New Pacing Techniques and Non-Invasive Methods That May Improve Response to Cardiac Resynchronization Therapy

Although cardiac resynchronization therapy (CRT) is an evidence-based effective therapy of symptomatic heart failure with reduced ejection fraction (HFrEF), refractory to optimal medical treatment and associated with intraventricular conduction disturbance, the non-response rate to CRT is still around 30% [...].

Pilot study to evaluate left-to-right ventricular offset in biventricular pacing-comparison of electrocardiographic imaging and ECG

INTRODUCTION

Biventricular pacing (BiVp) improves outcomes in systolic heart failure patients with electrical dyssynchrony. BiVp is delivered from epicardial left ventricular (LV) and endocardial right ventricular (RV) electrodes. Acute electrical activation changes with different LV-RV stimulation offsets can help guide individually optimized BiVp programming. We sought to study the BiVp ventricular activation with different LV-RV offsets and compare with 12-lead ECG.

METHODS

In five patients with BiVp (63 ± 17-year-old, 80% male, LV ejection fraction 27 ± 6%), we evaluated acute ventricular epicardial activation, varying LV-RV offsets in 20 ms increments from -40 to 80 ms, using electrocardiographic imaging (ECGI) to obtain absolute ventricular electrical uncoupling (VEUabs, absolute difference in average LV and average RV activation time) and total activation time (TAT). For each patient, we calculated the correlation between ECGI and corresponding ECG (3D-QRS-area and QRS duration) with different LV-RV offsets.

RESULTS

The LV-RV offset to attain minimum VEUabs in individual patients ranged 20-60 ms. In all patients, a larger LV-RV offset was required to achieve minimum VEUabs (36 ± 17 ms) or 3D-QRS-area (40 ± 14 ms) than that for minimum TAT (-4 ± 9 ms) or QRS duration (-8 ± 11 ms). In individual patients, 3D-QRS-area correlated with VEUabs (r 0.65 ± 0.24) and QRS duration correlated with TAT (r 0.95 ± 0.02). Minimum VEUabs and minimum 3D-QRS-area were obtained by LV-RV offset within 20 ms of each other in all five patients.

CONCLUSIONS

LV-RV electrical uncoupling, as assessed by ECGI, can be minimized by optimizing LV-RV stimulation offset. 3D-QRS-area is a surrogate to identify LV-RV offset that minimizes LV-RV uncoupling.

Multimodality Imaging for Selecting Candidates for CRT: Do We Have a Single Alley to Increase Responders?

Cardiac resynchronization therapy has evolved in recent years to provide a reduction of morbidity and mortality for many patients with heart failure. Its application and optimization is an evolving field and its use requires a multidisciplinary approach for patient and device selection, technical preprocedural planning, and optimization. While echocardiography has always been considered the first line for the evaluation of patients, additional imaging techniques have gained increasing evidence in recent years. Today different details about heart anatomy, function, dissynchrony can be investigated by magnetic resonance, cardiac computed tomography, nuclear imaging, and more, with the aim of obtaining clues to reach a maximal response from the electrical therapy. The purpose of this review is to provide a practical analysis of the single and combined use of different imaging techniques in the preoperative and perioperative phases of cardiac resynchronization therapy, underlining their main advantages, limitations, and information provided.

A review of biomarker and imaging monitoring to predict heart failure recovery

Heart failure is a clinical syndrome caused by structural cardiac abnormalities that lead to increased intracardiac pressures and decreased cardiac output. Following cardiovascular insult or direct myocardial injury, neurohormonal activation triggers hemodynamic changes and cardiac remodeling to preserve cardiac output. While initially adaptive, cardiac remodeling eventually causes pathologic changes in cardiac structure that often compromise cardiac function. Reverse remodeling is the regression of abnormal cardiac chamber geometry and function after myocardial injury. In recent years, several classes of therapeutics have been associated with greater likelihood of reverse remodeling. Heart failure recovery and heart failure remission, terms encompassing the clinical correlates of reverse remodeling, have been associated with improved survival in patients with heart failure with reduced ejection. As such, identifying predictors of heart failure recovery can have important implications for guiding clinical practice and therapeutic innovation. This review addresses the role of biomarkers and imaging monitoring in predicting structural, functional, and clinical recovery in patients with acute and chronic heart failure.

