Cardiac Resynchronization Therapy Pacing Research Articles

Transvenous versus open chest lead placement for resynchronization therapy in patients with heart failure: comparison of ventricular electromechanical synchronicity.

BackgroundTransvenous lead placement is the standard approach for left ventricular (LV) pacing in cardiac resynchronization therapy (CRT), while the open chest access epicardial lead placement is currently the most frequently used second choice. Our study aimed to compare the ventricular electromechanical synchronicity in patients with heart failure after CRT with these two different LV pacing techniques.MethodsWe enrolled 33 consecutive patients with refractory heart failure secondly to dilated cardiomyopathy who were eligible for CRT in this study. Nineteen patients received transvenous (TV group) while 14 received open chest (OP group) LV lead pacing. Intra- and inter-ventricular electromechanical synchronicity was assessed by tissue Doppler imaging (TDI) before and one year after CRT procedure.ResultsBefore CRT procedure, the mean QRS-duration, maximum time difference to systolic peak velocity among 12 left ventricle segments (LV Ts-12), standard deviation of time difference to systolic peak velocity of 12 left ventricle segments (LV Ts-SD), and inter-ventricular mechanical delay (IVMD) in OP and TV group were 166 ± 17 ms and 170 ± 21 ms, 391 ± 42 ms and 397 ± 36 ms, 144 ± 30 ms and 148 ± 22 ms, 58 ± 25 ms and 60 ± 36 ms, respectively (all P > 0.05). At one year after the CRT, the mean QRS-duration, LV Ts-12, LV Ts-SD, and IVMD in TV and OP group were 128 ± 14 ms and 141 ± 22 ms (P = 0.031), 136 ± 37 ms and 294 ± 119 ms (P = 0.023), 50 ± 22 ms and 96 ± 34 ms (P = 0.015), 27 ± 11 ms and 27 ± 26 ms (P = 0.86), respectively. The LV lead implantation procedure time was 53.4 ± 16.3 min for OP group and 136 ± 35.1 min for TV group (P = 0.016). The mean LV pacing threshold increased significantly from 1.7 ± 0.6 V/0.5 ms to 2.3 ± 1.6 V/0.5 ms (P < 0.05) in TV group while it remained stable in the OP group.ConclusionsCompared to conventional endovascular approach, open chest access of LV pacing for CRT leads to better improvement of the intraventricular synchronization.

Heart rate and dyssynchrony in patients with cardiac resynchronization therapy: a pilot study

Objectives: The objective of this pilot study was to describe the impact of paced heart rate on left ventricular (LV) mechanical dyssynchrony in synchronous compared to dyssynchronous pacing modes in patients with heart failure.Methods: Echocardiography was performed in 14 cardiac resynchronization therapy (CRT) patients at paced heart rates of 70 and 90 bpm in synchronous- (CRT), and dyssynchronous (atrial pacing + wide QRS activation) pacing modes. LV dyssynchrony was quantified using the 12-segment standard deviation model (Ts-SD) derived from Tissue Doppler Imaging. In addition, cardiac cycle intervals were assessed using cardiac state diagrams and stroke volume (SV) and filling pressure were estimated.Results: Ts-SD decreased significantly with CRT at 90 bpm (25 ± 12 ms) compared to 70 bpm (35 ± 15 ms, p = .01), but remained unchanged with atrial pacing at different paced heart rates (p = .96). The paced heart rate dependent reduction in Ts-SD was consistent when Ts-SD was indexed to average Ts and systolic time interval. Cardiac state diagram derived analysis of cardiac cycle intervals demonstrated a significant reduction of the pre-ejection interval and an increase in diastole with CRT compared to atrial pacing. SV was maintained at the higher paced heart rate with CRT pacing but decreased with atrial pacing.Discussion: Due to the small sample size in this pilot study general and firm conclusions are difficult to render. However, the data suggest that pacing at higher heart rates acutely reduces remaining LV dyssynchrony during CRT, but not during atrial pacing with dyssynchronous ventricular activation. These results need confirmation in a larger patient cohort.

Left univentricular pacing for cardiac resynchronization therapy using rate-adaptive atrioventricular delay.

