Adaptive Cardiac Resynchronization Therapy Research Articles

Effect of adaptive cardiac resynchronization therapy in heart failure patients with pacemaker dependency

Effect of adaptive cardiac resynchronization therapy in heart failure patients with pacemaker dependency

Right Atrial Septal Lead Enhances the Favorable Effects of the Adaptive Cardiac Resynchronization Therapy Algorithm

The adaptive cardiac resynchronization therapy (CRT) algorithm provides synchronized left ventricular pacing (sLVP). However, ensuring a high sLVP rate is challenging. We assessed the association between the sLVP rate and pacing sites in the right atrium. We evaluated 71 patients who underwent CRT and in whom the adaptive CRT algorithm was applied (53 men; mean age, 66 ± 14 years; median follow-up period, 301 days; IQR: 212-596 days). The atrial pacing leads were positioned in the right atrial (RA) septum in 17 patients (septal group) and in the RA appendage in 54 patients (RA appendage group), with significantly higher sLVP rates in the septal group compared with the RA appendage group (81% ± 30% vs 63% ± 37%; P = 0.045). In patients with first-degree atrioventricular blocks, the sLVP rates tended to be higher in the septal group. Therefore, RA septal pacing increased sLVP rates in patients undergoing CRT.

Evaluation of synchronized left ventricular pacing rate over biventricular pacing in cardiac resynchronization therapy

BackgroundThe adaptive cardiac resynchronization therapy (aCRT) algorithm enables synchronized left ventricular pacing (sLVP) to achieve fusion with intrinsic right ventricular activation. Although sLVP presents benefits over biventricular pacing, the adequate sLVP rate for better clinical outcomes remains unclear. We aimed to assess the association between sLVP rates and clinical outcomes. MethodsOur study cohort included 271 consecutive patients, who underwent CRT implantation between April 2016 and August 2021. ResultsWe evaluated 63 patients on whom we applied the aCRT algorithm [48 men, mean age: 64 ± 14 years; median follow-up period: 316 days (interquartile range: 212–809 days)]. At the 6-month follow-up after CRT implantation, the frequency of CRT responders was 71 % (n = 45). The sLVP rate was significantly higher in responders than in non-responders (75 ± 30 % vs. 47 ± 40 %, p = 0.003). Receiver operating characteristics curve analysis revealed that the optimal cut-off value during the sLVP rate was 59.4 % for the prediction of CRT responders (area under the curve, 0.70; sensitivity, 80 %; specificity, 61 %; positive predictive value, 84 %; and negative predictive value, 55 %). Kaplan–Meier analysis demonstrated that the higher-sLVP group (sLVP ≧59.4 %, n = 43) had a better prognosis (cardiac death and heart failure hospitalization) than the lower-sLVP group (sLVP <59.4 %, n = 20) (log-rank p < 0.001). Multivariate Cox hazard analysis revealed that a higher sLVP rate was associated with a good prognosis (p < 0.001). ConclusionssLVP was associated with CRT response, and a higher sLVP rate (≧59.4 %) was important for good prognosis in patients with aCRT.

Significance of effective cardiac resynchronization therapy pacing for clinical responses: An analysis based on the effective cardiac resynchronization therapy algorithm

High percent ventricular pacing maximizes cardiac resynchronization therapy (CRT) response. An effective CRT algorithm classifies each left ventricular (LV) pace as effective or ineffective on the basis of the detection of QS or QS-r morphology on the electrogram; however, the relationship between percent effective CRT pacing (%e-CRT) and responses is unclear. We aimed to clarify the association between %e-CRT and clinical outcomes. Of the 136 consecutive CRT patients, 49 using the adaptive and effective CRT algorithm with percent ventricular pacing > 90% were evaluated. The primary and secondary outcomes were heart failure (HF) hospitalization and prevalence of CRT responders, defined as patients with an improvement in LV ejection fraction of ≥10% or a reduction in LV end-systolic volume of ≥15% after CRT device implantation, respectively. We divided the patients into the effective group (n = 25) and the less effective group (n = 24) by the median value of %e-CRT (97.4%). During the median follow-up period of 507 days (interquartile range 335-730 days), the effective group had a significantly lower risk of HF hospitalization than did the less effective group as revealed by Kaplan-Meier analysis (log-rank, P = .016). Univariate analysis revealed %e-CRT ≥ 97.4% (hazard ratio 0.12; 95% confidence interval 0.01-0.95; P = .045) as a predictor of HF hospitalization. The effective group had a higher prevalence of CRT responders than did the less effective group (23 [92%] vs 9 [38%]; P < .001). Univariate analysis revealed that %e-CRT ≥ 97.4% (odds ratio 19.20; 95% confidence interval 3.63-101.00; P < .001) was a predictor of CRT response. High %e-CRT is associated with high CRT responder prevalence and low HF hospitalization risk.