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.

Cardiac remodelling - Part 2: Clinical, imaging and laboratory findings. A review from the Study Group on Biomarkers of the Heart Failure Association of the European Society of Cardiology

In patients with heart failure, the beneficial effects of drug and device therapies counteract to some extent ongoing cardiac damage. According to the net balance between these two factors, cardiac geometry and function may improve (reverse remodelling, RR) and even completely normalize (remission), or vice versa progressively deteriorate (adverse remodelling, AR). RR or remission predict a better prognosis, while AR has been associated with worsening clinical status and outcomes. The remodelling process ultimately involves all cardiac chambers, but has been traditionally evaluated in terms of left ventricular volumes and ejection fraction. This is the second part of a review paper by the Study Group on Biomarkers of the Heart Failure Association of the European Society of Cardiology dedicated to ventricular remodelling. This document examines the proposed criteria to diagnose RR and AR, their prevalence and prognostic value, and the variables predicting remodelling in patients managed according to current guidelines. Much attention will be devoted to RR in patients with heart failure with reduced ejection fraction because most studies on cardiac remodelling focused on this setting.

ACR Appropriateness Criteria® Dyspnea-Suspected Cardiac Origin (Ischemia Already Excluded): 2021 Update

Dyspnea is the symptom of perceived breathing discomfort and is commonly encountered in a variety of clinical settings. Cardiac etiologies of dyspnea are an important consideration; among these, valvular heart disease (Variant 1), arrhythmia (Variant 2), and pericardial disease (Variant 3) are reviewed in this document. Imaging plays an important role in the clinical assessment of these suspected abnormalities, with usually appropriate procedures including resting transthoracic echocardiography in all three variants, radiography for Variants 1 and 3, MRI heart function and morphology in Variants 2 and 3, and CT heart function and morphology with intravenous contrast for Variant 3. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

The Effect of Cardiac Resynchronization without a Defibrillator on Morbidity and Mortality: An Individual-Patient-Data Meta-Analysis of COMPANION and CARE-HF

BACKGROUND

Cardiac resynchronization therapy (CRT) reduces morbidity and mortality for patients with heart failure, reduced left ventricular ejection fraction, QRS duration >130 ms and in sinus rhythm.

OBJECTIVES

To identify patient-characteristics that predict the effect, specifically, of CRT-pacemakers (CRT-P) on all-cause mortality or the composite of hospitalisation for heart failure or all-cause mortality.

METHODS

An individual patient-data meta-analysis of the Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure (COMPANION) and Cardiac Resynchronization - Heart Failure (CARE-HF) trials. Only patients assigned to CRT-P or control (n = 1738) were included in order to avoid confounding from concomitant defibrillator therapy. The influence of baseline characteristics on treatment effects was investigated.

RESULTS

Median age was 67 (59-73) years, most patients were men (70%), 68% had a QRS duration of 150-199 ms and 80% had left bundle branch block (LBBB). Patients assigned to CRT-P had lower rates for all-cause mortality (HR 0.68 (95% CI 0.56 to 0.81; p < 0.0001) and the composite outcome (HR 0.67 (95% CI 0.58 to 0.78; p < 0.0001). No pre-specified characteristic, including sex, aetiology of ventricular dysfunction, QRS duration (within the studied range) or morphology or PR interval significantly influenced the effect of CRT-P on all-cause mortality or the composite outcome. However, CRT-P had a greater effect on the composite outcome for patients with lower body surface area (BSA) and those prescribed beta-blockers.

CONCLUSIONS

CRT-P reduces morbidity and mortality in appropriately selected patients with heart failure. Benefits may be greater in smaller patients and in those receiving beta-blockers. Neither QRS duration nor morphology independently predicted the benefit of CRT-P.

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.

Quantitative mechanical dyssynchrony in dilated cardiomyopathy measured by deformable registration algorithm

OBJECTIVES

To investigate the diagnostic value and reproducibility of deformable registration algorithm (DRA)-derived mechanical dyssynchrony parameters in dilated cardiomyopathy (DCM) patients.

