Clinical versus echocardiographic parameters to assess response to cardiac resynchronization therapy

R-R' interval in the left bundle branch block predicts long-term outcomes after cardiac resynchronization therapy by estimating greater mechanical dyssynchrony and viable myocardium

BACKGROUND

Typical left bundle branch block (LBBB) shows 2 peaks of the R wave, which reflect activation reaching the interventricular septum (R) and posterolateral wall (R') sequentially.

OBJECTIVE

The purpose of this study was to investigate the relationship among R-R' interval (RR'), mechanical dyssynchrony, extent of viable myocardium, and long-term outcomes in cardiac resynchronization therapy (CRT) candidates.

METHODS

The study enrolled 49 patients (34 men; mean age: 69 ± 11 years) with LBBB who received CRT. The LBBB definition used requires the presence of mid-QRS notching in leads V1, V2, V5, V6, I, and aVL. Baseline evaluations were QRS duration (QRSd) and RR' measured from the 12-lead electrocardiogram; eyeball dyssynchrony (apical rocking and septal flash) and opposing-wall delay by speckle tracking from echocardiography, and extent of viable myocardium assessed by thallium-201 single-photon emission computed tomography. Primary outcomes included the combination of all-cause death and heart failure-related hospitalization.

RESULTS

RR' predicted volumetric response better than QRSd (area under the curve 0.73 vs 0.67, respectively). The long RR' group (≥48 ms) revealed more frequent eyeball dyssynchrony and significantly greater radial (SL) and circumferential dyssynchrony (AP and SL) and %viable segment than the short RR' group. In multivariate regression analysis, only RR' ≥48 ms was independently associated with higher event-free survival rates following CRT (hazard ratio 0.21; P = .014).

CONCLUSION

These findings suggest that RR' in complete LBBB was associated with mechanical dyssynchrony, extent of viable myocardium, and long-term outcomes following CRT.

A method using deep learning to discover new predictors from left-ventricular mechanical dyssynchrony for CRT response

BACKGROUND

Studies have shown that the conventional parameters characterizing left ventricular mechanical dyssynchrony (LVMD) measured on gated SPECT myocardial perfusion imaging (MPI) have their own statistical limitations in predicting cardiac resynchronization therapy (CRT) response. The purpose of this study is to discover new predictors from the polarmaps of LVMD by deep learning to help select heart failure patients with a high likelihood of response to CRT.

METHODS

One hundred and fifty-seven patients who underwent rest gated SPECT MPI were enrolled in this study. CRT response was defined as an increase in left ventricular ejection fraction (LVEF) > 5% at 6 [Formula: see text] 1 month follow up. The autoencoder (AE) technique, an unsupervised deep learning method, was applied to the polarmaps of LVMD to extract new predictors characterizing LVMD. Pearson correlation analysis was used to explain the relationships between new predictors and existing clinical parameters. Patients from the IAEA VISION-CRT trial were used for an external validation. Heatmaps were used to interpret the AE-extracted feature.

RESULTS

Complete data were obtained in 130 patients, and 68.5% of them were classified as CRT responders. After variable selection by feature importance ranking and correlation analysis, one AE-extracted LVMD predictor was included in the statistical analysis. This new AE-extracted LVMD predictor showed statistical significance in the univariate (OR 2.00, P = .026) and multivariate (OR 1.11, P = .021) analyses, respectively. Moreover, the new AE-extracted LVMD predictor not only had incremental value over PBW and significant clinical variables, including QRS duration and left ventricular end-systolic volume (AUC 0.74 vs 0.72, LH 7.33, P = .007), but also showed encouraging predictive value in the 165 patients from the IAEA VISION-CRT trial (P < .1). The heatmaps for calculation of the AE-extracted predictor showed higher weights on the anterior, lateral, and inferior myocardial walls, which are recommended as LV pacing sites in clinical practice.

CONCLUSIONS

AE techniques have significant value in the discovery of new clinical predictors. The new AE-extracted LVMD predictor extracted from the baseline gated SPECT MPI has the potential to improve the prediction of CRT response.

Conduction System Pacing Versus Conventional Cardiac Resynchronization Therapy in Congenital Heart Disease

BACKGROUND

Dyssynchrony-associated left ventricular systolic dysfunction is a major contributor to heart failure in congenital heart disease (CHD). Although conventional cardiac resynchronization therapy (CRT) has shown benefit, the comparative efficacy of cardiac conduction system pacing (CSP) is unknown.

OBJECTIVES

To compare the clinical outcomes of CSP vs conventional CRT in CHD with biventricular, systemic left ventricular anatomy.

METHODS

Retrospective CSP data from 7 centers were compared with propensity score-matched conventional CRT control subjects. Outcomes were lead performance, change in left ventricular ejection fraction (LVEF), and QRS duration at 12 months.

RESULTS

A total of 65 CSP cases were identified (mean age 37 ± 21 years, 46% men). The most common CHDs were tetralogy of Fallot (n = 12 [19%]) and ventricular septal defect (n = 12 [19%]). CSP was achieved after a mean of 2.5 ± 1.6 attempts per procedure (38 patients with left bundle branch pacing, 17 with HBP, 10 with left ventricular septal myocardial). Left bundle branch area pacing [LBBAP] vs HBP was associated with a smaller increase in pacing threshold (Δ pacing threshold 0.2 V vs 0.8 V; P = 0.05) and similar sensing parameters at follow-up. For 25 CSP cases and control subjects with baseline left ventricular systolic dysfunction, improvement in LVEF was non-inferior (Δ LVEF 9.0% vs 6.0%; P = 0.3; 95% confidence limits: -2.9% to 10.0%) and narrowing of QRS duration was more pronounced for CSP (Δ QRS duration 35 ms vs 14 ms; P = 0.04). Complications were similar (3 [12%] CSP, 4 [16%] conventional CRT; P = 1.00).

CONCLUSIONS

CSP can be reliably achieved in biventricular, systemic left ventricular CHD patients with similar improvement in LVEF and greater QRS narrowing for CSP vs conventional CRT at 1 year. Among CSP patients, pacing electrical parameters were superior for LBBAP vs HBP.

The response to cardiac resynchronization therapy in LMNA cardiomyopathy

AIMS

Cardiac implantable electronic device (CIED) therapy is fundamental to the management of LMNA cardiomyopathy due to the high frequency of atrioventricular block and ventricular tachyarrhythmias. We aimed to define the role of cardiac resynchronization therapy (CRT) in impacting heart failure in LMNA cardiomyopathy.

