Cardiac Resynchronization Therapy Response In Patients Research Articles

Novel electrocardiographic dyssynchrony criteria that may improve patient selection for cardiac resynchronization therapy.

Cardiac resynchronization therapy (CRT) is an evidence-based effective therapy of symptomatic heart failure with reduced ejection fraction refractory to optimal medical treatment associated with intraventricular conduction disturbance, that results in electrical dyssynchrony and further deterioration of systolic ventricular function. However, the non-response rate to CRT is still 20%−40%, which can be decreased by better patient selection. The main determinant of CRT outcome is the presence or absence of significant ventricular dyssynchrony and the ability of the applied CRT technique to eliminate it. The current guidelines recommend the determination of QRS morphology and QRS duration and the measurement of left ventricular ejection fraction for patient selection for CRT. However, QRS morphology and QRS duration are not perfect indicators of electrical dyssynchrony, which is the cause of the not negligible non-response rate to CRT and the missed CRT implantation in a significant number of patients who have the appropriate substrate for CRT. Using imaging modalities, many ventricular dyssynchrony criteria were devised for the detection of mechanical dyssynchrony, but their utility in patient selection for CRT is not yet proven, therefore their use is not recommended for this purpose. Moreover, CRT can eliminate only mechanical dyssynchrony due to underlying electrical dyssynchrony, for this reason ECG has a greater role in the detection of ventricular dyssynchrony than imaging modalities. To improve assessment of electrical dyssynchrony, we devised two novel ECG dyssynchrony criteria, which can estimate interventricular and left ventricular intraventricular dyssynchrony in order to improve patient selection for CRT. Here we discuss the results achieved by the application of these new ECG dyssynchrony criteria, which proved to be useful in predicting the CRT response in patients with nonspecific intraventricular conduction disturbance pattern (the second greatest group of CRT candidates), and the significance of other new ECG dyssynchrony criteria in the potential improvement of CRT outcome.

Pulmonary perfusion and NYHA classification improve after cardiac resynchronization therapy

BackgroundEvaluation of cardiac resynchronization therapy (CRT) often includes New York Heart Association (NYHA) classification, and echocardiography. However, these measures have limitations. Perfusion gradients from ventilation/perfusion single-photon emission computed tomography (V/P SPECT) are related to left-heart filling pressures and have been validated against invasive right-heart catheterization. The aim was to assess if changes in perfusion gradients are associated with improvements in heart failure (HF) symptoms after CRT, and if they correlate with currently used diagnostic methods in the follow-up of patients with HF after receiving CRT. Methods and resultsNineteen patients underwent V/P SPECT, echocardiography, NYHA classification, and the quality-of-life scoring system “Minnesota living with HF” (MLWHF), before and after CRT. CRT caused improvement in perfusion gradients from V/P SPECT which were associated with improvements in NYHA classification (P = .0456), whereas improvements in end-systolic volume (LVESV) from echocardiography were not. After receiving CRT, the proportion of patients who improved was lower using LVESV (n = 7/19, 37%) than perfusion gradients (n = 13/19, 68%). Neither change in perfusion gradients nor LVESV was associated with changes in MLWHF (P = 1.0, respectively). ConclusionsMeasurement of perfusion gradients from V/P SPECT is a promising quantitative user-independent surrogate measure of left-sided filling pressure in the assessment of CRT response in patients with HF.

Epicardial Adipose Tissue Measured From Computed Tomography Predicts Cardiac Resynchronization Therapy Response in Patients With Non-ischemic Systolic Heart Failure.