Adaptive CRT algorithm and electrical synchrony

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): United Hospital Medical Education and Research Committee, United Hospital Foundation. Background We have previously shown that optimization of cardiac resynchronization therapy (CRT) nonresponders using a novel electrical dyssynchrony mapping (EDM) system significantly improves electrical dyssynchrony, left ventricle (LV) size and systolic function. Whether this methodology can improve electrical dyssynchrony (and potentially LV function) in nonresponder patients programmed with the adaptive CRT (aCRT) algorithm is not known. Purpose To quantify electrical dyssynchrony in CRT nonresponders programmed using aCRT and determine if it can be improved using EDM. Methods We studied 97 patients programmed with the aCRT algorithm at multiple device settings with an ECG system of 9 anterior and 9 posterior electrodes. We quantified electrical dyssynchrony using a measure of wavefront fusion, cardiac resynchronization index (CRI), calculated as % change in area under the curve between all combinations of anterior and posterior electrodes as compared to native LBBB (CRT off). CRI results were displayed on an electrical dyssynchrony map (EDM) showing atrial-to-right ventricle-paced intervals (A-RVp) on the y-axis and atrial-to-left ventricle-paced intervals (A-LVp) on the x-axis. Results Figure 1 shows an EDM for a typical patient with CRI values marked at different programmed settings. Figure 2 shows CRI for 58 patients programmed LV-only by aCRT at baseline (red bars) and 39 patients programmed biventricular (BiV) by aCRT at baseline (blue bars). CRI at baseline was significantly (p≤0.001) higher in patients programmed LV-only vs. those programmed BiV. In both groups programming to LV-only at the optimal atrial-ventricular delay (AVD) and to sequential BiV pacing at the optimal ventricular-ventricular delay (VVD) produced significantly and markedly better CRI as compared to CRI at aCRT baseline settings. In the patients programmed by aCRT at baseline to LV-only, BiV VV=0 at standard device setting (SAV 120 ms) had significantly worse CRI than baseline. Conclusions Electrical dyssynchrony as measured by CRI is better in patients programmed aCRT LV-only than those programmed aCRT BiV. CRI can be improved by 20% or more by using EDM to program patients to LV-only pacing at the optimal AVD or to BiV pacing at the optimal VVD. EDM technology offers the possibility of substantially improving electrical synchrony in nonresponder patients programmed with aCRT.

Abstract 11446: Impact of Higher Synchronized Left Ventricular Pacing Rate for Prognosis on Cardiac Resynchronization Therapy

Background: The adaptive cardiac resynchronization therapy (aCRT) algorithm provides synchronized left ventricular pacing (sLVP) to produce fusion with the intrinsic right ventricular activation in normal atrioventricular (AV) conduction. Although sLVP has benefits over biventricular pacing (BiV), the adequate sLVP rate for better clinical outcome is still unclear. Purpose: The aim of this study was to assess the association between sLVP rate and clinical outcome. Methods: Among our cohort of 271 consecutive patients who had CRT implantation between April 2016 and August 2021, we evaluated 63 CRT patients without considerably prolonged AV conduction to whom we applied the aCRT algorithm (48 males, mean age: 64±14 years old, and the median follow up period: 316 days [interquartile range: 212-809days]). Results: At follow-up 6 months after CRT implantation, the frequency of CRT responder was 71% (n=45). The sLVP rate was significantly higher in responder compared to non-responder (75±30 vs 47±40 %, p=0.003). Receiving operating characteristics (ROC) curve analysis revealed that optimal cut-off value during sLVP rate was 59.4% for prediction of CRT responder (an area under the curve: 0.70, sensitivity: 80%, specificity: 61%, positive predictive value: 84%, and negative predictive value: 55%). Kaplan-Meier analysis demonstrated that higher sLVP group (sLVP≥59.4%, n=43) had better prognosis (cardiac death and heart failure hospitalization) compared to lower sLVP group (sLVP&lt;59.4%, n=20) (log-rank p&lt;0.001) (Figure) and multivariate Cox hazard analysis revealed that higher rate was associated with good prognosis (p&lt;0.001). Conclusion: sLVP was associated with CRT response and higher sLVP rate (≥59.4%) may be important for good prognosis in patient with aCRT.