ObjectiveTo evaluate left univentricular (LUV) pacing for cardiac resynchronization therapy (CRT) using a rate-adaptive atrioventricular delay (RAAVD) algorithm to track physiological atrioventricular delay (AVD).MethodsA total of 72 patients with congestive heart failure (CHF) were randomized to RAAVD LUV pacing versus standard biventricular (BiV) pacing in a 1: 1 ratio. Echocardiography was used to optimize AVD for both groups. The effects of sequential BiV pacing and LUV pacing with optimized A-V (right atrio-LV) delay using an RAAVD algorithm were compared. The standard deviation (SD) of the S/R ratio in lead V1 at five heart rate (HR) segments (RS/R-SD5), defined as the “tracking index,” was used to evaluate the accuracy of the RAAVD algorithm for tracking physiological AVD.ResultsThe QRS complex duration (132 ± 9.8 vs. 138 ± 10 ms, P < 0.05), the time required for optimization (21 ± 5 vs. 50 ± 8 min, P < 0.001), the mitral regurgitant area (1.9 ± 1.1 vs. 2.5 ± 1.3 cm2, P < 0.05), the interventricular mechanical delay time (60.7 ± 13.3 ms vs. 68.3 ± 14.2 ms, P < 0.05), and the average annual cost (13,200 ± 1000 vs. 21,600 ± 2000 RMB, P < 0.001) in the RAAVD LUV pacing group were significantly less than those in the standard BiV pacing group. The aortic valve velocity-time integral in the RAAVD LUV pacing group was greater than that in the standard BiV pacing group (22.7 ± 2.2 vs. 21.4 ± 2.1 cm, P < 0.05). The RS/R-SD5 was 4.08 ± 1.91 in the RAAVD LUV pacing group, and was significantly negatively correlated with improved left ventricular ejection fraction (LVEF) (ΔLVEF, Pearson's r = −0.427, P = 0.009), and positively correlated with New York Heart Association class (Spearman's r = 0.348, P = 0.037).ConclusionsRAAVD LUV pacing is as effective as standard BiV pacing, can be more physiological than standard BiV pacing, and can decrease the average annual cost of CRT.

Reevaluating Modality of Cardiopulmonary Exercise Testing in Patients with Heart Failure and Resynchronization Therapy: Relevance of Heart Rate-Adaptive Pacing

BackgroundChronotropic incompetence (CI) in heart failure (HF) patients with cardiac resynchronization therapy (CRT) and activity sensors may vary according to exercise modality. We hypothesized that chronotropic response and exercise capacity differ when HF patients with CRT and heart rate (HR) adaptive pacing are exercised on cycloergometer versus treadmill. Methods and ResultsThis is a crossover study in which stable HF patients with CRT and HR-adaptive pacing triggered by activity sensors underwent maximal symptom-limited cardiopulmonary exercise testing on both a cycloergometer and treadmill. Adjusted percent of HR reserve (%HRR) was calculated as HRR/age-predicted HRR. CI was defined as ≤62% of age-predicted HRR. Among 16 patients (59 ± 10 years, ejection fraction 27 ± 12%, 87% on beta-blockers), prevalence of CI was high irrespective of exercise modality (87.5% on cycloergometer vs 62.5% on treadmill; P = .12). Chronotropic responses were better on the treadmill; %HRR was higher on a treadmill vs cycloergometer (61 ± 26% vs 22 ± 31%; P = .003). Peak oxygen consumption was increased by 24% on a treadmill vs cycloergometer (15.8 vs 12.7 mL/kg/min; P < .0001). ConclusionsIn HF patients with CRT and HR-adaptive pacing, treadmill cardiopulmonary exercise testing enhances chronotropic response, HRR, and peak oxygen consumption compared with a cycloergometer. These findings may have implications in exercise prescription and thresholds for advanced therapies such as heart transplantation and ventricular assist devices.