METHODS AND RESULTS

From nine referral centres, LMNA cardiomyopathy patients who underwent CRT with available pre- and post-echocardiograms were identified retrospectively. Factors associated with CRT response were identified (defined as improvement in left ventricular ejection fraction [LVEF] ≥5% 6 months post-implant) and the associated impact on the primary outcome of death, implantation of a left ventricular assist device or cardiac transplantation was assessed. We identified 105 patients (mean age 51 ± 10 years) undergoing CRT, including 70 (67%) who underwent CRT as a CIED upgrade. The mean change in LVEF ∼6 months post-CRT was +4 ± 9%. A CRT response occurred in 40 (38%) patients and was associated with lower baseline LVEF or a high percentage of right ventricular pacing prior to CRT in patients with pre-existing CIED. In patients with a European Society of Cardiology class I guideline indication for CRT, response rates were 61%. A CRT response was evident at thresholds of LVEF ≤45% or percent pacing ≥50%. There was a 1.3 year estimated median difference in event-free survival in those who responded to CRT (p = 0.04).

CONCLUSION

Systolic function improves in patients with LMNA cardiomyopathy who undergo CRT, especially with strong guideline indications for implantation. Post-CRT improvements in LVEF are associated with survival benefits in this population with otherwise limited options.

Prognostic value of the MELD-XI score in patients undergoing cardiac resynchronization therapy

Aims

Multi‐organ dysfunction was recently reported to be a common condition in patients with heart failure (HF). The Model for End‐stage Liver Disease eXcluding International normalized ratio (MELD‐XI) score reflects liver and kidney function. The prognostic relevance of this score has been reported in patients with a variety of cardiovascular diseases who are undergoing interventional therapies. However, the relationship between the severity of hepatorenal dysfunction assessed by the MELD‐XI score and the long‐term clinical outcomes of HF patients receiving cardiac resynchronization therapy (CRT) has not been evaluated.

Methods and results

Clinical records of 283 patients who underwent CRT implantation between March 2003 and October 2020 were retrospectively evaluated (mean age 67 ± 12, 22.6% female). Blood samples were collected before CRT implantation. Patients were divided into three groups based on tertiles of the MELD‐XI score: first tertile (MELD‐XI = 9.44, n = 95), second tertile (9.44 < MELD‐XI < 13.4, n = 94), and third tertile (MELD‐XI ≥ 13.4, n = 94). The primary endpoint was all‐cause mortality. Compared with the other groups, the third tertile group exhibited significantly older age, higher prevalence of diabetes mellitus and hypertension, lower haemoglobin level, and higher N‐terminal pro‐brain natriuretic peptide level (all P < 0.05). The functional CRT response rate was also significantly lower in the third tertile group (P = 0.011). During a median follow‐up of 30 months (inter‐quartile range, 9–67), 105 patients (37.1%) died. Kaplan–Meier analysis revealed that patients with a higher MELD‐XI score had a greater risk of all‐cause mortality (log‐rank test: P < 0.001). Even after adjustment for clinically relevant factors and a conventional risk score, the MELD‐XI score was still associated with mortality (adjusted hazard ratio: 1.04, 95% confidence interval: 1.00–1.07, P = 0.014, and adjusted hazard ratio: 1.04, 95% confidence interval: 1.01–1.09, P = 0.005, respectively). A higher MELD‐XI score was associated with a greater risk of all‐cause mortality than a lower MELD‐XI score regardless of whether a pacemaker or defibrillator was implanted (log‐rank test: P = 0.010 and P < 0.001, respectively).

Conclusions

Impaired hepatorenal function assessed by the MELD‐XI score was associated with older age, higher prevalence of multiple co‐morbidities, severity of HF, lower CRT response rates, and subsequent all‐cause mortality in HF patients undergoing CRT implantation. These results suggest that the MELD‐XI score can provide additional prognostic information and may be useful for improving risk stratification in this population.

Albumin-Bilirubin Score for Prediction of Outcomes in Heart Failure Patients Treated with Cardiac Resynchronization Therapy

Background: Liver function may be a useful indicator of response to cardiac resynchronization therapy (CRT). We aimed to investigate the clinical significance of albumin-bilirubin (ALBI) score, an assessment tool of liver function, on outcomes in heart failure (HF) patients treated with CRT. Methods: We studied 180 patients undergoing CRT. The ALBI score, derived from albumin and total bilirubin, and left ventricular ejection fraction (LVEF) were assessed before and 6 months after CRT. The patients were classified according to the ALBI score before CRT; High (>−2.60) or Low (≤−2.60) ALBI groups. The patients were then reclassified based on the ALBI score before and 6 months after CRT; High/High, High/Low, Low/High, and Low/Low ALBI groups. We evaluated the prognostic value of the ALBI score for HF deaths after CRT. Results: During a median follow-up period of 50 months, there were 41 (22.7%) HF deaths. A Cox proportional hazard analysis revealed that high ALBI scores at baseline were not related to HF deaths (hazard ratio, 1.907, p = 0.068). However, High/High ALBI scores, but not High/Low or Low/High ALBI scores, were an independent predictor of HF deaths compared with Low/Low ALBI scores (hazard ratio, 3.449, p = 0.008), implying that consistently high ALBI scores were associated with poor prognosis. The percentage change in LVEF from baseline to 6 months after CRT did not differ among the four groups, suggesting that left ventricular systolic function was not linked with the ALBI score. Conclusions: ALBI scores before and after CRT are a new indicator of CRT response, and have a predictive value for HF deaths in HF patients.

Prognostic value of galectin-3 and right ventricular function for long-term mortality in heart failure patients treated with cardiac resynchronization therapy

Recently, associations between the biomarker galectin-3 and numerous pathological processes involved in heart failure (HF) and right ventricular (RV) function have been observed. We aimed to assess the long-term prognostic ability of galectin-3 and RV function parameters for all-cause mortality in HF patients treated with cardiac resynchronization therapy (CRT). We prospectively studied 63 symptomatic HF patients with a left ventricular (LV) ejection fraction (EF) ≤ 35%. The median serum galectin-3 concentration was 13.4 ng/mL (IQR 11.05, 17.15). A detailed assessment of LV and RV geometry and function was performed with echocardiography. CRT defibrillator implantation was achieved in all patients without major complications. The follow-up lasted 5 years. In the multivariable Cox regression model, independent predictors for all-cause mortality were log baseline galectin-3 and baseline RV function expressed as tricuspid annular plane systolic excursion with HR 2.96 (p = 0.037) and HR 0.88 (p = 0.023), respectively. Analysis of subgroups defined by galectin-3 concentration and CRT response showed that patients with high baseline galectin-3 concentrations and a lack of response to CRT had a significantly lower probability of survival. In our patient cohort, the baseline galectin-3 concentration and RV function were independent predictors of long-term all-cause mortality in HFrEF patients following CRT implantation.

Prognostic importance of the Controlling Nutritional Status (CONUT) score in patients undergoing cardiac resynchronisation therapy

Aims

Malnutrition is common and associated with worse clinical outcomes in patients with heart failure (HF). The Controlling Nutritional Status (CONUT) score is an integrated index for evaluating diverse aspects of the complex mechanism of malnutrition. However, the relationship between the severity of malnutrition assessed by the CONUT score and clinical outcomes of HF patients receiving cardiac resynchronisation therapy (CRT) has not been fully clarified.