Impact of synchronized left ventricular pacing rate on risk for ventricular tachyarrhythmias after cardiac resynchronization therapy in patients with heart failure.

The adaptive cardiac resynchronization therapy (aCRT) algorithm automatically produces synchronized left ventricular pacing (sLVP) with intrinsic atrioventricular conduction to improve clinical outcomes. However, relationship between sLVP percentage and risk for ventricular tachyarrhythmia (VT/VF) remains unclear. This study aimed to evaluate the clinical impact of sLVP rate on VT/VF occurrence. In total, 1,419 device interrogation data from 42 consecutive patients who underwent new aCRT device implantation were retrospectively analyzed. The primary endpoint was the first time VT/VF episode after aCRT device implantation. During a median follow-up of 34months, 15 patients had VT/VF episodes. Patients were divided into a high sLVP (the average sLVP percentage of ≥ 51.5%, n = 27) or low sLVP group (< 51.5%, n = 15). The high sLVP group had a significantly lower VT/VF incidence (22% vs. 60%; p = 0.014) and an independent predictor for VT/VF occurrence on multivariate analysis (hazard ratio 0.21; p = 0.007). LV ejection fraction improvements after 6months (12.3 ± 8.7% vs. 2.8 ± 10.3%; p = 0.004) and 12months (13.8 ± 9.3% vs. 6.2 ± 11.1%; p = 0.030) were significantly greater in the high sLVP group than in the low sLVP group. Age, PR interval, and left atrial diameter were significantly associated with the sLVP rate after aCRT. Patients with high sLVP percentage after aCRT had lower long-term risk of VT/VF incidence with a favorable response to CRT. A synchronized pacing algorithm using intrinsic conduction may prevent malignant arrhythmias, as well as recover cardiac functions.

Design of Mid-Q Response: A prospective, randomized trial of adaptive cardiac resynchronization therapy in Asian patients.

AimsThe aim of the Mid‐Q Response study is to test the hypothesis that adaptive preferential left ventricular‐only pacing with the AdaptivCRT algorithm has superior clinical outcomes compared to conventional cardiac resynchronization therapy (CRT) in heart failure (HF) patients with moderately wide QRS duration (≥120 ms and <150 ms), left bundle branch block (LBBB), and normal atrioventricular (AV) conduction (PR interval ≤200 ms).MethodsThis prospective, multi‐center, randomized, controlled, clinical study is being conducted at approximately 60 centers in Asia. Following enrollment and baseline assessment, eligible patients are implanted with a CRT system equipped with the AdaptivCRT algorithm and are randomly assigned in a 1:1 ratio to have AdaptivCRT ON (Adaptive Bi‐V and LV pacing) or AdaptivCRT OFF (Nonadaptive CRT). A minimum of 220 randomized patients are required for analysis of the primary endpoint, clinical composite score (CCS) at 6 months post‐implant. The secondary and ancillary endpoints are all‐cause and cardiovascular death, hospitalizations for worsening HF, New York Heart Association (NYHA) class, Kansas City Cardiomyopathy Questionnaire (KCCQ), atrial fibrillation (AF), and cardiovascular adverse events at 6 or 12 months.ConclusionThe Mid‐Q Response study is expected to provide additional evidence on the incremental benefit of the AdaptivCRT algorithm among Asian HF patients with normal AV conduction, moderately wide QRS, and LBBB undergoing CRT implant.

Impact of adaptive cardiac resynchronization therapy in patients with systolic heart failure: Beyond QRS duration and morphology

