Cardiac resynchronization therapy: Part 1--issues before device implantation

Myocardial Perfusion SPECT Imaging Radiomic Features and Machine Learning Algorithms for Cardiac Contractile Pattern Recognition

A U-shaped contraction pattern was shown to be associated with a better Cardiac resynchronization therapy (CRT) response. The main goal of this study is to automatically recognize left ventricular contractile patterns using machine learning algorithms trained on conventional quantitative features (ConQuaFea) and radiomic features extracted from Gated single-photon emission computed tomography myocardial perfusion imaging (GSPECT MPI). Among 98 patients with standard resting GSPECT MPI included in this study, 29 received CRT therapy and 69 did not (also had CRT inclusion criteria but did not receive treatment yet at the time of data collection, or refused treatment). A total of 69 non-CRT patients were employed for training, and the 29 were employed for testing. The models were built utilizing features from three distinct feature sets (ConQuaFea, radiomics, and ConQuaFea + radiomics (combined)), which were chosen using Recursive feature elimination (RFE) feature selection (FS), and then trained using seven different machine learning (ML) classifiers. In addition, CRT outcome prediction was assessed by different treatment inclusion criteria as the study's final phase. The MLP classifier had the highest performance among ConQuaFea models (AUC, SEN, SPE = 0.80, 0.85, 0.76). RF achieved the best performance in terms of AUC, SEN, and SPE with values of 0.65, 0.62, and 0.68, respectively, among radiomic models. GB and RF approaches achieved the best AUC, SEN, and SPE values of 0.78, 0.92, and 0.63 and 0.74, 0.93, and 0.56, respectively, among the combined models. A promising outcome was obtained when using radiomic and ConQuaFea from GSPECT MPI to detect left ventricular contractile patterns by machine learning.

Ventricular sense response pacing in cardiac resynchronisation therapy: a potentially effective treatment option for heart failure in patients with atrial fibrillation

Cardiac resynchronisation therapy (CRT) for atrial fibrillation (AF) with intraventricular conduction and low cardiac output may not allow high-frequency biventricular pacing (BiVP). To this end, drugs and ablation treatments are commonly used. Ventricular sense response pacing (VSRP) senses self-pulse and can produce a state comparable with BiVP. If found to be effective for cardiac resynchronisation, the benefit of CRT with VSRP is expected to extend to patients with AF. Herein, we describe the case of a man in his early 60s with low cardiac output caused by AF and left bundle branch block. CRT-defibrillator (CRT-D) implantation was performed, and VSRP was applied. We found VSRP to be more effective in improving cardiac function than drug-induced BiVP. VSRP may become an effective treatment option following CRT-D implantation in patients with AF.

Incidence and predictors of pacemaker-induced cardiomyopathy with right ventricular pacing: a systematic review

INTRODUCTION

This systematic review aims to evaluate the incidence and predictors of PICM in patients undergoing right ventricular pacing.

AREAS COVERED

A literature review was conducted using Mesh terms (Right ventricular pacing, Pacemaker-related cardiomyopathy, Pacemaker-induced cardiomyopathy) in PubMed, EMBASE, Web of science CINAHL, and the Cochrane Library until October 2021. All data reporting the incidence of PICM after implantation of right-sided pacemakers or implantable cardioverter-defibrillator (ICD) were retrieved from the eligible studies.

EXPERT OPINION

Out of 3,625 articles, 20 studies met the inclusion criteria that included 5,381 patients with PICM. The mean age of the patients ranged between 55.8 ± 13.5 and 77.4 ± 10.8 years. The mean incidence of PICM was 25.7%. Mean EF at baseline ranged from 48 ± 1% and 62.1 ± 11.2%, while mean EF at follow up ranged between 33.7± 7.4% and 53.2 ± 8.2%. Three studies reported a decline of >20% EF at follow-up. RV pacing was associated with a considerable risk of PICM, with biological factors such as male gender, old age, increased QRS duration, and chronic RV pacing burden playing an important role in the development of disease.

Exercise-Based Cardiac Rehabilitation Improves Exercise Capacity Regardless of the Response to Cardiac Resynchronization Therapy in Patients With Heart Failure and Reduced Ejection Fraction

BACKGROUND

In patients with chronic heart failure with reduced ejection fraction (HFrEF), cardiac resynchronization therapy (CRT) improves left ventricular ejection fraction (LVEF) and exercise-based cardiac rehabilitation (ECR) enhances exercise capacity. This study examined the relationship between the 2 responses.

METHODS AND RESULTS

Sixty-four consecutive HFrEF patients who participated in a 3-month ECR program after CRT were investigated. Patients were categorized according to a median improvement in peak oxygen uptake (PV̇O2) after ECR of 7% as either good (n=32; mean percentage change in PV̇O2[%∆PV̇O2]=23.2%) or poor (n=32; mean %∆PV̇O2=2.5%) responders. There was no significant difference in baseline characteristics between the good and poor responders, except for PV̇O2(51% vs. 59%, respectively; P=0.01). The proportion of good CRT responders was similar between the good and poor responders (%∆LVEF ≥10%; 53% vs. 47%, respectively; P=NS). Overall, there was no significant correlation between %∆LVEF after CRT and %∆PV̇O2after ECR. Notably, among poor CRT responders (n=32), the prevalence of atrial fibrillation (0% vs. 29%; P<0.03) and baseline PV̇O2(48% vs. 57%; P<0.05) were significantly lower among those with a good (n=15) than poor (n=17) response to ECR.

CONCLUSIONS

In patients with HFrEF, good ECR and CRT responses are unrelated. A good PV̇O2response to ECR can be achieved even in poor CRT responders, particularly in those with a sinus rhythm or low baseline PV̇O2.

The Prognostic Value of Left Ventricular Mechanical Dyssynchrony Derived from Cardiac MRI in Patients with Idiopathic Dilated Cardiomyopathy

Purpose

To investigate the prognostic value of mechanical dyssynchrony evaluated by deformable registration algorithm (DRA) analysis of cardiac MRI (CMR) in patients with idiopathic dilated cardiomyopathy (DCM).

Materials and Methods

This secondary analysis of a prospective study (clinical trial no. ChiCTR1800017058) enrolled 409 patients (mean age, 48 years ± 14:300 men) with idiopathic DCM who underwent CMR between June 2012 and September 2018. Mechanical dyssynchrony was measured as standard deviation of time-to-peak (sdTTP) and uniformity ratio estimate (URE) indexes by DRA strain analysis. The primary endpoint included all-cause mortality and heart transplantation. The secondary endpoint included primary endpoint, aborted sudden cardiac death, and heart failure readmission. Cox regression analyses and Kaplan-Meier survival analysis were performed to identify the association between variables and outcomes.

