Predictors of left ventricular reverse remodeling after cardiac resynchronization therapy for heart failure secondary to idiopathic dilated or ischemic cardiomyopathy

A Comparative Analysis of Apical Rocking and Septal Flash: Two Views of the Same Systole?

Heart failure (HF) is a complex medical condition characterized by both electrical and mechanical dyssynchrony. Both dyssynchrony mechanisms are intricately linked together, but the current guidelines for cardiac resynchronization therapy (CRT) rely only on the electrical dyssynchrony criteria, such as the QRS complex duration. This possible inconsistency may result in undertreating eligible individuals who could benefit from CRT due to their mechanical dyssynchrony, even if they fail to fulfill the electrical criteria. The main objective of this literature review is to provide a comprehensive analysis of the practical value of echocardiography for the assessment of left ventricular (LV) dyssynchrony using parameters such as septal flash and apical rocking, which have proven their relevance in patient selection for CRT. The secondary objectives aim to offer an overview of the relationship between septal flash and apical rocking, to emphasize the primary drawbacks and benefits of using echocardiography for evaluation of septal flash and apical rocking, and to offer insights into potential clinical applications and future research directions in this area. Conclusion: there is an opportunity to render resynchronization therapy more effective for every individual; septal flash and apical rocking could be a very useful and straightforward echocardiography resource.

Comparison of serum N-terminal pro-brain natriuretic peptide levels, conventional echocardiography, exercise parameters, and dyssynchrony measurements in Fontan patients

INTRODUCTION

Little data are available concerning the methods used in the long-term follow-up of Fontan patients. We analyzed the association between serum N-terminal pro-brain natriuretic peptide levels, conventional echocardiography findings, exercise parameters, and dyssynchrony measurements in patients who underwent Fontan surgery.

METHODS

This study included 28 patients who underwent Fontan surgery (mean age 12.8 ± 4.36 years) and 27 healthy controls (mean age 12.5 ± 3.76 years). Echocardiography examinations and exercise tests were performed in both groups. The systemic ventricle was examined via echocardiography, dyssynchrony measurement was performed, the systemic ventricular myocardial performance index was calculated, and serum N-terminal pro-brain natriuretic peptide levels were measured for all subjects.

RESULTS

Lower cardiac output, stroke volume, maximal work, chronotropic index, maximal oxygen uptake, and higher N-terminal pro-brain natriuretic peptide levels were observed in the Fontan group than in the control group (p < 0.05). A negative correlation was found between physical exercise parameters and N-terminal pro-brain natriuretic peptide levels and dyssynchrony measurements.

CONCLUSION

Measurements of exercise capacity, serum N-terminal pro-brain natriuretic peptide levels, and dyssynchrony measurement were more valuable than conventional methods for assessing patients' clinical and functional status. Dyssynchrony measurements provided better information about ventricular status than did conventional echocardiography studies. While patients' systolic function determined by conventional echocardiography was normal, dyssynchrony measurements showed the opposite result. The negative relationship between serum N-terminal pro-brain natriuretic peptide levels, dyssynchrony measurements, and exercise capacity suggests that these parameters should be investigated further in Fontan patients.

The saga of dyssynchrony imaging: Are we getting to the point

Cardiac resynchronisation therapy (CRT) has an established role in the management of patients with heart failure, reduced left ventricular ejection fraction (LVEF &lt; 35%) and widened QRS (&gt;130 msec). Despite the complex pathophysiology of left ventricular (LV) dyssynchrony and the increasing evidence supporting the identification of specific electromechanical substrates that are associated with a higher probability of CRT response, the assessment of LVEF is the only imaging-derived parameter used for the selection of CRT candidates.

This review aims to (1) provide an overview of the evolution of cardiac imaging for the assessment of LV dyssynchrony and its role in the selection of patients undergoing CRT; (2) highlight the main pitfalls and advantages of the application of cardiac imaging for the assessment of LV dyssynchrony; (3) provide some perspectives for clinical application and future research in this field.

Conclusion

the road for a more individualized approach to resynchronization therapy delivery is open and imaging might provide important input beyond the assessment of LVEF.

Considering Diastolic Dyssynchrony as a Predictor of Favorable Response in LV-Only Fusion Pacing Cardiac Resynchronization Therapy

Background: CRT improves systolic and diastolic function, increasing cardiac output. Aim of the study: to assess the outcome of LV diastolic dyssynchrony in a population of fusion pacing CRT. Methods: Diastolic dyssynchrony was measured by offline speckle-tracking-derived TDI timing assessment of the simultaneity of E″ and A″ basal septal and lateral walls. New parameters introduced: E″ and, respectively, A″ time (E″T/A″T) as the time difference between E″ (respectively, A″) peak septal and lateral wall. Patients were divided into super-responders (SR), responders (R), and non-responders (NR). Results: Baseline characteristics: 62 pts (62 ± 11 y.o.) with idiopathic DCM, EF 27 ± 5.2%; 29% type III diastolic dysfunction (DD), 63% type II, 8% type I. Average follow-up 45 ± 19 months: LVEF 37 ± 7.9%, 34%SR, 61%R, 5%NR. The E″T decreased from 90 ± 20 ms to 25 ± 10 ms in SR with significant LV reverse remodeling (LV end-diastolic volume 193.7 ± 81 vs. 243.2 ± 82 mL at baseline, p < 0.0028) and lower LV filling pressures (E/E' 13.2 ± 4.6 vs. 11.4 ± 4.5, p = 0.0295). DD profile improved in 65% of R with a reduction in E/E' ratio (21 ± 9 vs. 14 ± 4 ms, p < 0.0001). Significant cut-off value calculated by ROC curve for LV diastolic dyssynchrony is E″T > 80 ms and A″T > 30 msec. Conclusions: The study identifies the cut-off values of diastolic dyssynchrony parameters as predictors of favorable outcomes in responders and super-responder patients with fusion CRT pacing. These findings may have important implications in patient selection and follow-up.

Beta-blockers and mechanical dyssynchrony in heart failure assessed by radionuclide ventriculography

BACKGROUND

Radionuclide ventriculography (RNVG) can be used to quantify mechanical dyssynchrony and may be a valuable adjunct in the assessment of heart failure with reduced ejection fraction (HFrEF). The study aims to investigate the effect of beta-blockers on mechanical dyssynchrony using novel RNVG phase parameters.

METHODS

A retrospective study was carried out in a group of 98 patients with HFrEF. LVEF and dyssynchrony were assessed pre and post beta-blockade. Dyssynchrony was assessed using synchrony, entropy, phase standard deviation, approximate entropy, and sample entropy from planar RNVG phase images. Subgroups split by ischemic etiology were also investigated.

RESULTS

An improvement in dyssynchrony and LVEF was measured six months post beta-blockade for both ischemic and non-ischemic groups.

CONCLUSIONS

A significant improvement in dyssynchrony and LVEF was measured post beta-blockade using novel measures of dyssynchrony.

The Role of Cardiac Resynchronization Therapy for the Management of Functional Mitral Regurgitation

Valve leaflets and chordae structurally normal characterize functional mitral regurgitation (FMR), which in heart failure (HF) setting results from an imbalance between closing and tethering forces secondary to alterations in the left ventricle (LV) and left atrium geometry. In this context, FMR impacts the quality of life and increases mortality. Despite multiple medical and surgical attempts to treat FMR, to date, there is no univocal treatment for many patients. The pathophysiology of FMR is highly complex and involves several underlying mechanisms. Left ventricle dyssynchrony may contribute to FMR onset and worsening and represents an important target for FMR management. In this article, we discuss the mechanisms of FMR and review the potential therapeutic role of CRT, providing a comprehensive review of the available data coming from clinical studies and trials.

