VV Delay Research Articles

Short term outcome of different lower pacing rates in patients with recently implanted CRT

Abstract Funding Acknowledgements Type of funding sources: None. Background Cardiac Resynchronization Therapy (CRT) is a well-established treatment for patients with congestive heart failure, impaired ejection fraction and QRS duration more than 130 msec. Around one third of patients remains to be non-responders. Several parameters have been tested aiming at improving the response rate. Purpose We aim at comparing the effect of two bi-ventricularly base pacing rates (DDD 60 Bpm vs DDD 80 Bpm) on the composite endpoint of mortality and hospitalization due to heart failure. Methods We included patients with recently implanted CRT, all patients had LBBB, QRS duration more than 130 msec and ejection fraction less than 35%. Patients were randomized using randomization table into two groups (DDD 60 bpm and DDD 80 bpm). Patients with atrial fibrillation, active coronary artery disease and those who refused to sign a consent were excluded from the study. Patients were followed 3 months after randomization and then every 6 months thereafter. CRT programming was done, the following pacing parameters were standardized for all patients as per protocol: Mode of pacing was set at DDD, sensor was set as passive, VV delay at 0msec, sensed AV delay at 120ms and paced AV delay at 150ms. Dynamic AV and VV delay optimization algorithms were intentionally turned off. Results Fifty-one patients were enrolled, 45 patients were included in the final analysis (one died before the randomization, two patients were excluded due to average heart more than 80 beats/min at the time of randomization and three were lost to follow up). Mean age was 51.67 ± 11.1 years, 23 patients (51.1%) were females. Thirty-seven patients (82.2%) had dilated Cardiomyopathy, 16 patients (35.6%) had New York heart association (NYHA) functional class (FC) III heart failure (HF) and 29 patients (64.4%) had NYHA class IV (ambulant) HF. At baseline, Minnesota living with heart failure questionnaire score was (52.56 ± 14.3), six minutes-walk distance was 242 ± 95.9 meters and EF was 24.6± 7.4%. Patients were followed for mean duration of 23.2 ± 11.5 months. More patients reached the primary endpoint of death or hospitalization due to heart failure in the DDD 80 bpm group [ 3 (13.6%) vs 13 (56.5%), P=0.003]. This was driven mainly by hospitalization due to heart failure. Death was numerically higher in the DDD 80 group but this was not statistically significant [1 (4.5%) vs 4 (17.4%), P=0.18]. Patients in DDD 60 group had significant improvement in the 6MWD, NYHA functional class, EF % and Minnesota living with heart failure score compared to non-significant improvement in the DDD 80 group. (Table 1) Conclusions In CRT recipients, Base pacing rate 60 beats/min shows less incidence of the composite endpoint of mortality and hospitalization due to heart failure and base pacing rate 80 beats/min could potentially be harmful.

Right ventricular cardiac resynchronization therapy in patients with right ventricular conduction delay and heart failure

Right ventricular cardiac resynchronization therapy in patients with right ventricular conduction delay and heart failure

Inadvertent QRS prolongation by an optimization device-based algorithm in patients with cardiac resynchronization therapy.

Device-based algorithms offer the potential for automated optimization of cardiac resynchronization therapy (CRT), but the process for accepting them into clinical use is currently still ad-hoc, rather than based on pre-clinical and clinical testing of specific features of validity. We investigated how the QuickOpt-guided VV delay (VVD) programming performs against the clinical and engineering heuristic of QRS complex shortening by CRT. A prospective, 2-center study enrolled 37 consecutive patients with CRT. QRS complex duration (QRSd) was assessed during intrinsic atrioventricular conduction, synchronous biventricular pacing, and biventricular pacing with QuickOpt-proposed VVD. The measurements were done manually by electronic calipers in signal-averaged and magnified 12-lead QRS complexes. Native QRSd was 174 ± 22 ms. Biventricular pacing with empiric AVD and synchronous VVD resulted in QRSd 156 ± 20 ms, a significant narrowing from the baseline QRSd by 17 ± 27 ms, P = 0.0003. In 36 of 37 patients, the QuickOpt algorithm recommended left ventricular preexcitation with VVD of 42 ± 18 ms (median 40 ms; interquartile range 30-55 ms, P <0.00001). QRSd in biventricular pacing with QuickOpt-based VVD was significantly longer compared with synchronous biventricular pacing (168 ± 25 ms vs. 156 ± 20 ms; difference 12 ± 11ms; P <0.00001). This prolongation correlated with the absolute VVD value (R = 0.66, P <0.00001). QuickOpt algorithm systematically favours a left-preexcitation VVD which translates into a significant prolongation of the QRSd compared to synchronous biventricular pacing. There is no reason to believe that a manipulation that systematically widens QRSd should be considered to optimize physiology. Device-based CRT optimization algorithms should undergo systematic mechanistic pre-clinical evaluation in various scenarios before they are tested in large clinical studies.