Results

During a median follow-up of 25.1 months, 57 and 132 patients reached primary and secondary endpoints, respectively. Most URE indexes were significantly lower in patients reaching primary endpoint. In multivariable analysis, circumferential URE (CURE) at apical level was independently associated with primary endpoints (hazard ratio, 0.307 [95% CI: 0.106, 0.883]; P = .03) and secondary endpoints (hazard ratio, 0.452 [95% CI: 0.209, 0.979]; P = .04), whereas most sdTTP measures were not. Furthermore, among patients with left ventricular ejection fraction of less than 35% or presence of late gadolinium enhancement, those with CURE at apical level of less than 0.917 had a significantly higher rate of adverse outcomes.

Conclusion

URE indexes were more predictive of prognostic outcomes compared with sdTTP measurements; the CURE at apical level was an independent predictor of adverse cardiac events in patients with DCM.Keywords: Heart, Outcomes Analysis, MR-ImagingClinical trial registration no. ChiCTR1800017058 Supplemental material is available for this article. See also commentary by Rajiah and François in this issue.© RSNA, 2021.

Sex differences in CRT device implantation rates, efficacy, and complications following implantation: protocol for a systematic review and meta-analysis of cohort studies

INTRODUCTION

There is abundant evidence for sex differences in the diagnosis, implantation, and outcomes for cardiac resynchronization therapy (CRT) devices. Controversial data suggesting women are less likely to receive the device regardless of the greater benefit. The aim of this review is to assess sex differences in the implantation rate, clinical effectiveness, and safety of patients receiving CRT devices.

METHODS

We will conduct a systematic literature search of MEDLINE, Embase, and Web of Science to identify cohort studies that meet our eligibility criteria. Title and full text screening will be conducted in duplicate independently. Eligible studies report clinical effectiveness or safety of patients receiving CRT device while providing sex-disaggregated data. Implantation rate will be extracted from the baseline characteristics tables of the studies. The effectiveness outcomes include the following: all-cause death, hospitalization, peak oxygen consumption (pVO₂), quality of life (QoL), 6-min walk test, NYHA class reduction, LVEF, and heart failure hospitalization. The complication outcomes include the following: contrast-induced nephropathy, pneumothorax, pocket-related hematoma, pericardial tamponade, phrenic nerve stimulation, device infection, death, pulmonary edema, electrical storm, cardiogenic shock, and hypotension requiring resuscitation. Description of included studies will be reported in detail and outcomes will be meta-analyzed and presented using forest plots when feasible. Risk of bias will be assessed using the Newcastle-Ottawa Scale (NOS) by two review authors independently. GRADE approach will be used to assess the certainty of evidence.

DISCUSSION

The aim of this review is to determine the presence of differences in CRT implantation between women and men as well as differences in clinical effectiveness and safety of CRT after device implantation. Results from this systematic review will provide important insights into sex differences in CRT devices that could contribute to the development of sex-specific recommendations and inform policy.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020204804.

Value of intraventricular dyssynchrony assessment by gated-SPECT myocardial perfusion imaging in the management of heart failure patients undergoing cardiac resynchronization therapy (VISION-CRT)

BACKGROUND

Placing the left ventricular (LV) lead in a viable segment with the latest mechanical activation (vSOLA) may be associated with optimal cardiac resynchronization therapy (CRT) response. We assessed the role of gated SPECT myocardial perfusion imaging (gSPECT MPI) in predicting clinical outcomes at 6 months in patients submitted to CRT.

METHODS

Ten centers from 8 countries enrolled 195 consecutive patients. All underwent gSPECT MPI before and 6 months after CRT. The procedure was performed as per current guidelines, the operators being unaware of gSPECT MPI results. Regional LV dyssynchrony (Phase SD) and vSOLA were automatically determined using a 17 segment model. The lead was considered on-target if placed in vSOLA. The primary outcome was improvement in ≥1 of the following: ≥1 NYHA class, left ventricular ejection fraction (LVEF) by ≥5%, reduction in end-systolic volume by ≥15%, and ≥5 points in Minnesota Living With Heart Failure Questionnaire (MLHFQ).

RESULTS

Sixteen patients died before the follow-up gSPECT MPI. The primary outcome occurred in 152 out of 179 (84.9%) cases. Mean change in LV phase standard deviation (PSD) at 6 months was 10.5°. Baseline dyssynchrony was not associated with the primary outcome. However, change in LV PSD from baseline was associated with the primary outcome (OR 1.04, 95% CI 1.01-1.07, P = .007). Change in LV PSD had an AUC of 0.78 (0.66-0.90) for the primary outcome. Improvement in LV PSD of 4° resulted in the highest positive likelihood ratio of 7.4 for a favorable outcome. In 23% of the patients, the CRT lead was placed in the vSOLA, and in 42% in either this segment or in a segment within 10° of it. On-target lead placement was not significantly associated with the primary outcome (OR 1.53, 95% CI 0.71-3.28).

CONCLUSION

LV dyssynchrony improvement by gSPECT MPI, but not on-target lead placement, predicts clinical outcomes in patients undergoing CRT.

Cardiovascular Imaging Applications in Clinical Management of Patients Treated with Cardiac Resynchronization Therapy

Cardiovascular imaging techniques, including echocardiography, nuclear cardiology, multi-slice computed tomography, and cardiac magnetic resonance, have wide applications in cardiac resynchronization therapy (CRT). Our aim was to provide an update of cardiovascular imaging applications before, during, and after implantation of a CRT device. Before CRT implantation, cardiovascular imaging techniques may integrate current clinical and electrocardiographic selection criteria in the identification of patients who may most likely benefit from CRT. Assessment of myocardial viability by ultrasound, nuclear cardiology, or cardiac magnetic resonance may guide optimal left ventricular (LV) lead positioning and help to predict LV function improvement by CRT. During implantation, echocardiographic techniques may guide in the identification of the best site of LV pacing. After CRT implantation, cardiovascular imaging plays an important role in the assessment of CRT response, which can be defined according to LV reverse remodeling, function and dyssynchrony indices. Furthermore, imaging techniques may be used for CRT programming optimization during follow-up, especially in patients who turn out to be non-responders. However, in the clinical settings, the use of proposed functional indices for different imaging techniques is still debated, due to their suboptimal feasibility and reproducibility. Moreover, identifying CRT responders before implantation and turning non-responders into responders at follow-up remain challenging issues.