Device pacing diagnostics overestimate effective cardiac resynchronization therapy pacing results of the hOLter for Efficacy analysis of CRT (OLÉ CRT) study

A high percentage of biventricular (BiV) or left ventricular (LV) pacing in cardiac resynchronization therapy (CRT) devices has been associated with superior clinical outcomes. However, the percent ventricular (%V) pacing reported by CRT devices simply indicates the number of paces the device has delivered and not the proportion of pacing that has captured the LV effectively. The purpose of this study was to determine whether a beat-by-beat evaluation of effective pacing would provide a more accurate evaluation of CRT delivery. An automatic electrogram (EGM)-based algorithm that classifies each LV pace as effective or ineffective based on detection of QS/QS-r morphology on the unipolar LV EGM during pacing was developed and validated. LV EGMs that were recorded by 24-hour Holter from 57 CRT patients were postprocessed. The percent effective CRT (%e-CRT) pacing was calculated by dividing the time spent in e-CRT pacing by the total time of the recording. In this CRT cohort, the average %V pacing (94.8% ± 8%) significantly overestimated the %e-CRT pacing (87.5% ± 23%; P <.001). A significant minority of subjects (18%) had a discrepancy of at least 3 percentage points between %V pacing and %e-CRT pacing (mean 39% ± 41%). Current device pacing diagnostics overestimate the amount of CRT pacing actually delivered. The new algorithm quantifies ineffective CRT pacing, which enables clinicians to identify patients with this issue and to address the reasons behind suboptimal CRT delivery.

Endocardial left ventricular pacing for cardiac resynchronization: systematic review and meta-analysis.

Endocardial left ventricular (LV) pacing for Cardiac Resynchronization Therapy has been proposed as an alternative to conventional LV lead placement via the coronary sinus. In order to assess the relative benefits and risks of this technique, we have performed a meta-analysis of published reports. A systemic search was performed using online databases to identify studies of lead-based endocardial pacing. A random-effects meta-analysis was performed, to assess the rate of complications and clinical response (defined as ≥1 decrease in NYHA class). We selected 23 studies, including 384 patients. The trans-atrial septal technique was used in 20 studies, 1 used the trans-ventricular apical technique, and 2 used the trans-ventricular septal technique. Mean age was 66 years, male 66%, EF 26%, NYHA class 3.0. Procedural success rates were over 95% in all studies. Clinical response was reported by 16 studies for 262 patients, giving a response estimate of 82% (95% CI 71-89%). There was significant heterogeneity, and response in the only large study was 59%. Thromboembolic (TE) complications were reported by all studies, over 22 ±32 months follow up. The rate of stroke was 2.5 events per 100 patient years (95% CI 1.5-4.3), and TIA 2.6 (1.1-6.1). The mortality rate was 4.5 (1.5-13.6) per 100 patient years. LV endocardial pacing appears to be a viable technique when conventional lead placement is not possible. Response rates were heterogeneous but comparable with conventional CRT. There is likely to be a small increase over expected rates of stroke, although included patients were high risk.

Modalities of ventricular pacing for cardiac resynchronization therapy in patients with heart failure: a meta-analysis and systematic review.

IntroductionThis meta-analysis evaluated 14 studies which compared clinical and functional outcomes after different cardiac resynchronization therapy (CRT) modalities.Material and methodsRelevant studies were selected from the Medline, PubMed, Cochrane, and Google Scholar databases until June 27th, 2016. We analyzed and compared the clinical outcomes (peak O2 consumption and LVEF) and functional outcomes (6-min walk distance and quality of life (SF-36)) of HF patients who received different CRT modalities with outcomes in patients who received conventional univentricular therapy.ResultsThere was no significant difference in post-treatment 6-min walking distance between the biventricular (BiV) and left/right univentricular (LUV/RUV) groups (standardized difference in means = 0.049, 95% CI: –0.119 to 0.217, p = 0.566), or between the BiV and triventricular (TriV) groups (standardized difference in means = 0.035, 95% CI: –0.270 to 0.340, p = 0.822). Peak O2 consumption was comparable between BiV and LUV/RUV groups (standardized difference in means = 0.306, 95% CI: –0.002 to 0.614, p = 0.052). Patients in the TriV group had a significant improvement in LVEF compared to the BiV group (standardized difference in means = 0.647, 95% CI: 0.313 to 0.982, p < 0.001).ConclusionsTriV CRT is an attractive alternative to univentricular or BiV pacing for heart failure patients. It is necessary to conduct further large randomized trials to validate our present data.