Accuracy of non-invasive anatomical lead localization in CRT patients: BSPM vs 12-lead ECG

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Grant agency AZV, Ministry of Health of the Czech Republic Background Non-invasive, inverse ECG (iECG), estimating the cardiac activation from ECG signals, may be useful both to support CRT implant and optimization. However, most iECG strategies require a 32-250 electrode body surface potential mapping (BSPM), limiting their clinical utility. Objective This proof of concept study evaluates the accuracy of our novel PaceView iECG method to localize the LV/RV pacemaker lead to the cardiac anatomy using either a 96-electrode BSPM or the 12-lead ECG. Methods PaceView generates activation sequences in combination with the equivalent double layer source model to simulate the corresponding ECG signals. An initial activation sequence is iteratively optimized to match simulated and measured ECG signals. A BSPM with 96 electrodes and CT were recorded for every patient with implanted CRT. The CT was used to create patient-specific heart/torso model and to localize the ECG electrodes and CRT leads. From a BSPM, 9 signals were selected to obtain the 12-lead ECG. Both BSPM and 12-lead ECG were used to localize the RV/LV lead as the earliest ventricular activation site. Results In this study 14 consecutive patients with dilated cardiomyopathy were enrolled: mean age 58±9 years, 7 females. The localization error for the RV/LV lead was 10.4±5.4 (max 22) / 11.3±5.5 (max 20.4) mm using the 12 lead ECG and 11.7±6.1 (max 26.2) / 13.5±5.8 (max 24.5) mm for the BSPM. The time used for a 3D activation map computation was 0.9-1.8 s. Conclusion Our preliminary results show that the non-invasive lead localization error, using the 12-lead ECG, is small and comparable with a 96-lead BSPM. Therefore PaceView might be clinically beneficial, by actively localizing the LV/RV pacing sites during CRT implant, and optimize AV or VV delays at CRT follow-ups.

Usefulness of Optimization of Interventricular Delay Using an Electrical Cardiometry Method in Patients with Cardiac Resynchronization Therapy Implantation.

There are no studies examining interventricular (VV) delay optimization by an electrical cardiometry method in relation to subsequent cardiac function in cardiac resynchronization therapy (CRT) -implanted patients. This study aimed to compare the VV delay in CRT-implanted patients by the dp/dt and electrical cardiometry and to examine the optimization of VV delay and improvement of cardiac function. We examined 19 consecutive CRT-implanted patients. The protocol included biventricular stimulation with either simultaneous or sequential pacing, and we evaluated systolic volume (SV) using an electrical cardiometry and the dp/dt of the left ventricle. The optimal VV delay was determined by the maximum SV using the electrical cardiometry. Two groups were defined, those whose increase in SV was at or above the median and those whose SV increase was below the median; changes in left ventricular ejection fraction (LVEF). The correlation between the VV delay optimized by the electrical cardiometry and dp/dt methods was high (R = 0.61, P = 0.006). Compared to the baseline SV (43.4 mL), the SV increased to 47.8 mL with simultaneous biventricular pacing (versus baseline P = 0.008) and further increased to 49.8 mL with optimized VV delay (versus simultaneous biventricular pacing P = 0.020). LVEF after 6 months significantly improved in the above-median SV increase group (37.6 versus 28.2%, P = 0.041), but not in the below-median SV increase group (26.5 versus 26.5%, P = 0.985). In conclusion, the optimal VV delay by electrical cardiometry method was almost concordant with that by the dp/dt method. Cardiac function significantly improved in the group with the above-median SV increase.