Evaluation of the anatomical variations of the coronary venous system in patients with coronary artery calcification using 256-slice computed tomography

The factors that determine the anatomical variations of the coronary venous system (CVS) are poorly understood. The objective of this study was to evaluate the anatomical variations of the CVS in patients with coronary artery calcification. 196 patients underwent non-contrast CT and coronary CT angiography using 256-slice CT. All subjects were divided into four groups based on their coronary artery calcium score (CACS): 50 patients with CACS = 0 Agatston unit (AU), 52 patients with CACS = 1–100 AU, 44 patients with CACS = 101–400 AU, and 50 patients with CACS > 400 AU. The presence of the following cardiac veins was evaluated: the coronary sinus (CS), great cardiac vein (GCV), posterior interventricular vein (PIV), posterior vein of the left ventricle (PVLV), left marginal vein (LMV), anterior interventricular vein (AIV), and small cardiac vein (SCV). Vessel diameters were also measured. We found that the CS, GCV, PIV, and AIV were visualized in all patients, whereas the PVLV and LMV were identified in a certain proportion of patients: 98% and 96% in the CACS = 0 AU group, 100% and 78.8% in the CACS = 1–100 AU group, 93.2% and 77.3% in the CACS = 101–400 AU group, and 98% and 78% in the CACS > 400 AU group, respectively. The LMV was less often identified in the last three groups than in the first group (p < 0.05). The frequency of having either one PVLV or LMV was higher in the last three groups than in the first group (p < 0.05). No significant differences in vessel diameters were observed between the groups. It was concluded that patients with coronary artery calcification were less likely to have the LMV, which might hamper the left ventricular lead implantation in cardiac resynchronization therapy.

Intraventricular synchronism assessment by gated-SPECT myocardial perfusion imaging in cardiac resynchronization therapy. Does cardiomyopathy type influence results?

Purpose

To analyze the evolution post-cardiac resynchronization therapy (CRT) in left ventricular non-compaction (LVNC) cardiomyopathy (CM) patients compared to other types of CM, according to clinical and functional variables, by using gated-SPECT myocardial perfusion imaging (MPI).

Methods

Ninety-three patients (60 ± 11 years, 28% women) referred for pre-CRT assessment were studied and divided into three groups: 1 (non-ischemic CM with LVNC, 11 patients), 2 (ischemic CM, 28 patients), and 3 (non-ischemic CM, 53 patients). All were studied by a ^99mTc-MIBI gated-SPECT MPI at rest pre-CRT implantation and 6 ± 1 months after, including intraventricular dyssynchrony assessment by phase analysis. Quality of life was measured by the Minnesota Living with Heart Failure Questionnaire (MLHFQ).

Results

No differences in sex, atherosclerotic risk factors other than smoking habit, and MLHFQ results were found among groups. LVNC CM patients were younger, with greater QRS width and lower left ventricular ejection fraction (LVEF) at baseline, but the differences were not significant. No significant differences were found at baseline regarding ventricular function, although end-systolic volume was slightly higher in LVNC CM patients. Mean SRS was significantly higher (p < 0.0001) in ischemic patients (14.9) versus non-ischemic ones (8.7 in group 1 and 9 in group 2). At baseline, LVNC CM patients were significantly more dyssynchronous: Their phase standard deviation (PSD) was higher (89.5° ± 14.2°) versus groups 2 (65.2° ± 23.3°) and 3 (69.7° ± 21.7°), p = 0.007. Although the quality of life significantly improved in all groups, non-ischemic patients (with or without LVNC) showed a higher LVEF increase and volumes reduction at 6 months post-CRT. Dyssynchrony reduced post-CRT in all groups. Nevertheless, those more dyssynchronous at baseline (LVNC CM) exhibited the most significant intraventricular synchronism improvement: PSD was reduced from 89.5° ± 14.2° at baseline to 63.7° ± 20.5° post-CRT (p = 0.028). Six months post-CRT, 89% of patients were responders: 11 (100%) of those with LVNC CM, 25 (86%) of those with ischemic CM, and 47 (89%) of patients with non-ischemic CM. No patient with LVNC CM had adverse events during the follow-up.

Conclusion

CRT contributes to a marked improvement in non-ischemic CM patients with non-compaction myocardium. Phase analysis in gated-SPECT MPI is a valuable tool to assess the response to CRT.

Mechanical contraction to guide CRT left-ventricular lead placement instead of electrical activation in myocardial infarction with left ventricular dysfunction: An experimental study based on non-invasive gated myocardial perfusion imaging and invasive electroanatomic mapping

BACKGROUND

Whether the region of the latest electrical activation (LEA) corresponds with the segment of the latest mechanical contraction (LMC) in ischemic cardiomyopathy (ICM) is uncertain. We aimed to investigate the relationship between the left-ventricular (LV) viable segments with LEA and with LMC after myocardial infarction (MI) and analyze the acute hemodynamic responses (dP/dtmax) after cardiac resynchronization therapy (CRT) pacing at different LV sites.

METHODS AND RESULTS

Bama suckling pigs (n = 6) were subjected to create MI models. Both gated myocardial perfusion imaging (GMPI) and electroanatomic mapping (EAM) were performed successfully before MI and 4 weeks after MI. LMC was assessed by phase analysis of GMPI, while LEA was evaluated by EAM. The dP/dtmax was measured before CRT and when the CRT LV electrode was implanted in viable segments of LMC, viable segments of lateral wall and scar, respectively. The viable segments of LEA were consistent with the sites of LMC for five in six cases. The dP/dtmax increased significantly compared with that before CRT when the CRT LV electrode was implanted in viable segments of LMC (1103.33 ± 195.76 vs 717.83 ± 80.74 mmHg·s-1, P = .001), which was also significantly higher than in viable segments of lateral wall (751.17 ± 105.62 mmHg·s-1, P = .000) and scar (679.50 ± 60.87 mmHg·s-1, P = .001).

CONCLUSIONS

Non-invasive GMPI may be a better option than invasive EAM for guiding LV electrode implantation for CRT in ICM.

[Resynchronization Therapy for Chronic Heart Failure: Diagnostic and Therapeutic Approaches]

Chronic heart failure (CHF) remains one of the most important problems of modern cardiology. One of the effective treatment methods is resynchronization therapy (RT). The article presents an analysis of literature data on the effectiveness of RT in improving the quality of life, reducing the number of hospitalizations and mortality in patients with heart failure with severe left ventricular systolic dysfunction and expanding QRS complex, and also discusses key methods for optimizing RT.

Incidence and predictors of super-response to cardiac resynchronization therapy

OBJECTIVES

Cardiac resynchronization therapy (CRT) has significantly improved management of patients with heart failure with reduced ejection fraction (HFrEF). A significant number of patients have a dramatic response and have been termed "super-responders". The characteristics of this subset of patients in Indian and Asian population have not been well studied. In this study, we sought to assess the prevalence and clinical characteristics of this cohort of patients.

METHODS

This was a retrospective study involving patients undergoing CRT. Changes in ejection fraction and LVESV at the end of one year of follow-up following device implantation were assessed, and patients were stratified into non-responders, responders, and super-responders. Responders had a 15-29% decrease in LVESV while super-responders had a >30% decrease in LVESV.