BackgroundMechanical and electrical restoration by cardiac resynchronization therapy (CRT) with adaptive pacing algorithm (aCRT) in heart failure patients with a moderately wide (120–149 ms) QRS has not been fully evaluated. The purpose of this study was to investigate the therapeutic effect of aCRT compared with conventional biventricular CRT (BiV-CRT) regardless of QRS morphology. MethodsSeventeen consecutive patients with a QRS ≥120 ms, regardless of morphology, underwent CRT device implantation with an aCRT pacing algorithm. Propensity score matched analysis was performed to evaluate the impact of aCRT on the improvement in mechanical and electrical parameters after CRT device implantation using historical controls (HC) from the clinical registry of BiV-CRT (START trial). ResultsLeft ventricular (LV) volume significantly decreased after CRT in all patients in both the aCRT and HC groups. The difference in relative reduction of LV end-systolic volume (LVESV) was not significantly different between the 2 arms. QRS shortening after CRT was significantly greater in the aCRT group than in the BiV-CRT group, and the difference was prominent in patients with a moderately wide QRS (120–149 ms). In patients with a moderately wide QRS, the relative reduction in LVESV [39 (29–47)% vs. 2 (−6–20)%, p = 0.04] and proportion of LV volume responders (90% vs. 38%, p = 0.04) were significantly greater in the aCRT group than in the HC group. The proportion of volume responders was not significantly different in patients with a wide QRS (≥150 ms). ConclusionsThe aCRT algorithm improved electrical and mechanical parameters in patients with a moderately wide QRS, regardless of QRS morphology.

B-AB19-03 ADAPTIVE LEFT VENTRICULAR PACING-INDUCED QT PROLONGATION AND POLYMORPHIC VENTRICULAR TACHYCARDIA IN A PATIENT WITH A NEWLY IMPLANTED CARDIAC RESYNCHRONIZATION DEVICE

Adaptive cardiac resynchronization therapy (aCRT) algorithms have improved outcomes via dynamic left ventricular (LV) and biventricular (Bi-V) pacing strategies based on real-time assessments of intrinsic atrioventricular (AV) delays. Few cases have shown potential proarrhythmic effects. NA NA A 42-year-old man with a long history of non-ischemic cardiomyopathy underwent implantation of a prophylactic CRT-defibrillator. In the 24-hour period following implantation, there was progressive QT prolongation (Fig.1) followed by non-sustained torsades de pointes and ultimately 8 episodes of sustained, polymorphic VT. Device interrogation revealed 98.5% LV pacing and 1.4% Bi-V pacing. No additional ventricular arrhythmias were observed after programming changes, including increasing the lower rate limit to 90 bpm, turning off aCRT, and reinstitution of simultaneous Bi-V pacing with short AV intervals. We hypothesize that recurrent non-ischemic polymorphic VT in this case was related to induced alteration in transmyocardial repolarization with LV pacing from an epicardial coronary vein. Accentuation of normal dispersion by altering normal depolarization and thus repolarization sequence may precipitate phase 2 reentry. The termination of VT by turning off aCRT and programming a set Bi-V pacing sequence suggests that alteration of transmural repolarization was the proarrhythmic mechanism. Novel programming algorithms intended to minimize non-physiologic right ventricular pacing and more closely mimic physiologic electro-mechanical biventricular activation carry the potential for ventricular proarrhythmia.

Adaptive Cardiac Resynchronization Therapy Effect on Electrical Dyssynchrony (aCRT-ELSYNC): A randomized controlled trial.

BackgroundAdaptive cardiac resynchronization therapy (aCRT) is known to have clinical benefits over conventional CRT, but the mechanisms are unclear.ObjectiveCompare effects of aCRT and conventional CRT on electrical dyssynchrony.MethodsA prospective, double-blind, 1:1 parallel-group assignment randomized controlled trial in patients receiving CRT for routine clinical indications. Participants underwent cardiac computed tomography and 128-electrode body surface mapping. The primary outcome was change in electrical dyssynchrony measured on the epicardial surface using noninvasive electrocardiographic imaging before and 6 months post-CRT. Ventricular electrical uncoupling (VEU) was calculated as the difference between the mean left ventricular (LV) and right ventricular (RV) activation times. An electrical dyssynchrony index (EDI) was computed as the standard deviation of local epicardial activation times.ResultsWe randomized 27 participants (aged 64 ± 12 years; 34% female; 53% ischemic cardiomyopathy; LV ejection fraction 28% ± 8%; QRS duration 155 ± 21 ms; typical left bundle branch block [LBBB] in 13%) to conventional CRT (n = 15) vs aCRT (n = 12). In atypical LBBB (n = 11; 41%) with S waves in V5-V6, conduction block occurred in the anterior RV, as opposed to the interventricular groove in strict LBBB. As compared to baseline, VEU reduced post-CRT in the aCRT (median reduction 18.9 [interquartile range 4.3–29.2 ms; P = .034]), but not in the conventional CRT (21.4 [-30.0 to 49.9 ms; P = .525]) group. There were no differences in the degree of change in VEU and EDI indices between treatment groups.ConclusionThe effect of aCRT and conventional CRT on electrical dyssynchrony is largely similar, but only aCRT harmoniously reduced interventricular dyssynchrony by reducing RV uncoupling.