Methods

Clinical records of 263 patients who underwent pacemaker or defibrillator implantation for CRT between March 2003 and October 2020 were retrospectively evaluated. The CONUT score was calculated from laboratory data obtained before CRT device implantation. Patients were divided into three groups: normal nutrition (CONUT scores 0–1, n=58), mild malnutrition (CONUT scores 2–4, n=132) and moderate or severe malnutrition (CONUT scores 5–12, n=73). The primary endpoint was all-cause mortality.

Results

The moderate or severe malnutrition group had a lower body mass index, more advanced New York Heart Association functional class, higher Clinical Frailty Scale score, lower levels of haemoglobin and higher levels of N-terminal probrain natriuretic peptide (all p<0.05). In the moderate or severe malnutrition group, the CRT response rate was significantly lower than for the other two groups (p=0.001). During a median follow-up period of 31 (10–67) months, 103 (39.1%) patients died. Kaplan-Meier analysis revealed that the moderate or severe malnutrition group had a significantly higher mortality rate (log-rank p<0.001). A higher CONUT score and CONUT score ≥5 remained significantly associated with all-cause mortality after adjusting for previously reported clinically relevant factors and the conventional risk score (VALID-CRT risk score) (all p<0.05).

Conclusions

A higher CONUT score before CRT device implantation was strongly associated with HF severity, frailty, lower CRT response rate and subsequent long-term all-cause mortality.

Relationship of Mechanical Dyssynchrony and LV Remodeling With Improvement of Mitral Regurgitation After CRT

OBJECTIVES

The aim of this study was to explore the association between mechanical dyssynchrony of the left ventricle before cardiac resynchronization therapy (CRT) and improvement of mitral regurgitation (MR) after CRT.

BACKGROUND

MR is very frequent among patients with dilated cardiomyopathy and conduction delay.

METHODS

Echocardiograms (pre-CRT and 12 ± 3.8 months thereafter) of 314 patients with dilated cardiomyopathy and any degree of MR, who underwent CRT device implantation according to guidelines, were analyzed. Left ventricular (LV) mechanical dyssynchrony was assessed by apical rocking (ApRock) and septal flash (SF), while MR severity was graded from I to IV on the basis of vena contracta width, regurgitation jet size, and proximal isovelocity surface area.

RESULTS

At baseline, 30% of patients presented with severe MR (grade III or IV). In 62% of patients, MR decreased after CRT, and these patients more frequently had left bundle branch block, had more severe MR, had more dilated left ventricles, had lower ejection fractions, and more often had ApRock and SF. Reverse remodeling was more frequent among patients with MR reduction (ΔLV end-systolic volume -35.5% ± 27.2% vs -4.1% ± 33.2%; P < 0.001). In a multivariable logistic stepwise regression, only ApRock (odds ratio [OR]: 3.8; 95% CI: 1.7-8.5; P = 0.001), SF (OR: 3.6; 95% CI: 1.6-7.9; P = 0.002), and baseline MR (OR: 1.4; 95% CI: 1.0-1.9; P = 0.046) remained significantly associated with MR reduction.

CONCLUSIONS

ApRock, SF, and severity of MR at baseline are strongly associated with MR reduction after CRT, while LV reverse remodeling is its underlying mechanism. Therefore, in patients with heart failure with LV dyssynchrony on optimal medical treatment, CRT should be the primary treatment attempt for relevant MR.

Contemporary ICD Use in Patients with Heart Failure

Despite constant breakthroughs in heart failure (HF) therapy, the population of HF patients resume to grow and is linked to increased mortality and morbidity. Ventricular arrhythmias (VA) are one of the leading causes of mortality in HF subjects. Implantable cardioverter-defibrillators (ICDs) are currently the gold standard in treatment, preventing arrhythmic sudden cardiac death (SCD) episodes. However, the death rates related to HF remain elevated, as not all HF subjects benefit equally. Cardiac resynchronization therapy (CRT) has emerged as a novel approach for HF patients. These devices have been thoroughly investigated in major randomized controlled studies but continue to be underutilized in various countries. This review discusses the use of ICD in HF populations on top of treatments.

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.

The value of non-invasive myocardial work indices derived from left ventricular pressure-strain loops in predicting the response to cardiac resynchronization therapy

Background

Non-invasive left ventricular (LV) pressure-strain loops (PSLs), which are generated by combining LV longitudinal strain with brachial artery blood pressure, provide a novel method of quantifying global and segmental myocardial work (MW) indices with potential advantages over conventional echocardiographic strain data, which suffers from being load-dependent. This method has been recently introduced in echocardiographic software, enhancing the efficiency of MW calculations. This study aimed to evaluate the role of non-invasive MW indices derived from LV PSLs in predicting cardiac resynchronization therapy (CRT) response.

Methods

A total of 106 heart failure (HF) patients scheduled for CRT were included in the MW analysis. Global and segmental (septal and lateral at the mid-ventricular level) MW indices were assessed before CRT and at a 6-month follow-up. Response to CRT was defined as ≥15% reduction in LV end-systolic volume and ≥1 NYHA functional class improvement at 6-month follow-up compared to baseline.

Results

CRT response was observed in 78 (74%) patients. At baseline, the global work index (GWI) and global constructive work (GCW) were significantly higher in CRT responders than in non-responders (both P<0.05). Furthermore, responders exhibited significantly higher mid lateral MW and mid lateral constructive work (CW) (both P<0.001), but significantly lower mid septal MWI and mid septal myocardial work efficiency (MWE) than non-responders (all P<0.01). Baseline mid septal MWE (OR 0.975, 95% CI: 0.959-0.990, P=0.002) and mid lateral MWI (OR 1.003, 95% CI: 1.002-1.004, P<0.001) were identified as independent predictors of CRT response in multivariate regression analysis. Mid septal MWE ≤42% combined with mid lateral MWI ≥740 mmHg% predicted CRT response, with an optimal sensitivity of 79% and specificity of 82% [area under the receiver operating characteristic curve (AUC) =0.830, P<0.001].

Conclusions

Assessment of MW indices before CRT could identify the marked imbalance in LV MW distribution and can be widely used as a reliable complementary tool for guiding patient selection for CRT in clinical practice.

Six months clinical outcome comparison between quadripolar and bipolar left ventricular leads in cardiac resynchronization therapy: A prospective, non-randomized, single-centre observational study

Background and objectives

Quadripolar left ventricular (LV) leads in cardiac resynchronization therapy (CRT) offer multi-vector pacing with different pacing configurations and hence enabling LV pacing at most suitable site with better lead stability. We aim to compare the outcomes between quadripolar and bipolar LV lead in patients receiving CRT.