First-Phase Ejection Fraction Predicts Response to Cardiac Resynchronization Therapy and Adverse Outcomes

OBJECTIVES

The aim of this study was to examine the value of first-phase ejection fraction (EF1), to predict response to cardiac resynchronization therapy (CRT) and clinical outcomes after CRT.

BACKGROUND

CRT is an important treatment for patients with chronic heart failure. However, even in carefully selected cases, up to 40% of patients fail to respond. EF1, the ejection fraction up to the time of maximal ventricular contraction, is a novel sensitive echocardiographic measure of early systolic function and might relate to response to CRT.

METHODS

An initial retrospective study was performed in 197 patients who underwent CRT between 2009 and 2018 and were followed to determine clinical outcomes at King's Health Partners in London. A validation study (n = 100) was performed in patients undergoing CRT at Barts Heart Centre in London.

RESULTS

Volumetric response rate (reduction in end-systolic volume ≥15%) was 92.3% and 12.1% for those with EF1 in the highest and lowest tertiles (P < 0.001). A cutoff value of 11.9% for EF1 had >85% sensitivity and specificity for prediction of response to CRT; on multivariate binary logistic regression analysis incorporating previously defined predictors, EF1 was the strongest predictor of response (odds ratio [OR]: 1.56 per 1% change in EF1; 95% CI: 1.37-1.78; P < 0.001). EF1 was also the strongest predictor of improvement in clinical composite score (OR: 1.11; 95% CI: 1.04-1.19; P = 0.001). Improvement in EF1 at 6 months after CRT implantation (6.5% ± 5.8% vs 1.8% ± 4.3% in responders vs nonresponders; P < 0.001) was the best predictor of heart failure rehospitalization and death after median follow-up period of 20.3 months (HR: 0.81; 95% CI: 0.73-0.90; P < 0.001). In the validation cohort, EF1 was a similarly 1strong predictor of response (OR: 1.45; 95% CI: 1.23-1.70; P < 0.001) as in the original cohort.

CONCLUSIONS

EF1 is a promising marker to identify patients likely to respond to CRT.

Left atrial reverse remodeling predicts long-term survival after cardiac resynchronization therapy

BACKGROUND

Left ventricular (LV) reverse remodeling has been identified as a strong predictor of long-term survival in patients receiving CRT. Interestingly, CRT induces reverse remodeling in the left atrium (LA) as well. It is currently unknown to what extent LA reverse remodeling is correlated to long-term survival after CRT. This study aims to assess the long-term prognostic value of left atrium (LA) reverse remodeling in patients undergoing cardiac resynchronization therapy (CRT).

METHODS

Baseline and 3-months follow-up echocardiograms after CRT implantation were prospectively assessed to determine changes in left ventricular end-systolic volume (LVESV), left ventricular ejection fraction (LVEF), left atrial volume (LAV), and left atrial reservoir strain (LAS_r). Multivariate Cox regression analysis was performed to identify predictors for long-term survival.

RESULTS

In our study population of 99 patients with a mean follow-up of 6.3 ± 2.1 years, 43 patients (43%) reached the end-point of all-cause mortality. More extensive LA reverse remodeling, as measured by a relative increase in LAS_r, was observed in survivors compared to non-survivors (43 [29-64] % vs. 8 [2-28] %, P < 0.001, respectively). After multivariate analysis, delta LAS_r remained the only significant predictor of mortality [HR per 5%: 0.90 (0.86-0.95); AUC 0.78 (0.68-0.88)].

CONCLUSION

An increase in LAS_r is associated with favorable long-term outcome after CRT. The observed clinical importance of LA reverse remodeling after CRT asks for further validation in larger prospective cohorts.

Left ventricular dyssynchrony and post-systolic shortening in young bodybuilders using anabolic-androgenic steroids

Left ventricular (LV) remodeling, characterized by increased LV hypertrophy and depressed systolic and diastolic function, is observed in strength-trained athletes who use anabolic-androgenic steroids (AAS). Previous studies suggested a pathological remodeling with an increase in cardiac fibrosis in these athletes, which could promote intraventricular dyssynchrony. In this context, this study evaluated LV dyssynchrony in strength-trained athletes using AAS, hypothesizing that the use of AAS would lead to an increase in post-systolic shortening. Forty-four male subjects (aged 20-40 yr) were divided into three age-matched groups: strength-trained athletes using (users, n = 14) or not (nonusers, n = 15) AAS and healthy sedentary men (controls, n = 15). After completing a survey, each participant was assessed with two-dimensional (2D)-strain echocardiography. LV dyssynchrony was quantified using the standard deviation (SD) of the time to peak for longitudinal strain of the 18 LV-segments (from the apical 4, 3, and 2 chambers views), the longitudinal strain delay index (LSDI), and the segmental post-systolic index (PSI). Users showed mean AAS dosages of 564 ± 288 mg[Formula: see text]wk^-1 with a mean protocol duration of 12 ± 6 wk and a history of use of 4.7 ± 1.8 yr. They exhibited a greater LV mass index and depressed systolic and diastolic function when compared with both nonusers and controls. The decrease in LV strain in users was predominantly observed at the interventricular septum level (-16.9% ± 2.5% vs. -19.2% ± 1.8% and -19.0% ± 1.6% in users, nonusers, and controls, respectively, P < 0.01). Users showed higher SD than controls (43 ± 8 ms vs. 32 ± 5 ms, respectively, P < 0.01). The LSDI was significantly higher in users compared with both nonusers and controls (-23.4 ± 9.5 vs. -15.9 ± 9.3 and -9.8 ± 3.9, respectively, P < 0.01). PSI, calculated on the basal inferoseptal, basal anteroseptal, and basal inferolateral segments, were also greater in users compared with the two other groups. Our results reported an increase in LV dyssynchrony in young AAS users that brought new evidences of a pathologic cardiac remodeling in this specific population.NEW & NOTEWORTHY Illicit androgenic anabolic steroids (AAS) use is widespread, but data on LV dyssynchrony are lacking, although it could be increased by a higher prevalence of myocardial fibrosis reported in this population. In AAS users, the decrease in LV strain was predominantly observed in interventricular segments. All dyssynchrony indices were higher in AAS users and several segments exhibited post-systolic shortening. These results showed an association between AAS consumption, LV remodeling, and dyssynchrony.

Association of QRS narrowing with response to cardiac resynchronization therapy-a systematic review and meta-analysis of observational studies

Prolonged QRS duration, which reflects a higher degree of mechanical dysynchrony, is a predictor of response to CRT. However, the association of QRS narrowing after biventricular pacing with CRT response rates is not clear. Our aim was to conduct a systematic review and meta-analysis on the association between QRS narrowing after cardiac resynchronization therapy (CRT) and clinical and echocardiographic response to CRT in patients with heart failure. Two independent investigators searched MedLine and EMBASE databases through July 2018 without any limitations. Studies providing estimates (continuous data) on the association of QRS shortening with either clinical (defined as New York Heart Association (NYHA) reduction ≥ 1) or echocardiographic (defined as left ventricular end-systolic volume (LVESV) reduction ≥ 15%) response to CRT were finally included in the quantitative synthesis. We included 32 studies (14 studies (1274 patients mean age 64 years old, males 79.3%) using clinical CRT response and 18 studies (1270 patients, mean age 64 years old, males 69.1%) using echocardiographic CRT response). A significant association between QRS narrowing and shorter attained QRS duration with clinical and echocardiographic CRT response was observed. The observed association was independent of the timing of QRS width measurement after CRT implantation. Acute and late improvement of electrical dysynchrony as depicted by QRS narrowing following biventricular pacing is associated with clinical and echocardiographic response to CRT. However, large prospective studies are needed to further examine our findings.