Efficacy of a Device-Based Continuous Optimization Algorithm for Patients With Cardiac Resynchronization Therapy.

Cardiac resynchronization therapy (CRT) is less effective in patients with mildly wide QRS or non-left bundle branch block (non-LBBB). A new algorithm of every minute's optimization (adaptive CRT: aCRT algorithm) is effective in patients with CRT devices. This study investigated the clinical effect of the aCRT algorithm, especially in mildly wide QRS (120≤QRS<150 ms) or non-LBBB patients receiving CRT.Methods and Results:This study included 104 CRT patients (48 patients using the aCRT algorithm [adaptive group] and 56 patients not using the aCRT algorithm [non-adaptive group]). The primary endpoint was a composite clinical outcome of cardiac death and/or heart failure (HF) hospitalization. During a median follow-up of 700 days (interquartile range 362-1,173 days), aCRT reduced the risk of the clinical outcome, even in patients with mildly wide QRS or non-LBBB (log-rank P=0.0030 and P=0.0077, respectively) by Kaplan-Meier analysis. Use of the aCRT algorithm was an independent predictor of clinical outcomes in the multivariate analysis (hazard ratio (HR) 0.28, 95% confidence interval (CI): 0.096-0.78, P=0.015), the same as in patients with mildly wide QRS (HR 0.12, 95% CI: 0.006-0.69, P=0.015). The new aCRT algorithm was useful and significantly reduced the risk of the clinical outcome, even in patients with mildly wide QRS.

&lt;p&gt;Heart failure hospitalization reduction and cost savings achieved by improved delivery of effective biventricular pacing: economic implications of the OLE study under the US setting&lt;/p&gt;

Background: The hOLter for Efficacy analysis (OLE) study demonstrated that current device pacing diagnostics overestimate the amount of cardiac resynchronization therapy (CRT) pacing that effectively stimulates the cardiac tissue. Sub-optimal pacing increases mortality, hospitalizations, and associated health-care costs. We sought to estimate the expected number of hospital admissions due to heart failure (HF) and its respective financial impact in patients with maximized effective pacing versus conventional pacing.Methods: A Markov model was developed to project HF hospitalizations and quantify the costs that could be avoided if pacing was maximally effective. OLE data were used to inform the prevalence of ineffective pacing among CRT patients and and average loss of pacing by causes. Adaptive CRT trial data quantified the reduction in underlying hospitalization risk by increasing effective pacing delivered. Survival was informed by a meta-analysis of 5 randomized clinical trials. Costs were analyzed from a US payer perspective.Results: Projected average hospitalizations totaled 4.58 over a lifetime horizon for CRT patients with conventional pacing. Maximizing effective pacing delivery was projected to avoid 1.83 HF admissions/patient over the lifetime. This equates to a savings of 40% (US$22,802) compared with conventional pacing from the Medicare perspective. In a sensitivity analysis, CRT with effective pacing was projected to provide cost savings in all scenarios.Conclusions: Maximized effective pacing leads to a lower number of HF hospitalizations, thus allowing significant cost offsets in the US setting.

Adaptive cardiac resynchronization therapy is associated with decreased risk of incident atrial fibrillation compared to standard biventricular pacing: A real-world analysis of 37,450 patients followed by remote monitoring