METHODS

The present study included 80 DCM patients (40 with normal QRS duration (NQRS-DCM); 40 with left bundle branch block (LBBB-DCM)) and 20 healthy volunteers. The balanced steady-state free-precession (bSSFP) cine images were acquired using a 3.0T scanner. Mechanical dyssynchrony parameters were calculated based on DRA-derived segmental strain, including uniformity ratio estimate (URE) and standard derivation of time-to-peak (T2Psd) parameters in circumferential, radial, and longitudinal orientations.

RESULTS

DCM patients showed significant mechanical dyssynchrony reflected by both URE and T2Psd parameters compared with controls. Among DCM patients, LBBB-DCM showed decreased CURE (0.78 ± 0.21 vs. 0.93 ± 0.05, p < 0.001) and RURE (0.69 ± 0.14 vs. 0.83 ± 0.15, p = 0.001), and increased T2Psd-Ecc (median with interquartile range, 94.1 (54.4-123.2) ms vs. 63.7 (44.9-80.4) ms, p = 0.003) and T2Psd-Err (91.1 (61.1-103.2) ms vs. 62.3 (46.3-104.5) ms, p = 0.041) compared with NQRS-DCM patients. CURE showed a strong correlation with QRS duration (r = - 0.54, p < 0.001), with maximum AUC (0.791) to differentiate LBBB-DCM from NQRS-DCM patients. Improved intra- and inter-observer reproducibility was found using URE indices (coefficient of variation (CoV), 1.20-3.17%) than T2Psd parameters (CoV, 15.28-41.18%).

CONCLUSIONS

The DRA-based CURE showed significant correlation with QRS duration and the highest discriminatory value between LBBB-DCM and NQRS-DCM patients. URE indices showed greater reproducibility compared with T2Psd parameters for assessing myocardial dyssynchrony in DCM patients.

KEY POINTS

• The strain analyses based on DRA suggested that DCM patients have varying degrees of mechanical dyssynchrony and there is a significant difference from normal controls. • CURE showed the strongest correlation with QRS duration and was the best parameter for differentiating DCM patients with normal QRS duration from patients with LBBB, and with normal controls. • URE indices showed improved reproducibility compared with T2Psd parameters in all three orientations (circumferential, radial, and longitudinal).

Reproducibility of Left Ventricular Dyssynchrony Indices by Three-Dimensional Speckle-Tracking Echocardiography: The Impact of Sub-optimal Image Quality

Background: 3D speckle-tracking echocardiography (3D-STE) is a novel method to quantify left ventricular (LV) mechanical dyssynchrony. 3D-STE is influenced by image quality, but studies on the magnitude of its effect on 3D-STE derived LV systolic dyssynchrony indices (SDIs) and their test-retest reproducibility are limited. Methods: 3D-STE was performed in two groups, each comprising 18 healthy volunteers with good echocardiographic windows. In study 1, optimal and inferior-quality images, by intentionally poor echocardiographic technique, were acquired. In study 2, sub-optimal quality images were acquired by impairing ultrasound propagation using neoprene rubber sheets (thickness 2, 3, and 4 mm) mimicking mildly, moderately, and severely impaired images, respectively. Measures (normalized to cardiac cycle duration) were volume- and strain-based SDIs defined as the standard deviation of time to minimum segmental values, and volume- and strain-derived dispersion indices. For both studies test-retest reproducibility was assessed. Results: Test-retest reproducibility was better for most indices when restricting the analysis to good quality images; nevertheless, only volume-, circumferential strain-, and principal tangential strain-derived LV dyssynchrony indices achieved fair to good reliability. There was no evidence of systematic bias due to sub-optimal quality image. Volume-, circumferential strain-, and principal tangential strain-derived SDIs correlated closely. Radial strain- and longitudinal strain-SDI correlated moderately or weakly with volume-SDI, respectively. Conclusions: Sub-optimal image quality compromised the reliability of 3D-STE derived dyssynchrony indices but did not introduce systematic bias in healthy individuals. Even with optimal quality images, only 3D-STE indices based on volume, circumferential strain and principal tangential strain showed acceptable test-retest reliability.