Reverse cardiac remodeling in patients with dilated cardiomyopathy post Cardiac Resynchronization Therapy (CRT) and its clinical implication

Aim: To track the reverse cardiac remodeling in patients with dilated cardiomyopathy post cardiac resynchronization therapy (ON and OFF modes) and its implication on patients clinical condition emphasizing the factors achieving that remodeling. Patients and Methods: 30 patients indicated for the device were enrolled and studied before and three to six months after device insertion by history taking, clinical examination, transthoracic echocardiogram, ECG and six minutes' walk test. Results: 30 patients (23 males and 7 females, mean age (54.50 ± 6.24years) with implanted CRT. All patients were in sinus rhythm, QRS duration ≥120 ms and LBBB with dilated cardiomyopathy (ischemic etiology was excluded by coronary angiography in patients having risk factors for IHD). There was clinical response to CRT as NYHA class improved p < 0.001 and 6 min walk test p < 0.001, electrocardiographically, there were significant differences in HR, PR interval, QRS duration ,axis and morphology between pre and post CRT measurements (P<0.001) and echocardiographic response as LV volume improved in 80%, EF in 76.6% and change (∆QRSD) significantly correlated with changes in NYHA, LVEDD, LVESD, and LVEF. s. Area under the curve was 0.824 for ∆QRSD (p=0.005), ∆QRSD of ≥-20 ms as a cutoff value had high specificity for predicting both clinical and Echocardiographic response. Coronary sinus lead selection and positioning had a major role in achieving that remodeling with best response was shown with the lateral veins (70 % of responders ) and worst response with mid vein ( 65 % of non- responders);Achieving that targeted significant ∆QRSD of ≥-20 ms sometimes required a more than usual programmable VV delay up to 60 ms in some patients. Conclusion: Reverse cardiac remodeling post CRT in patients with DCM in both (CRT ON + OFF modes ) was associated with a significant improvement in patients clinical conditions with subsequent reduction of the incidence of their need to hospital admissions.

The back-up lead in his bundle pacing: evolution over the years

Abstract Background His bundle pacing (HBP) can be affected by high thresholds and low sensing. Thus, in selected patients including a back-up lead is advisable. Objective Single-centre retrospective analysis of a large HBP experience, focusing on the back-up lead utilization over the years. Methods 677 pts (76±8 years; 433 males) were implanted with HBP from 2004 to 2019 July. The pts received S-HBP (67%) or NS-HBP by the 3830 lead. The pacing indications were AV block 54%, sinus node disease 17%, slow atrial fibrillation 23%, heart failure 6%. Ischemic cardiopathy was found in 26%; hypertension in 83%, diabetes in28% pts. Baseline QRS duration was 123±32 ms and EF 56±12%. Results 266 (39%) pts received the back-up lead. In sinus rhythm we implanted 3-chamber PM (His lead:LV port; VV delay 80 ms: His pulses and apical pacing during the refractory period). 30 pts (11%) received a particular type of 3-chamber PM which provides back-up pacing only if His capture fails, thus saving energy. In atrial fibrillation 2-chamber PM was implanted (His lead: atrial port, DVI). We recorded a significant decrease of back-up lead use over the years, strictly related to operators/centre experience (&amp;gt;70% during the first years, nearly 10% during the last year). The C315 fixed curve sheath, strongly contributed to the rapid reduction of back-up lead use thanks to better lead fixation and stability. Conclusion The back-up lead utilization is progressively decreasing. It is strictly related to the operator/centre experience. The presence of the back-up lead could strengthen the Hisian pacing reliability, potentially impacting pacing indication even in advanced conduction disturbances and saving device longevity. Funding Acknowledgement Type of funding source: None

Impact of interventricular delay on repolarization parameters in patients with biventricular pacing

A 48-year-old man who was previously a responder to cardiac resynchronization therapy (CRT) presented with worsening of heart failure and reduction in the percentage biventricular (BiV) pacing. Device interrogation revealed T-wave oversensing that was eliminated by optimizing the interventricular (VV) delay. Compared to simultaneous BiV pacing, both sequential left ventricle-right ventricle (LV-RV) and univentricular LV pacing shortened the QTc, T peak-end intervals and reduced the T wave amplitude. Modification of VV delays can result in changes in wavefront of activation and thereby affect ventricular repolarization patterns.