Two to one CRTD pacing: When the T wave and the P wave interact

We presented a unique phenomenon of 2:1 cardiac resynchronization therapy pacing due to T wave oversensing. Ultimately, by utilizing a unique feature of integrated bipolar sensing, we succeeded to eliminate the T wave oversensing signals, and restore 1:1 CRTD pacing. Importantly, this feature enabled us to overcome the T wave oversensing issue, without the need to decrease the ventricular sensitivity, which could potentially interfere with ventricular arrhythmia detection and appropriate shock delivery when required.

Imaging the Propagation of the Electromechanical Wave in Heart Failure Patients with Cardiac Resynchronization Therapy.

Current electrocardiographic and echocardiographic measurements in heart failure (HF) do not take into account the complex interplay between electrical activation and local wall motion. The utilization of novel technologies to better characterize cardiac electromechanical behavior may lead to improved response rates with cardiac resynchronization therapy (CRT). Electromechanical wave imaging (EWI) is a noninvasive ultrasound-based technique that uses the transient deformations of the myocardium to track the intrinsic EW that precedes myocardial contraction. In this paper, we investigate the performance and reproducibility of EWI in the assessment of HF patients and CRT. EWI acquisitions were obtained in five healthy controls and 16 HF patients with and without CRT pacing. Responders (n = 8) and nonresponders (n = 8) to CRT were identified retrospectively on the basis of left ventricular (LV) reverse remodeling. Electromechanical activation maps were obtained in all patients and used to compute a quantitative parameter describing the mean LV lateral wall activation time (LWAT). Mean LWAT was increased by 52.1 ms in HF patients in native rhythm compared to controls (P< 0.01). For all HF patients, CRT pacing initiated a different electromechanical activation sequence. Responders exhibited a 56.4-ms ± 28.9-ms reduction in LWAT with CRT pacing (P < 0.01), while nonresponders showed no significant change. In this initial feasibility study, EWI was capable of characterizing local cardiac electromechanical behavior as it pertains to HF and CRT response. Activation sequences obtained with EWI allow for quantification of LV lateral wall electromechanical activation, thus providing a novel method for CRT assessment.

Left univentricular pacing for cardiac resynchronization therapy.

This review describes the rationale and published evidence for left univentricular pacing for cardiac resynchronization therapy, gives an overview of the existing optimization algorithms featuring this mode, and discusses future perspectives.

96-63: Long-Term Results OF Left Ventricular Endocardial Pacing For CRT In Patients With Heart Failure Use Puncture Of Interventricular Septum

Background: In last years endocardial left ventricular (LV) pacing for cardiac resynchronization therapy (CRT) became an alternative to epicardial approach. We present our long-term results of LV endocardial pacing for CRT using puncture of interventricular septum (IVS) and apex of LV in 18 pts. Methods and Results: 18 patients - 12 males, age 27–67 years, mean 49+ 7 years, mean NYHA functional class 3.2+ 0.4 with indication for CRT were operated using puncture IVS. 15 of them (83.3%) have had previous failed transvenous attempts. AFib was in 14 pts (77.8%). IVS puncture successfully performed under general anesthesia and intubation guided TEE in 17 of 18 pts (94.4%). This patient operated using thoracotomy and puncture of the apex of LV. All pts post implant received warfarin (INR 2.5-3.5). During mean 11 + 4 months of follow-up (4-17) there were no strokes, transient ischemic attacks and systemic thromboembolism. One patient died (5.9%) from increasing heart failure. All 17 pts had adequate acute sensing (12.1 ± 4 mV) and pacing thresholds parameters (0.72 ± 0.2 V), after 3 and 6, 12 months - 11.1 ± 2.9 mV, 0.99 ± 0.23 V and 10.4 ± 3.2 mV, 1.29 ± 0.20 V, 10.8 ± 2.9 mV, 1.34 ± 0.22 V respectively. Dislocation of the electrode on the third day after procedure occurred in one patients, successfully corrected. 15 of 17 (88.2%) pts were responders with ≥ 1 NYHA class improvement. Ejection fraction (EF) increased from 21 ± 5% to 35 ± 8 after 6 months and to 39 ± 8% after 12 months (p < 0.01) Conclusion: The proposal method technically feasible in most patients, characterized by stable parameters of the stimulation threshold. Adequate endocardial resynchronisation therapy leads to significant improvement of EF and functional status of patients. Administration of anticoagulants allows to minimize thromboembolic complications. This approach can be used for troubled cases if standard CRT implantation fails.