RESULTS

Of the 74 patients who had undergone CRT-P/CRT-D implantation, 16 patients did not have echocardiograms at the end of one year of follow-up and were excluded from the analysis. Thus, 58 patients were enrolled for analysis. We identified 16 patients (27.6%) to be super-responders, 26 patients (44.8%) to be responders, and 16 patients (27.6%) to be non-responders. Factors associated with a super-response were a diagnosis of dilated cardiomyopathy as against ischemic cardiomyopathy (93.7% vs 6.3%; p - 0.01), prior right ventricular (RV) apical pacing (25% vs 2.4%; p - 0.02) and absence of a prior history of myocardial infarction (MI) (0% vs 33.3%; p - 0.02).

CONCLUSION

In our study, 27.6% of patients were super-responders, and a diagnosis of dilated cardiomyopathy, absence of a prior history of MI and prior RV apical pacing predicted a super-response to CRT.

Comparison of CZT SPECT and conventional SPECT for assessment of contractile function, mechanical synchrony and myocardial scar in patients with heart failure

AIM

The aim of this study was to compare CZT-SPECT (CZT SPECT) to conventional SPECT (C-SPECT) in the assessment of left ventricular myocardial scar, contractile function, and mechanical synchrony in patients with heart failure (HF).

METHODS

Fifty-nine patients with HF who were referred for myocardial perfusion/metabolism imaging were enrolled. All patients underwent resting 99mTc-MIBI gated myocardial perfusion imaging using a CZT SPECT camera and a C-SPECT camera, respectively, and 18F-FDG PET myocardial metabolism imaging within three days. Summed rest score (SRS) and total perfusion defect (TPD) (as indices of perfusion abnormality), left ventricular (LV), end diastolic volume (EDV), end systolic volume (ESV), and ejection fraction (EF) (as indices of LV systolic function), and histogram band width (BW) and standard deviation (SD) (as indices of mechanical synchrony) were analyzed by automated software while the perfusion/metabolism patterns were analyzed visually.

RESULTS

There was a good correlation between CZT SPECT and C-SPECT for SRS and TPD. CZT SPECT tended to underestimate SRS and TPD compared to C-SPECT. CZT-SPECT and C-SPECT showed excellent agreement in assessing the perfusion/metabolism pattern though a small proportion of normal segments (6.6%) identified by CZT/PET exhibited mismatch pattern on C-SPECT/PET. CZT SPECT also showed excellent correlation with C-SPECT in measuring EDV, ESV, and EF. Finally, BW and SD measured by CZT SPECT correlated well with C-SPECT but CZT SPECT tended to overestimate BW and SD compared to C-SPECT.

CONCLUSION

CZT SPECT provided comparable data to C-SPECT for measuring LV scar, function and synchrony at a considerable reduction in imaging time. CZT SPECT holds a promise for comprehensive evaluation of myocardial performance in patients with HF.

Cardiac Magnetic Resonance as a Tool to Assess Dyssynchrony

Cardiac resynchronization therapy (CRT) improves cardiac mechanics and quality of life in many patients with evidence of electromechanical cardiac dyssynchrony. However, up to 30% of patients receiving CRT do not respond to therapy. The mediator for poor response likely varies among patients; however, careful evaluation of mechanical dyssynchrony may inform management strategies. In this article, some of the methods and supporting evidence for dyssynchrony assessment with MRI as a predictor for CRT response are presented. The case is made for pre-implant assessment with MRI because of its ability to characterize scar, coronary venous distribution, and regional strain patterns.

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

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

Myocardial viability as shown by left ventricular lead pacing threshold and improved dyssynchrony by QRS narrowing predicts the response to cardiac resynchronization therapy

INTRODUCTION

Patients with advanced heart failure and dyssynchrony can benefit from cardiac resynchronization therapy (CRT). To predict the response to CRT, myocardial viability and improved dyssynchrony are suggested to be important.

METHODS

We retrospectively investigated 93 patients who underwent CRT implantation in Nagoya University Hospital. We assessed QRS narrowing the day after implantation to measure the improvement in dyssynchrony and measured the left ventricular pacing threshold (LVPT) to determine the local myocardial viability in all patients. Responders to CRT were defined as those having a greater than or equal to 15% decrease in left ventricular end-systolic volume by echocardiography at their 6-month follow-up.

RESULTS

Sixty-two patients (67%) were classified as responders. The QRS width before CRT implantation, QRS narrowing after implantation, left atrial diameter, septal-to-posterior wall motion delay, left ventricular end-diastolic diameter, radial strain, and LVPT were significantly different between the responder and nonresponder groups. On multivariate analysis, QRS narrowing (odds ratio [OR], 1.03; 95% confidence interval [CI], 1.01-1.05; P = 0.005) and LVPT (OR, 0.42; 95% CI, 0.22-0.82; P = 0.011) were independent predictors of a response to CRT. We calculated the cutoff values from the receiver operating characteristic curves as 22.5 milliseconds of QRS narrowing and 1.55 V of LVPT. The response rates in patients with both predictive factors (QRS narrowing ≥ 22.5 milliseconds and LVPT ≤ 1.55 V), one factor, and no factors were 91%, 61%, and 25%, respectively (P < 0.001).

CONCLUSION

Both myocardial viability and improved electrical dyssynchrony may be essential to predict a good response to CRT.

Speckle tracking echocardiography analyses of myocardial contraction efficiency predict response for cardiac resynchronization therapy

BACKGROUND

In patients with left ventricular (LV) dysssynchrony, contraction that doesn't fall into ejection period (LVEj) results in a waste of energy due to inappropriate contraction timing, which was now widely treated by cardiac resynchronization therapy(CRT). Myocardial Contraction Efficiency was defined as the ratio of Efficient Contraction Time (ECTR) and amplitude of efficient contraction (ECR) during LVEj against that in the entire cardiac cycle. This study prospectively investigated whether efficiency indexes could predict CRT outcome.

METHODS

Our prospective pilot study including 70 CRT candidates, parameters of myocardial contraction timing and contractility were measured by speckle tracking echocardiography (STE) and efficiency indexes were calculated accordingly at baseline and at 6-month follow-up. Primary outcome events were predefined as death or HF hospitalization, and secondary outcome events were defined as all-cause death during the follow-up. 16-segement Standard deviation of time to onset strain (TTO-16SD) and time to peak strain (TTP-16SD) were included as the dyssynchrony indexes.

RESULTS

According to LV end systolic volume (LVESV) and LV eject fraction(LVEF) values at 6-month follow-up, subjects were classified into responder and non-responder groups, ECR (OR 0.87, 95%CI 0.78-0.97, P < 0.05) and maximum longitudinal strain (MLS) (OR 2.22, 95%CI 1.36-3.61, P < 0.01) were the two independent predictors for CRT response, Both TTO-16SD and TTP-16SD failed to predict outcome. Patients with poorer myocardial contraction efficiency and better contractility are more likely to benefit from CRT.