Echocardiographic view and feature selection for the estimation of the response to CRT

Cardiac resynchronization therapy (CRT) is an implant-based therapy applied to patients with a specific heart failure (HF) profile. The identification of patients that may benefit from CRT is a challenging task and the application of current guidelines still induce a non-responder rate of about 30%. Several studies have shown that the assessment of left ventricular (LV) mechanics by speckle tracking echocardiography can provide useful information for CRT patient selection. A comprehensive evaluation of LV mechanics is normally performed using three different echocardioraphic views: 4, 3 or 2-chamber views. The aim of this study is to estimate the relative importance of strain-based features extracted from these three views, for the estimation of CRT response. Several features were extracted from the longitudinal strain curves of 130 patients and different methods of feature selection (out-of-bag random forest, wrapping and filtering) have been applied. Results show that more than 50% of the 20 most important features are calculated from the 4-chamber view. Although features from the 2- and 3-chamber views are less represented in the most important features, some of the former have been identified to provide complementary information. A thorough analysis and interpretation of the most informative features is also provided, as a first step towards the construction of a machine-learning chain for an improved selection of CRT candidates.

The non-invasive assessment of myocardial work by pressure-strain analysis: clinical applications

Pressure–volume (PV) analysis is the most comprehensive way to describe cardiac function, giving insights into cardiac mechanics and energetics. However, PV analysis still remains a highly invasive and time-consuming method, preventing it from integration into clinical practice. Most of the echocardiographic parameters currently used in the clinical routine to characterize left ventricular (LV) systolic function, such as LV ejection fraction and LV global longitudinal strain, do not take the pressure developed within the LV into account and therefore fall too short in describing LV function as a hydraulic pump. Recently, LV pressure-strain analysis has been introduced as a new technique to assess myocardial work in a non-invasive fashion. This new method showed new insights in comparison to invasive measurements and was validated in different cardiac pathologies, e.g., for the detection of coronary artery disease, cardiac resynchronization therapy (CRT)-response prediction, and different forms of heart failure. Non-invasively assessed myocardial work may play a major role in guiding therapies and estimating prognosis. However, its incremental prognostic validity in comparison to common echocardiographic parameters remains unclear. This review aims to provide an overview of pressure-strain analysis, including its current application in the clinical arena, as well as potential fields of exploitation.

Associations of the Prognostic Nutritional Index with the Cardiac Function and Survival after Cardiac Resynchronization Therapy

Objective The relationship between changes in the nutritional status after cardiac resynchronization therapy (CRT) and the prognosis has not been fully elucidated. We aimed to evaluate the changes in the nutritional status as assessed by the prognostic nutritional index (PNI) and their associations with the improvement in the cardiac function and subsequent clinical outcomes. Methods The study population consisted of 119 patients with a CRT-device. They were divided into 2 groups, based on whether their PNI had increased at 6 months after CRT-device implantation (positive ΔPNI group, n=73) or not (negative ΔPNI group, n=46). The left ventricular (LV) end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), and LV ejection fraction (LVEF) were measured before and six months after CRT-device implantation. We compared the changes in the cardiac function and prevalence of adverse events (re-hospitalization due to worsening heart failure or all cause death) between the two groups. Results In the positive ΔPNI group, the LVEDV (186±93 mL vs. 149±71 mL, p<0.05) and LVESV (134±75 mL vs. 98±62 mL, p<0.05) were significantly decreased 6 months after CRT-device implantation. In addition, the LVEF (31±11% vs. 37±12%, p<0.05) was significantly increased after CRT-device implantation. In the negative ΔPNI group, no significant changes were observed in any echocardiographic parameters. During a median follow-up period of 914 days, there were 67 (56.3%) adverse events. In the Kaplan-Meier analysis, the positive ΔPNI group was associated with a lower risk of adverse events than the negative ΔPNI group (50.6% vs. 65.2%, log-rank p=0.042). Conclusion Our results suggest that improvement in the cardiac function after CRT-device implantation is associated with increases in the PNI, resulting in favorable outcomes.

Economic implications of adding a novel algorithm to optimize cardiac resynchronization therapy: rationale and design of economic analysis for the AdaptResponse trial

AIMS

Although cardiac resynchronization therapy (CRT) has proven beneficial in several randomized trials, a subset of patients have limited clinical improvement. The AdaptivCRT algorithm provides automated selection between synchronized left ventricular or biventricular pacing with optimization of atrioventricular delays. The rationale and design of the economic analysis of the AdaptResponse clinical trial are described.

RATIONALE

The costs associated with HF hospitalization are substantial and are compounded by a high rate of readmission. HF hospitalization payments range from $1,001 for Greece to $12,235 for US private insurance. When examining the breakdown of HF-related costs, it is clear that approximately 55% of the hospitalization costs are directly attributable to length of stay. Notably, the mean costs of a CRT patient in need of a HF-related hospitalization are currently estimated to be an average of $10,679.

METHODS

The economic analysis of the AdaptResponse trial has two main objectives. The hospital provider objective seeks to test the hypothesis that AdaptivCRT reduces the incidence of all-cause re-admissions after a heart failure admission within 30 days of the index event. A negative binomial regression model will be used to estimate and compare the number of readmissions after an index HF hospitalization. The payer economic objective will assess cost-effectiveness of CRT devices with the AdaptivCRT algorithm relative to traditional CRT programming. This analysis will be conducted from a U.S. payer perspective. A decision analytic model comprised of a 6-month decision tree and a Markov model for long term extrapolation will be used to evaluate lifetime costs and benefits.

CONCLUSION

AdaptivCRT may offer improvements over traditional device programming in patient outcomes. How the data from AdaptResponse will be used to demonstrate if these clinical benefits translate into substantial economic gains is herein described.

Lateral left ventricular lead position is superior to posterior position in long-term outcome of patients who underwent cardiac resynchronization therapy

Aims

Preferring side branch of coronary sinus during cardiac resynchronization therapy (CRT) implantation has been empirical due to the limited data on the association of left ventricular (LV) lead position and long‐term clinical outcome. We evaluated the long‐term all‐cause mortality by LV lead non‐apical positions and further characterized them by interlead electrical delay (IED).

Methods and results

In our retrospective database, 2087 patients who underwent CRT implantation were registered between 2000 and 2018. Those with non‐apical LV lead locations were classified into anterior (n = 108), posterior (n = 643), and lateral (n = 1336) groups. All‐cause mortality was assessed by Kaplan–Meier and Cox analyses. Echocardiographic response was measured 6 months after CRT implantation. During the median follow‐up time of 3.7 years, 1150 (55.1%) patients died—710 (53.1%) with lateral, 78 (72.2%) with anterior, and 362 (56.3%) with posterior positions. When we investigated the risk of all‐cause mortality, there was a significantly lower rate of death in patients with lateral LV lead location when compared with those with an anterior (P < 0.01) or posterior (P < 0.01) position. Multivariate analysis after adjustment for relevant clinical covariates such as age, sex, ischaemic aetiology, left bundle branch block morphology, atrial fibrillation, and device type revealed consistent results that lateral position is associated with a significant risk reduction of all‐cause mortality when compared with anterior [hazard ratio 0.69; 95% confidence interval (CI) 0.55–0.87; P < 0.01] or posterior (hazard ratio 0.84; 95% CI 0.74–0.96; P < 0.01) position. When echocardiographic response was evaluated within the lateral group, patients with an IED longer than 110 ms (area under the receiver operating characteristic curve, 0.63; 95% CI 0.53–0.73; P = 0.012) showed 2.1 times higher odds of improvement in echocardiographic response 6 months after the implantation.

Conclusions

In this study, we proved in a real‐world patient population that after CRT implantation, lateral LV lead location was associated with long‐term mortality benefit and is superior to both anterior and posterior positions. Moreover, patients with this position showed the greatest echocardiographic response over 110 ms IED.