Methods

In this prospective, non-randomized, single-center observational study, we enrolled 93 patients receiving CRT with bipolar (BiP) (n = 31) and quadripolar (Quad) (n = 62) LV lead between August 2016 to August 2019. Patients were followed for six months, and outcomes were compared with respect to CRT response (defined as ≥5% absolute increase in left ventricle ejection fraction), electrocardiographic, echocardiographic parameters, NYHA functional class improvement, and incidence of LV lead-related complication.

Results

At the end of six months follow up, CRT with quadripolar lead was associated with better response rate as compared to bipolar pacing (85.48% vs 64.51%; p = 0.03), lesser heart failure (HF) hospitalization events (1.5 vs 2; p = 0.04) and better improvement in HF symptoms (patients with ≥1 NYHA improvement 87.09% vs 67.74%; p = 0.04). There were fewer deaths per 100 patient-year (6.45 vs 9.37; p = 0.04) and more narrowing of QRS duration (Δ12.56 ± 3.11 ms vs Δ7.29 ± 1.87 ms; p = 0.04) with quadripolar lead use. Lead related complications were significantly more with the use of bipolar lead (74.19% vs 41.94%; p = 0.02).

Conclusions

Our prospective, non-randomized, single-center observational study reveals that patients receiving CRT with quadripolar leads have a better response to therapy, lesser heart failure hospitalizations, lower all-cause mortality, and fewer lead-related complications, proving its superiority over the bipolar lead.

What Are the Expectations for Cardiac Resynchronization Therapy? A Validation of Two Response Definitions

BACKGROUND

The definition of response to cardiac resynchronization therapy (CRT) varies across clinical trials. There are two main definitions, i.e., echocardiographic response and functional response. We assessed which definition was more reasonable.

METHODS

In this study of 260 patients who had undergone CRT, an echocardiographic response was defined as a reduction in a left ventricular end-systolic volume of greater than or equal to 15% or an improvement in left ventricular ejection fraction of greater than or equal to 5%. A functional response was defined as an improvement of at least one class category in the New York Heart Association functional classification. We assessed the response to CRT at 6 months after device implantation, based on each definition, and investigated the relationship between response and clinical outcomes.

RESULTS

The echocardiographic response rate was 74.2%. The functional response rate was 86.9%. Non-responder status, based on both definitions, was associated with higher all-cause mortality. Cardiac death was only associated with functional non-responder status (hazard ratio (HR) 2.65, 95% confidence interval (CI) 1.19-5.46, p = 0.0186) and heart failure hospitalization (HR 2.78, 95% CI, 1.29-5.26, p = 0.0111).

CONCLUSION

After CRT implantation, the functional response definition of CRT response is associated with a higher response rate and better clinical outcomes than that of the echocardiographic response definition, and therefore it is reasonable to use the functional definition to assess CRT response.

Blood flow patterns estimation in the left ventricle with low-rate 2D and 3D dynamic contrast-enhanced ultrasound

BACKGROUND AND OBJECTIVE

Left ventricle (LV) dysfunction always occurs at early heart-failure stages, producing variations in the LV flow patterns. Cardiac diagnostics may therefore benefit from flow-pattern analysis. Several visualization tools have been proposed that require ultrafast ultrasound acquisitions. However, ultrafast ultrasound is not standard in clinical scanners. Meanwhile techniques that can handle low frame rates are still lacking. As a result, the clinical translation of these techniques remains limited, especially for 3D acquisitions where the volume rates are intrinsically low.

METHODS

To overcome these limitations, we propose a novel technique for the estimation of LV blood velocity and relative-pressure fields from dynamic contrast-enhanced ultrasound (DCE-US) at low frame rates. Different from other methods, our method is based on the time-delays between time-intensity curves measured at neighbor pixels in the DCE-US loops. Using Navier-Stokes equation, we regularize the obtained velocity fields and derive relative-pressure estimates. Blood flow patterns were characterized with regard to their vorticity, relative-pressure changes (dp/dt) in the LV outflow tract, and viscous energy loss, as these reflect the ejection efficiency.

RESULTS

We evaluated the proposed method on 18 patients (9 responders and 9 non-responders) who underwent cardiac resynchronization therapy (CRT). After CRT, the responder group evidenced a significant (p<0.05) increase in vorticity and peak dp/dt, and a non-significant decrease in viscous energy loss. No significant difference was found in the non-responder group. Relative feature variation before and after CRT evidenced a significant difference (p<0.05) between responders and non-responders for vorticity and peak dp/dt. Finally, the method feasibility is also shown with 3D DCE-US.

CONCLUSIONS

Using the proposed method, adequate visualization and quantification of blood flow patterns are successfully enabled based on low-rate DCE-US of the LV, facilitating the clinical adoption of the method using standard ultrasound scanners. The clinical value of the method in the context of CRT is also shown.

Correlation of newer indices of dyssynchrony with clinical response in patients undergoing cardiac resynchronisation therapy

The benefits of CRT in select subsets of systolic heart failure patients with LBBB are proven. We prospectively evaluated conventional and newer echocardiographic parameters of left ventricular dyssynchrony in 35 patients who underwent CRT and were followed up after 6 months. Of the 33 surviving patients, 21 were echocardiographic responders and 24 were clinical responders. The parameters in clinical responders and non-responders were compared. The anatomic M Mode parameters of delays improved, while the radial strain and the mitral valve velocity time integral (MVVTI) did not show any significant change after CRT.

Left ventricular remodelling and change in left ventricular global longitudinal strain after cardiac resynchronization therapy: prognostic implications

AIMS

Cardiac resynchronization therapy (CRT) can reduce left ventricular end-systolic volume (LVESV), and a decrease of ≥15% is defined as a response. CRT can also improve LV global longitudinal strain (GLS). Changes in LVESV and LV GLS are individually associated with outcome post-CRT. We investigated LVESV and LV GLS changes and prognostic implications of improvement in LVESV and/or LV GLS, compared with no improvement in either parameter.

METHODS AND RESULTS

Baseline and 6-month echocardiograms were analysed from CRT recipients with heart failure. LV reverse remodelling was defined as a ≥15% reduction in LVESV at 6 months post-CRT. A ≥5% absolute improvement in LV GLS was defined as a change in LV GLS. A total of 1185 patients were included (mean age 65 ± 10 years, 73% male), and those with an improvement in LVESV and LV GLS (n = 131, 11.1%) had significantly lower mortality compared with other groups. On multivariable analysis, an improvement in both LVESV and LV GLS [hazard ratio (HR): 0.47; 95% confidence interval (CI): 0.31-0.71; P < 0.001] or an improvement in either LVESV or LV GLS (HR: 0.57; 95% CI: 0.47-0.71; P < 0.001) were independently associated with better prognosis, compared with no improvement in either parameter.

