Assessment of left ventricular ejection fraction in patients eligible for ICD therapy: Discrepancy between cardiac magnetic resonance imaging and 2D echocardiography

Leisure time physical activity is associated with improved diastolic heart function and is partly mediated by unsupervised quantified metabolic health

Objectives

To investigate the association between leisure time physical activity (LTPA) and MRI-based diastolic function and the mediating role of metabolic health.

Methods

This cross-sectional analysis comprised 901 participants (46% women, mean age (SD): 56 (6) years (The Netherlands, 2008-2012)). LTPA was assessed via questionnaire, quantified in metabolic equivalent of tasks (METs)-minutes per week and participants underwent abdominal and cardiovascular MRI. Confirmatory factor analysis was used to construct the metabolic load factor. Piecewise structural equation model with adjustments for confounders was used to determine associations between LTPA and diastolic function and the mediating effect of metabolic load.

Results

Significant differences in mitral early/late peak filling rate (E/A) ratio per SD of LTPA (men=1999, women=1870 MET-min/week) of 0.18, (95% CI= 0.03 to 0.33, p=0.021) were observed in men, but not in women: -0.01 (-0.01 to 0.34, p=0.058). Difference in deceleration time of mitral early filling (E-DT) was 0.13 (0.01 to 0.24, p=0.030) in men and 0.17 (0.05 to 0.28, p=0.005) in women. Metabolic load, including MRI-based visceral and subcutaneous adipose tissue, fasting glucose, high-density lipoprotein cholesterol and triglycerides, mediated these associations as follows: E/A-ratio of 0.030 (0.000 to 0.067, 19% mediated, p=0.047) in men but not in women: 0.058 (0.027 to 0.089, p<0.001) and E-DT not in men 0.004 (-0.012 to 0.021, p=0.602) but did in women 0.044 (0.013 to 0.057, 27% mediated, p=0.006).

Conclusions

A larger amount of LTPA was associated with improved diastolic function where confirmatory factor analysis-based metabolic load partly mediated this effect. Future studies should assess whether improving indicators of metabolic load alongside LTPA will benefit healthy diastolic function even more.

Utilities and Limitations of Cardiac Magnetic Resonance Imaging in Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) is one of the most common types of non-ischemic cardiomyopathy. DCM is characterized by left ventricle (LV) dilatation and systolic dysfunction without coronary artery disease or abnormal loading conditions. DCM is not a single disease entity and has a complex historical background of revisions and updates to its definition because of its diverse etiology and clinical manifestations. In cases of LV dilatation and dysfunction, conditions with phenotypic overlap should be excluded before establishing a DCM diagnosis. The differential diagnoses of DCM include ischemic cardiomyopathy, valvular heart disease, burned-out hypertrophic cardiomyopathy, arrhythmogenic cardiomyopathy, and non-compaction. Cardiac magnetic resonance (CMR) imaging is helpful for evaluating DCM because it provides precise measurements of cardiac size, function, mass, and tissue characterization. Comprehensive analyses using various sequences, including cine imaging, late gadolinium enhancement imaging, and T1 and T2 mapping, may help establish differential diagnoses, etiological work-up, disease stratification, prognostic determination, and follow-up procedures in patients with DCM phenotypes. This article aimed to review the utilities and limitations of CMR in the diagnosis and assessment of DCM.

Left Bundle Branch Pacing for Heart Failure and Left Bundle Branch Block Patients With Mildly Reduced and Preserved Left Ventricular Ejection Fraction

BACKGROUND

Left bundle branch block (LBBB) may induce or aggravate heart failure (HF). Few data are available on patients with HF and LBBB with mildly reduced ejection fraction (HFmrEF; left ventricular ejection fraction [LVEF] 40%-50%) and those with preserved EF (HFpEF. LVEF ≥ 50%). We aimed to assess the long-term outcomes of left bundle branch pacing (LBBP) on cardiac function and remodelling in patients with LBBB and symptomatic HFmrEF and HFpEF.