Usefulness of Hemodynamic Device-Based Optimization in Heterogeneous Patients Implanted with Cardiac Resynchronization Therapy Defibrillator.

Optimization of the atrioventricular (AV) and interventricular (VV) timings of the CRT is the most supposed correctable variable to improve the rate of CRT responder. The aim of the present study has been to evaluate if there is a specific subgroup of patients who can actually benefit the most from a hemodynamic optimization of AV. This is a prospective, observational single-center study that enrolled consecutive patients with clinical indication for CRT; all patients were implanted with CRT-D devices with SonR technology, able to automatically adjust AV and VV delay on a weekly basis. Among 57 patients, 39 (69%) showed a LVESV reduction > 15%. The SonR was able to modify the pacing parameters, but an increase of left atrial diameter was associated to a reduced AV variability, suggesting that an impaired left atrial function could potentially reduce the ability of the SonR algorithm to adjust the correct timing of pacing. Graphical abstract Patients with respectively a high (A) and low (B) AV timing variability, among several parameters that could potentially influence the AV timing, only left atrial dimensions demonstrated a significant impact. In fact an increase of left atrial diameter was associated to a reduced AV variability, suggesting that an impaired left atrial function could potentially reduce the ability of the SonR algorithm to adjust the correct timing of pacing.

Automatic Continuous CRT Optimization to Improve Hemodynamic Response: An Italian Single-Center Experience

Background. Optimization of cardiac resynchronization therapy (CRT) settings after implant can improve response to therapy. In this Italian single-center experience, we investigated the rate of hemodynamic and clinical response in heart failure patients treated with continuously and automatically optimized CRT. Methods. Patients were selected from June 2015 to April 2017 according to the most recent CRT guidelines; all were in sinus rhythm at implant and received a CRT-defibrillator system equipped with SonR, which automatically optimizes AV and VV delays every week. SonR was activated just after implant and remained active during follow-up. The rate of hemodynamic response (R-HR) was defined as ΔLVEF&gt;5%, super-response (R-HSR) as ΔLVEF&gt;15%, and clinical response as a negative transition of NYHA class≥−1 at 6 months follow-up vs. baseline (preimplant). Results. Mean follow-up for the 31 patients (aged 69.9±9.4 years; 61% male; NYHA class II/III 19%/81%; ischemic etiology 65%) was 6±0.7 months. At baseline, LVEF was 29.1%±4.7% and QRS duration 146±13 ms. LBBB morphology was observed in 65%. At 6 months, R-HR was 74% (23/31), R-HSR 32% (10/31), and clinical response rate 77% (24/31). Hemodynamically, patients with ischemic etiology benefited more than those without ischemic etiology, both in terms of response (80% versus 64%) and super-response (35% versus 27%). Conclusions. Continuous automatic weekly optimization of CRT over 6 months consistently improved R-HR, R-HSR, and clinical response in NYHA class II/III heart failure patients versus baseline. Patients with ischemic etiology in particular may benefit hemodynamically from this type of CRT optimization.