The AdaptivCRT algorithm (aCRT) automatically adjusts atrioventricular delays each minute to achieve ventricular fusion through left ventricular (LV) or biventricular (BiV) pacing. aCRT is associated with superior clinical outcomes compared to standard BiV pacing, but the association of aCRT and subsequent atrial fibrillation (AF) in a real-world population has not been fully evaluated. The purpose of this study was to investigate the incidence of AF ≥48 hours with aCRT vs standard BiV pacing after implant. Patients implanted with a cardiac resynchronization therapy (CRT) device between 2013 and 2016 were studied via the de-identified Medtronic CareLink database. For univariate and multivariate survival analyses, Kaplan-Meier and Cox proportional hazards were used, respectively. Of 37,450 patients (mean age 69.1 ± 11.0 years; 67.9% male) followed for a mean 15.5 ± 9.1 months, 9.7% (n = 3647) developed ≥48 hours of AF. In univariate analysis, compared with standard BiV pacing, the aCRT BiV and LV mode was associated with a 54% lower risk of ≥48 hours of AF (P <.001) at 2 years, which persisted after multivariate adjustment (hazard ratio 0.53; 95% confidence interval 0.49-0.57; P <.001), even when stratified by sensed PR interval ≤200 ms and >200 ms. Higher percentages of LV-only pacing with aCRT were associated with lower incidence of AF (comparing >92% LV-only pacing vs 0%-5% LV-only pacing: HR 0.05; 95% CI 0.04-0.06; P <.001). In a large, real-world population of CRT recipients, aCRT pacing compared to standard BiV pacing was associated with a lower incidence of AF in patients with both long and short PR intervals. A higher percentage of LV-only pacing during aCRT was also associated with lower incidence of AF.

Efficacy of Cardiac Resynchronization Therapy Using Automated Dynamic Optimization and Left Ventricular-only Pacing.

BackgroundAlthough device-based optimization has been developed to overcome the limitations of conventional optimization methods in cardiac resynchronization therapy (CRT), few real-world data supports the results of clinical trials that showed the efficacy of automatic optimization algorithms. We investigated whether CRT using the adaptive CRT algorithm is comparable to non-adaptive biventricular (BiV) pacing optimized with electrocardiogram or echocardiography-based methods.MethodsConsecutive 155 CRT patients were categorized into 3 groups according to the optimization methods: non-adaptive BiV (n = 129), adaptive BiV (n = 11), and adaptive left ventricular (LV) pacing (n = 15) groups. Additionally, a subgroup of patients (n = 59) with normal PR interval and left bundle branch block (LBBB) was selected from the non-adaptive BiV group. The primary outcomes included cardiac death, heart transplantation, LV assist device implantation, and heart failure admission. Secondary outcomes were electromechanical reverse remodeling and responder rates at 6 months after CRT.ResultsDuring a median 27.5-month follow-up, there was no significant difference in primary outcomes among the 3 groups. However, there was a trend toward better outcomes in the adaptive LV group compared to the other groups. In a more rigorous comparisons among the patients with normal PR interval and LBBB, similar patterns were still observed.ConclusionIn our first Asian-Pacific real-world data, automated dynamic CRT optimization showed comparable efficacy to conventional methods regarding clinical outcomes and electromechanical remodeling.

Systolic Stretch Characterizes the Electromechanical Substrate Responsive to Cardiac Resynchronization Therapy

ObjectivesIn this study, the authors tested the hypotheses that the systolic stretch index (SSI) developed by computer modeling and applied using echocardiographic strain imaging may characterize the electromechanical substrate predictive of outcome following cardiac resynchronization therapy (CRT). They included patients with QRS width 120 to 149 ms or non-left bundle branch block (LBBB), where clinical uncertainty for CRT exists. They further tested the hypothesis that global longitudinal strain (GLS) has additional prognostic value. BackgroundResponse to CRT is variable. Guidelines favor patient selection by electrocardiographic LBBB with QRS width ≥150 ms. MethodsThe authors studied 442 patients enrolled in the Adaptive CRT 94-site randomized trial with New York Heart Association functional class III–IV heart failure, ejection fraction ≤35%, and QRS ≥120 ms. A novel computer program semiautomatically calculated the SSI from strain curves as the sum of posterolateral prestretch percent before aortic valve opening and the septal rebound stretch percent during ejection. The primary endpoint was hospitalization for heart failure (HF) or death, and the secondary endpoint was death over 2 years after CRT. ResultsIn all patients, high longitudinal SSI (≥ group median of 3.1%) was significantly associated with freedom from the primary endpoint of HF hospitalization or death (hazard ratio [HR] for low SSI: 2.17; 95% confidence interval [CI]: 1.45 to 3.24, p < 0.001) and secondary endpoint of death (HR for low SSI: 4.06; 95% CI: 1.95 to 8.45, p < 0.001). Among the 203 patients with QRS 120 to 149 ms or non-LBBB, those with high longitudinal SSI (≥ group median of 2.6%) had significantly fewer HF hospitalizations or deaths (HR for low SSI: 2.08; 95% CI: 1.27 to 3.41, p = 0.004) and longer survival (HR for low SSI: 5.08; 95% CI: 1.94 to 13.31, p < 0.001), similar to patients with LBBB ≥150 ms. SSI by circumferential strain had similar associations with clinical outcomes, and GLS was additive to SSI in predicting clinical events (p = 0.001). ConclusionsSystolic stretch by strain imaging characterized the myocardial substrate associated with favorable CRT response, including in the important patient subgroup with QRS width 120 to 149 ms or non-LBBB. GLS had additive prognostic value.