METHODS

Nonischemic cardiomyopathy (NICM) patients with HFmrEF and HFpEF (LVEF from 40% to 60% as defined with the use of echocardiography) with LBBB who successfully underwent LBBP (n = 50) were prospectively included from 4 centres. Patient characteristics and echocardiographic and lead parameters were recorded at implantation and during follow-ups of 1, 3, 6, and 12 months.

RESULTS

All patients completed 1-year follow up. The LVEF was significantly improved from 46.5 ± 5.2% at baseline to 60.0 ± 6.1% (n = 50; P < 0.001) after 1-year follow up. Higher ΔLVEF and super-response rate were observed in the HFmrEF group (n = 30) than in the HFpEF group (n = 20).

CONCLUSIONS

LBBP improved symptoms and reversed remodelling in patients with LBBB and symptomatic HF at 1-year follow-up. Improvement occurred even in HFpEF patients, and the resynchronisation effect was better in HFmrEF group.

Imaging Modality for Left Ventricular Ejection Fraction Estimation and Effect of Implantable Cardioverter Defibrillator on Mortality in Patients with Heart Failure

BACKGROUND

Implantable cardioverter-defibrillators (ICD) improve outcomes in patients with heart failure (HF) with left ventricular ejection fraction (LVEF) ≤35%. Less is known whether outcomes varied between the two non-invasive imaging modalities used to estimate LVEF, the 2-dimensional echocardiography (2DE) and multi-gated acquisition radionuclide ventriculography (MUGA), which use different principles (geometric vs. count-based, respectively).

OBJECTIVES

To examine if the effect of ICD on mortality in patients with HF and LVEF ≤35% varied based on LVEF measured by 2DE or MUGA.

METHODS

Of the 2521 patients with HF with LVEF ≤35% in the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT), 1676 were randomized to either placebo or ICD, of whom 1386 had LVEF measured by 2DE (n=971) or MUGA (n=415). Hazard ratios (HRs) and 97.5% CIs for mortality associated with ICD use were estimated overall, checking for interaction, and within the two imaging subgroups.

RESULTS

Among the 1386 patients in the current analysis, all-cause mortality occurred in 23.1% (160/692) and 29.7% (206/694) of patients randomized to ICD or placebo, respectively (HR, 0.77; 97.5% CI, 0.61-0.97), which is consistent with that in 1676 patients in the original report. HRs (97.5% CIs) for all-cause mortality in the 2DE and MUGA subgroups were 0.79 (0.60-1.04) and 0.72 (0.46-1.11), respectively (p for interaction, 0.693). Similar associations were observed for cardiac and arrhythmic mortalities.

CONCLUSIONS

We found no evidence that in patients with HF and LVEF ≤35%, the effect of ICD on mortality varied by the non-invasive imaging method used to measure LVEF.

The role of multimodality imaging in the selection for implantable cardioverter-defibrillators in heart failure: A narrative review

Advanced pharmacologic and interventional therapies have improved survival in heart failure. Implantable cardioverter-defibrillators (ICD) have been shown to reduce mortality in patients with heart failure, but the benefit appears to be uneven in this population. We reviewed the evidence showing the benefit of ICD therapy in heart failure patients, the main issues arising from these studies, and the possible answers for a better risk stratification. In addition, we showed that multimodality imaging could improve patient selection for the implantation of ICDs, in both primary and secondary prevention, beyond the selection using only the left ventricular ejection fraction, by concentrating on arrhythmic substrate.