Imaging, Biomarker, and Clinical Predictors of Cardiac Remodeling in Heart Failure With Reduced Ejection Fraction

In response to injury, hemodynamic changes, or neurohormonal activation, the heart undergoes a series of structural and functional changes that have been termed cardiac remodeling. Remodeling is defined as changes in cardiac geometry and/or function over time and can be measured in terms of changes in cardiac chamber dimensions, wall thickness, volumes, mass, and ejection fraction at serial imaging examinations. As to cardiac chambers, left ventricular (LV) remodeling has been best studied in patients with heart failure with reduced ejection fraction. Although LV remodeling may compensate for abnormal hemodynamic parameters and function in the short term, left unchecked, it is associated with worsening cardiac function and poor prognosis. On the other hand, reversing LV geometry and/or function closer to that of a normal heart (also known as reverse remodeling) is associated with improved cardiac function and better prognosis. Because of its close relationship with clinical outcomes, remodeling may potentially be targeted in clinical management and used in trials as a surrogate endpoint. Standardized definition of remodeling and reliable tools to predict and monitor the presence, direction, and magnitude of cardiac remodeling are needed. Together with clinical and imaging findings, circulating biomarkers (most notably N-terminal pro-B-type natriuretic peptide, high-sensitivity troponin, and soluble suppression of tumorigenesis-2) may be helpful in this respect.

Interactions between myocardial sympathetic denervation and left ventricular mechanical dyssynchrony: A CZT analysis

BACKGROUND

A correlation between left ventricular (LV) dyssynchrony (LVD) and impaired myocardial sympathetic tone has been hypothesized. We sought to assess the interactions between regional LV sympathetic innervation, perfusion, and mechanical dyssynchrony.

METHODS

Eighty-three patients underwent evaluation of LV perfusion and sympathetic innervation on 99mTc-tetrofosmin/123I-metaiodobenzylguanidine (123I-MIBG) imaging. The summed rest score and summed 123I-MIBG score (SS-MIBG) were computed. The extent of "innervation/perfusion" mismatch was defined as the number of denervated LV segments with relatively preserved perfusion. LVD was evaluated on phase analysis and the wall with latest mechanical activation identified.

RESULTS

LVD was revealed in 36 (43%) patients. Patients with LVD had more abnormal values of SRS (21 ± 9 vs 10 ± 8, P < 0.001) and SS-MIBG (29 ± 9 vs 17 ± 11, P < 0.001) than those without LVD. The presence of LVD also clustered with a higher burden of "innervation/perfusion" mismatch (P = 0.019). On per-wall analysis, LV walls with delayed mechanical activation showed a higher burden of "innervation/perfusion" mismatch (2.3 ± 1.4 segments) than normally contracting walls (1.3 ± 1.2 segments; P < 0.001). On multivariate analysis, the extent of "innervation/perfusion" mismatch was the only predictor of delayed mechanical activation (P = 0.029).

CONCLUSIONS

Patients with LVD show an elevated burden of "innervation/perfusion" mismatch that is concentrated at the level of the most dyssynchronous walls.

Why Dyssynchrony Matters in Heart Failure?

Cardiac resynchronization therapy (CRT) is an electrical therapy to resolve an electrical problem. Any method to predict CRT response must specifically reflect the electrical substrate. Time-to-peak dyssynchrony is too unspecific for prediction of response because dyssynchrony by this approach may reflect the presence of scar or fibrosis even in the absence of conduction delay. New methods are based on the actual physiology of activation delay-induced heart failure (HF) and are superior to time-to-peak methods in predicting CRT response. Time-to-peak dyssynchrony may be used for prognosis in HF patients without signs of delayed ventricular activation and for monitoring CRT response.

The impact of age on cardiac electromechanical function in asymptomatic individuals

BACKGROUND AND AIM

Whether aging affects left ventricular (LV) filling and ejection and the LV electric function is not well established. We investigated the effect of normal aging on echocardiographic measurements of LV morphology and function, LV electric function and the relationship between LV electric and mechanical function in asymptomatic individuals.

METHODS

As part of a cross-sectional survey for the prevalence of coronary risk factors in the general population in Caltanissetta, Italy, individuals without signs or symptoms of coronary artery disease or heart failure were randomly selected and underwent electrocardiographic and echocardiographic examination. QRS duration and amplitude, PR, QT and QTc intervals, were automatically measured. Echocardiographic examination included the measurement of LV systolic and diastolic dimensions, volumes and ejection fraction (EF). From the spectral Doppler flow LV early diastolic (E wave) and atrial systolic (A wave) velocities, isovolumic relaxation time (IVRT) and isovolumic contraction time (IVCT) were measured. Global LV dyssynchrony was assessed using the total isovolumic time (T-IVT) and the Tei index.