P1583 Usefulness of remote intrathoracic impedance alerts for echo-guided CRT optimization

Abstract Background Cardiac resynchronisation therapy (CRT) is a strong recommendation in heart failure (HF) patients having sinus rhythm, left bundle branch block, QRS duration ≥ 120 ms and left ventricular (LV) ejection fraction (EF) ≤ 35%, despite optimized medication. Echocardiographic parameters still have a controversial role in the selection of patients ongoing CRT, and no single parameter is recommended to identify a positive CRT response. Even their role in the management after implantation remains still troubleshooting. Atrioventricular (AV) and interventricular (VV) delay reprogramming could be a variable that may influence CRT outcome and, although a systematic AV and VV optimization is not required, it could be useful in selected patients. Remote monitoring networks allow HF patients having a CRT device to be constantly monitored, and notifications of some intrathoracic impedance indexes, may be helpful in the management of HF patients. Purpose To evaluate the usefulness of intrathoracic impedance notifications in the selection of HF patients to have echo-guided AV and/or VV delays optimization, the following study was undertaken. Methods 27 CRT patients having an intrathoracic impedance enabled remote monitoring, with at least one impedance notification during the first six months from implantation, were considered for study. The primary endpoint was a composite of improvement in NYHA functional class and EF, reduction of LV end-systolic volume and rehospitalization for decompensated HF. Secondary endpoint was the effectiveness of echo-guided dealys optimization based on intrathoracic impedance alerts. The AV delay optimization was mainly driven by mitral inflow pattern, whereas VV delay optimization was guided by the assessment of LV synchrony using color Tissue Doppler Imaging (TDI). Patients were weekle evaluated through remote monitoring network over a six-month follow-up. LVEF and LV end-systolic volume were determind at baseline and after six months. Results After the six-month follow-up, an improvement of at least 1 NYHA functional class was obtained in 23 patients (85%), while 2 patients (7.4%) experienced an improvement of two NYHA classes. In 21 Patients (77.7%) LVEF increased at least 5%. Optimization was associated with an average 11.9 ± 6.4% increas in EF, from a mean baseline of 28.2 ± 3.2% to 37.8 ±6.2%. End-systolic volume decreased from 161.56 ± 9.87 ml to 143.22 ± 15.83 ml. Among the 27 patients with impedance alerts at baseline, only 6 (22.2%) reported new notifications during follow-up, with a significant reduction (p &amp;lt; 0.03) after optimization. Conclusions Intrathoracic impedance monitoring improved the selection of non responders feasible to have echo-guided AV and/or VV delays optimization. Functional status and LVEF increased. Although time-consuming, this multidisciplinary network may increase close cooperation between electrophysiologist and HF physicians to better manage HF patients having a CRT system implanted.

P6547The energy cost of His bundle pacing can be curtailed

Abstract Introduction His bundle pacing (HBP) allows physiological ventricular activation and prevents the electrical and mechanical desynchronization generally induced by myocardial stimulation, which can increase the risk of atrial fibrillation and heart failure. On the other hand, reliable HBP capture often requires higher energy than conventional myocardial pacing. This reduces the expected life of the stimulator and might limit the diffusion of HBP in the clinical practice. Purpose Decreasing HBP current drain by careful management of stimulation safety margin and pulse duration. Methods In 28 patients undergoing DDD pacing with HBP, a third lead was implanted in RV apex to provide back-up pacing on demand. HBP and apical leads were connected, respectively, to the V1 and V2 channels of a 3-chamber stimulator. When HBP was effective, apical sensing occurred within the VV delay and prevented V2 stimulation. In contrast, in case of HBP failure, V2 sensing was missing and apical back-up pacing was promptly delivered at the end of the VV delay. The availability of a back-up pulse on demand allowed reducing the HBP safety margin with no risk. Furthermore, the individual HBP strength-duration curve was derived in the aim of optimizing the Hisian pulse parameters, which are the major determinants of the device current drain. Results Correct back-up inhibition by successful HBP and stimulation in the event of capture loss was achieved in all the patients. The latency from Hisian pacing to apical sensing averaged 96±14 ms. According to the pacemaker counters, no back-up pulse was delivered in daily life in 59% of patients. In the remaining, the prevalence of back-up stimulation never exceeded 15% of paced ventricular cycles. The high HBP threshold was essentially due to an increased rheobase (1.2±0.6 V), while the chronaxie ranged from 0.30 to 0.53 ms in 71% of patients (median 0.44 ms), exceeding 0.6 ms only in 29% of the cases. An average current saving of 5.4±3.0 μA was obtained at the expense of a mild reduction in HBP safety margin (from 1.6±0.2 to 1.4±0.1 times). HBP and apical back-up Conclusions Back-up stimulation on demand is a reliable option to decrease HBP current drain and prolong the stimulator service life with full safety. In most of the cases, significant saving can be achieved by pulse shortening, as the chronaxie time is in the same range as with myocardial stimulation and longer pulses are not required. A pulse duration exceeding 0.6 ms is indicated in less than 1/3 of the implants.