Advanced imaging for risk stratification for ventricular arrhythmias and sudden cardiac death

Sudden cardiac death (SCD) is a leading cause of mortality, comprising approximately half of all deaths from cardiovascular disease. In the US, the majority of SCD (85%) occurs in patients with ischemic cardiomyopathy (ICM) and a subset in patients with non-ischemic cardiomyopathy (NICM), who tend to be younger and whose risk of mortality is less clearly delineated than in ischemic cardiomyopathies. The conventional means of SCD risk stratification has been the determination of the ejection fraction (EF), typically via echocardiography, which is currently a means of determining candidacy for primary prevention in the form of implantable cardiac defibrillators (ICDs). Advanced cardiac imaging methods such as cardiac magnetic resonance imaging (CMR), single-photon emission computerized tomography (SPECT) and positron emission tomography (PET), and computed tomography (CT) have emerged as promising and non-invasive means of risk stratification for sudden death through their characterization of the underlying myocardial substrate that predisposes to SCD. Late gadolinium enhancement (LGE) on CMR detects myocardial scar, which can inform ICD decision-making. Overall scar burden, region-specific scar burden, and scar heterogeneity have all been studied in risk stratification. PET and SPECT are nuclear methods that determine myocardial viability and innervation, as well as inflammation. CT can be used for assessment of myocardial fat and its association with reentrant circuits. Emerging methodologies include the development of "virtual hearts" using complex electrophysiologic modeling derived from CMR to attempt to predict arrhythmic susceptibility. Recent developments have paired novel machine learning (ML) algorithms with established imaging techniques to improve predictive performance. The use of advanced imaging to augment risk stratification for sudden death is increasingly well-established and may soon have an expanded role in clinical decision-making. ML could help shift this paradigm further by advancing variable discovery and data analysis.

Cardiac Magnetic Resonance and Ventricular Arrhythmia Risk Assessment in Chronic Ischemic Cardiomyopathy: An Unmet Need?

Ischemic cardiomyopathy (ICM) constitutes a major public health issue, directly involved in the prevalence and incidence of heart failure, ventricular arrhythmias (VA) and sudden cardiac death (SCD). Severe impairment of left ventricular ejection fraction (LVEF) is considered a high-risk marker for SCD, conditioning the criteria that determine an implantable cardiac defibrillator (ICD) placement in primary prevention according to current clinical guidelines. However, its sensitivity and specificity values for the prediction of SCD in ICM may not be highest. Myocardial characterization using cardiac magnetic resonance with late gadolinium enhancement (CMR-LGE) sequences has made it possible to answer clinically relevant questions that are currently not assessable with LVEF alone. There is growing scientific evidence in favor of the relationship between fibrosis evaluated with CMR and the appearance of VA/SCD in patients with ICM. This evidence should make us contemplate a more realistic clinical value of LVEF in our daily clinical decision-making.

Confirmatory factor analysis including MRI-derived adipose tissues quantification improves associations of metabolic dysregulation to diastolic dysfunction

AIMS

To quantify metabolic impairment via a one-factor approach with confirmatory factor analysis (CFA) including MRI-derived visceral and subcutaneous adipose tissues and to associate it with diastolic dysfunction.

METHODS

In this cross-sectional analysis, 916 participants (53% female, mean age (SD): 56 (6)) underwent abdominal and cardiovascular MRI. With CFA a metabolic-load factor of metabolic-syndrome variables and visceral and subcutaneous adipose tissues was constructed. A piecewise structural equation model approach with adjustment for confounding factors was used to determine associations with left-ventricular diastolic function, cardiac morphology and hemodynamics.

RESULTS

Model fitting excluding blood pressure and waist circumference but including visceral and subcutaneous adipose tissues, fasting glucose, HDL-c and triglycerides was used to construct the metabolic-load factor. Evaluating measurement invariance demonstrated sex-specificity. Change in mitral early/late peak filling rate ratio was -0.12 for both males [-0.20; -0.05, p > 0.05] and females [-0.17; -0.07, p > 0.001] per SD of metabolic-load factor. Change in deceleration time of mitral early filling was -11.83 ms in females [-17.38; -6.27] per SD of metabolic-load factor.

CONCLUSION

A single latent metabolic-load factor via CFA including MRI-derived adipose tissues increased sensitivity for metabolic impairment obsoleting waist circumference and is associated with a decreased left-ventricular diastolic function, more apparent in females than in males.