Background: Epicardial adipose tissue (EAT) has been linked with the pathogenesis of heart failure (HF). Limited data have been reported about the clinical value of EAT for cardiac resynchronization therapy (CRT) in non-ischemic systolic HF. We aimed to explore the values of EAT measured from CT to predict the response to CRT in patients with non-ischemic systolic HF.Methods: Forty-one patients with CRT were consecutively recruited for our study. All patients received both gated resting Single Photon Emission CT (SPECT) myocardial perfusion imaging (MPI) and dual-source multi-detector row CT scans. EAT thickness was assessed on both the parasternal short and horizontal long-axis views. The area of EAT was calculated at the left main coronary artery level. Left ventricular systolic mechanical dyssynchrony (LVMD) was measured by phase standard deviation (PSD) and phase histogram bandwidth (PBW). The definition of CRT response was an improvement of 5% in left ventricular ejection fraction (LVEF) at 6 months after CRT implantation.Results: After 6 months of follow-up, 58.5% (24 of 41) of patients responded to CRT. A greater total perfusion deficit (TPD) was observed in the left ventricle, and a narrower QRS complex was observed in the nonresponse group than in the response group (p < 0.05). Meanwhile, the systolic PSD and systolic PBW were statistically greater in the CRT group with no response than in the response group (p < 0.05). Meanwhile, the baseline QRS duration, TPD, systolic PSD, systolic PBW, EAT thicknesses of the left ventricular (LV) apex, right atrioventricular (AV) groove, and left AV groove were all significantly related to the CRT response in the univariate logistic regression analysis. Furthermore, the QRS duration and EAT thicknesses of the right AV groove and left AV groove were independent predictors of CRT response in the multivariate logistic regression analysis.Conclusions: The EAT thickness of the left AV groove in patients with non-ischemic systolic HF is associated with the TPD of LV and LV systolic dyssynchrony. The EAT thickness of the AV groove has a good predictive value for the CRT response in patients with non-ischemic systolic HF.

Abstract 15815: Left Atrial Strain Characterizes the Atrio-ventricular Substrate Responsive to Cardiac Resynchronization Therapy in Patients With Intermediate Electrocardiographic Criteria

Introduction: Guidelines favor patient selection by left bundle branch block (LBBB) with QRS width ≥150 ms for cardiac resynchronization therapy (CRT). Predicting CRT response in patients with QRS width 120 to 149 ms or non-LBBB remains difficult. Left ventricular (LV) global longitudinal strain (GLS) and systolic stretch index (SSI) have shown to characterize the ventricular substrate responsive to CRT. However, the potential application of longitudinal left atrial (LA) strain remains unclear. Hypothesis: Baseline LA strain has prognostic value in CRT patients with intermediate ECG criteria. Methods: We studied 195 patients who underwent CRT based on routine indications: ejection fraction ≤35% and QRS width ≥120 ms. GLS was assessed using the 3 standard apical views. Radial SSI was derived from the mid LV short axis view. Peak longitudinal LA strain was derived from the 2 and 4-chamber apical view. The predefined combined clinical endpoint was death, heart transplant or left ventricular assist device over 4 years after CRT. Results: LA strain was feasible in 162 (83%) of the CRT candidates: QRS duration 156 ± 26 ms, 39.5% had LBBB with QRS ≥ 150ms, 60.5% had intermediate ECG criteria. High peak longitudinal strain (&gt;median, 10.1%) was associated with favorable event-free survival (p&lt;0.001). Patients with intermediate ECG criteria for CRT and both high peak longitudinal LA strain and high GLS (&gt;median, 8.4%) had similar outcome to those with Class I indications for CRT. Multivariable analysis revealed that LA strain had independent prognostic value (hazard ratio 0.9 per LA strain %, p &lt; 0.001) even after adjusted for other clinical, electrophysiological and echocardiographic covariates including QRS morphology and duration, GLS and SSI. Conclusions: Peak LA strain had important prognostic value in candidates for CRT. Prognostic value of LA strain was additive to LV strain characteristics and most significant in CRT patients with intermediate ECG criteria for CRT.