Multi-Modality Imaging in Dilated Cardiomyopathy: With a Focus on the Role of Cardiac Magnetic Resonance

Heart failure (HF) is recognized as a leading cause of morbidity and mortality worldwide. Dilated cardiomyopathy (DCM) is a common phenotype in patients presenting with HF. Timely diagnosis, appropriate identification of the underlying cause, individualized risk stratification, and prediction of clinical response to treatment have improved the prognosis of DCM over the last few decades. In this article, we reviewed the current evidence on available imaging techniques used for DCM patients. In this direction, we evaluated appropriate scenarios for the implementation of echocardiography, nuclear imaging, and cardiac computed tomography, and we focused on the primordial role that cardiac magnetic resonance (CMR) holds in the diagnosis, prognosis, and tailoring of therapeutic options in this population of special clinical interest. We explored the predictive value of CMR toward left ventricular reverse remodeling and prediction of sudden cardiac death, thus guiding the decisions for device therapy. Principles underpinning the use of state-of-the-art CMR techniques such as parametric mapping and feature-tracking strain analysis are also provided, along with expectations for the anticipated future advances in this field. We also attempted to correlate the evidence with clinical practice, with the intent to address questions on selecting the optimal imaging method for different indications and clinical needs. Overall, we recommend a comprehensive assessment of DCM patients at baseline and at follow-up intervals depending on the clinical status, with the addition of CMR as a second-line modality to other imaging techniques. We also provide an algorithm to guide the detailed imaging approach of the patient with DCM. We expect that future guidelines will upgrade their clinical recommendations for the utilization of CMR in DCM, which is expected to further improve the quality of care and the outcomes. This review provides an up-to-date perspective on the imaging of dilated cardiomyopathy patients and will be of clinical value to training doctors and physicians involved in the area of heart failure.

Biventricular pacemaker therapy improves exercise capacity in patients with non-obstructive hypertrophic cardiomyopathy via augmented diastolic filling on exercise

AIMS

Treatment options for patients with non-obstructive hypertrophic cardiomyopathy (HCM) are limited. We sought to determine whether biventricular (BiV) pacing improves exercise capacity in HCM patients, and whether this is via augmented diastolic filling.

METHODS AND RESULTS

Thirty-one patients with symptomatic non-obstructive HCM were enrolled. Following device implantation, patients underwent detailed assessment of exercise diastolic filling using radionuclide ventriculography in BiV and sham pacing modes. Patients then entered an 8-month crossover study of BiV and sham pacing in random order, to assess the effect on exercise capacity [peak oxygen consumption (VO₂ )]. Patients were grouped on pre-specified analysis according to whether left ventricular end-diastolic volume increased (+LVEDV) or was unchanged/decreased (-LVEDV) with exercise at baseline. Twenty-nine patients (20 male, mean age 55 years) completed the study. There were 14 +LVEDV patients and 15 -LVEDV patients. Baseline peak VO₂ was lower in -LVEDV patients vs. +LVEDV patients (16.2 ± 0.9 vs. 19.9 ± 1.1 mL/kg/min, P = 0.04). BiV pacing significantly increased exercise ΔLVEDV (P = 0.004) and Δstroke volume (P = 0.008) in -LVEDV patients, but not in +LVEDV patients. Left ventricular ejection fraction and end-systolic elastance did not increase with BiV pacing in either group. This translated into significantly greater improvements in exercise capacity (peak VO₂  + 1.4 mL/kg/min, P = 0.03) and quality of life scores (P = 0.02) in -LVEDV patients during the crossover study. There was no effect on left ventricular mechanical dyssynchrony in either group.

CONCLUSION

Symptomatic patients with non-obstructive HCM may benefit from BiV pacing via augmentation of diastolic filling on exercise rather than contractile improvement. This may be due to relief of diastolic ventricular interaction.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT00504647.

Patient-tailored SyncAV algorithm: A novel strategy to improve synchrony and acute hemodynamic response in heart failure patients treated by cardiac resynchronization therapy

INTRODUCTION

Several automatic algorithms have developed to optimize the timing cycle setting in cardiac resynchronization therapy (CRT). The present study aims to investigate whether the novel device-based SyncAV algorithm could elicit better synchrony and acute hemodynamic response.

METHODS AND RESULTS

Thirty five patients undergoing CRT implantation were prospectively studied. The device was programmed to three biventricular (BiV) pacing modes sequentially after the procedure: QuickOpt algorithm (mode I), SyncAV algorithm with default 50 ms offset (mode II), and SyncAV algorithm with optimized offset minimizing QRS duration (QRSd) (mode III). After each setting, electrocardiographic and echocardiographic data were collected. As a result, QRSd was reduced from 172.8 ± 17.9 ms during intrinsic conduction to 153.1 ± 15.9 ms in mode I, further narrowed to 140.5 ± 16.7 ms in mode II, and reached shortest (134.8 ± 16.1 ms) in mode III (P < .01 for all). Besides, significantly shorter QT intervals were observed in mode I (453.2 ± 45.5 ms), mode II (443.9 ± 34.2 ms) and mode III (444.1 ± 28.7 ms), compared with native condition (472.5 ± 51.2 ms) (P < .01). All three BiV modes exhibited comparable T_p T_e interval and T_p T_e /QT ratio (P > .05). Mode I presented significantly higher aortic velocity time integral than intrinsic conduction (21.0 ± 6.4 cm vs 18.4 ± 5.5 cm; P < .01), which was even higher in mode II (22.0 ± 6.5 cm) and mode III (23.7 ± 6.5 cm). All three BiV modes significantly reduced standard deviation of time to peak contraction of 12-LV segments (Ts-SD) (Mode I: 55.2 ± 16.5 ms, Mode II: 50.2 ± 14.7 ms, Mode III: 45.4 ± 14.4 ms) compared with intrinsic conduction (66.3 ± 18.4 ms) (P < .01), with Mode III demonstrating the smallest (P < .01).

CONCLUSION

SyncAV CRT ameliorated electrical and mechanical synchrony as well as acute hemodynamic response beyond conventional QuickOpt optimization. An additional individualized adjustment to the SyncAV offset added to its advantage.

Predictors of Left Ventricular Remodeling Post Acute Myocardial Infarction. Protocol for a Clinical Study

Heart failure is a clinical syndrome that appears as a consequence of a structural disease, and the most common cause of left ventricular systolic dysfunction results from myocardial ischemia. Cardiac remodeling and neuroendocrine activation are the major compensatory mechanisms in heart failure. The main objective of the study is to identify the association between serum biomarkers illustrating the extent of myocardial necrosis (highly sensitive troponin as-says), left ventricular dysfunction (NT-proBNP), and systemic inflammatory response (illustrated via serum levels of hsCRP and interleukins) during the acute phase of a myocardial infarction, and the left ventricular remodeling process at 6 months following the acute event, quantified via speckle tracking echocardiography. The study will include 400 patients diagnosed with acute myocardial infarction without signs and symptoms of heart failure at the time of enrollment that will undergo a complex clinical examination and speckle tracking echocardiography. Serum samples from the peripheral blood will be collected in order to determine the inflammatory serum biomarkers. After 6 months, patients will be divided into 2 groups according to the development of ventricular remodeling, quantified by speckle tracking echocardiography: group 1 will consist of patients with a remodeling index lower than 15%, and group 2 will consist of patients with a remodeling index higher than 15%. All clinical and imaging data obtained at the baseline will be compared between these two groups in order to determine the features associated with a higher risk of deleterious ventricular remodeling and heart failure.

Index of contractile asymmetry improves patient selection for CRT: a proof-of-concept study

BACKGROUND

Nearly one-third of heart failure (HF) patients do not respond to cardiac resynchronization therapy (CRT) despite having left bundle branch block (LBBB). The aim of the study was to investigate a novel method of quantifying left ventricular (LV) contractile asymmetry in HF.