CONCLUSION

Either a reduction in LVESV and/or an improvement in LV GLS at 6 months post-CRT are independently associated with improved long-term prognosis, compared with no change in both LVESV and LV GLS. This supports the use of LV GLS as a meaningful parameter in defining CRT response.

Relationship between myocardial energy expenditure and postoperative ejection fraction in patients with severe mitral regurgitation

Objective:

This prospective study aimed to investigate the myocardial energy metabolism in severe mitral regurgitation (MR) and explore its effect on postoperative differentiation of ejection fraction (EF).

Methods:

A total of 85 patients with severe MR were prospectively enrolled from October 2018 to June 2019. During the study period, a total of 50 patients underwent mitral valve surgery and 49 patients were finally enrolled due to 1 missing data. Left ventricular function, circumferential end-systolic stress (cESS), and myocardial energy expenditure (MEE) were measured by transthoracic echocardiography preoperatively and 3 months after surgery. Patients were divided into 2 groups according to absolute difference of postoperative differentiation of EF.

Results:

Nine patients underwent mitral valve repair and 40 underwent prosthetic valve replacement. Patients with reduced EF had higher MEE demonstrated with cESS and MEE. Negative correlation between preoperative EF and N-terminal pro-brain natriuretic peptide (NT-proBNP), cESS, MEEs, and MEEm and positive correlation between preoperative EF and effective regurgitant orifice area were found. Complications occurred in 12 patients during hospitalization. Basal NT-proBNP, left atrium (LA), and cESS were significantly higher in postoperatively decreased EF group. Taking into consideration the covariates of multiple logistic regression analysis, LA and cESS were found to be independent predictors of EF reduction postoperatively.

Conclusion:

Higher LA and cESS are independent predictors of postoperative EF reduction. Preoperative high end-systolic stress could predict postoperative EF reduction and hence could be helpful for determining the timing of mitral valve surgery. Although MEE was higher in postoperatively decreased EF group, it did not reach statistical significance.

The effect of iron deficiency on cardiac resynchronization therapy: results from the RIDE-CRT Study

Aims

Cardiac resynchronization therapy (CRT) improves functional status, induces reverse left ventricular remodelling, and reduces hospitalization and mortality in patients with symptomatic heart failure, left ventricular systolic dysfunction, and QRS prolongation. However, the impact of iron deficiency on CRT response remains largely unclear. The purpose of the study was to assess the effect of functional and absolute iron deficiency on reverse cardiac remodelling, clinical response, and outcome after CRT implantation.

Methods and results

The relation of iron deficiency and cardiac resynchronization therapy response (RIDE‐CRT) study is a prospective observational study. We enrolled 77 consecutive CRT recipients (mean age 71.3 ± 10.2 years) with short‐term follow‐up of 3.3 ± 1.9 months and long‐term follow‐up of 13.0 ± 3.2 months. Primary endpoints were reverse cardiac remodelling on echocardiography and clinical CRT response, assessed by change in New York Heart Association classification. Echocardiographic CRT response was defined as relative improvement of left ventricular ejection fraction ≥ 20% or left ventricular global longitudinal strain ≥ 20%. Secondary endpoints were hospitalization for heart failure and all‐cause mortality (mean follow‐up of 29.0 ± 8.4 months). At multivariate analysis, iron deficiency was identified as independent predictor of echocardiographic (hazard ratio 4.97; 95% confidence interval 1.15–21.51; P = 0.03) and clinical non‐response to CRT (hazard ratio 4.79; 95% confidence interval 1.30–17.72, P = 0.02). We found a significant linear‐by‐linear association between CRT response and type of iron deficiency (P = 0.004 for left ventricular ejection fraction improvement, P = 0.02 for left ventricular global longitudinal strain improvement, and P = 0.003 for New York Heart Association response). Iron deficiency was also significantly associated with an increase in all‐cause mortality (P = 0.045) but not with heart failure hospitalization.

Conclusions

Iron deficiency is a negative predictor of effective CRT therapy as assessed by reverse cardiac remodelling and clinical response. Assessment of iron substitution might be a relevant treatment target to increase CRT response and outcome in chronic heart failure patients.

The Temporal Relation between Cardiomyopathy and LBBB and Response to Cardiac Resynchronization Therapy: Case Series and Literature Review

Background: Left bundle branch block (LBBB)-induced cardiomyopathy has been proposed, but the association between LBBB and cardiac resynchronization therapy (CRT) response remains unclear and practical criteria for selecting CRT candidates are needed.Methods: One hundred and seventeen consecutive heart failure patients were reviewed, 24 of whom received CRT. Only two patients had a clear temporal relation between cardiomyopathy and LBBB.Results: Compared with the patient with “cardiomyopathy-induced LBBB,” the patient with “LBBB-induced cardiomyopathy” had higher left ventricular (LV) wall thickness, higher LV wall thickening rate, higher peak circumferential strain, and longer peak circumferential strain delay. The LV deformation patterns in the two patients were obviously distinct on cardiovascular magnetic resonance tissue tracking. During follow-up, the patient with LBBB-induced cardiomyopathy had a good response to CRT (LV ejection fraction 23 before CRT vs. 30% at 6 months vs. 29 at 12 months vs. 32% at 18 months; LV end-diastolic diameter 77 mm before CRT vs. 66 mm at 6 months vs. 62 mm at 12 months vs. 63 mm at 18 months), and the other patient had no response to CRT (LV ejection fraction 29 before CRT vs. 29% at 6 months vs. 26 at 12 months vs. 22% at 24 months; LV end-diastolic diameter 85 mm before CRT vs. 88 mm at 6 months vs. 85 mm at 12 months vs. 84 mm at 24 months).Conclusion: The temporal relation between cardiomyopathy and LBBB could be a determinant for CRT response. Cardiovascular magnetic resonance tissue tracking may be a useful tool to identify the chronological order and a principal consideration for selecting candidates for CRT. Larger prospective clinical trials are needed to study the prevalence of, time course of, and risk factors for LBBB-induced cardiomyopathy.

Design and rationale for the Stimulation Of the Left Ventricular Endocardium for Cardiac Resynchronization Therapy in non-responders and previously untreatable patients (SOLVE-CRT) trial

BACKGROUND

Cardiac resynchronization therapy (CRT) improves outcomes, functional capacity and quality of life in patients with heart failure. Despite two decades of experience with CRT, the rate of non-response remains approximately 30%. CRT efficacy is impacted by pacing location, which is anatomically limited in conventional systems. A new wireless endocardial left ventricular (LV) pacing system allows CRT without such limitations and has shown promise in open-label studies. The purpose of this study is to evaluate its use in a patient population with poor therapeutic alternatives.