RESULTS

Aging reduced LV long-axis function, LV filling time and E wave velocity and prolonged T-IVT, IVRT and Tei index. It did not affect LV dimensions, ejection fraction, IVCT or QRS amplitude and duration. QRS duration correlated with LV dimensions, wall thickness and left atrial area. QRS amplitude and QTc interval correlated with the markers of LV dyssynchrony T-IVT and Tei index.

CONCLUSIONS

Overall, systolic and electric LV function are not affected by age, whereas subendocardial function, diastolic and synchronous function are significantly influenced.

Prognostic importance of mechanical dyssynchrony in predicting heart failure development after ST-segment elevation myocardial infarction

The aim of this study is to assess the prognostic value of mechanical dyssynchrony defined as the standard deviation of the time to peak longitudinal strain (SD T2P LS) in predicting the development of heart failure (HF) after an ST-segment elevation myocardial infarction (STEMI). Three hundred and seventy-three patients were admitted with STEMI and treated with primary percutaneous coronary intervention. Left ventricular (LV) mechanical dyssynchrony was examined through speckle tracking echocardiography and defined as SD T2P LS. The association with the outcome of HF hospitalization was assessed using Cox proportional hazard models. During a median follow-up of 5.12 years, 144 patients (38.6%) were admitted due to HF. Worse dyssynchrony was associated with the outcome in unadjusted and multivariable analysis (multivariable hazard ratio 1.05, 95% confidence interval 1.00-1.10, p-value 0.039, per 10 ms increase), but not after further adjustment for LV ejection fraction (LVEF), E/e' and global longitudinal strain (GLS) (hazard ratio 1.01, 95% confidence interval 1.00-1.07, p-value 0.71, per 10 ms increase), nor in a model only adjusting for GLS (hazard ratio 1.01, 95% confidence interval 1.00-1.06, p-value 0.61, per 10 ms increase). These findings were reproduced in a competing risk analysis treating all-cause mortality as a competing risk. LV mechanical dyssynchrony, as assessed by SD T2P LS is not an independent predictor of post-STEMI HF development and mechanical dyssynchrony does not provide independent prognostic information regarding HF when GLS is known.

Prognostic implications of left ventricular global longitudinal strain in heart failure patients with narrow QRS complex treated with cardiac resynchronization therapy: a subanalysis of the randomized EchoCRT trial

Aim

Left ventricular (LV) global longitudinal strain (GLS) reflects LV systolic function and correlates inversely with the extent of LV myocardial scar and fibrosis. The present subanalysis of the Echocardiography Guided CRT trial investigated the prognostic value of LV GLS in patients with narrow QRS complex.

Methods and results

Left ventricular (LV) global longitudinal strain (GLS) was measured on the apical 2-, 4- and 3-chamber views using speckle tracking analysis. Measurement of baseline LV GLS was feasible in 755 patients (374 with cardiac resynchronization therapy (CRT)-ON and 381 with CRT-OFF). The median value of LV GLS in the overall population was 7.9%, interquartile range 6.2-10.1%. After a mean follow-up period of 19.4 months, 95 patients in the CRT-OFF group and 111 in the CRT-ON group reached the combined primary endpoint of all-cause mortality and heart failure hospitalization. Each 1% absolute unit decrease in LV GLS was independently associated with 11% increase in the risk to reach the primary endpoint (Hazard ratio 1.11; 95% confidence interval 95% 1.04-1.17, P < 0.001), after adjusting for ischaemic cardiomyopathy and randomization treatment among other clinically relevant variables. When categorizing patients according to quartiles of LV GLS, the primary endpoint occurred more frequently in patients in the lowest quartile (<6.2%) treated with CRT-ON vs. CRT-OFF (45.6% vs. 28.7%, P = 0.009) whereas, no differences were observed in patients with LV GLS ≥6.2% treated with CRT-OFF vs. CRT-ON (23.7% vs. 24.5%, respectively; P  = 0.62).