METHODS

Patients with HF and LBBB undergoing CRT (n = 89, 37.1% females, 68 ± 9 years, ischemic etiology in 61%, LV ejection fraction 27.1 ± 7.1%) were analyzed. LV longitudinal systolic strain rate values were extracted from curved anatomical M-mode plots of standard long-axis 2D-echocardiography images and cubic spline interpolation was used to generate a 3D-phantom. Index of contractile asymmetry (ICA) was calculated based on standard deviation of differences in strain rate of opposing walls. Average ICA was individually assessed pairwise in 12 opposing 30-degree LV sectors. Reduction in LV end-systolic volume (ESV) ≥15% after 6 months was considered as positive response to CRT.

RESULTS

CRT response was found in 66 (74.2%) patients. Responders with both ischemic and non-ischemic cardiomyopathy had a higher and more extensive contractile asymmetry at baseline and achieved a greater ICA reduction after CRT than non-responders. Higher baseline ICA predicted higher degree and wider extent of ICA improvement. Also, both ICA at baseline and reduction of ICA correlated with the degree of ESV reduction after CRT.

CONCLUSIONS

Quantification of asymmetrical LV activation in 3D by ICA provides valuable insights into LV contraction in case of LBBB and is a promising tool for improved patient selection for CRT.

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

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.

Cardiac Resynchronisation Therapy and Cellular Bioenergetics: Effects Beyond Chamber Mechanics

Cardiac resynchronisation therapy is a cornerstone in the treatment of advanced dyssynchronous heart failure. However, despite its widespread clinical application, precise mechanisms through which it exerts its beneficial effects remain elusive. Several studies have pointed to a metabolic component suggesting that, both in concert with alterations in chamber mechanics and independently of them, resynchronisation reverses detrimental changes to cellular metabolism, increasing energy efficiency and metabolic reserve. These actions could partially account for the existence of responders that improve functionally but not echocardiographically. This article will attempt to summarise key components of cardiomyocyte metabolism in health and heart failure, with a focus on the dyssynchronous variant. Both chamber mechanics-related and -unrelated pathways of resynchronisation effects on bioenergetics – stemming from the ultramicroscopic level – and a possible common underlying mechanism relating mechanosensing to metabolism through the cytoskeleton will be presented. Improved insights regarding the cellular and molecular effects of resynchronisation on bioenergetics will promote our understanding of non-response, optimal device programming and lead to better patient care.

Influence of beta-blockers on mechanical dyssynchrony and cardiac remodeling in patients with ischemic chronic heart failure in the setting of revascularization

Introduction: Diastolic dysfunction (DD) and cardiac dyssynchrony (DS) are involved in the progression of chronic heart failure (CHF). A comparative analysis was conducted of the effect of a 6-month course of nebivolol and bisoprolol on DD, DS and metalloproteinase-9 (MMP-9) level in patients with ischemic chronic heart failure with preserved ejection fraction (HFpEF) and with midrange ejection fraction (HFmrEF), as well as in patients with comorbid type 2 diabetes mellitus (T2DM) in the setting of coronary artery bypass grafting (CABG) after 6 months of therapy.

Materials and methods: The study included 308 patients with CHFFC I-II, left ventricular ejection fraction (LVEF) &gt;40%, who had undergone CABG. The average dose of nebivolol in patients with DS 6 months later was 5.1±2.6 mg/day, and bisoprolol – 4.9±2.4 mg/day. Echocardiography (EchoCG) and evaluation of MMP-9 in blood plasma were performed. Mechanical myocardial asynchrony was determined by calculating the standard deviation of time to peak systolic myocardial velocity (TS-SD) and maximum segment delay (TS12) using a 6-basal and-midsegment model.

Results and discussion: MMP-9 level in patients with CHF before CABG was 4.7 times higher (p&lt;0.001). MMP-9 correlated with LVEF (r=-0.60, p&lt;0.001), E/A (r=-0.49, p&lt;0.001), DT (r=0.43, p&lt;0.001), E` (r=-0.58, p&lt;0.001) and DS: TS12 (r=0.54, p&lt;0.001), TS-SD (r=0.49, p&lt;0.001). The six-month course of nebivolol improved the values of DS: TS12 – by 30% (p&lt;0.001), TS-SD – by 32% (p&lt;0.01) and reduced the MMP-9 level by 11% (p&lt;0.001). In patients with HFmrEF without DSnebivolol increased E/A by 19% (p&lt;0.01), E` – by 16% (P&lt;0.05), and decreased E/E’ by 9% (p&lt;0.05), DT – by 12% (p&lt;0.05). In patients with HFpEF and DM2, nebivolol reduced TS12 by 37% (p&lt;0.01), TS-SD – by 29% (p&lt;0.05) and MMP-9 – by 13% (p&lt;0.05).

Conclusion: The positive effect of nebivolol on the DS, DD of the LV in patients with HFpEF, HFmrEF and with comorbid type 2 diabetes mellitus. The six-month course of nebivolol decreased the MMP-9 level in patients with ischemic CHF after CABG, including patients with T2DM.

Echocardiography for prediction of 6-month and late response to cardiac resynchronization therapy: implementation of stress echocardiography and comparative assessment along with widely used dyssynchrony indices

Non-response cardiac resynchronization therapy (CRT) remains an issue, despite the refinement of selection criteria. The purpose of this study was to investigate the role of stress echocardiography along with dyssynchrony parameters for identification of CRT responders or late responders. 106 symptomatic heart failure patients were examined before, 6 months and 2-4 years after CRT implementation. Inotropic contractile reserve (ICR) and inferolateral (IL) wall viability were studied by stress echocardiography. Dyssynchrony was assessed by: (1) Septal to posterior wall motion delay (SPWMD) by m-mode. (2) Septal to lateral wall delay (SLD) by TDI. (3) Interventricular mechanical delay (IVMD) by pulsed wave Doppler for (4) difference in time to peak circumferential strain (TmaxCS) by speckle tracking. (5) Apical rocking (ApR) and septal flash (SF) by visual assessment. At 6 months there were 54 responders, with 12 additional late responders. TmaxCS had the greatest predictive value with an area under curve (AUC) of 0.835, followed by the presence of both ICR and viability of IL wall (AUC 0.799), m-mode (AUC = 0.775) and presence of either ApR or SF (AUC = 0.772). Predictive ability of ApR and of ICR is augmented if late responders are also included. Performance of dyssynchrony parameters is enhanced, in patients with both ICR and IL wall viability. Stress echocardiography and dyssynchrony parameters are simple and reliable predictors of 6-month and late CRT response. A stepwise approach with an initial assessment of ICR and viability and, if positive, further dyssynchrony analysis, could assist decision making.

Role of cardiovascular imaging in cardiac resynchronization therapy: a literature review

: Cardiac resynchronization therapy (CRT) is an established treatment in patients with symptomatic drug-refractory heart failure and broad QRS complex on the surface ECG. Despite the presence of either mechanical dyssynchrony or viable myocardium at the site where delivering left ventricular pacing being necessary conditions for a successful CRT, their direct assessment by techniques of cardiovascular imaging, though feasible, is not recommended in clinical practice by the current guidelines. Indeed, even though there is growing body of data providing evidence of the additional value of an image-based approach as compared with routine approach in improving response to CRT, these results should be confirmed in prospective and large multicentre trials before their impact on CRT guidelines is considered.

Cardiac resynchronization therapy outcomes in patients under nonoptimal medical therapy

BACKGROUND

Cardiac resynchronization therapy (CRT) is indicated in symptomatic heart failure (HF) patients after achieving optimal medical therapy (OMT). However, many patients may not be under OMT when the CRT device is implanted. Here, we evaluate the long-term benefits of CRT in symptomatic HF patients receiving or not OMT.