METHODS

The SOLVE CRT study is an international, multi-center, randomized, double-blind, sham-controlled trial of patients with Class I and IIa indications for CRT who have either failed to respond to or have been unable to receive conventional CRT. Enrollment will comprise 350 patients implanted with the wireless CRT system randomized 1:1 to therapy on (Treatment) or therapy off (Control) for the six-month period over which trial primary endpoints will be evaluated. The primary safety endpoint will measure the proportion of patients free from system- and procedure-related complications. Primary efficacy endpoints will assess absolute change in LV end-systolic volume LVESV, proportion of patients reducing LVESV by ≥15% and clinical composite score for Treatment versus Control patients. Primary endpoints will be evaluated on an intention-to-treat basis, though per-protocol and as-treated analysis will also be performed.

CONCLUSION

SOLVE-CRT will quantify the safety and effectiveness of wireless CRT in non-responders to conventional CRT and indicated patients who have been unable to receive CRT via the usual transvenous approach.

Devices in Heart Failure Patients-Who Benefits From ICD and CRT?

Despite advances in heart failure treatment, this condition remains a relevant medical issue and is associated with a high morbidity and mortality. The cause of death in patients suffering from heart failure is not only a result of hemodynamic failure, but can also be due to ventricular arrhythmias. Implantable cardioverter defibrillators (ICDs) are these days the only tool to significantly reduce arrhythmic sudden death; but not all patients benefit to the same extend. In addition, cardiac resynchronization therapy (CRT) is another tool which is used in patients suffering from heart fialure. Even though both devices have been investigated in large randomized trials, both ICD and CRT remain underutilized in many countries. This brief review focuses on various aspects in this regard including a short overview on upcoming device novelties in the near future.

Prognostic implications of global, left ventricular myocardial work efficiency before cardiac resynchronization therapy

Aims

Cardiac resynchronization therapy (CRT) restores mechanical efficiency to the failing left ventricular (LV) by resynchronization of contraction. Global, LV myocardial work efficiency (GLVMWE) can be quantified non-invasively with echocardiography. The prognostic implication of GLVMWE remains unexplored, and we therefore related GLVMWE before CRT to long-term prognosis.

Methods and results

Data were analysed from an ongoing registry of patients with Class I indications for CRT. GLVMWE was defined as the ratio of constructive work in all LV segments, divided by the sum of constructive and wasted work in all LV segments, as a percentage. It was derived from speckle tracking strain echocardiography and non-invasive blood pressure measurements, taken pre-CRT. Patients were dichotomized according to baseline, median GLVMWE [75%; interquartile range (IQR) 66–81%]. A total of 153 patients (66 ± 10 years, 72% male, 48% ischaemic heart disease) were analysed. After a median follow-up of 57 months (IQR 28–76 months), 31% of patients died. CRT recipients with less efficient baseline energetics (GLVMWE &lt;75%) demonstrated lower event rates than patients with more efficient baseline energetics (GLVMWE ≥75%) (log-rank test, P = 0.029). On multivariable analysis, global LV wasted work ratio &lt;75% pre-CRT was independently associated with a decreased risk of all-cause mortality (hazard ratio 0.48, 95% confidence interval 0.25–0.92; P = 0.027), suggesting that the potential for improvement in LV efficiency is important for CRT benefit.

Conclusion

GLVMWE can be derived non-invasively from speckle tracking strain echocardiography and non-invasive blood pressure recordings. A lower GLVMWE before CRT is independently associated with improved long-term outcome.

Left Ventricular End-Systolic Volume Can Predict 1-Year Hierarchical Clinical Composite End Point in Patients with Cardiac Resynchronization Therapy

PURPOSE

This study aimed to elucidate which echocardiographic criteria at three time points, for cardiac resynchronization therapy (CRT) response, are accurate in discriminating the hierarchical clinical composite end point (HCCEP).

MATERIALS AND METHODS

We included 120 patients (age, 66.1±12.6 years; men, 54.2%) who underwent CRT implantation for heart failure (HF). Echocardiography was performed before and at 3, 6, and 12 months after CRT implantation. The 1-year HCCEP included all-cause mortality, hospitalization for HF, and New York Heart Association functional class for 12 months. CRT response criteria were decrease in left ventricular (LV) end-systolic volume (LVESV) >15%, decrease in LV end-diastolic volume >15%, absolute increase in LV ejection fraction (LVEF) ≥5%, relative increase in LVEF ≥15%, and decrease in mitral regurgitation ≥1 grade. Temporal changes in CRT response rates, accuracy of CRT response criteria at each time and cutoff value for the discrimination of improvement in HCCEP, and agreements with improvement in HCCEP were analyzed.

RESULTS

HCCEP improvement rates were 65.8% in total group. In nonischemic group, CRT response rates according to all echocardiographic criteria significantly increased with time. In ischemic group, CRT response rate did not significantly change with time. In total group, ΔLVESV at 6 months (ΔLVESV6) had the most significant accuracy for the discrimination of HCCEP (area under the curve=0.781). The optimal cutoff value of ΔLVESV6 was 13.5% (sensitivity=0.719, specificity=0.719). ΔLVESV6 had fair agreement with HCCEP (κ=0.391, p<0.001).

CONCLUSION

ΔLVESV6 is the most useful echocardiographic CRT response criterion for the prediction of 1-year HCCEP.

Effect of Functional Mitral Regurgitation on Outcome in Patients Receiving Cardiac Resynchronization Therapy for Heart Failure

Functional mitral regurgitation (FMR) is common in heart failure (HF), and negatively impacts prognosis. Cardiac resynchronization therapy (CRT) can improve FMR, but the long-term changes in and impact of FMR after CRT are still unclear. The present study investigated the prevalence, evolution and impact on mortality of FMR before and after CRT in patients with HF. A total of 1,313 patients (66 ± 11 years, 77% male, 59% ischemic heart disease) treated with CRT were evaluated. Patients were divided into 4 groups of FMR according to the evolution at 6 months after CRT: no or mild FMR at baseline which remained unchanged at 6 months (grade 0-1 FMR unchanged, n = 609 [51%]), no or mild FMR which worsened to moderate to severe (grade 0-1 FMR worsened, n = 66 [6%)]), moderate to severe FMR which improved to no or mild (grade 2-4 improved, n = 209 [18%]), and moderate to severe FMR which remained unchanged (grade 2-4 unchanged, n = 309 [26%]). Over a mean follow-up of 51 ± 38 months, 297 (25%) patients died. Those with baseline FMR grade 0-1 which remained unchanged at 6-month follow-up, as well as baseline FMR grade 2-4 which improved, had lower mortality rates than patients with 6-month FMR grade 2-4 regardless of baseline FMR grade (p <0.001). Baseline FMR grade 2-4 that remained unchanged at 6-month follow-up was associated with increased mortality, independent of the clinical and left ventricular volumetric responses to CRT (hazard ratio, 1.77; 95% confidence interval, 1.41-2.22, p <0.001). In conclusion, moderate to severe FMR at baseline which remains unchanged at 6 months after CRT implantation is strongly associated with long-term mortality in patients with HF.