P1237Left ventricular myocardial work characteristics and CRT response in patients with LBBB according to Strauss criteria and ESC 2013 definition

Abstract Background The impact of left bundle branch block (LBBB) on left ventricular (LV) myocardial work may vary according to the specific definition of a LBBB. Quantification of the interplay between LV myocardial work and the underlying electrical dyssynchrony may improve our understanding of cardiac resynchronization therapy (CRT) response. Objective To evaluate the impact of LBBB, defined according to Strauss and ESC 2013 ECG criteria, as well as non-LBBB morphologies on different LV myocardial work indices and response to CRT. Methods LBBB was defined according to the Strauss criteria and ESC 2013 guidelines on heart failure. LV myocardial constructive and wasted work (CW and WW) were derived from pressure-strain loop analysis integrating valvular opening and closing times, speckle tracking strain echocardiography and noninvasive blood pressure measurement. LV myocardial work efficiency (WE) was calculated from the ratio of constructive work, divided by the sum of constructive and wasted work. CRT response was defined as a decrease in LV end-diastolic volume (EDV) ≥15% at 6 months' follow-up. Results Patients were divided into 3 groups: 1) LBBB according to Strauss criteria (group 1, n=109, age 64±10 years), 2) LBBB according to ESC 2013 criteria (group 2, n=22, age 64±10 years) and 3) non-LBBB (group 3, n=44, age 69±10 years). Patients from group 1 were 4.2 times more likely to respond to CRT than patients from group 3 (odds ratio [OR] 4.182; 95% confidence interval [CI], 1.999–8.750; p&lt;0.001), whereas CRT response between groups 2 and 3 did not differ significantly (OR 1.100; 95% CI 0.387–3.124; p=0.859). Patients in group 1, were characterized by significantly lower WE, compared to groups 2 and 3 (67.6±9.9 mmHg% vs. 72.7±9.7 mmHg% and 75.4±9.6 mmHg%, respectively; p&lt;0.001) as well as higher WW (313.2±144.9 mmHg% vs. 215.1±102.5 mmHg% and 229.0±113.5 mmHg%, respectively; p&lt;0.001). There was no significant difference in CW between any of the groups (811.6±353.4 mmHg% vs. 798.6±440.6 mmHg% and 893.6±420.2 mmHg% respectively for groups 1, 2 and 3; p=0.447). Conclusion Patients with a LBBB according to Strauss criteria had a higher probability of response to CRT, compared to those with a LBBB defined by ESC 2013 guidelines criteria or with non-LBBB morphology. This is reflected in a greater amount of wasted work and more impaired LV myocardial work efficiency at baseline in patients with LBBB satisfying Strauss criteria, compared to the other two groups, representing the substrate for CRT. Acknowledgement/Funding Study was supported by ESC Research grant 2018

An S wave in ECG lead V6 predicts poor response to cardiac resynchronization therapy and long-term outcome

Cardiac resynchronization therapy (CRT) is a standard treatment for selected patients with chronic heart failure(HF). However, up to 30%-50% of patients still do not respond to CRT. Our aim was to identify the predictive value of an S wave in lead V6 in CRT response in patients with complete left bundle branch block (CLBBB). The CLBBB definition included the Strauss left bundle branch block criteria and the absence of q waves in leads I, V5, and V6. According to the electrocardiogram at baseline, CLBBB patients were divided into 3 groups: T-CLBBB group (CLBBB without an S wave in lead V5 or V6), V5S group (CLBBB with an S wave in lead V5 and no S wave in lead V6), and V5&V6S group (CLBBB with S waves in leads V5 and V6). CRT response was defined as left ventricular end-systolic volume reduction ≥ 15% at 6-month follow-up. The combined end point included HF rehospitalization or all-cause death. Of 181 patients with left bundle branch block-like pattern, 112 patients with CLBBB were included into 3 groups: 54 in the T-CLBBB group, 32 in the V5S group, and 26 in the V5&V6S group. The CRT response rate was 85.2% (46), 65.6% (21), and 38.5% (10), respectively (P < .001). Kaplan-Meier curves demonstrated that patients in the V5&V6S group had a higher incidence of HF rehospitalization or all-cause death than those in the other 2 groups (P < .001). In a multivariate logistic regression model analysis, an S wave in lead V6 was significantly associated with CRT nonresponse (hazard ratio 0.33; 95% confidence interval 0.11-0.96; P = .042). An S wave in lead V6 can predict poor response to CRT and long-term outcome.