169-05: Atrial high rate episodes are frequently detected in patients with cardiac resynchronization therapy and longer episodes increases the risk of thromboembolic events

Background: Knowledge about the incidence of atrial high rate episodes (AHRE) in patients with cardiac resynchronization therapy (CRT) is limited and conflicting, likewise whether the duration of AHRE have implication for the risk of thromboembolic events (TE). Methods: This observational study included patients who received a CRT device at Aarhus University Hospital between 2000-2010, and with no history of atrial fibrillation. All patients had standard indication for CRT treatment. All device-detected AHRE ≥6 minutes were included, and patients were divided into 3 groups; no AHRE, short AHRE (between 6 minutes and 24 hours) and long AHRE (>24 hours). The annual risk was calculated as events per patient-year with 95% confidence intervals (CI). Results: Of 304 patients, 79 (26%) develop short AHRE and 63 (21%) had long AHRE during a median follow-up of 4.8 years, resulting in an annual risk of short AHRE of 13 (95% CI, 11–15) % and long AHRE of 4 (95% CI, 3–6) %. The mean age was 65 (SD 13) years, mean LVEF was 24 (SD 6) % and median CHA2DS2-VASc score was 3 (IQR 2–5) with no significant difference between the three groups. CRT pacing was lower in patients with long AHRE than those with short or no AHRE (97 (IQR 94–99) vs. 99 (IQR 97–100) vs. 99 (IQR 96–100) %, P < 0.001 and P = 0.44). Anticoagulation therapy was more likely to be initiated in patients with long AHRE than those with short or no AHRE (68 vs. 25 vs. 17%; P < 0.001 and P = 0.12). The annual risk of TE events was similar in patients without AHRE and in patients after the detection of short AHRE, but significantly increased after detection of long AHRE (1.4 (95% CI, 0.9–2.4) % vs. 1.8 (95% CI, 0.8–4.0) % vs. 4.0 (95% CI, 2.0–8.0) %, P = 0.65 and P = 0.03). Conclusion: AHRE ≥6 minutes are detected in nearly half of the patients with no prior atrial fibrillation after CRT implantation, but only AHRE lasting longer than 24 hours are significantly associated with TE events.

Long-term outcome of transvenous pacemaker implantation in infants: a retrospective cohort study.

Evaluation of long-term outcome of transvenous pacemaker (PM) implantation in infants. A retrospective analysis of all transvenous PM implantations in infants <10 kg between September 1997 and October 2001 was made. Indications for PM implantation, age at implantation, and determinants of long-term outcome including cardiac function, PM function, and PM (system) complications were noted. Seven patients underwent transvenous VVI(R) PM implantation. Median age at implantation was 3 days (range: 1 day to 14 months), median weight 3.5 kg (range: 2.3-8.7 kg), and median follow-up 14 years (range: 12.3-16.3 years). Pacemaker indications were congenital complete atrioventricular block (n = 4), long QT syndrome with heart block (n = 2), and post-operative complete atrioventricular block with sinus node dysfunction (n = 1). No procedural complications were noted. Today all patients are alive and symptom free with good PM and cardiac function. Two patients underwent PM generator relocation for imminent skin necrosis and skin traction. Two patients suffered from asymptomatic left subclavian vein occlusion and developed thrombosis on the PM electrode. Three patients were converted to an epicardial PM system, due to atrial perforation after upgrading procedure (n = 1), syncope with need for implantable cardioverter defibrillator implantation (n = 1), and systolic dysfunction with development of dilated cardiomyopathy, which normalized under cardiac resynchronization therapy pacing (n = 1). Two patients needed atrioventricular (AV) valve repair for severe insufficiency. Two patients underwent repositioning of dysfunctional PM leads. In five patients, transvenous leads were removed. Indications were elective lead replacement (n = 1), atrial perforation (n = 1), and switch to an epicardial system (n = 3). Transvenous PM implantation in infants (<10 kg) is associated with a high incidence of vascular occlusion, thrombosis, and severe atrioventricular valve regurgitation during long-term follow-up. We advocate an epicardial approach for PM implantation in small children.