Cardiac resynchronization therapy reprogramming to improve electrical synchrony in patients with existing devices

BackgroundOptimal programming of cardiac resynchronization therapy (CRT) has not yet been fully elucidated. A novel algorithm (SyncAV) has been developed to improve electrical synchrony by fusion of the triple wavefronts: intrinsic, right ventricular (RV)-paced, and left ventricular (LV)-paced. MethodsConsecutive patients at a single tertiary care center with a previously implanted CRT device with SyncAV algorithm (programmable negative AV hysteresis) were evaluated. QRS duration (QRSd) was measured during 1) intrinsic conduction, 2) existing CRT pacing as chronically programmed by treating physician, 3) using the device-based QuickOpt™ algorithm for optimization of AV and VV delays, and 4) ECG-based optimized SyncAV programming. The paced QRSd was assessed and compared to intrinsic conduction and between the different modes of programming. ResultsOf 64 consecutive, potentially eligible patients who underwent assessment, 34 patients who were able to undergo SyncAV programming were included. Mean intrinsic conduction QRSd was 163 ± 24 ms. In comparison, the mean QRSd was 152 ± 25 ms (−11.1 ± 19.0) during existing CRT pacing, 160 ± 25 ms (−4.1 ± 25.2) using the QuickOpt™ algorithm and 138 ± 23 (−24.9 ± 17.2) using ECG-based optimized SyncAV programming. SyncAV optimization resulted in significant reductions in QRSd compared to existing CRT pacing (P = 0.02) and QuickOpt™ (P < 0.001). Of the 32% of patients who did not have QRS narrowing with existing CRT, 72% experienced QRS narrowing with SyncAV. ConclusionECG-based atrio-ventricular delay optimization using SyncAV significantly improved electrical synchrony in patients with a previously implanted CRT. Further studies are needed to assess the impact on long-term outcomes.

Shortening of paced QRS duration after electrocardiographic optimization of left ventricular pacing vector in patients treated with Cardiac Resynchronization Therapy

BackgroundChoice of left ventricular pacing vector (LVPV) affects the QRS-duration (QRSd) in patients with Cardiac Resynchronization Therapy (CRT). It is not known whether testing all LVPVs reduces QRSd compared to device-based “standard-programming”. MethodsIn patients implanted with CRT several ECGs were recorded for each usable LVPV (no phrenic nerve stimulation and threshold <3.5 V) and during “standard-programming” after device-based optimization of AV/VV delays. Results22 consecutive patients were included. Average QRSd reduction after CRT + “standard-programming” was 27.3 ± 22 ms. Additional QRSd-reduction was possible in 4 patients by changing the LVPV, and in 5 other patients after optimization of AV- and VV delays without changing LVPV. ConclusionsShortening of QRSd compared to “standard-programming” was possible approximately 40% of these patients treated with CRT by testing all LVPVs and re-optimizing AV/VV delays during follow-up. Studies of clinical effects are needed.

Combination of the best pacing configuration and atrioventricular and interventricular delays optimization in cardiac resynchronization therapy.