QRS Area Is a Strong Determinant of Outcome in Cardiac Resynchronization Therapy

The combination of left bundle branch block (LBBB) morphology and QRS duration is currently used to select patients for cardiac resynchronization therapy (CRT). These parameters, however, have limitations. This study evaluates the value of QRS area compared with that of QRS duration and morphology in the association with clinical and echocardiographic outcomes in a large cohort of CRT patients. A retrospective multicentre study was conducted in 1492 CRT patients. LBBB morphology, QRS duration, and QRS area in the baseline 12-lead ECG were evaluated for their association with the occurrence of the combined primary end point of all-cause mortality, cardiac transplantation, and left ventricular assist device implantation. Secondary end points were heart failure hospitalization within the first year after implantation and echocardiographic reduction in left ventricular end-systolic volume. During a mean follow-up period of 3.4 years, 32% of patients reached the primary end point. The association of QRS area with all outcomes was stronger than that of LBBB morphology and QRS duration separately and at least as strong as their combination. QRS area identified patients who did not experience the primary end point better than QRS morphology and QRS duration (area under the curve, 0.61 versus 0.55 and 0.51, respectively; P<0.001). Furthermore, QRS area identifies patients with echocardiographic remodeling in response to CRT better than QRS morphology and duration (area under the curve, 0.69 versus 0.58 and 0.58, respectively; P<0.001). QRS area was the only independent electrocardiographic determinant associated with the primary end point; hazard ratio, 0.50 (0.35-0.71). Furthermore, QRS area showed significant association with outcomes in both patients with and without LBBB and QRS ≥150 ms. QRS area has a strong association to clinical and echocardiographic response to CRT, at least as strong as current patient selection parameters. QRS area may be particularly useful to predict CRT response in patients without a wide LBBB.

Positive impact of pulmonary vein isolation on biventricular pacing in nonresponders to cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) is less effective in patients with atrial fibrillation (AF) because of impaired ventricular CRT capture. We investigated the effects of catheter ablation in patients with AF and previous nonresponse to CRT. Consecutive patients with AF and CRT nonresponse who underwent catheter ablation for AF were analyzed. CRT nonresponse was defined as one of the following: (1) reduced biventricular capture <95% due to rapidly conducted AF, (2) <1 point improvement in New York Heart Association (NYHA) class after CRT implantation, or (3) insufficient increase in left ventricular ejection fraction (LVEF; ≤5%) after CRT implantation. Thirty-eight patients (8 women [21%]; mean age 68±10 years; LVEF 30% ± 7%, biventricular capture 88.0% [25th, 75th percentile 75.3%, 98.5%]) underwent catheter ablation. One major and 1 minor complication occurred (1 lethal atrioesophageal fistula and 1 hemodynamically nonrelevant pericardial effusion). The Kaplan-Meier estimates for arrhythmia-free survival after single and multiple ablation procedures were 29% (95% confidence interval 16%-51%) and 67% (95% confidence interval 53%-86%) after 24 months. After a median follow-up of 817 days (25th, 75th percentile 179, 1741 days), biventricular capture and LVEF were significantly higher (median [25th, 75th percentile] 99% [96%, 99%], difference 8% [0.2%, 3.75%], P < .0001; mean 32.1% ± 9.1%, difference 2.2%± 7.1%, P = .0225) and patients had a significantly lower functional NYHA class (28 of 37 patients with improvement of at least 1 point; P < .0001). Catheter ablation of AF significantly improves CRT response in patients with heart failure and concomitant AF in terms of increased biventricular capture and LVEF and improved functional NYHA class.