Influence of automatic frequent pace-timing adjustments on effective left ventricular pacing during cardiac resynchronization therapy.

Cardiac resynchronization therapy (CRT) requires effective left ventricular (LV) pacing (i.e. sufficient energy and appropriate timing to capture). The AdaptivCRT™ (aCRT) algorithm serves to maintain ventricular fusion during LV or biventricular pacing. This function was tested by comparing the morphological consistency of ventricular depolarizations and percentage effective LV pacing in CRT patients randomized to aCRT vs. echo-optimization. Continuous recordings (≥20 h) of unipolar LV electrograms from aCRT (n = 38) and echo-optimized patients (n = 22) were analysed. Morphological consistency was determined by the correlation coefficient between each beat and a template beat. Effective LV pacing of paced beats was assessed by algorithmic analysis of negative initial EGM deflection in each evoked response. The %CRT pacing delivered, %effective LV pacing (i.e. % of paced beats with effective LV pacing), and overall %effective CRT (i.e. product of %CRT pacing and %effective LV pacing) were compared between aCRT and echo-optimized patients. Demographics were similar between groups. The mean correlation coefficient between individual beats and template was greater for aCRT (0.96 ± 0.03 vs. 0.91 ± 0.13, P = 0.07). Although %CRT pacing was similar for aCRT and echo-optimized (median 97.4 vs. 98.6%, P = 0.14), %effective LV pacing was larger for aCRT [99.6%, (99.1%, 99.9%) vs. 94.3%, (24.3%, 99.8%), P=0.03]. For aCRT vs. echo-optimized groups, the proportions of patients with ≥90% effective LV pacing was 92 vs. 55% (P = 0.002), and with ≥90% effective CRT was 79 vs. 45%, respectively (P = 0.018). AdaptivCRT™ significantly increased effective LV pacing over echo-optimized CRT.

BLOCK HF: how far does it extend indications for cardiac resynchronization therapy?

The Biventricular versus Right Ventricular Pacing in Heart Failure Patients with Atrioventricular Block (BLOCK HF) trial, published in April 2013 [Curtis AB, Worley SJ, Adamson PB, et al; Biventricular versus Right Ventricular Pacing in Heart Failure Patients with Atrioventricular Block (BLOCK HF) Trial Investigators. Biventricular pacing for atrioventricular block and systolic dysfunction. N Engl J Med 2013; 368:1585-1593], explored whether cardiac resynchronization therapy (CRT) was superior to conventional pacing in patients with conventional indications for pacing, left ventricular dysfunction and NYHA (New York Heart Association) class I-III. The trial took 8 years and a source of concern is selection bias, because participating centers had an average of two patients enrolled per center, per year. Both the internal and external validity of the trial merit some comments. BLOCK HF showed a relatively low treatment effect of CRT as compared with other CRT trials. As a matter of fact, the absolute risk reduction for death or hospitalization because of heart failure was 4.8%, in a relatively long follow-up, with a number needed to treat (NNT) of 21, much higher than the NNT of other CRT trials. We estimate that at least one third of patients in BLOCK HF could meet current indications for CRT. Moreover, the study did not consider the additional risks and costs of CRT versus conventional pacing, both having important implications for cost-effectiveness estimates. For these and other reasons, uncertainties arise as to how far BLOCK HF extends current recommendations for CRT and how much it should be implemented in daily clinical practice.

Impact of cardiac reverse remodeling after cardiac resynchronization therapy assessed by myocardial perfusion imaging on ventricular arrhythmia

