Optimal Atrioventricular Delay Research Articles

Clinical benefit of atrio-ventricular delay optimization in patients with a dual-chamber pacemaker: a pilot study. The CBRAVO trial (NCT01998256)

Objective Outcome data on exercise capacity following atrio-ventricular (AV) optimization of dual-chamber pacing are sparse. Pacemaker settings are often left at manufacturers’ nominal values upon implantation. We studied the short-term effect of AV optimization on exercise capacity in patients with a dual-chamber pacemaker.Methods and results Twenty-eight patients (mean age 73 ± 14 y) with a dual-chamber pacemaker, were randomized towards either nominal AV settings (group 1) or echo-guided AV optimization using the iterative mitral inflow VTI (velocity time integral) method (group 2) at baseline. At 4 weeks, patients were crossed-over to AV optimization in group 1 and returned to nominal AV settings in group 2 for another period of 4 weeks.Oxygen uptake efficiency slope improved significantly after AV optimization (by 126.7 mL/logL ± 190.7 mL/logL; P= 0.003).Conclusions AV optimization in dual-chamber pacing significantly improved functional capacity after 4 weeks. These data provide the background for further validation studies.

Simultaneous His Bundle and Left Ventricular Pacing for Optimal Cardiac Resynchronization Therapy Delivery: Acute Hemodynamic Assessment by Pressure-Volume Loops.

Previous studies have investigated the role of intrinsic conduction in optimizing cardiac resynchronization therapy. We investigated the role of fusing pacing-induced activation and intrinsic conduction in cardiac resynchronization therapy by evaluating the acute hemodynamic effects of simultaneous His-bundle (HIS) and left ventricular (LV) pacing. We studied 11 patients with systolic heart failure and left bundle-branch block scheduled for cardiac resynchronization therapy implantation. On implantation, LV pressure-volume data were determined via conductance catheter. Standard leads were placed in the right atrium, at the right ventricular apex, and in a coronary vein. An additional electrode was temporarily positioned in the HIS. The following pacing configurations were systematically assessed: standard biventricular (right ventricular apex+LV), LV-only, HIS, simultaneous HIS and LV (HIS+LV). Each configuration was compared with the AAI mode at multiple atrioventricular delays (AVD). In comparison with the AAI, right ventricular apex+LV and LV-only pacing resulted in improved stroke volume (85±32 mL and 86±33 mL versus 58±23 mL; P<0.001), stroke work, maximum pressure derivative, and systolic dyssynchrony at individually optimized AVD. The optimal AVD was close to the P-H interval in the majority of patients. By contrast, HIS-LV pacing improved hemodynamic indexes at all AVD (stroke volume >76 mL at all fixed intervals and 88±31 mL at optimal interval; all P<0.001). Standard right ventricular apex+LV and LV-only pacing enhanced systolic function and LV synchrony at individually optimized AVD close to the measured intrinsic P-H interval. By contrast, HIS+LV pacing yielded improvements, regardless of AVD setting. These findings support the hypothesis of the crucial role of intrinsic right ventricular conduction in optimal cardiac resynchronization therapy delivery.

Outcomes Related to First-Degree Atrioventricular Block and Therapeutic Implications in Patients With Heart Failure.

The prevalence of first-degree atrioventricular block in the general population is approximately 4%, and it is associated with an increased risk of atrial fibrillation. Cardiac pacing for any indication in patients with first-degree heart block is associated with worse outcomes compared with patients with normal atrioventricular conduction. Among patients withheart failure, first-degree atrioventricular block is present in anywhere between 15% and 51%. Data from cardiac resynchronization therapy studies have shown that first-degree atrioventricular block is associated with an increased risk of mortality and heart failure hospitalization. Recent studies suggest that optimization of atrioventricular delay in patients with cardiac resynchronization therapy is an important target for therapy; however, the optimal method for atrioventricular resynchronization remains unknown. Understanding the role of first-degree atrioventricular block in the treatment of patients with heart failure will improve medical and device therapy.