Role of obstructive sleep apnea on the response to cardiac resynchronization therapy and all-cause mortality

The role of obstructive sleep apnea (OSA) on the response to cardiac resynchronization therapy (CRT) and all-cause mortality in patients with advanced heart failure (HF) is unknown. We assessed the association between OSA, response to CRT, and all-cause mortality in patients with HF. We analyzed records of 548 consecutive patients (mean age 65 ± 13 years; 216 (39%) women; mean follow-up period 76 ± 17 months) who received a CRT-defibrillator device from January 15, 2007 to March 30, 2016 at our tertiary care referral center. A total of 180 patients (33%) had OSA. Fewer patients in the OSA group (109 [61%]) had improvement in left ventricular ejection fraction (EF) than did those in the non-OSA group (253 [69%]) (P = .001). A total of 144 patients (27%) died by the end of follow-up (OSA group: 61 [33%]; non-OSA group 83 [23%]; P < .001). OSA diagnosis was associated with a lower chance of improvement in EF (hazard ratio 0.71; 95% confidence interval 0.60-0.89) and a higher risk of all-cause mortality (hazard ratio 3.7; 95% confidence interval 2.5-6.8). This was true in continuous positive airway pressure-compliant patients and in patients with nonischemic cardiomyopathy. However, among patients with ischemic cardiomyopathy, the chance of improvement in EF and all-cause mortality was similar in patients with OSA and those without OSA. OSA is associated with a decreased response to CRT and an increase in all-cause mortality in patients with HF. The differential effect of OSA on CRT response in patients with ischemic cardiomyopathy and nonischemic cardiomyopathy needs further study.

Patients with right bundle branch block and concomitant delayed left ventricular activation respond to cardiac resynchronization therapy.

Right bundle branch block (RBBB) typically presents with only delayed right ventricular activation. However, some patients with RBBB develop concomitant delayed left ventricular (LV) activation. Such patients may show a specific electrocardiographic (ECG) pattern resembling RBBB in the precordial leads in association with an insignificant S-wave in lateral limb leads (atypical RBBB). We therefore postulated that the ECG pattern of atypical RBBB might be able to identify a subgroup of patients likely to respond to cardiac resynchronization therapy (CRT). The purpose of this study was to assess the impact of RBBB ECG morphology on CRT response in patients with heart failure (HF). We evaluated the echocardiographic clinical response of 66 patients with RBBB treated with CRT and followed up for almost 2 years. The patients were divided electrocardiographically into 2 groups: 31 with typical RBBB and 35 with atypical RBBB. Responders were classified in terms of reduction in LV end-systolic volume index (ESVi) ≥ 15% or reduction in the New York Heart Association (NYHA) Class ≥ 1 or Packer score variation (NYHA response with no HF-related hospitalization events or death). The atypical RBBB group presented a longer LV activation time compared with the typical RBBB group (111.9 ± 17.6 vs. 73.2 ± 15.4 ms; P < 0.001). In the atypical and typical RBBB groups, respectively, 71.4% and 19.4% of patients were ESVi responders (P = 0.001) 74.3% and 32.3% were NYHA responders (P = 0.002); similarly, 71.4% and 29.0% of patients exhibited a 2-year Packer score of 0 (P = 0.002). Patients with atypical RBBB, which is a pattern highly suggestive of concomitant delayed LV conduction, may show a satisfactory response to CRT.

Does permanent atrial fibrillation modify response to cardiac resynchronization therapy in heart failure patients?