BackgroundAlthough cardiac resynchronization therapy (CRT) has been a useful treatment of heart failure, patients with CRT are still in risk of sudden cardiac death due to ventricular arrhythmia. The aim of this study was to investigate the impact of cardiac reverse remodeling after CRT on the prevalence of ventricular tachycardia or fibrillation (VT/VF). Methods and ResultsForty-one heart failure patients (26 men, age 66 ± 10 years), who were implanted with CRT for at least 12 months, were enrolled. All patients received myocardial perfusion imaging (MPI) under CRT pacing to evaluate left ventricle (LV) function, dyssynchrony, and scar. VT/VF episodes during the follow-up period after MPI were recorded by the CRT devices. Sixteen patients (N = 16/41, 39%) were found to have VT/VF. Multivariate Cox regression analysis and receiver operating characteristic curve analysis showed that five risk factors were significant predictors of VT/VF, including increased left ventricle ejection fraction (LVEF) by ≤7% after CRT, low LVEF after CRT (≤30%), change of intrinsic QRS duration (iQRSd) by ≤7 ms, wide iQRSd after CRT (≥121 ms), and high systolic dyssynchrony after CRT (phase standard deviation ≥45.6°). For those patients with all of the 5 risk factors, 85.7% or more developed VT/VF. ConclusionsThe characteristics of cardiac reverse remodeling after CRT as assessed by MPI are associated with the prevalence of ventricular arrhythmia.

ALternate Site Cardiac ResYNChronization (ALSYNC): a prospective and multicentre study of left ventricular endocardial pacing for cardiac resynchronization therapy.

The ALternate Site Cardiac ResYNChronization (ALSYNC) study evaluated the feasibility and safety of left ventricular endocardial pacing (LVEP) using a market-released pacing lead implanted via a single pectoral access by a novel atrial transseptal lead delivery system. ALSYNC was a prospective clinical investigation with a minimum of 12-month follow-up in 18 centres of cardiac resynchronization therapy (CRT)-indicated patients, who had failed or were unsuitable for conventional CRT. The ALSYNC system comprises the investigational lead delivery system and LVEP lead. Patients required warfarin therapy post-implant. The primary study objective was safety at 6-month follow-up, which was defined as freedom from complications related to the lead delivery system, implant procedure, or the lead ≥70%. The ALSYNC study enrolled 138 patients. The LVEP lead implant success rate was 89.4%. Freedom from complications meeting the definition of primary endpoint was 82.2% at 6 months (95% CI 75.6-88.8%). In the study, 14 transient ischaemic attacks (9 patients, 6.8%), 5 non-disabling strokes (5 patients, 3.8%), and 23 deaths (17.4%) were observed. No death was from a primary endpoint complication. At 6 months, the New York Heart Association class improved in 59% of patients, and 55% had LV end-systolic volume reduction of 15% or greater. Those patients enrolled after CRT non-response showed similar improvement with LVEP. The ALSYNC study demonstrates clinical feasibility, and provides an early indication of possible benefit and risk of LVEP. NCT01277783.

Multiple BiV Stimulation Combinations by using Two RV Leads Improve Potential for Response to CRT: Results of the TriV HF ICD Study

Aims: Cardiac resynchronization therapy (CRT) nonresponder rates continue to be approximately 30%. To demonstrate the potential benefit of multiple pacing site combination options, the effect of three CRT pacing configurations with differing right ventricular (RV) lead placements were evaluated. Methods: This single center, randomized, feasibility trial evaluated three CRT pacing configurations with two RV lead positions-RV-apex (“BiV Apex”), RV-septum close to His Bundle (“BiV His”) and RV-apex+RV-septum close to His Bundle (“TriV”)-with a left ventricular (LV) lead. Changes in intraoperative LV dP/dtmax were evaluated and acute response was defined as an increase of ≥10% versus intrinsic rhythm. Chronic measures included the Packer Heart Failure Composite Response score, 6 minute hall walk (6MHW); echocardiographic, electrocardiographic and exercise tolerance parameters, B-type natriuretic peptide (BNP) and Quality of Life. Results: Acute hemodynamic testing was completed in 34/39 patients and resulted in significant increases in LV dP/dtmax in each CRT configuration. Choosing the best of the tested BiV configurations 85% of all patients showed at least one configuration with significant dP/dtmax rise. During follow up, Packer scores improved for the majority (73%) of patients, which was consistent with improvements in QRS width, 6MHW, BNP, ejection fraction, mitral regurgitation, NYHA class, quality of life, CPX workload and peak VO2, but overall there were no significant differences in either acute or chronic response rates between the three configurations. Conclusions: Concomitant multisite pacing at the RV apex and septum nearby His bundle is feasible and effective and may provide an additional option for CRT nonresponders.