PROGNOSTIC VALUE OF ECHO-DOPPLER GUIDED AV DELAY OPTIMIZATION FOLLOWING CARDIAC RESYNCHRONIZATION THERAPY

The utility of Atrio-Ventricular (AV) delay optimization following Cardiac Resynchronization Therapy (CRT) remains unclear. We aimed to determine the utility and outcome of interrogating and selectively optimizing AV synchrony using Echo-Doppler-Guided (EDG) AV optimization following CRT. All

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

0329 : Automatic AV delay adaptation to exercise in CRT-D patients according to underlying heart disease

Several studies have shown the benefit of optimizing inter-ventricular (VV) and atrio-ventricular (AV) delays in improving the response to CRT. We evaluated AV delay automatic adaptation at rest and during exercise according to underlying heart disease in patients implanted with a SonR CRT-D device (Sorin CRM, Clamart, France). This device is connected to the atrial SonRTip™ 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 (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. No difference was found between both groups (ICM and DCM). In ICM group, 11 (78,6%) patients were responders (optimization success 99%) and non-responders (optimization success 66%). In the DCM group, 4 (26,7%) patients were hyper-responders, 6 (40%) responders and 5 (33,3%) non-responders with respectively 99, 97 and 60% of optimization success. no difference was found in AV delay mean values in responders and nonresponders in both groups. AV delay automatic adaptation at exercise in patients implanted with the SonR CRT-D device was not different between ICM and DCM patients. The author hereby declares no conflict of interest

Optimizing the Atrioventricular Delay in Dual Chamber Pacemakers; Is It Worth?

Background: The number of patients treated with a dual chamber (DDD) pacemaker is continually increased each year. The Optimal AV synchrony will not only maximize cardiac output by increasing ventricular preload, thus lowering mean atrial pressure, but it will also minimize the diastolic mitral regurgitation. Until now, individualized optimization of the AVI is not performed in the clinical routine. This is mainly because of the time-consuming process of manual optimization and the lack of guideline recommendations. Objective: To assess the optimal AV delay for each patient and to decide whether this optimization is worth doing it for all patients. Patients and methods: After approval of Local Ethics Committee and obtaining written informed consent, a prospective, comparative randomized study was conducted on 56 patients with symptomatic bradyarrhythmia requiring adual chamber pacemaker implantation. All patients were assessed by thorough history taking, clinical examination, 12 lead surface ECG, and Echocardiography, They were randomly divided into two groups. Group A (28 patients): where their AVD was set at the default values, while in group B the AVD was optimized with guidance of the trans-mitral Doppler waves on echocardiography. Then echocardiography follow up was done after 12 months. Results: Statistically significant increase was found in the LVEF in group B from 67.71±4.58 to 73.43±4.74 (p<0.0001) while it was found to decrease in group A from 72.21±6.28 to 69.43±5.41 after 12 months of device implantation (p<0.0001). Similar results were observed as regard the RVEF which decreased non significantly in group A after 12 months from 49.0±5.82 to 48.07±5.13 (p: 0.07), while in group B a significant increase from 48.57±5.1 to 53.14±7.31 was observed (p<0.0001). Confirming these results again by analyzing the total change in LVEF and RVEF after one year and comparing the two groups directly. Both LVEF and RVEF show a highly significant increase in group B in comparison with group A (P<0.0001). Also the LAP decreased significantly in both groups (P<0.001). Conclusion: Optimizing the AVD for all patients of DDD pacemakers may lead to long term beneficial effects mainly on the systolic functions.

Cardiac resynchronization therapy: Twelve-month effects of echocardiographic atrio-ventricular and inter-ventricular delay optimization. Rationale and design of the CARTEDO trial

Cardiac resynchronization therapy: Twelve-month effects of echocardiographic atrio-ventricular and inter-ventricular delay optimization. Rationale and design of the CARTEDO trial