CONCLUSIONS

STE can evaluate left ventricular contraction efficiency and contractility to predict CRT response. When analyzing myocardial strain by STE, contraction during LVEj should be highlighted.

Cardiac resynchronization therapy with a defibrillator (CRTd) in failing heart patients with type 2 diabetes mellitus and treated by glucagon-like peptide 1 receptor agonists (GLP-1 RA) therapy vs. conventional hypoglycemic drugs: arrhythmic burden, hospitalizations for heart failure, and CRTd responders rate

Objectives

To evaluate clinical outcomes in patients with diabetes, treated by cardiac resynchronization therapy with a defibrillator (CRT-d), and glucagon-like peptide 1 receptor agonists (GLP-1 RA) in addition to conventional hypoglycemic therapy vs. CRTd patients under conventional hypoglycemic drugs.

Background

Patients with diabetes treated by CRTd experienced an amelioration of functional New York Association Heart class, reduction of hospital admissions, and mortality, in a percentage about 60%. However, about 40% of CRTd patients with diabetes experience a worse prognosis.

Materials and methods

We investigated the 12-months prognosis of CRTd patients with diabetes, previously treated with hypoglycemic drugs therapy (n 271) vs. a matched cohort of CRTd patients with diabetes treated with GLP-1 RA in addition to conventional hypoglycemic therapy (n 288).

Results

At follow up CRTd patients with diabetes treated by GLP-1 RA therapy vs. CRTd patients with diabetes that did not receive GLP-1 RA therapy, experienced a significant reduction of NYHA class (p value < 0.05), associated to higher values of 6 min walking test (p value < 0.05), and higher rate of CRTd responders (p value < 0.05). GLP-1 RA patients vs. controls at follow up end experienced lower AF events (p value < 0.05), lower VT events (p value < 0.05), lower rate of hospitalization for heart failure worsening (p value < 0.05), and higher rate of CRTd responders (p value < 0.05). To date, GLP-1 RA therapy may predict a reduction of AF events (HR 0.603, CI [0.411–0.884]), VT events (HR 0.964, CI [0.963–0.992]), and hospitalization for heart failure worsening (HR 0.119, CI [0.028–0.508]), and a higher CRT responders rate (HR 3.707, CI [1.226–14.570]).

Conclusions

GLP-1 RA drugs in addition to conventional hypoglycemic therapy may significantly reduce systemic inflammation and circulating BNP levels in CRTd patients with diabetes, leading to a significant improvement of LVEF and of the 6 min walking test, and to a reduction of the arrhythmic burden. Consequently, GLP-1 RA drugs in addition to conventional hypoglycemic therapy may reduce hospital admissions for heart failure worsening, by increasing CRTd responders rate.

Trial registration NCT03282136. Registered 9 December 2017 “retrospectively registered”

Rational and design of EuroCRT: an international observational study on multi-modality imaging and cardiac resynchronization therapy

Aims

Assessment of left ventricular (LV) volumes and ejection fraction (LVEF) with cardiac imaging is important in the selection of patients for cardiac resynchronization therapy (CRT). Several observational studies have explored the role of imaging-derived LV dyssynchrony parameters to predict the response to CRT, but have yielded inconsistent results, precluding the inclusion of imaging-derived LV dyssynchrony parameters in current guidelines for selection of patients for CRT.

Methods

The EuroCRT is a large European multicentre prospective observational study led by the European Association of Cardiovascular Imaging. We aim to explore if combing the value of cardiac magnetic resonance (CMR) and echocardiography could be beneficial for selecting heart failure patients for CRT in terms of improvement in long-term survival, clinical symptoms, LV function, and volumes. Speckle tracking echocardiography will be used to assess LV dyssynchrony and wasted cardiac work whereas myocardial scar will be assessed with late gadolinium contrast enhanced CMR. All data will be measured in core laboratories. The study will be conducted in European centres with known expertise in both CRT and multimodality cardiac imaging.

Utility of dual-source computed tomography in cardiac resynchronization therapy-DIRECT study

BACKGROUND

Dual-source computed tomography (CT) can evaluate left ventricular (LV) dyssynchrony, myocardial scar, and coronary venous anatomy in patients undergoing cardiac resynchronization therapy (CRT).

OBJECTIVE

We aimed to determine whether dual-source CT predicts clinical CRT outcomes and reduces intraprocedural time.

METHODS

In this prospective study, 54 patients scheduled for CRT (mean age 63 ± 11 years; 74% men) underwent preprocedural CT to assess their venous anatomy as well as CT-derived dyssynchrony metrics and myocardial scar. Based on 1:1 randomization, the implanting physician had preimplant knowledge of the venous anatomy in half the patients. In blinded analyses, we measured time to maximal wall thickness and inward wall motion to determine (1) CT global and segmental dyssynchrony and (2) concordance of lead location to regional LV mechanical contraction. End points were 6-month CRT response measured using heart failure clinical composite score and 2-year major adverse cardiac events (MACE).

RESULTS

There were 72% CRT responders and 17% with MACE. Two wall motion dyssynchrony indices-global wall motion and opposing anteroseptal-inferolateral wall motion-predicted MACE (P < .01). Lead location concordant to regions of maximal wall thickness was associated with less MACE (P < .01). No CT dyssynchrony metrics predicted 6-month CRT response (P = NS for all). Myocardial scar (43%), posterolateral wall scar (28%), and total scar burden did not predict outcomes (P = NS for all). Preknowledge of coronary venous anatomy by CT did not reduce implant or fluoroscopy time (P = NS for both).

CONCLUSION

Two CT dyssynchrony metrics predicted 2-year MACE, and LV lead location concordant to regions of maximal wall thickness was associated with less MACE. Other CT factors had little utility in CRT.

Recent technological advancements in cardiac ultrasound imaging

About 92.1 million Americans suffer from at least one type of cardiovascular disease. Worldwide, cardiovascular diseases are the number one cause of death (about 31% of all global deaths). Recent technological advancements in cardiac ultrasound imaging are expected to aid in the clinical diagnosis of many cardiovascular diseases. This article provides an overview of such recent technological advancements, specifically focusing on tissue Doppler imaging, strain imaging, contrast echocardiography, 3D echocardiography, point-of-care echocardiography, 3D volumetric flow assessments, and elastography. With these advancements ultrasound imaging is rapidly changing the domain of cardiac imaging. The advantages offered by ultrasound imaging include real-time imaging, imaging at patient bed-side, cost-effectiveness and ionizing-radiation-free imaging. Along with these advantages, the steps taken towards standardization of ultrasound based quantitative markers, reviewed here, will play a major role in addressing the healthcare burden associated with cardiovascular diseases.