Abstract 16450: The Impact of Left Ventricular versus Simultaneous Biventricular Pacing on Structural and Biochemical Reverse Remodeling in Patients With Heart Failure: Insights From the EvAluation of Resynchronization Therapy for Heart Failure (EARTH) Trial

Introduction: Cardiac Resynchronization Therapy (CRT) with simultaneous biventricular pacing (BiVP) is recommended for patients with heart failure and wide QRS, however up to a third of patients do not respond. GREATER-EARTH has demonstrated similar benefits with BiVP or LV pacing (LVP). Herein, we evaluate the effects of these two CRT modes on cardiac remodeling, evaluated by echocardiography and circulating biomarkers. Methods: 121 patients (LVEF≤35% and QRS≥120ms) referred for defibrillator implantation were randomized to BiVP or LVP for consecutive 6-month periods with cross-over. The primary endpoint was the change in LV end-systolic volume (LVESV) between patients with BiVP vs LVP from baseline to 6 months. Secondary endpoints included changes in LVEF, mitral regurgitation, RV and diastolic function. Changes in levels of markers of cardiac remodeling were also compared. Results: Both CRT pacing modes led to remodeling benefits after 6-months of therapy: LVESV decreased from 162±57mL at baseline to 130±63mL with BiVP vs 130±60 mL with LVP (p=0.68 between CRTs), with a positive response (≥15% LVESV reduction) being observed in 49% of patients with BiVP and 33% of LVP, p=0.09. Similarly, RV remodeling (dimension and RV-MPI) was equally improved with both pacing strategies (p=0.69 and p=0.38 respectively, between CRTs). Interestingly, estimated systolic PAP (from 43±14 to 37±10 and 41±14, p=0.008), selected indices of LV diastolic function such as indexed LA volume (p=0.045) and diastolic dysfunction grade (p=0.019), as well as changes in MR grade (p=0.004) were significantly improved only with BiVP. In parallel, there was a non-statistically significant decrease in NT-proBNP, from 2559±3296 to 1554±2092 and 1630±1950 ng/L, with BiVP and LVP respectively (p=0.093) as well as a trend in decreasing PIIINP levels, from 8.3±3.0 to 7.5±2.7 and 7.6±2.3 with BiVP and LVP respectively, p=0.097. Conclusions: In this prospective, multicenter, randomized, double-blind study, both BiVP and LVP resulted in improvements in LV remodelling assessed by echocardiography, while more patients responded to BiVP. BiVP may be superior to LVP to improve multiple aspects of myocardial remodeling and should remain the preferred mode of CRT in patients with advanced HF.

Clinical Outcomes of Cardiac Resynchronization with Epicardial Left Ventricular Lead.

Left ventricular (LV) pacing in cardiac resynchronization therapy (CRT) can be achieved via a transvenous or epicardial route. A surgically implanted epicardial LV (eLV) lead is used after a standard transvenous LV (tLV) lead implantation has failed. However, studies of clinical outcomes in patients with eLV leads and comparisons of outcome between tLV and eLV-CRT are sparse. Therefore, the purpose of this study is to compare clinical response between tLV-CRT and eLV-CRT, as well as to understand the differences within the eLV-CRT population. Forty-four patients received eLV-CRT following unsuccessful attempts of tLV-CRT implantation between 2002 and 2013 at the University of California, San Diego (UCSD) and Mayo Clinics. These patients were matched for age, gender, and etiology of cardiomyopathy in a 1:2 ratio with a cohort of patients who received tLV-CRT during the same time period. During a mean follow-up of 57 months, similar clinical outcomes and survival rate were noted between tLV and eLV-CRT patients (all P > 0.05). Within the eLV-CRT group, dilated cardiomyopathy patients had significant improvement in New York Heart Association class and ejection fraction (both P < 0.05), while ischemic cardiomyopathy patients did not (both P > 0.05). eLV-CRT patients with nonanterior lead location had significantly improved survival (P < 0.001). There was also a trend for improved survival in those with nonapical lead location (P = 0.09). In this case-matched two-centered study, comparable improvements were noted in patients with tLV-CRT and eLV-CRT. Operators should target nonanterior and nonapical locations during eLV-CRT implantation. Use of eLV-CRT should be considered a viable alternative for CRT candidates.