Cardiac resynchronization therapy optimization can be pursued by left ventricular pacing vector selection and atrioventricular (AV) and interventricular (VV) delays optimization. The combination of these methods and its comparison with multipoint pacing (MPP) is scarcely studied. Using noninvasive cardiac output (CO) measurement, the best of five left ventricular pacing vectors was determined, then AV and VV delays optimization was applied on top of the best vector. Response to the optimization protocol was defined as a>5% CO increase compared to the standard biventricular configuration. Twenty-two patients (18 men, age 71 ± 9 years) were included. Standard biventricular configuration increased CO compared to baseline (4.65 ± 1.55L/min vs 4.27 ± 1.53 L/min, respectively, P=0.02). The best quadripolar configuration increased CO to 4.85 ± 1.67 L/min (P=0.03 compared to the standard biventricular configuration). AV then VV delay optimization both provided additional benefit (final CO 5.56 ± 2.03 L/min, P=0.001 compared to the best quadripolar configuration). Fifteen (68%) patients responded to the optimization protocol. Anatomical MPP (based on maximal anatomical separation between electrodes) and electrical MPP (based on maximal electrical activation difference between electrodes) were evaluated in 16 patients and yielded a CO similar to that of the optimization procedure. The combination of choosing the best quadripolar pacing configuration and optimizing atrioventricular and interventricular delays resulted in an improvement of cardiac output compared to standard biventricular stimulation in 68% of patients. The final cardiac output was comparable to multipoint pacing.

Cardiac resynchronization therapy – A comparison of VV delay optimization by 3D echocardiography using systolic dyssynchrony index and QRS width assessment at 6 months after CRT implantation

AimThe aim of this study was to compare the setting of interventricular (VV) delay by 3D echocardiography (3DE) using systolic dyssynchrony index (SDI) versus QRS width measurement in new cardiac resynchronization therapy (CRT) recipients. We observed the impact on the reduction of left ventricle volumes and increase in volumetric responders (defined as a ≥15% reduction in left ventricular end-systolic volume (LVESv)) at the 6-month follow-up. MethodsWe included 63 patients with recently implanted CRT in this open-label, randomized trial. Patients were randomized into two groups. VV delay was set by the QRS width in the group 1 (n 31) to obtain the narrowest QRS complex and by SDI in the group 2 (n 32) to achieve the lowest possible value. We evaluated LVESv, left ventricular ejection fraction (LVEF) by 3DE, before CRT implantation and at 6-month follow-up, in all patients. We also obtained clinical parameters and the level of NT-proBNP. ResultsThe second group showed only a trend toward greater reduction of LVESv (−33±55ml vs. −48±43ml; P 0.367), increase in LVEF (+7.3±10.9% vs. +10.2±9.4%; P 0.210) and greater number of volumetric responders (14 vs. 18; P 0.612) compared with the group 1 at 6-month follow-up. There were also no significant differences in clinical outcomes and the level of NT-proBNP. ConclusionIndividual CRT optimization using SDI compared with QRS duration assessment did not reveal any significant differences in echocardiographic parameters and clinical outcomes at 6-month follow-up.

Cardiac resynchronisation therapy optimisation of interventricular delay by the systolic dyssynchrony index: A comparative, randomised, 12-month follow-up study

BackgroundThe aim of our study was to compare the effect of interventricular (VV) delay optimisation in CRT recipients on the basis of systolic dyssynchrony index (SDI) derived from the three-dimensional echocardiography (3DE) versus QRS width assessment on left ventricle volume reduction at the 12-month follow-up. MethodsWe included 63 patients with recently implanted CRT in this randomised, open-label trial. Patients were randomised to VV delay optimisation according to QRS complex width measurement in group 1 (n = 31) to obtain the narrowest QRS complex and SDI in group 2 (n = 32) to achieve its lowest possible value. We evaluated left ventricular end-systolic volume (LVESv), left ventricular ejection fraction (LVEF) and SDI by 3DE before CRT implantation and at a 12-month follow-up in all the patients. We also obtained the New York Heart Association functional class, the 6-minute walk test, the quality of life questionnaire and the level of NT-proBNP. ResultsThe number of volumetric responders was similar in both groups (17 vs. 20, P = 0.786). There were also no significant differences in the reduction of LVESv (−41 ± 55 mL vs. - 61 ± 51 mL, P = 0.111), improvement in LVEF (+10.1 ± 10.6% vs. + 13.0 ± 9.9%, P = 0.213) or differences in clinical outcomes between both groups at the 12-month follow-up. ConclusionCRT optimisation of interventricular delay using SDI compared with QRS width assessment did not reveal any significant difference in terms of volumetric and clinical response at the 12-month follow-up.

Non-invasive, model-based measures of ventricular electrical dyssynchrony for predicting CRT outcomes.