IntroductionThe benefits of cardiac resynchronization therapy (CRT) documented in heart failure (HF) may be influenced by atrial fibrillation (AF). We aimed to compare CRT response in patients in AF and in sinus rhythm (SR). MethodsWe prospectively studied 101 HF patients treated by CRT. Rates of clinical, echocardiographic and functional response, baseline NYHA class and variation, left ventricular ejection fraction, volumes and mass, atrial volumes, cardiopulmonary exercise test (CPET) duration (CPET dur), peak oxygen consumption (VO2max) and ventilatory efficiency (VE/VCO2 slope) were compared between AF and SR patients, before and at three and six months after implantation of a CRT device. ResultsAll patients achieved ≥95% biventricular pacing, and 5.7% underwent atrioventricular junction ablation. Patients were divided into AF (n=35) and SR (n=66) groups; AF patients were older, with larger atrial volumes and lower CPET dur and VO2max before CRT. The percentages of clinical and echocardiographic responders were similar in the two groups, but there were more functional responders in the AF group (71% vs. 39% in SR patients; p=0.012). In SR patients, left atrial volume and left ventricular mass were significantly reduced (p=0.015 and p=0.021, respectively), whereas in AF patients, CPET dur (p=0.003) and VO2max (p=0.001; 0.083 age-adjusted) showed larger increases. ConclusionClinical and echocardiographic response rates were similar in SR and AF patients, with a better functional response in AF. Improvement in left ventricular function and volumes occurred in both groups, but left ventricular mass reduction and left atrial reverse remodeling were seen exclusively in SR patients (ClinicalTrials.gov identifier: NCT02413151; FCT code: PTDC/DES/120249/2010).

Does permanent atrial fibrillation modify response to cardiac resynchronization therapy in heart failure patients?

IntroductionThe benefits of cardiac resynchronization therapy (CRT) documented in heart failure (HF) may be influenced by atrial fibrillation (AF). We aimed to compare CRT response in patients in AF and in sinus rhythm (SR). MethodsWe prospectively studied 101 HF patients treated by CRT. Rates of clinical, echocardiographic and functional response, baseline NYHA class and variation, left ventricular ejection fraction, volumes and mass, atrial volumes, cardiopulmonary exercise test (CPET) duration (CPET dur), peak oxygen consumption (VO2max) and ventilatory efficiency (VE/VCO2 slope) were compared between AF and SR patients, before and at three and six months after implantation of a CRT device. ResultsAll patients achieved ≥95% biventricular pacing, and 5.7% underwent atrioventricular junction ablation. Patients were divided into AF (n=35) and SR (n=66) groups; AF patients were older, with larger atrial volumes and lower CPET dur and VO2max before CRT. The percentages of clinical and echocardiographic responders were similar in the two groups, but there were more functional responders in the AF group (71% vs. 39% in SR patients; p=0.012). In SR patients, left atrial volume and left ventricular mass were significantly reduced (p=0.015 and p=0.021, respectively), whereas in AF patients, CPET dur (p=0.003) and VO2max (p=0.001; 0.083 age-adjusted) showed larger increases. ConclusionClinical and echocardiographic response rates were similar in SR and AF patients, with a better functional response in AF. Improvement in left ventricular function and volumes occurred in both groups, but left ventricular mass reduction and left atrial reverse remodeling were seen exclusively in SR patients (ClinicalTrials.gov identifier: NCT02413151; FCT code: PTDC/DES/120249/2010).

Cardiac resynchronization therapy when no lateral pacing option exists: vectorcardiographic guided non-lateral left ventricular lead placement predicts acute hemodynamic response.