A novel curve fitting method for AV optimisation of biventricular pacemakers

In this study, we designed and tested a new algorithm, which we call the ‘restricted parabola’, to identify the optimum atrioventricular (AV) delay in patients with biventricular pacemakers. This algorithm automatically restricts the hemodynamic data used for curve fitting to the parabolic zone in order to avoid inadvertently selecting an AV optimum that is too long.We used R, a programming language and software environment for statistical computing, to create an algorithm which applies multiple different cut-offs to partition curve fitting of a dataset into a parabolic and a plateau region and then selects the best cut-off using a least squares method. In 82 patients, AV delay was adjusted and beat-to-beat systolic blood pressure (SBP) was measured non-invasively using our multiple-repetition protocol. The novel algorithm was compared to fitting a parabola across the whole dataset to identify how many patients had a plateau region, and whether a higher hemodynamic response was achieved with one method.In 9/82 patients, the restricted parabola algorithm detected that the pattern was not parabolic at longer AV delays. For these patients, the optimal AV delay predicted by the restricted parabola algorithm increased SBP by 1.36 mmHg above that predicted by the conventional parabolic algorithm (95% confidence interval: 0.65 to 2.07 mmHg, p-value = 0.002).AV optima selected using our novel restricted parabola algorithm give a greater improvement in acute hemodynamics than fitting a parabola across all tested AV delays. Such an algorithm may assist the development of automated methods for biventricular pacemaker optimisation.

Right ventricular septal pacing in patients with right bundle branch block

BackgroundCardiac resynchronization therapy (CRT) has been shown to improve left ventricular (LV) function and exercise performance in patients with left bundle branch block. Patients with right bundle branch block (RBBB) do not have a similar positive response to standard CRT. We hypothesized that single site pacing of the right ventricular septum (RVS) near the proximal right bundle could restore more normal activation of the LV in RBBB patients. Methods78 consecutive patients (56M, 22F) with baseline RBBB underwent pacemaker or ICD implantation. Leads were placed in the right atrium and RVS. ResultsBaseline QRS duration was 120–220ms (mean QRSd=147ms). At the optimal AV delay, the fused QRSd was 56–160ms (mean QRSd=112ms). The mean decrease in QRSd was 34±20.4ms (p<0.001). ConclusionRVS pacing in patients with RBBB resulted in a marked decrease in QRS duration and often normalized the ECG.

Comparison of echocardiography and device based algorithm for atrio-ventricular delay optimization in heart block patients.

To compare the atrio-ventricular (AV/PV) delay optimization by echocardiography and intra-cardiac electrocardiogram (IEGM) based QuickOpt algorithm in complete heart block (CHB) patients, implanted with a dual chamber pacemaker. We prospectively enrolled 20 patients (age 59.45 ± 18.1 years; male: 65%) with CHB, who were implanted with a dual chamber pacemaker. The left ventricular outflow tract velocity time-integral was measured after AV/PV delay optimization by both echocardiography and QuickOpt algorithm method. Bland-Altman analysis was used for agreement between the two techniques. The optimal AV and PV delay determined by echocardiography was 155.5 ± 14.68 ms and 122.5 ± 17.73 ms (P < 0.0001), respectively and by QuickOpt method was 167.5 ± 16.73 and 117.5 ms ± 9.10 ms (P < 0.0001), respectively. A good agreement was observed between optimal AV and PV delay as measured by two methods. However, the correlation of the optimal AV (r = 0.0689, P = 0.77) and PV (r = 0.2689, P = 0.25) intervals measured by the two techniques was poor. The time required for AV/PV optimization was 45.26 ± 1.73 min by echocardiography and 0.44 ± 0.08 min by QuickOpt method (P < 0.0001). The programmer based IEGM method is an automated, quick, easier and reliable alternative to echocardiography for the optimization of AV/PV delay in CHB patients, implanted with a dual chamber pacemaker.

Feasibility of a novel atrioventricular delay optimization method using transmitral and pulmonary venous flow in patients with sequential ventricular pacing or cardiac resynchronization therapy.

BackgroundAlthough several echo-Doppler methods were proposed to optimize atrioventricular (AV) delay in patients with sequential ventricular pacing, “echo-guided” AV optimization has not been widely adopted clinically. A combination of trasmitral flow (TMF) and pulmonary venous flow (PVF) measurements may be beneficial to further optimize AV delay to achieve better cardiac function. The aim of this study was to assess the feasibility and usefulness of AV delay optimization by combined use of TMF and PVF.MethodsA total of 32 patients after sequential ventricular pacemaker implantation were enrolled and studied. The optimal AV delay was defined as the timing to minimize the duration between PVF reversal (a) wave and the duration of the “A” wave of TMF. Stroke volume was measured at the “optimized” AV delay (AVDOPT) and was compared with that obtained at shorter (AVDOPT − 50 ms) and longer (AVDOPT + 50 ms) AV delays.ResultsAV optimization was feasible in 27 of 32 patients (87 %). Stroke volume at AVDOPT was significantly higher than that at shorter or longer AV delay (63 ± 18 ml vs. 57 ± 15 ml vs. 56 ± 16 ml, P = 0.001).ConclusionsAV delay optimization using TMF and PV flow was feasible. Usefulness of this method requires further investigation with a larger study population.