METHODS

We investigated the effect of OMT on HF developing or death in 328 consecutive patients with a CRT device implanted between 2005 and 2015 in a single tertiary center. After the CRT implant, we categorized the patients into three groups: no OMT, OMT at baseline and after 1 year of follow-up, and OMT only at the 1-year follow-up but not at baseline. We used multivariate Cox proportional hazards model to determine the effect of OMT on clinical outcomes.

RESULTS

One hundred and twenty-two patients (37.2%) received OMT prior to CRT. OMT at baseline was not associated with a reduced risk of death or HF (HR 0.72; 95% CI 0.50-1.02; P = 0.067) compared with no-basal-OMT patients. After CRT, patients without OMT had a higher risk of death or HF than patients who received OMT in follow-up (HR 1.72, 95% CI 1.07-2.78, P = 0.025), and the risk of the patients who received OMT at baseline and at the 1-year follow-up was similar to that of the patients who achieved OMT at the 1-year follow-up (HR 0.90, 95% CI 0.54-1.50, P = 0.682).

CONCLUSION

Basal OMT prior to CRT is not associated with better outcomes in terms of HF/death compared with no basal OMT. The subgroup of patients who achieved OMT at the 1-year follow-up exhibited a reduced risk of HF and death compared with patients who did not.

Optimal site selection and image fusion guidance technology to facilitate cardiac resynchronization therapy

INTRODUCTION

Cardiac resynchronization therapy (CRT) has emerged as one of the few effective treatments for heart failure. However, up to 50% of patients derive no benefit. Suboptimal left ventricle (LV) lead position is a potential cause of poor outcomes while targeted lead deployment has been associated with enhanced response rates. Image-fusion guidance systems represent a novel approach to CRT delivery, allowing physicians to both accurately track and target a specific location during LV lead deployment.

AREAS COVERED

This review will provide a comprehensive evaluation of how to define the optimal pacing site. We will evaluate the evidence for delivering targeted LV stimulation at sites displaying favorable viability or advantageous mechanical or electrical properties. Finally, we will evaluate several emerging image-fusion guidance systems which aim to facilitate optimal site selection during CRT.

EXPERT COMMENTARY

Targeted LV lead deployment is associated with reductions in morbidity and mortality. Assessment of tissue characterization and electrical latency are critical and can be achieved in a number of ways. Ultimately, the constraints of coronary sinus anatomy have forced the exploration of novel means of delivering CRT including endocardial pacing which hold promise for the future of CRT delivery.

Device Management in Heart Failure

PURPOSE OF REVIEW

Medical devices have become an integral part of comprehensive heart failure management. Not all heart failure patients, however, accrue benefit from every new device, and even with extensive practice guidelines, this remains an evolving field.

RECENT FINDINGS

The addition of implantable devices, like internal cardioverter defibrillators (ICDs), and novel pacing technologies, including cardiac resynchronization therapy (CRT), have helped to compliment goal-directed medical therapy and positively impact prognosis in multiple high-quality clinical trials. This review attempts to summarize the rapidly evolving literature with respect to existing device guidelines for routine implantable devices as well as some available and future technologies that are not yet a part of routine guidelines. ICD, CRT, and other implantable devices continue to save lives, decrease hospitalizations, and evolve the management of patients with heart failure beyond the capabilities of optimal guideline-directed medical therapy alone.

Successful Catheter Ablation as a Substitute for Cardiac Resynchronization Therapy in Patient with an Accessory Pathway-induced Cardiomyopathy

A 50-year-old man presented with exertional dyspnea and orthopnea. An electrocardiogram showed a delta wave and a wide QRS complex, similar to left bundle branch block. Cardiac echocardiography revealed diffuse severe hypokinesis and dyssynchrony. The patient was diagnosed with congestive heart failure. We considered that the patient's condition was caused by an accessory pathway-induced cardiomyopathy after heart failure compensation with guideline-oriented medical therapy. We therefore performed catheter ablation for right-sided pre-excitation syndrome as cardiac resynchronization therapy. The left ventricular dyssynchrony was resolved immediately after the procedure, and the patient's ventricular contraction improved, with a reduced cardiac volume at 6 months after the procedure-thus suggesting that the accessory pathway had affected the patient's cardiac function.

Overview of implantable cardioverter defibrillator and cardiac resynchronisation therapy in heart failure management

Clinical trials have established the benefits of implantable cardioverter defibrillators (ICDs) and cardiac resynchronisation therapy (CRT) in the treatment of heart failure patients. As adjuncts to guideline-directed medical therapy, ICDs confer mortality benefits from sudden cardiac arrest, while CRT reduces mortality, hospitalisation rates and improves functional capacity. This review discusses the use of ICDs and CRT devices in heart failure management, outlining the evidence supporting their use, indications and contraindications.

Combined myocardial deformation to predict cardiac resynchronization therapy response in nonischemic cardiomyopathy

BACKGROUND

20-30% of patients do not benefit from cardiac resynchronization therapy (CRT) when the established selection criteria were applied. We hypothesized that a combined assessment of mechanical dyssynchrony, myocardial deformation, and diastolic function would identify patients who would benefit most from CRT.

METHOD

In 36 CRT patients, clinical evaluation and echocardiography were performed before and after CRT. Patients were classified into three subgroups according to their amount of response: echocardiographic responders, clinical responders, and nonresponders. Radial dyssynchrony and left ventricular (LV) global longitudinal, radial, and circumferential peak strain was assessed by speckle-tracking image. Diastolic function was quantified by conventional echocardiography.

RESULT

In addition to left bundle branch block, nonspecific intraventricular conduction disturbance with intraventricular dyssynchrony could also improve LV remodeling. Echocardiographic responders had better global longitudinal strain, global circumferential peak strain, and global radial strain at baseline which significantly increased at 12-month follow-up. An improvement in estimates of LV filling pressure and a decrease in mitral regurgitation and left atrial dimensions were observed only in echocardiographic responders to CRT. Patients with clinical but without echocardiographic response showed a significant improvement in atrioventricular (AV) synchrony and a nonsignificant improvement in other parameters. The nonresponder group did not improve the AV and intraventricular dyssynchrony. CRT could not improve restrictive filling pattern with normal filling time. Overall, those patients with AV and intraventricular dyssynchrony and those with best contractile function and short diastolic filling time of restrictive filling pattern at baseline demonstrated the greatest benefit from CRT.

CONCLUSIONS

Mechanical dyssynchrony, contractile function, and filling pattern are important determinants of the benefits in CRT.

Abnormal diastolic function underlies the different beneficial effects of cardiac resynchronization therapy on ischemic and non-ischemic cardiomyopathy

OBJECTIVES:

To investigate the association between diastolic function and the different beneficial effects of cardiac resynchronization therapy in patients with heart failure due to different causes.

METHODS:

The 104 enrolled patients were divided into an ischemic cardiomyopathy group (n=27) and a non-ischemic cardiomyopathy group (n=77) according to the cause of heart failure. Before implantation, left ventricular diastolic function was evaluated in all patients using echocardiography. After six months of follow-up, the beneficial effects of cardiac resynchronization therapy were evaluated using a combination of clinical symptoms and echocardiography parameters.

RESULTS:

The ischemic cardiomyopathy group included significantly more patients with restrictive filling than the non-ischemic cardiomyopathy group. The response rate after the implantation procedure was significantly higher in the non-ischemic cardiomyopathy group than in the ischemic cardiomyopathy group. Degrees of improvement in echocardiography parameters were significantly greater in the non-ischemic cardiomyopathy group than in the ischemic cardiomyopathy group. Multivariate regression analysis showed that a restrictive filling pattern was an independent factor that influenced responses to cardiac resynchronization therapy.