Left ventricular activation delay due to left bundle branch block (LBBB) is an important determinant of the severity of dyssynchronous heart failure (DHF). We investigated whether patient-specific computational models constructed from non-invasive measurements can provide measures of baseline dyssynchrony and its reduction after CRT that may explain the degree of long-term reverse ventricular remodelling. LV end-systolic volume reduction (ΔESVLV) measured by 2D trans-thoracic echocardiography in eight patients following 6 months of CRT was significantly (P < 0.05) greater in responders (26 ± 20%, n = 4) than non-responders (11 ± 16%, n = 4). LV reverse remodelling did not correlate with baseline QRS duration or its change after biventricular pacing, but did correlate with baseline LV endocardial activation measured by electroanatomic mapping (R2 = 0.71, P < 0.01). Patient-specific models of LBBB ventricular activation with parameters obtained by matching model-computed vectorcardiograms (VCG) to those derived from standard patient ECGs yielded LV endocardial activation times that correlated well with those measured from endocardial maps (R2 = 0.90). Model-computed 3D LV activation times correlated strongly with the reduction in LVESV (R2 = 0.93, P < 0.001). Computed decreases due to simulated CRT in the time delay between LV septal and lateral activation correlated strongly with ΔESVLV (R2 = 0.92, P < 0.001). Models also suggested that optimizing VV delays may improve resynchronization by this measure of activation delay. Patient-specific computational models constructed from non-invasive measurements can compute estimates of LV dyssynchrony and their changes after CRT that may be as good as or better than electroanatomic mapping for predicting long-term reverse remodelling.

169-03: Echocardiographic Vs Non-invasive Hemodyanamic Optimization of AV and VV delay for Cardiac Resynchronization Therapy: The Prospective, multi-centre, randomized, cross-over, non-inferiority BRAVO study

169-03: Echocardiographic Vs Non-invasive Hemodyanamic Optimization of AV and VV delay for Cardiac Resynchronization Therapy: The Prospective, multi-centre, randomized, cross-over, non-inferiority BRAVO study

0335 : Impact of heart-rate-lowering drugs on automatic AV delay adaptation at exercise in patients implanted with a SONRTM sensor device

We evaluated the impact of heart-rate-lowering drugs (betablokers, Ivabradine and Amiodarone) on the success of AV delay adaptation during exercise in patients implanted with a CRT-D This device is connected to the atrial SonRTipTM lead with a hemodynamic SonR sensor allowing automatic weekly AV and VV delays optimization, at rest and exercise. This prospective study evaluated patients implanted with a SonR CRT-D device in our center between November 2011 and November 2014. Only patients in sinus rhythm with a CRT optimization function programmed “on” were included. Optimization success was evaluated according to the percentage of weeks where the device succeeded AV delay optimization. Twenty-nine patients patients (67.8±9 years; 75.9% M) were included: 14 (48.2%) had an ischemic cardiomyopathy (ICM) and 15 (51.8%) a dilated cardiomyopathy (DCM). QRS duration was 165±19 msec. LVEF was 28±5%. AV delay at rest was 87±14 msec. and at exercise 54±7 msec. Beta-blockers, Amiodarone and Ivabradine were prescribed in respectively 27 (93,1%), 12(41,4%) and 4 (13,7%) patients. In 7 (24,1%) patients AV delay optimization at exercise failed due to chronotropic incompetence): 5 (35,7%) patients in the ICM group and 2 (13,3%) in the DCM group. Beta-blockers were associated to amiodarone in 4 patients, to Ivabradine in 2 patients, and beta-blockers were used alone in one patient. In both groups, the association of betablockers to Ivabradine resulted in a very poor success rate of AV delay optimization during exercise (3% in an ICM patient and 17% in a DCM patient). In patients implanted with a CRT-D device with automatic optimization of AV delay at exercise are also often treated with heart-rate-lowering drugs. Chronotropic incompetence should be anticipated by programming rate responsive algorithm in order to increase automatic AV delay optimization when a SONR™ sensor device is used. The author hereby declares no conflict of interest