Conclusion

Low LV GLS is associated with poor outcome in heart failure patients with QRS width <130 ms, independent of randomization to CRT or not. Importantly, in the group of patients with the lowest LV GLS quartile, CRT may have a detrimental effect on clinical outcomes.

Left ventricular diastolic and systolic dyssynchrony and dysfunction in heart failure with preserved ejection fraction and a narrow QRS complex

Aims: Mechanical dyssynchrony has been reported in heart failure with preserved ejection fraction (HFpEF), with a majority of patients having a narrow QRS complex; however, whether any benefit is observed with restoration of dyssynchrony remains unclear. We sought to assess left ventricular (LV) dyssynchrony and function in HFpEF and elucidate the underlying mechanisms that may account for HFpEF. Methods: Seventy-eighty patients with a narrow QRS complex including 47 with HFpEF, 31 with heart failure with reduced ejection fraction (HFrEF) patients, and 29 with asymptomatic left ventricular diastolic dysfunction (LVDD) were recruited. Forty-five normal subjects acted as controls. Systolic LV longitudinal strain (LS), systolic longitudinal strain rate (LSrS), early diastolic longitudinal strain rate (LSrE), and late diastolic longitudinal strain rate (LSrA) were measured using speckle tracking echocardiography. LV diastolic and systolic dyssynchrony (Te-SD and Ts-SD) were calculated. Results: Te-SD and Ts-SD were prolonged in HFpEF and HFrEF patients than in the control group (p<0.05). However, Ts-SD was shorter in HFpEF patients compared to HFrEF patients despite a narrow QRS complex (p<0.05). LV global LS, LSrS, and LSrE were decreased in patients with HFpEF and HFrEF compared to other groups, with HFrEF being even more reduced than HFpEF (p<0.05). Reduced LS, LSrS, and LSrE could effectively differentiate HF from asymptomatic LVDD patients (p<0.05). Conclusion: HFrEF exhibited increased systolic dyssynchrony compared to HFpEF despite a narrow QRS complex in addition to the more reduced diastolic and systolic function. Therefore, targeting to improve diastolic and systolic function instead of managing systolic dyssynchrony might be of great importance in the treatment of HFpEF.

Prognostic importance of left ventricular mechanical dyssynchrony in heart failure with preserved ejection fraction

AIMS

Left ventricular mechanical dyssynchrony has been described in heart failure with preserved ejection fraction (HFpEF), but its prognostic significance is not known.

METHODS AND RESULTS

Of 3445 patients with HFpEF enrolled in the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist (TOPCAT) trial, dyssynchrony analysis was performed on 424 patients (12%) by multiple speckle tracking echocardiography strain-based criteria. The primary dyssynchrony analysis was the standard deviation of the time to peak longitudinal strain (SD T2P LS). Cox proportional hazards models assessed the association of dyssynchrony with the composite outcome of cardiovascular death or heart failure hospitalization. Mean age was 70 ± 10 years, LVEF was 60 ± 8%, and QRS duration was 101 ± 27 ms. Worse dyssynchrony, reflected in SD T2P LS, was associated with wider QRS, prior myocardial infarction, larger LV volume and mass, and worse systolic (lower LVEF and global longitudinal strain) and diastolic (lower e' and higher E/e') function. During a median follow-up of 2.6 (interquartile range 1.5-3.8) years, 107 patients experienced the composite outcome. Worse dyssynchrony was associated with the composite outcome in unadjusted analysis [hazard ratio (HR) 1.04, 95% confidence interval (CI) 1.01-1.07; P = 0.021, per 10 ms increase], but not after adjusting for clinical characteristics, or after further adjustment for LVEF, AF, NYHA class, stroke, heart rate, creatinine, haematocrit, and QRS duration (HR 1.03, 95% CI 0.99-1.06; P = 0.16, per 10 ms increase).

CONCLUSION

Worse LV mechanical dyssynchrony, assessed by speckle tracking echocardiography, is not an independent predictor of adverse outcomes in HFpEF, suggesting that mechanical dyssynchrony is unlikely to be an important mechanism underlying this syndrome. These findings warrant validation in an independent study specifically designed to assess the prognostic utility of mechanical dyssynchrony in HFpEF.