Potential benefit of optimizing atrioventricular & interventricular delays in patients with cardiac resynchronization therapy

Background & objectives:

The clinical benefit of optimization (OPT) of atrioventricular delay (AVD) and interventricular delay (VVD) in cardiac resynchronization therapy (CRT) remains debatable. This study was aimed to determine the influence of AVD and VVD OPT on selected parameters in patients early after CRT implantation and at mid-term follow up (FU).

Methods:

Fifty two patients (61±10 yr, 23 males) with left bundle branch block, left ventricular ejection fraction (LVEF) ≤35 per cent and heart failure were selected for CRT implantation. Early on the second day (2DFU) after CRT implantation, the patients were assigned to the OPT or the factory setting (FS) group. Haemodynamic and electrical parameters were evaluated at baseline, on 2DFU after CRT and mid-term FU [three-month FU (3MFU)]. Echocardiographic measures were assessed before implantation and at 3MFU. The AVD/VVD was deemed optimal for the highest cardiac output (CO) with impedance cardiography (ICG) monitoring.

Results:

On 2DFU, the AVD was shorter in the OPT group, LV was paced earlier than in FS group and CO was insignificantly higher in OPT group. At 3MFU, improvement of CO was observed only in OPT patients, but the intergroup difference was not significant. At 3MFU in OPT group, reduction of LV in terms of LV end-diastolic diameter (LVeDD), LV end-systolic diameter, LV end-diastolic and systolic volume with the improvement in LVEF was observed. In FS group, only a reduction in LVeDD was present. In OPT group, the paced QRS duration was shorter than in FS group patients.

Interpretation & conclusions:

CRT OPT of AVD and VVD with ICG was associated with a higher CO and better reverse LV remodelling. CO monitoring with ICG is a simple, non-invasive tool to optimize CRT devices.

Multipoint pacing via a quadripolar left-ventricular lead: preliminary results from the Italian registry on multipoint left-ventricular pacing in cardiac resynchronization therapy (IRON-MPP)

Aims

This registry was created to describe the experience of 76 Italian centres with a large cohort of recipients of multipoint pacing (MPP) capable cardiac resynchronization therapy (CRT) devices.

Methods and results

A total of 507 patients in whom these devices had been successfully implanted were enrolled between August 2013 and May 2015. We analysed: (i) current clinical practices for the management of such patients, and (ii) the impact of MPP on heart failure clinical composite response and on the absolute change in ejection fraction (EF) at 6 months. Multipoint pacing was programmed to ‘ON’ in 46% of patients before discharge. Methods of optimizing MPP programming were most commonly based on either the greatest narrowing of the QRS complex (38%) or the electrical delays between the electrodes (34%). Clinical and echocardiographic follow-up data were evaluated in 232 patients. These patients were divided into two groups according to whether MPP was programmed to ‘ON’ (n = 94) or ‘OFF’ (n = 138) at the time of discharge. At 6 months, EF was significantly higher in the MPP group than in the biventricular-pacing group (39.1 ± 9.6 vs. 34.7 ± 7.6%; P < 0.001). Even after adjustments, early MPP activation remained an independent predictor of absolute increase in LVEF of ≥5% (odds ratio 2.5; P = 0.001). At 6 months, an improvement in clinical composite score was recorded in a greater proportion of patients with MPP-ON than in controls (56 vs. 38%; P = 0.009). On comparing optimal MPP and conventional vectors, QRS was also seen to have decreased significantly (P < 0.001).

Conclusion

This study provides information that is essential in order to deal with the expected increase in the number of patients receiving MPP devices in the coming years. The results revealed different practices among centres, and establishing the optimal programming that can maximize the benefit of MPP remains a challenging issue. Compared with conventional CRT, MPP improved clinical status and resulted in an additional increase in EF.

Clinical Trial Registration

http://www.clinicaltrial.gov/. Unique identifier: NCT02606071.

Triple-site pacing for cardiac resynchronization in permanent atrial fibrillation: follow-up results from a prospective observational study

Aims

Cardiac Resynchronization Therapy (CRT) is associated with a particularly high non-response rate in patients with atrial fibrillation (AF). We aimed to assess the effectiveness of triple-site (Tri-V) pacing CRT in this population.

Methods and results

Prospective observational study of patients with permanent AF who underwent CRT implantation with an additional right ventricle lead in the outflow tract septal wall. After implantation, programming mode (Tri-V or biventricular pacing) was selected based on cardiac output determination. Patients were classified as responders if NYHA class was reduced by at least one level and echocardiographic ejection fraction (EF) increased ≥ 10%, and as super-responders if in NYHA class I and EF ≥ 50%. Forty patients (93% male, mean age 72 ± 10 years) were included. Thirty-three were programmed in Tri-V. The following results pertain to this subgroup. At baseline, 58% were in NYHA class III and 36% NYHA class II. At 1 year follow-up, Minnesota QoL score was reduced (36 ± 23 vs. 8 ± 6; P = 0.001) and the 6MWT distance improved (384 ± 120 m to 462 ± 87 m, P = 0.003). Mean EF increased (26% ± 8 vs. 39 ± 10; P < 0.001 at 6 months and 41 ± 10; P < 0.001 at 12 months). Responder rate was 59% at 6 months and 79% at 12 months. Super-responder rate was 9% at 6 months and 16% at 12 months. One year survival free from heart failure hospitalization was 87.9%.

Conclusion

Tri-V CRT yielded higher response and super-response rates than usually reported for CRT in patients with permanent AF using clinical and remodeling criteria.

What happens to non-responders in cardiac resynchronization therapy?

INTRODUCTION AND OBJECTIVES

Left ventricular reverse remodeling (LVRR) is strongly related to the long-term prognosis of patients undergoing cardiac resynchronization therapy (CRT). The aim of this study was to assess the long-term clinical outcome of patients without LVRR at six months after CRT implantation and to determine the prognostic impact of clinical response in this population.

METHODS

We analyzed 178 consecutive patients who underwent successful CRT device implantation (age 64±11 years; 69% male; 89% in New York Heart Association [NYHA] functional class III; 35% with ischemic cardiomyopathy). Clinical status and echocardiographic parameters were determined before and six months after CRT implantation. We identified those without criteria for LVRR (≥10% increase in left ventricular ejection fraction with ≥15% reduction in left ventricular end-systolic diameter compared to baseline). Clinical responders were defined by a sustained improvement of at least one NYHA functional class.

RESULTS

At six-month assessment after CRT, 109 (61%) patients showed LVRR. During a mean follow-up of 56±21 months, 47 (26%) patients died, with higher mortality in the group without LVRR (36% vs. 20%, p=0.023). Clinical response was greater in patients with LVRR (88% vs. 55%, p<0.001). In patients without LVRR, clinical response to CRT was the strongest independent predictor of survival (hazard ratio: 0.120; 95% confidence interval: 0.039-0.366; p<0.001).