CONCLUSIONS:

This study again confirmed that the etiology of heart failure affects the beneficial effects of cardiac resynchronization therapy and a lower degree of improvement in ventricular systolic function and remodelling was observed in ischemic cardiomyopathy patients than in non-ischemic cardiomyopathy patients. In addition, systolic heart failure patients with severe diastolic dysfunction had poor responses to cardiac resynchronization therapy. Ischemic cardiomyopathy patients exhibited more severe diastolic dysfunction than non-ischemic cardiomyopathy patients, which may be a reason for the reduced beneficial effect of cardiac resynchronization therapy.

Pilot study using 3D-longitudinal strain computation in a multi-parametric approach for best selecting responders to cardiac resynchronization therapy

BACKGROUND

Almost all attempts to improve patient selection for cardiac resynchronization therapy (CRT) using echo-derived indices have failed so far. We sought to assess: the performance of homemade software for the automatic quantification of integral 3D regional longitudinal strain curves exploring left ventricular (LV) mechanics and the potential value of this tool to predict CRT response.

METHODS

Forty-eight heart failure patients in sinus rhythm, referred for CRT-implantation (mean age: 65 years; LV-ejection fraction: 26%; QRS-duration: 160 milliseconds) were prospectively explored. Thirty-four patients (71%) had positive responses, defined as an LV end-systolic volume decrease ≥15% at 6-months. 3D-longitudinal strain curves were exported for analysis using custom-made algorithms. The integrals of the longitudinal strain signals (I _L,peak) were automatically measured and calculated for all 17 LV-segments.

RESULTS

The standard deviation of longitudinal strain peak (SDI _L,peak ) for all 17 LV-segments was greater in CRT responders than non-responders (1.18% s^-1 [0.96; 1.35] versus 0.83% s^-1 [0.55; 0.99], p = 0.007). The optimal cut-off value of SDI _L,peak to predict response was 1.037%.s^-1. In the 18-patients without septal flash, SDI _L,peak was significantly higher in the CRT-responders.

CONCLUSIONS

This new automatic software for analyzing 3D longitudinal strain curves is avoiding previous limitations of imaging techniques for assessing dyssynchrony and then its value will have to be tested in a large group of patients.

Predicting Clinical and Echocardiographic Response After Cardiac Resynchronization Therapy With a Score Combining Clinical, Electrocardiographic, and Echocardiographic Parameters

The L₂ANDS₂ score was previously found to be able to assess the probability of left ventricular (LV) remodeling. We sought to evaluate this score in terms of clinical outcomes: 275 patients with heart failure, from 2 centers, implanted with a cardiac resynchronization therapy (CRT) device were followed at least 2 years after implantation. Baseline clinical, electrocardiographic, and echocardiographic characteristics including left bundle branch block, age >70 years, nonischemic etiology, LV end-diastolic diameter <40 mm/m², and septal flash by echocardiography were integrated in 4 scoring systems. Nonresponse to CRT was LV reverse remodeling <15% at 6 months' follow-up and/or occurrence of major cardiovascular event (cardiovascular death or transplantation or assistance) during a clinical follow-up of at least 2 years. Ninety-seven patients (36%) demonstrated nonresponse to CRT. The L₂ANDS₂ score demonstrated the best predictive value (C statistic of 0.783) for predicting absence of LV reverse remodeling and/or occurrence of major cardiovascular event during the 2 years follow-up compared with other scoring systems that do not include septal flash. A L₂ANDS₂ score ≤4 was associated with a worse outcome (38% survival vs 81% survival, hazard ratio 4.19, 95% CI 2.70 to 6.48, p <0.0001). In conclusion, the L₂ANDS₂ score is able to assess the probability of nonresponse to CRT in terms of no reverse LV remodeling and/or major cardiovascular event at long-term follow-up. Integrating septal flash in a scoring system adds value over left bundle branch block only.

Reverse Left Ventricular Remodelling in ST-Elevation Myocardial Infarction Patients Undergoing Primary Percutaneous Coronary Intervention: Incidence, Predictors, and Impact on Outcome

BACKGROUD

We investigated reverse left ventricular remodelling (r-LVR), defined as a reduction of >10% in left ventricular end-systolic volume (LVESV) during follow-up, in ST-elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary intervention (PPCI).

METHODS

STEMI patients (n=1,237) undergoing PPCI with echocardiography at baseline and 6-month follow-up were classified into r-LVR (n=466) and no r-LVR groups (n=771). The primary outcome was composite major adverse cardiac events (MACE; all-cause death, myocardial infarction, any revascularisation).

RESULTS

r-LVR occurred in 466 patients (37.7%) and was associated with maximum troponin, door-to-balloon time, direct arrival to PPCI-capable hospital, coronary disease extent, initial left ventricular ejection fraction (LVEF), and LVESV. After propensity score (PS)-matching, initial LVEF and LVESV remained significant. During a median 403-day follow-up, 2-year MACE occurred in 166 patients (13.4%); its frequency was similar between groups (entire cohort: 13.5% vs. 13.4%, p=0.247; PS-matched: 11.8% vs. 11.8%, p=0.987). Kaplan-Meier estimates showed that MACE-free survival was comparable between groups (entire cohort: 86.5% vs. 86.6%, log rank p=0.939; PS-matched: 88.2% vs. 88.2%, log rank p=0.867). In Cox proportional hazard analysis, r-LVR was not associated with MACE (entire cohort: hazard ratio [HR] 1.018, 95% confidential interval [CI] 0.675-1.534, p=0.934; PS-matched: HR 1.001, 95% CI 0.578-1.731, p=0.999).

CONCLUSION

We identified independent predictors of r-LVR and showed that while r-LVR occurred in 38% of our patients, it was not associated with clinical outcomes.

Comparison of diagnostic performance of four software packages for phase dyssynchrony analysis in gated myocardial perfusion SPECT

Background

Phase analysis of gated myocardial perfusion single-photon emission computed tomography (SPECT) for assessment of left ventricular (LV) dyssynchrony was investigated using the following dedicated software packages: Corridor4DM (4DM), cardioREPO (cREPO), Emory Cardiac Toolbox (ECTb), and quantitative gated SPECT (QGS). The purpose of this study was to evaluate the normal values of 95% histogram bandwidth, phase standard deviation (SD), and entropy and to compare the diagnostic performance of the four software packages. A total of 122 patients with normal myocardial perfusion and cardiac function (58.9 ± 12.3 years, 60 women, ejection fraction (EF) 74.3 ± 5.7%, and end-diastolic volume (EDV) 83.5 ± 3.6 mL) and 34 patients with suspected LV dyssynchrony (64.1 ± 12.2 years, 9 women, EF 52.0 ± 18.0%, and EDV 145.0 ± 6.8 mL) who underwent Tc-99m methoxy-isobutyl-isonitrile/tetrofosmin gated SPECT were retrospectively evaluated. Dyssynchrony indices of the 95% histogram bandwidth, phase SD, and entropy were computed with the four software programs. Diagnostic performance of LV phase dyssynchrony assessments was determined by receiver operator characteristic (ROC) analysis. The area under the ROC curve (AUC) was used to compare the software programs. The optimal cutoff point was determined by ROC curve based on the Youden index.

Results

The average of normal bandwidth significantly differed among the four software programs except in the comparison of 4DM and ECTb. Moreover, the normal phase SD significantly differed among the four software programs except in the comparison of cREPO and ECTb. The software programs showed high correlation levels for bandwidth, phase SD, and entropy (r ≥ 0.73, p < 0.001). ROC AUCs of bandwidth, phase SD, and entropy were ≥0.850, ≥0.858, and ≥0.900, respectively. Moreover, the ROC AUCs of bandwidth, phase SD, and entropy did not significantly differ among the four software programs. Optimal cutoff points for phase parameters were 24°–42° for bandwidth, 8.6°–15.3° for phase SD, and 31–48% for entropy.

Conclusions

Although the optimal cutoff value for determining LV phase dyssynchrony by ROC analysis varied depending on the use of the different software programs, all software programs can be used reliably for phase dyssynchrony analysis.