Prediction of prognosis in patients with left ventricular dysfunction using three-dimensional strain echocardiography and cardiac magnetic resonance imaging

BACKGROUND

We evaluated three-dimensional speckle tracking echocardiography (3DSTE) strain and cardiac magnetic resonance (CMR) with delayed contrast enhancement (DCE) for the prediction of cardiac events in left ventricular (LV) dysfunction.

METHODS

CMR and 3DSTE in 75 patients with ischaemic and 38 with non-ischaemic LV dysfunction were analysed and temporally correlated to cardiac events during 41 ± 9 months of follow-up.

RESULTS

Cardiac events occurred in 44 patients, more in patients with ischaemic LV dysfunction. LV ejection fraction (LVEF), global circumferential and global area strain were reduced more in patients with more cardiac events, whereas 3DSTE LV end-systolic volumes and 3DSTE LV masses were larger. However, the area under the curve using receiver-operating characteristic analysis showed modest sensitivity and specificity for all evaluated parameters. Additionally, DCE did not differ significantly between the two groups. Univariate analysis showed ischaemic aetiology of LV dysfunction, LVEF and LV mass by CMR to be predictors of cardiac events with an increased relative risk of 2.4, 1.6 and 1.5, respectively. By multivariate analysis, only myocardial ischaemia and LVEF ≤ 39% were independent predictors of events (p = 0.004 and 0.005, respectively). Subgroup analysis in ischaemic and non-ischaemic patients showed only 3DSTE LV mass in ischaemic patients to have a significant association (p = 0.033) but without an increased relative risk.

CONCLUSION

LVEF calculated by 3DSTE or CMR were both good predictors of cardiac events in patients with LV dysfunction. A reduced LVEF ≤ 39% was associated with a 1.6-fold higher probability of a cardiac event. 3DSTE strain measurements and DCE-CMR did not add to the prognostic value of LVEF.

Cardiac MRI in cardiomyopathies

Heart failure affects 1-2% of the adult population and one of the main contributors to its development is cardiomyopathy. Assessing a patient's risk for adverse events in heart failure is challenging and made more difficult by the heterogenous phenotypic expression of the disease. Cardiac MRI has long been a gold standard measure of myocardial function and anatomy due to its high spatial and temporal resolution. More recently, it has been posited to play a more critical role in the diagnosis and prognosis of cardiomyopathy-related heart failure. Given the limitations of more commonly used imaging modalities, increasing the clinical use of cardiac magnetic resonance imaging could potentially improve the prognosis of specific subgroups of patients at risk of adverse cardiac events.

Validation of electrocardiographic criteria for identifying left ventricular dysfunction in patients with previous myocardial infarction

Background

Eleven criteria correlating electrocardiogram (ECG) findings with reduced left ventricular ejection fraction (LVEF) have been previously published. These have not been compared head‐to‐head in a single study. We studied their value as a screening test to identify patients with reduced LVEF estimated by cardiac magnetic resonance (CMR) imaging.

Methods

ECGs and CMR from 548 patients (age 61 + 11 years, 79% male) with previous myocardial infarction (MI), from the DETERMINE and PRE‐DETERMINE studies, were analyzed. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of each criterion for identifying patients with LVEF ≤ 30% and ≤ 40% were studied. A useful screening test should have high sensitivity and NPV.

Results

Mean LVEF was 40% (SD = 11%); 264 patients (48.2%) had LVEF ≤ 40%, and 96 patients (17.5%) had LVEF ≤ 30%. Six of 11 criteria were associated with a significant lower LVEF, but had poor sensitivity to identify LVEF ≤ 30% (range 2.1%–55.2%) or LVEF ≤ 40% (1.1%–51.1%); NPVs were good for LVEF ≤ 30% (range 82.8%–85.9%) but not for LVEF ≤ 40% (range 52.1%–60.6%). Goldberger's third criterion (RV4/SV4 < 1) and combinations of maximal QRS duration > 124 ms + either Goldberger's third criterion or Goldberger's first criterion (SV1 or SV2 + RV5 or RV6 ≥ 3.5 mV) had high specificity (95.4%–100%) for LVEF ≤ 40%, although seen in only 48 (8.8%) patients; predictive values were similar on subgroup analysis.