5045The effect of adaptive cardiac resynchronization therapy in reducing atrial fibrillation in heart failure patients: insights from multicenter observational experience

5045The effect of adaptive cardiac resynchronization therapy in reducing atrial fibrillation in heart failure patients: insights from multicenter observational experience

531The effect of Adaptive Cardiac Resynchronization Therapy in reducing atrial fibrillation in heart failure patients: insights from multicenter observational experience

531The effect of Adaptive Cardiac Resynchronization Therapy in reducing atrial fibrillation in heart failure patients: insights from multicenter observational experience

SY6-5 - Adaptive CRT Algorithm—Reducing the Non-Responder in CRT Recipients With Left Bundle Branch Block and QRS 120–150 ms

Background: Efficacy of the cardiac resynchronization therapy (CRT) in patients with left bundle branch block (LBBB), but QRS duration of 120–150 ms is still limited. Adaptive CRT algorithm had shown to be more effective in patients with preserved AV conduction but the impact of the Adaptive CRT algorithm in patients with different QRS duration remains uncertain. Methods: Patients with LBBB and preserved AV conduction enrolled in the Adaptive CRT trial, randomized study comparing the aCRT or echo-optimized CRT (control group), were used in this analysis. Endpoints for this analysis were clinical composite score (CCS) at 6 months post-implant and time to first heart failure (HF) hospitalization or death. Results: Among the 199 patients, 80 patients (40%) had a baseline QRS of 120–150 ms. In this subgroup, a greater proportion of aCRT patients had an improved CCS (79% vs 50%) at 6 months compared to the control group (P = .03). There was also a trend toward a lower risk of death or HF hospitalization (hazard ratio: 0.53; 95% CI: 0.24–1.15; P = .10) in aCRT group compared to the control arm. In the wide QRS subgroup, the efficacy was comparable in both treatment arms. Conclusion: Adaptive CRT was associated with improved patient outcomes over echo-optimized bi-ventricular CRT in patients with preserved AV conduction, LBBB, and QRS of 120–150 ms.

Continuous optimization of cardiac resynchronization therapy reduces atrial fibrillation in heart failure patients: Results of the Adaptive Cardiac Resynchronization Therapy Trial

Data from randomized trials have suggested a modest or no effect of conventional cardiac resynchronization therapy (convCRT) on the incidence of atrial fibrillation (AF). AdaptivCRT (aCRT, Medtronic, Mounds View, MN) is a recently described algorithm for synchronized left ventricular (LV) pacing and continuous optimization of cardiac resynchronization therapy (CRT). We compared the long-term effects of aCRT with convCRT pacing on the incidence of AF. The Adaptive CRT trial randomized CRT-defibrillator (CRT-D)-indicated patients (2:1) to receive either aCRT or convCRT pacing. The aCRT algorithm evaluates intrinsic conduction every minute, providing LV-only pacing during normal atrioventricular (AV) conduction and AV and ventriculoventricular timing adjustments during prolonged AV conduction. The primary outcome of this subanalysis was an episode of AF >48 consecutive hours as detected by device diagnostics. Over a follow-up period with a mean and standard deviation of 20.2 ± 5.9 months, 8.7% of patients with aCRT and 16.2% with convCRT experienced the primary outcome (hazard ratio [HR] = 0.54; 95% confidence interval [CI] = 0.31-0.93; P= .03). In patients with prolonged baseline AV, the incidence of the primary outcome was 12.8% in patients randomized to aCRT compared with 27.4% in convCRT patients (HR = 0.45; 95% CI = 0.24-0.85; P = .01). Also, patients with AF episodes adjudicated as clinical adverse events were less common with aCRT (4.3%) than with convCRT (12.7%) (HR = 0.39; 95% CI = 0.19-0.79; P = .01). Patients receiving aCRT had a reduced risk of AF compared with those receiving convCRT. Most of the reduction in AF occurred in subgroups with prolonged AV conduction at baseline and with significant left atrial reverse remodeling.