Atrioventricular delay optimization of cardiac resynchronisation therapy: Comparison of non-invasive blood pressure with invasive haemodynamic measures

Cardiac resynchronisation therapy (CRT) has been shown to increase lifespan [1] and improve haemodynamics in heart failure patients [2]. By performing optimisation of the AV delay, further improvement in the haemodynamic response is achievable [3]. Many different variables both invasive and non-invasive [4,5] have been proposed as targets for maximisation during AV delay optimisation. Non-invasive methods have the advantage of being convenient to acquire, free from the risks associated with invasive measurements, and allow multiple measurements to be made which is necessary to minimise the effect of random noise [6,7].

55 * Testing the validity of electrogram based AV optimization schemes using real world patient data

Background: Manufacturers have each implemented manufacturer specific methods for electrogram based optimization of AV delay in CRT devices. Agreement between manufacturer algorithms has never been formally tested. Where the algorithms are fully published and available, we tested agreement between different device based AV optimisation scheme, and compared this to the AV optimum selected using non-invasive haemodynamic optimisation. Method & Results: Twenty two patients undergoing haemodynamic AV optimization as part of the British Randomized AV optimization trial (BRAVO) had the AV optimum calculated according to published algorithms for QuickOptTM (St Jude Medical), Adaptive CRT (aCRT, Medtronic), and ExpertEase for Heart Failure+(EEHF+, Boston Scientific). Agreement between the haemodynamic optimum and electrograms optima was poor (versus QuickOpt R2=0.001, p=0.9; versus aCRT R2= 0.031, p=0.43; versus EEHF+R2=0.039, p=0.39). Agreement between the different electrogram based optima was also poor (QuickOpt versus EEHF+R2=0.01, p=0.65; QuickOpt versus aCRT R2=0.001, p=0.45; aCRT versus EEHF+R2=0, p=0.64, p<0.001). While there was a correlation between the AV optimum selected by Adaptive CRT, and EEHF+, the optimum selected using aCRT was systematically longer with the aCRT optimum on average 20ms longer (p=0.02). These findings were replicated for both sensed and paced AV delays. Conclusion: Different manufacturers' electrogram methods are substantially contradictory. None has impressive agreement with a reproducible method for haemodynamic AV optimisation. These curious data warrant further, independent, exploration since manufacturer electrogram methods are widely used by clinicians assuming them to have a physiological basis, perhaps incorrectly. ![Graphic][1] Figure AV optima (ms) selected using the different electrogram based optimisation schemes are compared to each other and to the AV optimum selected by non-invasive haemodynamic optimisation. [1]: /embed/inline-graphic-1.gif

Response to ‘A simplified method for determination of the optimal atrioventricular delay in cardiac resynchronization therapy’ IJC-D-14-02689

Response to ‘A simplified method for determination of the optimal atrioventricular delay in cardiac resynchronization therapy’ IJC-D-14-02689

A simplified method for determination of the optimal atrioventricular delay in cardiac resynchronization therapy

We read with great interest the paper of Raphael et al. [1] regarding the evaluation of the iterative method of optimal atrioventricular (AV) delay for cardiac resynchronization therapy (CRT). The paper addressed an important issue that iterative AV optimization is not executed reliably by experts. Such optimization is essentially important in CRT, which could reduce morbidity and mortality in patients with severe heart failure if the value is settled appropriately [2]. However, despite the fact that several methods have been proposed, AV delay is often programmed via an empirical method or left to a predefined value.

41 Correlation and Reproducibility of Invasive and Non-invasive Haemodynamic Parameters for Identifying Optimal AV Delay in Cardiac Resynchronisation Therapy

BackgroundAcute haemodynamic measurements can be used for AV delay (AVD) optimisation of cardiac resynchronisation therapy (CRT). It is uncertain whether non-invasive measurements are as reliable as those measured invasively.Methods37 patients...