Conclusions

None of the ECG criteria qualified as a good screening test. Three criteria had high specificity for LVEF ≤ 40%, although seen in < 9% of patients. Whether other ECG criteria can better identify LV dysfunction remains to be determined.

Plasma big endothelin-1 is an effective predictor for ventricular arrythmias and end-stage events in primary prevention implantable cardioverter- defibrillator indication patients

OBJECTIVE

To investigate whether plasma big endothelin-1 (ET-1) predicts ventricular arrythmias (VAs) and end-stage events in primary prevention implantable cardioverter-defibrillator (ICD) indication patigents.

METHODS

In total, 207 patients fulfilling the inclusion criteria from Fuwai Hospital between January 2013 and December 2015 were retrospectively analyzed. The cohort was divided into three groups according to baseline plasma big ET-1 tertiles: tertile 1 (< 0.38 pmol/L, n = 68), tertile 2 (0.38-0.7 pmol/L, n = 69), and tertile 3 (> 0.7 pmol/L, n = 70). The primary endpoints were VAs. The secondary endpoints were end-stage events comprising all-cause mortality and heart transplantation.

RESULTS

During a mean follow-up period of 25.6 ± 13.9 months, 38 (18.4%) VAs and 78 (37.7%) end-stage events occurred. Big ET-1 was positively correlated with NYHA class (r = 0.165, P = 0.018), serum creatinine concentration (Scr; r = 0.147, P = 0.034), high-sensitivity C-reactive protein (hs-CRP; r = 0.217, P = 0.002), Lg NT-pro BNP (r = 0.463, P < 0.001), left ventricular end diastolic diameter (LVEDD; r = 0.234, P = 0.039) and negatively correlated with left ventricular ejection fraction (LVEF; r = -0.181, P = 0.032). Kaplan-Meier analysis showed that elevated big ET-1 was associated with increased risk of VAs and end-stage events (P < 0.05). In multivariate Cox regression models, big ET-1 was an independent risk factor for VAs (hazard ratio (HR) = 3.477, 95% confidence interval (CI): 1.352-8.940, P = 0.010, tertile 2 vs. tertile 1; HR = 4.112, 95% CI: 1.604-10.540, P = 0.003, tertile 3 vs. tertile 1) and end-stage events (HR = 2.804, 95% CI: 1.354-5.806, P = 0.005, tertile 2 vs. tertile 1; HR = 4.652, 95% CI: 2.288-9.459, P < 0.001, tertile 3 vs. tertile 1).

CONCLUSIONS

In primary prevention ICD indication patients, plasma big ET-1 levels can predict VAs and end-stage events and may facilitate ICD-implantation risk stratification.

Clinical outcomes after primary prevention defibrillator implantation are better predicted when the left ventricular ejection fraction is assessed by cardiovascular magnetic resonance

BACKGROUND

The left ventricular ejection fraction (LVEF) is the key selection criterion for an implanted cardioverter defibrillator (ICD) in primary prevention of sudden cardiac death. LVEF is usually assessed by two-dimensional echocardiography, but cardiovascular magnetic resonance (CMR) imaging is increasingly used. The aim of our study was to evaluate whether LVEF assessment using CMR imaging (CMR-LVEF) or two-dimensional echocardiography (2D echo-LVEF) may predict differently the occurrence of clinical outcomes.

METHODS

In this retrospective study, we reviewed patients referred for primary prevention ICD implantation to Caen University Hospital from 2005 to 2014. We included 173 patients with either ischemic (n = 120) or dilated cardiomyopathy (n = 53) and who had undergone pre-ICD CMR imaging. The primary composite end point was the time to death from any cause or first appropriate device therapy.