TRIAL REGISTRATION

NCT00094302.

What is the cost of non-response to cardiac resynchronization therapy? Hospitalizations and healthcare utilization in the CRT-D population

BACKGROUND

Cardiac resynchronization therapy (CRT) is an effective treatment for heart failure (HF) with left ventricular systolic dysfunction and prolonged QRS interval. However, one third of patients do not benefit from treatment. This study compares the heart failure hospitalization (HFH) rates and corresponding costs between responders and non-responders to CRT.

METHODS

At a single center in New Jersey, we enrolled patients with de novo CRT-D implants between January 2011 and July 2013. Medical history at implant and all subsequent hospitalizations were collected. A retrospective chart review of the cardiology visit at or closest to 12 months post-CRT implant was performed, and patients were classified into responders and non-responders. Universal billing records (UB-04), ICD-9-CM diagnoses, and procedure codes were used to determine whether each hospitalization was due to HF. For each heart failure hospitalization (HFH), an MS-DRG-based US national average Medicare reimbursement was determined. HFH rates and associated payor costs were compared between responders and non-responders using negative binomial regression and non-parametric bootstrapping (×10,000), respectively.

RESULTS

CRT response was determined in 135 patients (n = 103 responders, n = 32 non-responders, average follow-up 1.4 years). Demographics, pre-implant HF characteristics, NYHA Class, QRS duration, ejection fraction (EF), left bundle branch block (LBBB) status, and co-morbidities were not statistically different between the two groups. The HFH rate was significantly lower in responders (0.43/patient year) compared to non-responders (0.96/patient year, IRR = 0.45, 95 % CI (0.23 0.90), P = 0.0197). Average US national Medicare reimbursement for the responder group (US$7205/patient year) was 48 % lower than that for the non-responder group (US$13,861/patient year, P = 0.035).

CONCLUSION

In this single-center retrospective study, responders to CRT had significantly lower rates of post-implant heart failure hospitalization rate and reduced associated payor costs compared to non-responders. Therapies that increase CRT response rates can substantially reduce healthcare utilization.

Additive Prognostic Value of Echocardiographic Global Longitudinal and Global Circumferential Strain to Electrocardiographic Criteria in Patients With Heart Failure Undergoing Cardiac Resynchronization Therapy

Background—

Response to cardiac resynchronization therapy is most favorable in patients with heart failure with QRS duration ≥150 ms and left bundle branch block and less predictable in those with QRS width 120 to 149 ms or non–left bundle branch block.

Methods and Results—

We studied 205 patients with heart failure referred for cardiac resynchronization therapy with QRS ≥120 ms and ejection fraction ≤35%. We tested the hypothesis that contractile function using speckle-tracking echocardiographic global circumferential strain (GCS) from 2 short-axis views and global longitudinal strain (GLS) from 3 apical views add prognostic value to electrocardiographic criteria. There were 112 patients (55%) with GLS >−9% and 136 patients (66%) with GCS >−9%. During 4 years, 81 patients reached the combined primary end point (death, circulatory support, or transplant) and 120 reached the secondary end point (heart failure hospitalization or death). Both GLS >−9% and GCS >−9% were associated with increased risk of unfavorable events as follows: for the primary end point (hazard ratio=2.91; 95% confidence interval, 1.88–4.49; P <0.001) and (hazard ratio=3.73; 95% confidence interval, 2.39–5.82; P <0.001) for the secondary end point (hazard ratio=2.10; 95% confidence interval, 1.45–3.05; P <0.001) and (hazard ratio=3.25; 95% confidence interval, 2.23–4.75; P <0.001). In a prespecified subgroup of 120 patients with QRS 120 to 149 ms or non–left bundle branch block, significant associations of baseline GLS and GCS and outcomes remained: P =0.014 and P =0.002 for the primary end point and P =0.049 and P =0.001 for the secondary end point. Global strain measures had additive prognostic value to routine clinical or electrocardiographic parameters ( P <0.001).

Conclusions—

Baseline GCS and GLS were significantly associated with long-term outcome after cardiac resynchronization therapy and had additive prognostic value to routine clinical and electrocardiographic selection criteria for cardiac resynchronization therapy.