British randomised controlled trial of AV and VV optimization (“BRAVO”) study: rationale, design, and endpoints

BackgroundEchocardiographic optimization of pacemaker settings is the current standard of care for patients treated with cardiac resynchronization therapy. However, the process requires considerable time of expert staff. The BRAVO study is a non-inferiority trial comparing echocardiographic optimization of atrioventricular (AV) and interventricular (VV) delay with an alternative method using non-invasive blood pressure monitoring that can be automated to consume less staff resources.Methods/DesignBRAVO is a multi-centre, randomized, cross-over, non-inferiority trial of 400 patients with a previously implanted cardiac resynchronization device. Patients are randomly allocated to six months in each arm. In the echocardiographic arm, AV delay is optimized using the iterative method and VV delay by maximizing LVOT VTI. In the haemodynamic arm AV and VV delay are optimized using non-invasive blood pressure measured using finger photoplethysmography. At the end of each six month arm, patients undergo the primary outcome measure of objective exercise capacity, quantified as peak oxygen uptake (VO2) on a cardiopulmonary exercise test. Secondary outcome measures are echocardiographic measurement of left ventricular remodelling, quality of life score and N-terminal pro B-type Natriuretic Peptide (NT-pro BNP). The study is scheduled to complete recruitment in December 2013 and to complete follow up in December 2014.DiscussionIf exercise capacity is non-inferior with haemodynamic optimization compared with echocardiographic optimization, it would be proof of concept that haemodynamic optimization is an acceptable alternative which has the potential to be more easily implemented.Trial registrationClinicaltrials.gov NCT01258829

Continuously adjusting CRT therapy: clinical impact of adaptive cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) is a well-established therapy to reduce morbidity and mortality in patients with moderate and severe symptomatic congestive heart failure. Left ventricular (LV) pacing that fuses with intrinsic right ventricular (RV) conduction results in similar or even better cardiac performance compared to biventricular (Biv) pacing. Optimal programming of the atrio-ventricular (AV) and inter-ventricular (VV) delays is crucial to improve LV performance since suboptimal programming of AV and VV delays affect LV filling as well as cardiac output. CRT optimization using echocardiogram is resource-dependent and time consuming. Adaptive CRT (aCRT) algorithm provides a dynamic, automatic, ambulatory adjustment of CRT pacing configuration (Biv or LV pacing) and optimization of AV and VV delays. aCRT algorithm is safe and efficacious for CRT-indicated patients without permanent atrial fibrillation. It has been shown to improve CRT response and reduce morbidity and mortality for patients with normal AV conduction.

Effects of AV-delay optimization on hemodynamic parameters in patients with VDD pacemakers

Atrioventricular (AV) delay optimization improves hemodynamics and clinical parameters in patients treated with cardiac resynchronization therapy and dual-chamber-pacemakers (PM). However, data on optimizing AV delay in patients treated with VDD-PMs are scarce. We, therefore, investigated the acute and chronic effects of AV delay optimization on hemodynamics in patients treated with VDD-PMs due to AV-conduction disturbances. In this prospective, single-center interventional trial, we included 64 patients (38 men, 26 women, median age: 77 (70-82) years) with implanted VDD-PM. AV-delay optimization was performed using a formula based on the surface electrocardiogram (ECG). Hemodynamic parameters (stroke volume (SV), cardiac output (CO), heart rate (HR), and blood pressure (BP)) were measured at baseline and follow-up after 3 months using impedance cardiography. Using an ECG formula for AV-delay optimization, the AV interval was decreased from 180 (180-180) to 75 (75-100)ms. At baseline, AV-delay optimization led to a significant increase of both SV (71.3 ± 15.8 vs. 55.3 ± 12.7ml, p < 0.001, for optimized AV delay vs. nominal AV interval, respectively) and CO (5.1 ± 1.4 vs. 3.9 ± 1.0l/min, p < 0.001), while HR and BP remained unchanged. At follow-up, the improvement in CO remained stable (4.9 ± 1.3l/min, p = 0.09), while SV slightly, but significantly, decreased (to 65.1 ± 17.6, p < 0.01). AV-delay optimization in patients treated with VDD-PMs exhibits immediate beneficial effects on hemodynamic parameters that are sustained for 3 months.