RESULTS

The mean CMR-LVEF was significantly lower than the mean 2D echo-LVEF (24% ± 6 vs 28% ± 6, respectively; p < 0.001). CMR-LVEF was a better independent predictive factor for the occurrence of the primary composite endpoint with a cut-off value of 22% (Hazard Ratio [HR] = 2.22; 95% CI [1.34-3.69]; p = 0.002) than 2D echo-LVEF with a cut-off value of 26% (HR = 1.61; 95% CI [0.99-2.61]; p = 0.056). Combination of the presence of scar with CMR-LVEF< 22% improved the predictive value for the occurrence of the primary outcome (HR = 2.58; 95% CI [1.54-4.30]; p < 0.001). The overall survival was higher among patients with CMR-LVEF≥22% than among patients with CMR-LVEF< 22% (p = 0.026), whereas 2D echo-LVEF was not associated with death.

CONCLUSIONS

CMR-LVEF is better associated with clinical outcomes than 2D echo-LVEF in primary prevention using an ICD. Scar identification further improved the outcome prediction. The combination of CMR imaging and echocardiography should be encouraged in addition to other risk markers to better select patients.

Arrhythmic risk stratification by cardiac magnetic resonance tissue characterization: disclosing the arrhythmic substrate within the heart muscle

Sudden cardiac death (SCD) is a pivotal health problem worldwide. The identification of subjects at increased risk of SCD is crucial for the accurate selection of candidates for implantable cardioverter defibrillator (ICD) therapy. Current strategies for arrhythmic stratification largely rely on left ventricular (LV) ejection fraction (EF), mostly measured by echocardiography, and New York Heart Association functional status for heart failure with reduced EF. For specific diseases, such as hypertrophic and arrhythmogenic cardiomyopathy, some risk scores have been proposed; however, these scores take into account some parameters that are a partial reflection of the global arrhythmic risk and show a suboptimal accuracy. Thanks to a more comprehensive evaluation, cardiac magnetic resonance (CMR) provides insights into the heart muscle (the so-called tissue characterization) identifying cardiac fibrosis as an arrhythmic substrate. Combining sequences before and after administration of contrast media and mapping techniques, CMR is able to characterize the myocardial tissue composition, shedding light on both intracellular and extracellular alterations. Over time, late gadolinium enhancement (LGE) emerged as solid prognostic marker, strongly associated with major arrhythmic events regardless of LVEF, adding incremental value over current strategy in ischemic heart disease and non-ischemic cardiomyopathies. The evidence on a potential prognostic role of mapping imaging is promising. However, mapping techniques require further investigation and standardization. Disclosing the arrhythmic substrate within the myocardium, CMR should be considered as part of a multiparametric approach to personalized arrhythmic stratification.

Ratio of End-Systolic Volume to Left Atrial Area Is a Solid Benchmark of Systolic Dysfunction in Non-Ischemic Cardiomyopathies

Background

Impairment of systolic function and late gadolinium enhancement (LGE) are well-known negative prognostic markers in non-ischemic cardiomyopathies (NICMPs). There is limited knowledge of the geometrical rearrangements of the ventricle volumes over size of the left atrium and their connections with systolic dysfunction and existence of LGE.

Material/Methods

Consecutive cases of NICMPs with impaired systolic function and controls were included from a computerized database of cardiac magnetic resonance exams for a 2.5-year period. Ratios made from volumetric parameters over left atrial area (LAA) area were calculated.