The Role of Cardiovascular Magnetic Resonance in Cardiac Resynchronization Therapy

Randomized, controlled trials have shown that cardiac resynchronization therapy (CRT) is beneficial in patients with heart failure, impaired left ventricular (LV) systolic function, and a wide QRS complex. Other studies have shown that targeting the LV pacing site can also improve patient outcomes. Cardiovascular magnetic resonance (CMR) is a radiation-free imaging modality that provides unparalleled spatial resolution. In addition, emerging data suggest that targeted LV lead deployment over viable myocardium improves the outcome of patients undergoing CRT. This review explores the role of CMR in the preoperative workup of patients undergoing CRT.

Key Role of Pacing Site as Determinant Factor of Exercise Testing Performance in Pediatric Patients with Chronic Ventricular Pacing

Chronic right ventricular (RV) apical pacing has been associated with deterioration of functional capacity and chronotropic incompetence during exercise testing in children. The effects of alternative pacing site on exercise performance in pediatric population remain unknown. We evaluated the influence of ventricular pacing site on exercise capacity in pediatric patients with complete congenital atrioventricular block requiring permanent pacemaker therapy. Sixty-four children paced from RV apex (n = 26), RV midseptum (n = 15) and left ventricular (LV) apex (n = 23) were studied cross-sectionally. Treadmill exercise stress testing was performed according to modified Bruce protocol. LV apical pacing was associated with greater exercise capacity. In comparison with the other study groups, children with RV apical pacing showed significantly lower VO₂peak (37 ± 4.11; p = 0.003), O₂ pulse (8.78 ± 1.15; p = 0.006), metabolic equivalents (7 ± 0.15; p = 0.001) and exercise time (6 ± 3.28; p = 0.03). Worse values in terms of maximum heart rate (139 ± 8.83 bpm; p = 0.008) and chronotropic index (0.6 ± 0.08; p = 0.002) were detected in the RV apical pacing group although maximal effort (respiratory exchange ratio) did not differ among groups (p = 0.216). Pacing from RV apex (odds ratio 9.4; confidence interval 2.5-18.32; Wald 4.91; p = 0.0036) and low peak heart rate achieved (odds ratio 3.66; confidence interval 0.19-7.4; Wald 4.083; p = 0.015) predicted significantly decrease in exercise capacity. Duration of pacing, gender, VVIR mode, baseline heart rate and QRS duration had not significant impact on exercise capacity. The site of ventricular pacing has the major impact on exercise capacity in children requiring permanent pacing. Among the sites assessed, LV apex is related to the better exercise performance.

Gauging the response to cardiac resynchronization therapy: The important interplay between predictor variables and definition of a favorable outcome

AIMS

Selection of patients who are viable candidates for cardiac resynchronization therapy (CRT), prediction of the response to CRT as well as an optimal definition of a favorable response, all require further exploration. The purpose of this study was to evaluate the interplay between the prediction of the response to CRT and the definition of a favorable outcome.

METHODS

Seventy patients who received CRT were included. All patients met current guideline criteria for CRT. Forty-three echocardiographic parameters were evaluated before CRT and at 1, 3, 6, and 12 months. M-mode, 2D echocardiography, and Doppler imaging were used to quantify left ventricular (LV) systolic and diastolic function, mitral regurgitation, right ventricular systolic function, pulmonary artery pressure, and myocardial mechanical dyssynchrony. The following definitions of a favorable CRT response were used: left ventricular ejection fraction (LVEF) improvement more >5% acutely following CRT, LVEF improvement >20% at 12-month follow-up, and a LV end-systolic volume (LVESV) decrease >15% at 12-month follow-up.

RESULTS

For the LVEF improvement >5%, the best predictor was isovolumetric relaxation time (IVRT; P=.035). For improvement of LVEF >20%, the best predictors were left ventricular stroke index (LVSI; P=.044) and left ventricular fractional shortening (LVFS; P=.031). For the drop in left ventricular systolic volume (LVESV >15%), the best predictor was septal-to-lateral wall delay (ΔT) (P=.043, RR=1.023, 95% CI for RR=1.001-1.045).

CONCLUSION

The definition of a favorable CRT response influenced the optimal predictor variable(s). Standardization of defining a favorable response to CRT is needed to guide clinical decision making processes.

Multipoint Pacing versus conventional ICD in Patients with a Narrow QRS complex (MPP Narrow QRS trial): study protocol for a pilot randomized controlled trial

BACKGROUND

Despite an intensive search for predictors of the response to cardiac resynchronization therapy (CRT), the QRS duration remains the simplest and most robust predictor of a positive response. QRS duration of ≥ 130 ms is considered to be a prerequisite for CRT; however, some studies have shown that CRT may also be effective in heart failure (HF) patients with a narrow QRS (<130 ms). Since CRT can now be performed by pacing the left ventricle from multiple vectors via a single quadripolar lead, it is possible that multipoint pacing (MPP) might be effective in HF patients with a narrow QRS. This article reports the design of the MPP Narrow QRS trial, a prospective, randomized, multicenter, controlled feasibility study to investigate the efficacy of MPP using two LV pacing vectors in patients with a narrow QRS complex (100-130 ms).

METHODS

Fifty patients with a standard ICD indication will be enrolled and randomized (1:1) to either an MPP group or a Standard ICD group. All patients will undergo a low-dose dobutamine stress echo test and only those with contractile reserve will be included in the study and randomized. The primary endpoint will be the percentage of patients in each group that have reverse remodeling at 12 months, defined as a reduction in left ventricular end-systolic volume (LVESV) of >15% from the baseline.

DISCUSSION

This feasibility study will determine whether MPP improves reverse remodeling, as compared with standard ICD, in HF patients who have a narrow QRS complex (100-130 ms).

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02402816 . Registered on 25 March 2015.

Left ventricular shape predicts different types of cardiovascular events in the general population

OBJECTIVE

To investigate whether sphericity volume index (SVI), an indicator of left ventricular (LV) remodelling, predicts incident cardiovascular events (coronary heart disease, CHD; all cardiovascular disease, CVD; heart failure, HF; atrial fibrillation, AF) over 10 years of follow-up in a multiethnic population (Multi-Ethnic Study of Atherosclerosis).

METHODS

5004 participants free of known CVD had magnetic resonance imaging (MRI) in 2000-2002. Cine images were analysed to compute, [Formula: see text] equivalent to LV volume/volume of sphere with length of LV as the diameter. The highest (greatest sphericity) and lowest (lowest sphericity) quintiles of SVI were compared against the reference group (2-4 quintiles combined). Risk-factor adjusted hazard's ratio (HR) from Cox regression assessed the predictive performance of SVI at end-diastole (ED) and end-systole (ES) to predict incident outcomes over 10 years in retrospective interpretation of prospective data.

RESULTS

At baseline, participants were aged 61±10 years; 52% men and 39%/13%/26%/22% Cauc/Chinese/Afr-Amer/Hispanic. Low sphericity was associated with higher Framingham CVD risk, greater coronary calcium score and higher N-terminal pro-brain natriuretic peptide (NT-proBNP); while increased sphericity was associated with higher NT-proBNP and lower ejection fraction. Low sphericity predicted incident CHD (HR: 1.48, 1.55-2.59 at ED) and CVD (HR: 1.82, 1.47-2.27 at ED). However, both low (HR: 1.81, 1.20-2.73 at ES) and high (HR: 2.21, 1.41-3.46 at ES) sphericity predicted incident HF. High sphericity also predicted AF.

CONCLUSIONS

In a multiethnic population free of CVD at baseline, lowest sphericity was a predictor of incident CHD, CVD and HF over a 10-year follow-up period. Extreme sphericity was a strong predictor of incident HF and AF. SVI improved risk prediction models beyond established risk factors only for HF, but not for all CVD or CHD.