A difficult cardiac resynchronization therapy (CRT) implantation scenario emerges when no lateral pacing option exists. The aim of this study was to explore the effect of biventricular pacing (BIVP) on vectorcardiographic parameters in patients with a non-lateral left ventricular (LV) lead position. We hypothesized that perimeter and area reduction for both the QRS complex and T-wave would predict acute CRT response. Twenty-six patients (14 ischaemic) with a mean age of 63 ± 10 years and standard CRT indication underwent device implantation with continuous LV pressure registration. The LV lead was placed in either an anterior or apical position. Biventricular pacing was performed at a rate 10% above intrinsic rhythm with acute CRT response defined as LV ΔdP/dtmax >10%. Using this criterion 12 patients were identified as acute CRT responders (responders: 16.7 ± 4.8% vs. non-responders: 1.9 ± 5.3%, P < 0.001). Vectorcardiographic assessment of the QRS complex and T-wave were performed at baseline and under BIVP. Based on the observed changes in three-dimensional area and perimeter, ΔQRS-area (responders: -46.7 ± 39.6% vs. non-responders: 1.1 ± 50.9%, P = 0.006) was considered as the preferred parameter. Receiver operating characteristic curve analysis identified -40% as the optimal cut-off value (sensitivity 67% and specificity 93%) for prediction of acute CRT response (AUC = 0.81, P < 0.01). A significant correlation was observed between LV ΔdP/dtmax and ΔQRS-area (R2 = 0.37, P = 0.001). ΔQRS-area is correlated to LV ΔdP/dtmax and predicts acute CRT response in patients with a non-lateral LV lead position. Assessment of ΔQRS-area might be a useful tool for patient specific LV lead placement when no lateral pacing option exists.

The importance of myocardial contractile reserve in predicting response to cardiac resynchronization therapy.

To perform a meta-analysis and systematic review of published data to assess the relationship between contractile reserve and response to cardiac resynchronization therapy (CRT) in patients with heart failure. We searched MEDLINE/PubMed and Cochrane for all papers published up to 26 April 2016, supplemented by manual searches of reference lists from retrieved articles. The search strategy yielded nine observational studies that met our eligibility criteria with a total of 767 patients of which 757 provided data for this analysis. Contractile reserve after dobutamine infusion was present in 496 patients (66%). During follow-up 474 patients (63%) qualified as CRT responders. The presence of contractile reserve was associated with a higher chance of CRT response (odds ratio 4.42, 95% confidence interval 2.15-9.07, P < 0.001) using a random-effects model. There was evidence of publication bias. Imputation of missing studies attenuated the association to some extent, but the positive association between contractile reserve and CRT response remained with an odds ratio of 2.42 (95% confidence interval 1.17-5.05, P = 0.018). The presence of global contractile reserve at baseline, as assessed by dobutamine stress echocardiography, is associated with a higher chance of CRT response in patients with heart failure.

Influence of Epicardial Left Ventricular Pacing Lead on the Response to Cardiac Resynchronization Therapy

Objectives: Cardiac resynchronization therapy (CRT) represents a "gold standard“ in the treatment of advanced heart failure if pharmacological therapy alone is not sufficient. The rationale for CRT is the resynchronization of ventricular dyssynchrony and therefore improvement of the impaired pump function of failing ventricles. Moreover, a reverse remodeling of the ventricle may occur. However, it has been suggested that 20% to 30% of patients do not respond to CRT. A non-optimal LV pacing lead position may be a potential cause for nonresponse to CRT. Due to low invasivity nowadays almost all primary LV-lead implantations are conducted in a transvenous approach. In this scenario the presence of a suitable venous anatomy is prerequisite for placing of LV lead at its most effective position. Epicardial left ventricular (eLV) leads represent an alternative for CRT if transvenous lead implantation fails. However, this approach allows placing the leads independently of venous anatomy. In our study we retrospectively investigated the CRT response in patients with eLV.

Does prior valve surgery change outcome in patients treated with cardiac resynchronization therapy?

