimizing MPP programming were most commonly based on either the greatest narrowing of the QRS complex (38%) or the electrical delays between the electrodes (34%). Clinical and echocardiographic follow-up data were evaluated in 232 patients. These patients were divided into two groups according to whether MPP was programmed to ‘ON’ (n = 94) or ‘OFF’ (n = 138) at the time of discharge. At 6 months, EF was significantly higher in the MPP group than in the biventricular-pacing group (39.1 ± 9.6 vs. 34.7 ± 7.6%; P < 0.001). Even after adjustments, early MPP activation remained an independent predictor of absolute increase in LVEF of ≥5% (odds ratio 2.5; P = 0.001). At 6 months, an improvement in clinical composite score was recorded in a greater proportion of patients with MPP-ON than in controls (56 vs. 38%; P = 0.009). On comparing optimal MPP and conventional vectors, QRS was also seen to have decreased significantly (P < 0.001).

Conclusion

This study provides information that is essential in order to deal with the expected increase in the number of patients receiving MPP devices in the coming years. The results revealed different practices among centres, and establishing the optimal programming that can maximize the benefit of MPP remains a challenging issue. Compared with conventional CRT, MPP improved clinical status and resulted in an additional increase in EF.

Clinical Trial Registration

http://www.clinicaltrial.gov/. Unique identifier: NCT02606071.

Hemodynamic comparison of different multisites and multipoint pacing strategies in cardiac resynchronization therapies

PURPOSE

In order to increase the responder rate to CRT, stimulation of the left ventricular (LV) from multiple sites has been suggested as a promising alternative to standard biventricular pacing (BIV). The aim of the study was to compare, in a group of candidates for CRT, the effects of different pacing configurations-BIV, triple ventricular (TRIV) by means of two LV leads, multipoint (MPP), and multipoint plus a second LV lead (MPP + TRIV) pacing-on both hemodynamics and QRS duration.

METHODS

Fifteen patients (13 male) with permanent AF (mean age 76 ± 7 years; left ventricular ejection fraction 33 ± 7%; 7 with ischemic cardiomyopathy; mean QRS duration 178 ± 25 ms) were selected as candidates for CRT. Two LV leads were positioned in two different branches of the coronary sinus. Acute hemodynamic response was evaluated by means of a RADI pressure wire as the variation in LVdp/dtmax.

RESULTS

Per patient, 2.7 ± 0.7 veins and 5.2 ± 1.9 pacing sites were evaluated. From baseline values of 998 ± 186 mmHg/s, BIV, TRIV, MPP, and MPP-TRIV pacing increased LVdp/dtmax to 1200 ± 281 mmHg/s, 1226 ± 284 mmHg/s, 1274 ± 303 mmHg, and 1289 ± 298 mmHg, respectively (p < 0.001). Bonferroni post-hoc analysis showed significantly higher values during all pacing configurations in comparison with the baseline; moreover, higher values were recorded during MPP and MPP + TRIV than at the baseline or during BIV and also during MPP + TRIV than during TRIV. Mean QRS width decreased from 178 ± 25 ms at the baseline to 171 ± 21, 167 ± 20, 168 ± 20, and 164 ± 15 ms, during BIV, TRIV, MPP, and MPP-TRIV, respectively (p < 0.001).

CONCLUSIONS

In patients with AF, the acute response to CRT improves as the size of the early activated LV region increases.

Multipoint Pacing versus conventional ICD in Patients with a Narrow QRS complex (MPP Narrow QRS trial): study protocol for a pilot randomized controlled trial

Background

Despite an intensive search for predictors of the response to cardiac resynchronization therapy (CRT), the QRS duration remains the simplest and most robust predictor of a positive response. QRS duration of ≥ 130 ms is considered to be a prerequisite for CRT; however, some studies have shown that CRT may also be effective in heart failure (HF) patients with a narrow QRS (<130 ms). Since CRT can now be performed by pacing the left ventricle from multiple vectors via a single quadripolar lead, it is possible that multipoint pacing (MPP) might be effective in HF patients with a narrow QRS. This article reports the design of the MPP Narrow QRS trial, a prospective, randomized, multicenter, controlled feasibility study to investigate the efficacy of MPP using two LV pacing vectors in patients with a narrow QRS complex (100–130 ms).

Methods

Fifty patients with a standard ICD indication will be enrolled and randomized (1:1) to either an MPP group or a Standard ICD group. All patients will undergo a low-dose dobutamine stress echo test and only those with contractile reserve will be included in the study and randomized. The primary endpoint will be the percentage of patients in each group that have reverse remodeling at 12 months, defined as a reduction in left ventricular end-systolic volume (LVESV) of >15% from the baseline.

Discussion

This feasibility study will determine whether MPP improves reverse remodeling, as compared with standard ICD, in HF patients who have a narrow QRS complex (100–130 ms).

Trial registration

ClinicalTrials.gov, NCT02402816. Registered on 25 March 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1698-1) contains supplementary material, which is available to authorized users.

Haemodynamic effects of cardiac resynchronization therapy using single-vein, three-pole, multipoint left ventricular pacing in patients with ischaemic cardiomyopathy and a left ventricular free wall scar: the MAESTRO study

AIMS

The clinical response to cardiac resynchronization therapy (CRT) is variable. Multipoint left ventricular (LV) pacing could achieve more effective haemodynamic response than single-point LV pacing. Deployment of an LV lead over myocardial scar is associated with a poor haemodynamic response to and clinical outcome of CRT. We sought to determine whether the acute haemodynamic response to CRT using three-pole LV multipoint pacing (CRT3P-MPP) is superior to that to conventional CRT using single-site LV pacing (CRTSP) in patients with ischaemic cardiomyopathy and an LV free wall scar.

METHODS AND RESULTS

Sixteen patients with ischaemic cardiomyopathy [aged 72.6 ± 7.7 years (mean ± SD), 81.3% male, QRS: 146.0 ± 14.2 ms, LBBB in 14 (87.5%)] in whom the LV lead was intentionally deployed straddling an LV free wall scar (assessed using cardiac magnetic resonance), underwent assessment of LV + dP/dtmax during CRT3P-MPP and CRTSP. Interindividually, the ΔLV + dP/dtmax in relation to AAI pacing with CRT3P-MPP (6.2 ± 13.3%) was higher than with basal and mid CRTSP (both P < 0.001), but similar to apical CRTSP. Intraindividually, significant differences in the ΔLV + dP/dtmax to optimal and worst pacing configurations were observed in 10 (62.5%) patients. Of the 8 patients who responded to at least one configuration, CRT3P-MPP was optimal in 5 (62.5%) and apical CRTSP was optimal in 3 (37.5%) (P = 0.0047).

CONCLUSIONS

In terms of acute haemodynamic response, CRT3P-MPP was comparable an apical CRTSP and superior to basal and distal CRTSP. In the absence of within-device haemodynamic optimization, CRT3P-MPP may offer a haemodynamic advantage over a fixed CRTSP configuration.