Absence of Rapid Propagation through the Purkinje Network as a Potential Cause of Line Block in the Human Heart with Left Bundle Branch Block

Background: Cardiac resynchronization therapy is an effective device therapy for heart failure patients with conduction block. However, a problem with this invasive technique is the nearly 30% of non-responders. A number of studies have reported a functional line of block of cardiac excitation propagation in responders. However, this can only be detected using non-contact endocardial mapping. Further, although the line of block is considered a sign of responders to therapy, the mechanism remains unclear.

Methods: Herein, we created two patient-specific heart models with conduction block and simulated the propagation of excitation based on a cellmodel of electrophysiology. In one model with a relatively narrow QRS width (176 ms), we modeled the Purkinje network using a thin endocardial layer with rapid conduction. To reproduce a wider QRS complex (200 ms) in the second model, we eliminated the Purkinje network, and we simulated the endocardial mapping by solving the inverse problem according to the actual mapping system.

Results: We successfully observed the line of block using non-contact mapping in the model without the rapid propagation of excitation through the Purkinje network, although the excitation in the wall propagated smoothly. This model of slow conduction also reproduced the characteristic properties of the line of block, including dense isochronal lines and fractionated local electrocardiograms. Further, simulation of ventricular pacing from the lateral wall shifted the location of the line of block. By contrast, in the model with the Purkinje network, propagation of excitation in the endocardial map faithfully followed the actual propagation in the wall, without showing the line of block. Finally, switching the mode of propagation between the two models completely reversed these findings.

Conclusions: Our simulation data suggest that the absence of rapid propagation of excitation through the Purkinje network is the major cause of the functional line of block recorded by non-contact endocardial mapping. The line of block can be used to identify responders as these patients loose rapid propagation through the Purkinje network.

Comparison between a count-based and geometrical approach for the assessment of left ventricular dyssynchrony using myocardial perfusion scintigraphy

OBJECTIVE

There are two distinct approaches for the assessment of left ventricular (LV) dyssynchrony by myocardial perfusion scintigraphy (MPS). The aim of this study was to compare the performance of the count-based and geometrical approach in clinical data using gated single photon emission computed tomography MPS.

MATERIAL AND METHODS

Group 1 consisted of 113 patients (49 men, 64 women) with normal perfusion [summed rest score (SRS)≤3], normal LV ejection fraction (≥55%), and normal QRS duration (QRSd<120 ms). Group 2 consisted of 89 heart failure patients (79 men, 10 women) with no restriction for SRS, LV ejection fraction ≤35%, and QRSd ≥120 ms. All MPS parameters were obtained from the software Corridor4DM. Dyssynchrony parameters used were time to peak contraction, SD, and bandwidth (BW).

RESULTS

SD and BW were estimated higher (difference group 1: SD 3.0±2.3 and BW 11.3±9.3, P-values <0.001; difference group 2: SD 2.4±4.3 and BW 1.3±17.0, P-value <0.001 and 0.479 respectively) using the count-based approach in comparison with the geometrical method. A significant and good correlation was found between these two methods (R=0.763, 0.902, 0.896 for time to peak contraction, SD, and BW respectively, P-values ≤0.001). SD and BW in both approaches were equally good parameters for differentiating heart failure patients (area under the curve: 0.995-0.998), although using different cut-off values.

CONCLUSION

The count-based approach generally provides a wider phase distribution and subsequently greater SD and BW estimates compared with the geometrical algorithm. These differences result in clinically relevant deviations in normal and cut-off values that have to be recognized when evaluating patients.

New Management Strategies in Heart Failure

Despite >100 clinical trials, only 2 new drugs had been approved by the US Food and Drug Administration for the treatment of chronic heart failure in more than a decade: the aldosterone antagonist eplerenone in 2003 and a fixed dose combination of hydralazine-isosorbide dinitrate in 2005. In contrast, 2015 has witnessed the Food and Drug Administration approval of 2 new drugs, both for the treatment of chronic heart failure with reduced ejection fraction: ivabradine and another combination drug, sacubitril/valsartan or LCZ696. Seemingly overnight, a range of therapeutic possibilities, evoking new physiological mechanisms, promise great hope for a disease that often carries a prognosis worse than many forms of cancer. Importantly, the newly available therapies represent a culmination of basic and translational research that actually spans many decades. This review will summarize newer drugs currently being used in the treatment of heart failure, as well as newer strategies increasingly explored for their utility during the stages of the heart failure syndrome.

Monitoring of CRT-D devices during radiation therapy in vitro

Background

Using of active cardiac medical devices increases steadily. In Europe, there were 183 implants of ICD and 944 implants of PM, 119 of biventricular ICD and 41 of biventricular PM, all per million inhabitants in 2014. Healthcare environments, including radiotherapy treatment rooms, are considered challenging for these implantable devices. Exposure to radiation may cause the device to experience premature elective replacement indicator, decreased pacing amplitude or pacing inhibition, inappropriate shocks or inhibition of tachyarrhythmia therapy and loss of device function. These impacts may be temporary or permanent. The aim of this study was to evaluate the influence of linear accelerator ionizing radiation dose of 10 Gy on the activity of the biventricular cardioverter-defibrillator in different position in radiation beam.

Methods

Two identical wireless communication devices with all three leads were used for the measurement. Both systems were soused into solution saline and exposed in different position in the beam of linear accelerator per 10 Gy fractions. In comparison of usually used maximum recommended dose of 2 Gy, the radiation doses used in test were five times higher. Using the simultaneous monitoring wireless communication between device and its programmer allowed watching of the devices activities, noise occurrence or drop of biventricular pacing on the programmer screen, observed by local television loop camera.

Results

At any device position in radiation beam, there were no influences of the device activity at dose of 10 Gy neither a significant increase of a solution saline temperature in any of the measured positions of CRT-D systems in linear accelerator.

Conclusions

The results of the study indicated, that the recommendation dose for treating the patients with implantable devices are too conservative and the risk of device failure is not so high. The systems can easily withstand the dose fractions of tens Gy, which would allow current single-dose-procedure treatment in radiation therapy. Even though the process of the random alteration of device memory and electrical components by scatter particles not allowed to specify a safe dose during ionizing radiation, this study showed that the safe limit are above the today used dose fractions.

Tailor-made heart simulation predicts the effect of cardiac resynchronization therapy in a canine model of heart failure

Despite extensive studies on clinical indices for the selection of patient candidates for cardiac resynchronization therapy (CRT), approximately 30% of selected patients do not respond to this therapy. Herein, we examined whether CRT simulations based on individualized realistic three-dimensional heart models can predict the therapeutic effect of CRT in a canine model of heart failure with left bundle branch block. In four canine models of failing heart with dyssynchrony, individualized three-dimensional heart models reproducing the electromechanical activity of each animal were created based on the computer tomographic images. CRT simulations were performed for 25 patterns of three ventricular pacing lead positions. Lead positions producing the best and the worst therapeutic effects were selected in each model. The validity of predictions was tested in acute experiments in which hearts were paced from the sites identified by simulations. We found significant correlations between the experimentally observed improvement in ejection fraction (EF) and the predicted improvements in ejection fraction (P<0.01) or the maximum value of the derivative of left ventricular pressure (P<0.01). The optimal lead positions produced better outcomes compared with the worst positioning in all dogs studied, although there were significant variations in responses. Variations in ventricular wall thickness among the dogs may have contributed to these responses. Thus CRT simulations using the individualized three-dimensional heart models can predict acute hemodynamic improvement, and help determine the optimal positions of the pacing lead.