Cardiac valve surgery (CVS) has been implicated as a potential barrier to optimal response after cardiac resynchronization therapy (CRT) though prospective data regarding outcome remains limited. We sought to determine CRT response in patients with a prior history of CVS. We performed a retrospective analysis of a prospectively acquired cohort of CRT patients with history of CVS. Echocardiographic response was evaluated at baseline and 6 months. The coprimary endpoints were time to first heart failure (HF) hospitalization and a composite of all-cause mortality, transplantation and left ventricular assist device (LVAD) assessed over a 3-year follow-up period. The study group consisted of 569 patients undergoing CRT. Of these, 86 patients had a history of CVS (46.5% aortic, 37.2% mitral, 16.3% combined, and tricuspid), and were compared to 483 patients with no history of CVS. Baseline clinical and echocardiographic characteristics were not significantly different between the groups except for a higher incidence of atrial fibrillation (AF; 74.4% vs. 55.3%; P = 0.001), coronary artery bypass surgery (CABG; 58.1% vs. 38.7%; P = 0.001), and longer QRS duration (167.6 ± 29.3 milliseconds vs. 159.4 ± 27.5 milliseconds; P = 0.01) in those with prior CVS. Survival with respect to HF hospitalization and composite outcome was comparable in both groups. Echocardiographic response (improvement in left ventricular ejection fraction of ≥10%) was similar. No difference in clinical or echocardiographic outcome was found by type of valve surgery performed. Despite a higher incidence of AF, CABG, and longer QRS duration, history of CVS is not associated with worse clinical or echocardiographic outcome after CRT.

Septal flash predicts cardiac resynchronization therapy response in patients with permanent atrial fibrillation

Patients with heart failure (HF) as well as atrial fibrillation (AF) have suboptimal response to cardiac resynchronization therapy (CRT). Identification of mechanical abnormalities, amenable to correction with CRT, might improve the selection of candidates and CRT efficiency. We evaluated whether abnormal septal motion, assessed by the presence of septal flash (SF) is related to CRT response in patients with AF. Ninety-four CRT patients with AF were included. Echocardiography was performed in all subjects at baseline and at 12-month follow-up. Abnormal septal motion was defined by the presence of SF (early septal inward/outward motion within the isovolumic contraction period/QRS duration). Response to CRT was defined as a reduction (>15%) of the end-systolic volume of the left ventricle (LV). Univariate and multivariate analyses were performed to identify the predictors of CRT response. The mean age was 69 ± 8 years, 79% were males, and 59% of patients responded to CRT. Cardiovascular death was 14.4% and all-cause mortality was 16.5% during follow-up. Patients with SF at baseline that was acutely corrected by CRT were significantly more likely to respond than patients without SF. Baseline SF was an independent predictor of CRT response (OR 5.24; 95% CI 1.95-14.11). Abnormal septal motion, assessed by the presence of SF, is a mechanism amenable to CRT correction. Its correction is associated with a higher likelihood of CRT response in HF patients with long-standing AF. This could improve the selection of candidates to CRT in a subgroup with particularly poor response and long-term prognosis.

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Echocardiographic Myocardial Scar Burden Predicts Response to Cardiac Resynchronization Therapy in Ischemic Heart Failure

Because echocardiography is routinely applied for left ventricle (LV) evaluation before cardiac resynchronization therapy (CRT), it is important to know whether echocardiographic assessment of myocardial scar burden may also help to predict CRT response in patients with drug-refractory systolic heart failure of ischemic origin. Seventy-one patients with ischemic heart failure who underwent CRT were retrospectively analyzed. The number of LV scar segments was evaluated in each patient, defining transmural scar as an end-diastolic wall thickness < or = 5 mm associated with increased acoustic reflectance. CRT response was defined by LV end-systolic volume decrease by at least 10% after 6 months of treatment. The role of pacing site with respect to scar location was also assessed. Thirty-nine patients (55%) were responders and 32 patients (45%) were nonresponders to CRT. At baseline, responders had a lower number of scar segments (1.7 +/- 1.6 vs 3.5 +/- 2.5, P = .001). The number of scar segments was significantly associated with CRT response and correlated significantly with end-systolic volume variation (r = 0.57, P = .0001). The presence of 3 or more scar segments allowed the identification of nonresponders with a sensitivity of 62% and specificity of 71%. In responders, the pacing stimulus was more frequently delivered remote from scar segments, whereas in nonresponders it was more often delivered over the scar segments. Echocardiographic evaluation of transmural scar burden predicts CRT response after 6 months of treatment and should be performed in all candidates for CRT with ischemic heart failure before biventricular pacemaker implantation.