CONCLUSION

Although patients without LVRR six months after CRT implantation had a worse prognosis, with higher all-cause mortality, clinical response can be an independent predictor of survival in this population.

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.

Repetitive optimizing left ventricular pacing configurations with quadripolar leads improves response to cardiac resynchronization therapy: A single-center randomized clinical trial

BACKGROUND

This study aimed to investigate whether repetitive optimizing left ventricular pacing configurations (LVPCs) with quadripolar leads (QUAD) can improve response to cardiac resynchronization therapy (CRT).

METHODS

Fifty-two eligible patients were enrolled and 1:1 randomized to either the quadripolar LV leads (QUAD) group or the conventional bipolar leads (CONV) group. In the QUAD group, optimization of LVPC was performed for all patients before discharge and for nonresponders at 3 months follow-up. Clinical evaluations and transthoracic echocardiograms were performed before, 3, and 6 months after CRT implantation.

RESULTS

At 3 months follow-up, 16 of 25 (64%) patients in the CONV group (1 patient was lost to follow-up) and 18 of 26 (69%) patients in the QUAD group were classified as responders. After optimizing the LVPCs in 3-month nonresponders in the QUAD group, 21 of 26 (80.8%) patients in the QUAD group were classified as responders at 6 months as compared with 17 of 25 (68%) patients in the CONV group. Left ventricular end-systolic volume (LVESV) reduction, left ventricular ejection fraction (LVEF) increase, and New York Heart Association (NYHA) functional class reduction at 6 months were significantly greater in the QUAD group than in the CONV group (LVESV: -26.9 ± 13.8 vs -17.2 ± 13.3%; P = .013; LVEF: +12.7 ± 8.0 vs +7.8 ± 6.3 percentage points; P = .017; NYHA: -1.27 ± 0.67 vs -0.72 ± 0.54 functional classes; P = .002).

CONCLUSIONS

Compared with conventional bipolar leads, CRT using quadripolar leads with repetitive optimized LVPCs resulted in an additional increase in LVEF and reduction in LVESV and NYHA functional class at 6-month follow-up.

Echocardiographic, Electrocardiographic Changes and Clinical Outcomes of Patients Who Respond to Cardiac Resynchronization Therapy after One Year

Background

Response to cardiac resynchronization therapy (CRT) is commonly assessed after 6 or 12 months. We evaluated subsequent echocardiographic changes, serial QRS duration, and clinical outcomes in patients showing delayed responses to CRT after 12 months.

Methods

Among all patients who received CRT in Seoul St. Mary's Hospital, 36 one-year survivors were enrolled. Indicators of a positive CRT response were ≥ 15% reduction in left ventricular end-systolic volume (LVESV) or ≥ 10% increase in left ventricular ejection fraction (LVEF) on any follow up echocardiogram. We defined the early responders as patients responding before one year, the late responders as patients responding after one year, and the non-responders as patients who did not respond on any follow-up echocardiogram.

Results

We identified 17 early responders, 10 late responders, and 9 non-responders. The late responders showed modest improvement in LVESV and LVEF at two years after CRT. QRS duration was shortened the day after CRT in all three groups. Narrowed QRS was maintained for two years in early and late responders, whereas it was continuously prolonged over time in non-responders. Incidence of all-cause death or heart failure hospitalization was comparable between early and late responders, while non-responders showed worst prognosis.

Conclusion

Patients responding to CRT after one year show modest echocardiographic improvement but clinical outcome is similar to early responders. Shorter baseline QRS duration and long-term maintenance of QRS duration shortening are important features of the late responders to CRT.

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.

Prognostic significance of improvement in right ventricular systolic function during cardiac resynchronization therapy

Objectives There is conflicting evidence concerning the role of right ventricular (RV) systolic dysfunction in the long-term clinical outcome after cardiac resynchronization therapy (CRT). Therefore we aimed to assess evolution of RV systolic function during CRT, covariates associated with its improvement, and its impact on outcome. Methods and results All CRT device implantations (Jan 2009-Dec 2011) in our institution were reviewed. Records of 69 patients (25% female, mean age 62.8 ± 9.2 years, mean left ventricular (LV) ejection fraction 27 ± 8%) were analyzed. Baseline RV fractional area change (FAC) < 35% was present in 37 patients (54%). At one year, 24 of them (65%) improved in RV FAC. LV remodeling and mitral regurgitation were significantly associated with the likelihood of RV FAC improvement (OR 4.80, 95% CI 1.13-20.46, P = 0.034 and OR 0.32, 95% CI 0.12-0.89, P = 0.029, respectively). The composite endpoint of death or heart transplantation occurred in 23 patients (33%) over a mean follow-up of 2.8 ± 1.4 years. RV FAC at one year (HR 0.90, 95% CI 0.86-0.94, P < .001) was, independently of NYHA class and LV remodeling, associated with clinical outcome. Conclusions RV systolic function might improve during CRT. This seems mainly due to changed left-sided hemodynamics and LV remodeling. Good RV systolic function is independently related with better outcome.

Short-Term Availability of Viable Left Ventricular Pacing Sites with Quartet™ Quadripolar Leads

BACKGROUND Whether quadripolar leads can provide sufficient viable left ventricular pacing sites (LVPSs) for device optimization and multipoint pacing remains unclear. This study aimed to evaluate the acute and 3-month availability of viable LVPSs provided by a quadripolar LV pacing lead. MATERIAL AND METHODS A single-center cohort study evaluated consecutive patients who underwent a CRT implant with the QuartetTM LV lead under local guidelines. The availability of viable LVPSs was assessed at the pre-discharge and 3-month follow-up visit. Bipolar lead configurations, which served as the control group, were modeled by eliminating the 2 proximal electrodes on the Quartet™ LV lead. RESULTS A total of 24 patients were enrolled and finished 3-month follow-up. The mean follow-up period was 93±3 days. At pre-discharge, the Quartet™ LV lead provided more viable LVPSs compared with the bipolar equivalents (median 3 [IQR 2-4] vs. median 2 [IQR 1-2], P<0.001). The percentage of patients with at least 1, 2, 3, and 4 viable LVPSs were 100% (24/24), 91.7% (22/24), 58.3% (14/24), and 33.3% (8/24) for Quartet™ leads and 91.7% (22/24), 70.8% (17/24), 0% (0/24), and 0% (0/24) for bipolar lead configurations, respectively. The median and IQR values of viable LVPSs provided by the Quartet™ LV lead remained the same (3 [IQR 2-4]) between pre-discharge and 3-month follow-up (P=0.45). CONCLUSIONS Compared with the bipolar equivalent, QuartetTM LV lead provides more viable LVPSs and opportunities for CRT optimization and multipoint LV pacing. The number of LVPSs provided by Quartet™ leads remained unchanged between pre-discharge and 3-month follow-up.