Inflammatory Mediators and Clinical Outcome in Patients With Advanced Heart Failure Receiving Cardiac Resynchronization Therapy

Expression of different cytokines and growth factors after myocardial injury has been associated with fibroplasia and dilatation versus reverse remodeling and myocardial repair. Specifically, the proinflammatory/fibrotic mediators: interleukin (IL)-6, epidermal growth factor, and fibroblast growth factor (FGF)-2 cause fibroplasia, whereas reparative cytokines including: IL-1α, IL-1β, IL-4, and IL-13 can limit fibrosis. In appropriate patients, cardiac resynchronization therapy (CRT) reverses cardiomyopathy and improves outcome. However, a significant proportion will not respond to this therapy. We conducted this study to assess the association of proinflammatory/fibrotic and/or reparative immune response mediators at baseline with outcome after CRT. In the multicenter RISK study, plasma samples were collected prospectively before CRT implantation. Plasma IL-6, epidermal growth factor, FGF-2, IL-1α, IL-1β, IL-4, and IL-13 were evaluated by Luminex technology. The primary outcome was predefined as freedom from heart failure hospitalization or death and a decrease in echocardiographic end-systolic volume of >15% at 12 months. To determine associations with the outcome, multivariate logistic regression models including baseline clinical characteristics and the specific cytokines and growth factors were constructed. On multivariate analysis of 257 patients, detectable reparative cytokine IL-13 was significantly associated with the primary outcome (odds ratio 3.79; 95% CI 2.10 to 6.82, p <0.0001). In contrast, detectable proinflammatory/fibrotic growth factor FGF-2 was negatively associated (odds ratio 0.31; 95% CI, 0.14 to 0.68; p = 0.004). In conclusion, in CRT recipients, baseline levels of inflammatory mediators affecting cardiac fibrosis versus repair were associated with subsequent clinical outcome.

Incremental value of cystatin C over conventional renal metrics for predicting clinical response and outcomes in cardiac resynchronization therapy: The BIOCRT study

BACKGROUND

Despite the benefit of CRT in select patients with heart failure (HF), there remains significant need for predicting those at risk for adverse outcomes for this effective but costly therapy. CysC, an emerging marker of renal function, is predictive of worsening symptoms and mortality in patients with HF. This study assessed the utility of baseline and serial measures of cystatin C (CysC), compared to conventional creatinine-based measures of renal function (estimated glomerular filtration rate, eGFR), in predicting clinical outcomes following cardiac resynchronization therapy (CRT).

METHODS

In 133 patients, we measured peripheral venous (PV) and coronary sinus (CS) CysC concentrations and peripheral creatinine levels at the time of CRT implant. Study endpoints included clinical response to CRT at 6 months and major adverse cardiac events (MACE) at 2 years.

RESULTS

While all 3 renal metrics were predictive of MACE (all adjusted p ≤ 0.02), only CysC was associated with CRT non-response at 6 months (adjusted odds ratio 3.6, p = 0.02). CysC improved prediction of CRT non-response (p ≤ 0.003) in net reclassification index analysis compared to models utilizing standard renal metrics. Serial CysC > 1mg/L was associated with 6-month CRT non-response and reduced 6-minute walk distance as well as 2-year MACE (all p ≤ 0.04).

CONCLUSION

In patients undergoing CRT, CysC demonstrated incremental benefit in the prediction of CRT non-response when compared to standard metrics of renal function. Baseline and serial measures of elevated CysC were predictive of CRT non-response and functional status at 6 months as well as long-term clinical outcomes.

Radionuclide Assessment of Left Ventricular Dyssynchrony

Phase analysis of gated myocardial perfusion single-photon emission computed tomography is a widely available and reproducible measure of left ventricular (LV) dyssynchrony, which also provides comprehensive assessment of LV function, global and regional scar burden, and patterns of LV mechanical activation. Preliminary studies indicate potential use in predicting cardiac resynchronization therapy response and elucidation of mechanisms. Because advances in technology may expand capabilities for precise LV lead placement in the future, identification of specific patterns of dyssynchrony may have a critical role in guiding cardiac resynchronization therapy.

Nuclear medicine in the management of patients with heart failure: guidance from an expert panel of the International Atomic Energy Agency (IAEA)

Heart failure is increasing worldwide at epidemic proportions, resulting in considerable disability, mortality, and increase in healthcare costs. Gated myocardial perfusion single photon emission computed tomography or PET imaging is the most prominent imaging modality capable of providing information on global and regional ventricular function, the presence of intraventricular synchronism, myocardial perfusion, and viability on the same test. In addition, ¹²³I-mIBG scintigraphy is the only imaging technique approved by various regulatory agencies able to provide information regarding the adrenergic function of the heart. Therefore, both myocardial perfusion and adrenergic imaging are useful tools in the workup and management of heart failure patients. This guide is intended to reinforce the information on the use of nuclear cardiology techniques for the assessment of heart failure and associated myocardial disease.

Current concepts relating coronary flow, myocardial perfusion and metabolism in left bundle branch block and cardiac resynchronisation therapy

Cardiac resynchronisation therapy (CRT) improves mortality and symptoms in heart failure patients with electromechanically dyssynchronous ventricles. There is a 50% non-response rate and reproducible biomarkers to predict non-response have not been forthcoming. Therefore, there has been increasing interest in the pathophysiological effects of dyssynchrony particularly focusing on coronary flow, myocardial perfusion and metabolism. Studies suggest that dyssynchronous electrical activation effects coronary flow throughout the coronary vasculature from the epicardial arteries to the microvascular bed and that these changes can be corrected by CRT. The effect of both electrical and mechanical dyssynchrony on myocardial perfusion is unclear with some studies suggesting there is a reduction in septal perfusion whilst others propose that there is an increase in lateral perfusion. Better understanding of these effects offers the possibility for better prediction of non-response. CRT appears to improve homogeneity in myocardial perfusion where heterogeneity is described in the initial substrate. Novel approaches to the identification of non-responders via metabolic phenotyping both invasively and non-invasively have been encouraging. There remains a need for further research to clarify the interaction of coronary flow with perfusion and metabolism in patients who undergo CRT.

End-of-life care in patients with heart failure

Stage D heart failure (HF) is associated with poor prognosis, yet little consensus exists on the care of patients with HF approaching the end of life. Treatment options for end-stage HF range from continuation of guideline-directed medical therapy to device interventions and cardiac transplantation. However, patients approaching the end of life may elect to forego therapies or procedures perceived as burdensome, or to deactivate devices that were implanted earlier in the disease course. Although discussing end-of-life issues such as advance directives, palliative care, or hospice can be difficult, such conversations are critical to understanding patient and family expectations and to developing mutually agreed-on goals of care. Because patients with HF are at risk for rapid clinical deterioration or sudden cardiac death, end-of-life issues should be discussed early in the course of management. As patients progress to advanced HF, the need for such discussions increases, especially among patients who have declined, failed, or been deemed to be ineligible for advanced HF therapies. Communication to define goals of care for the individual patient and then to design therapy concordant with these goals is fundamental to patient-centered care. The objectives of this white paper are to highlight key end-of-life considerations in patients with HF, to provide direction for clinicians on strategies for addressing end-of-life issues and providing optimal patient care, and to draw attention to the need for more research focusing on end-of-life care for the HF population.

[Right ventricular septal stimulation would produce similar bi-ventricular dyssynchrony as does apical stimulation in patients with normal ejection fraction]

OBJECTIVE

To determine in patients with normal ejection fraction, undergoing permanent VVI pacing, if medial septal stimulation has lower dyssynchrony than apical stimulation assessed by echocardiography.

METHOD

A prospective trial, 19 patients>70 years old, scheduled for VVI pacemaker implantation for complete degenerative atrioventricular block, ventricular frequency<50beat per minute and ejection fraction≥45%. Patients with atrial fibrillation, heart failure, left bundle branch block and QRS durations longer than 120milliseconds in surface electrocardiogram with sinus rhythm were excluded. Patients were randomized to apical implantation group A: 47% and septal implantation group B: 53%. Echocardiographic parameters were measured previous to the implant, 48h, 5 and 48 months after implantation.

RESULTS

No patients had diagnosis of ischemic cardiomyopathy or heart failure. Echocardiographic parameters for interventricular dyssynchrony between groups were A: 14.44±19.76msec vs. B: 9±36.45msec; A: 6.11±62.11msec vs. B: 13±38.31msec; A: 77±53.51msec vs. B: 24.29±80.90msec, P=NS). For interventricular dyssynchrony were A: 46.44±19.76msec vs. B: 42.20±29.56msec; A: 45.33±45.67msec vs. B: 29.80±44.66msec; A: 46,38±20 msec vs. B: 21±27.20msec, P=NS) at 48h, 5 and 48 months, respectively.

CONCLUSION

Apical site of stimulation does not increase ventricular dyssynchrony rate in patients with preserved ejection fraction. Septal stimulation showed decreased trend in interventricular dyssynchrony.

Role of echocardiographic dyssynchrony parameters in predicting response to cardiac resynchronization therapy

AIMS

In the present study, we compare different echocardiographic cardiac dyssynchrony parameters, both of intraventricular and interventricular dyssynchrony, in order to predict response to cardiac resynchronization therapy (CRT).

METHODS AND RESULTS

In a population of 77 heart failure patients scheduled for CRT, we measured the interventricular mechanical delay (IVMD) and we analyzed six different parameters of intraventricular dyssynchony: the tissue Doppler imaging (TDI) septum-lateral wall delay, the systolic dyssynchrony index; the three-dimensional SD of the time to reach minimum systolic volume for 16 left ventricular segments (3D-SDI); the speckle-tracking radial, circumferential and longitudinal dyssynchrony. At 6 months of follow-up, 61 (79%) patients were responders (≤15% in left ventricular end-systolic volume). On baseline analysis, 3D-SDI, radial strain, longitudinal strain and circumferential strain and IVMD were significantly higher in responder group (10.8 ± 3.9 vs. 7.6 ± 1.8% for 3D-SDI; P = 0.003; 212 ± 91 vs. 125 ± 36 ms for radial strain, P = 0.0003; 185 ± 83 vs. 134 ± 53 ms for longitudinal strain, P = 0.02; 190 ± 80 vs. 130 ± 54 ms for circumferential strain, P = 0.006; 45 ± 21 vs. 30 ± 20 ms for IVMD; P = 0.01). On univariate and multivariate analysis, only IVMD was significantly associated with a complete echocardiographic response to CRT. 3D-SDI and radial strain present the better values of sensitivity and specificity, overall if associated to an evaluation of IVMD (sensitivity 76%, specificity 88%, for 3D-SDI + IVMD; sensitivity 80% and specificity 85% for radial strain + IVMD).

CONCLUSION

The novel parameters, such as 3D-SDI and speckle-tracking (particularly radial strain), offer better diagnostic accuracy in identifying patients who are responders to CRT. The addition of the contemporary parameter of IVMD improves the diagnostic accuracy.

Coronary sinus biomarker sampling compared to peripheral venous blood for predicting outcomes in patients with severe heart failure undergoing cardiac resynchronization therapy: the BIOCRT study

BACKGROUND

A significant minority of patients receiving cardiac resynchronization therapy (CRT) remain nonresponsive to this intervention.

OBJECTIVE

This study aimed to determine whether coronary sinus (CS) or baseline peripheral venous (PV) levels of established and emerging heart failure (HF) biomarkers are predictive of CRT outcomes.

METHODS

In 73 patients (aged 68 ± 12 years; 83% men; ejection fraction 27% ± 7%) with CS and PV blood samples drawn simultaneously at the time of CRT device implantation, we measured amino-terminal pro-B-type natriuretic peptide (NT-proBNP), galectin-3 (gal-3), and soluble ST2 (sST2) levels. NT-proBNP concentrations >2000 pg/mL, gal-3 concentrations >25.9 ng/mL, and sST2 concentrations >35 ng/mL were considered positive on the basis of established PV cut points for identifying "high-risk" individuals with HF. CRT response was adjudicated by the HF Clinical Composite Score. A major adverse cardiovascular event (MACE) was defined as the composite end point of death, cardiac transplant, left ventricular assist device, and HF hospitalization at 2 years.

RESULTS

NT-proBNP concentrations were 20% higher in the CS than in the periphery, while gal-3 and sST2 concentrations were 10% higher in the periphery than in the CS (all P < .001). There were 45% CRT nonresponders at 6 months and 16 (22%) patients with MACE. Triple-positive CS values yielded the highest specificity of 95% for predicting CRT nonresponse. Consistently, CS strategies identified patients at higher risk of developing MACE, with >11-fold adjusted increase for triple-positive CS patients compared to triple-negative patients (all P ≤ .04). PV strategies were not predictive of MACE.

CONCLUSION

Our findings suggest that CS sampling of HF biomarkers may be better than PV sampling for predicting CRT outcomes. Larger studies are needed to confirm our findings.