Results

Our study included 205 cases referred to cardiac magnetic resonance (CMR); age was 48.7±17.0 years (range 15.2–80.4), male-to-female ratio 137 (66.8%): 68 (33.2%), (both p>0.05). LGE was significantly correlated with impairment of systolic function (Rho CC=0.395; p<0.001). For detection of systolic impairment, a critical value of end-systolic-volume (ESV)/LAA of ≥2.7 had an area under curve (AUC) of 0.902 (0.853–0.939), p<0.001; stroke-volume (SV)/LAA ≤3.0 had AUC=0.782(0.719–0.837), p<0.001, and end-diastolic volume (EDV)/LAA <7.4 had an AUC of 0.671 (0.602–0.735); p<0.001. In analyses of LGE, a value of SV/LAA of ≤3.0 had an AUC of 0.681 (0.612–0.744), p<0.001; while ESV/LAA and EDV/LAA were not significant (both p<0.05). ESV/LAA was correlated with systolic dysfunction (Rho-correlation-coefficient: 0.688; p<0.001) and existence of linear midventricular LGE stripe (Rho-CC=0.446; p<0.001).

Conclusions

ESV/LAA was the most effective for detection of systolic impairment and was associated with the existence of LGE. Prospective validation for clinical applicability and prognostic relations are warranted in future studies.

Cardiac MRI and radionuclide ventriculography for measurement of left ventricular ejection fraction in ICD candidates

OBJECTIVE

Current guidelines provide left ventricular ejection fraction (LVEF) criterion for use of implantable cardioverter defibrillators (ICD) but do not specify which modality to use for measurement. We compared LVEF measurements by radionuclide ventriculography (RNV) vs cardiac MRI (CMR) in ICD candidates to assess impact on clinical decision making.

METHODS

This single-centre study included 124 consecutive patients referred for assessment of ICD implantation who underwent RNV and CMR within 30 days for LVEF measurement. RNV and CMR were interpreted independently by experienced readers.

RESULTS

Among 124 patients (age 64 ± 11 years, 77% male), median interval between CMR and RNV was 1 day; mean LVEF was 32 ± 12% by CMR and 33 ± 11% by RNV (p = 0.60). LVEF by CMR and RNV showed good correlation, but Bland-Altman analysis showed relatively wide limits of agreement (-12.1 to 11.4). CMR LVEF reclassified 26 (21%) patients compared to RNV LVEF (kappa = 0.58). LVEF by both modalities showed good interobserver reproducibility (ICC 0.96 and 0.94, respectively) (limits of agreement -7.27 to 5.75 and -8.63 to 6.34, respectively).

CONCLUSION

Although LVEF measurements by CMR and RNV show moderate agreement, there is frequent reclassification of patients for ICD placement based on LVEF between these modalities. Future studies should determine if a particular imaging modality for LVEF measurement may enhance ICD decision making and treatment benefit.

Optimization of large animal MI models; a systematic analysis of control groups from preclinical studies

Large animal models are essential for the development of novel therapeutics for myocardial infarction. To optimize translation, we need to assess the effect of experimental design on disease outcome and model experimental design to resemble the clinical course of MI. The aim of this study is therefore to systematically investigate how experimental decisions affect outcome measurements in large animal MI models. We used control animal-data from two independent meta-analyses of large animal MI models. All variables of interest were pre-defined. We performed univariable and multivariable meta-regression to analyze whether these variables influenced infarct size and ejection fraction. Our analyses incorporated 246 relevant studies. Multivariable meta-regression revealed that infarct size and cardiac function were influenced independently by choice of species, sex, co-medication, occlusion type, occluded vessel, quantification method, ischemia duration and follow-up duration. We provide strong systematic evidence that commonly used endpoints significantly depend on study design and biological variation. This makes direct comparison of different study-results difficult and calls for standardized models. Researchers should take this into account when designing large animal studies to most closely mimic the clinical course of MI and enable translational success.

Appropriate use criteria for echocardiography in the Netherlands

Introduction

Appropriate use criteria (AUC) for echocardiography based on clinical scenarios were previously published by an American Task Force. We determined whether members of the Dutch Working Group on Echocardiography (WGE) would rate these scenarios in a similar way.

Methods

All 32 members of the WGE were invited to judge clinical scenarios independently using a blanked version of the previously published American version of AUC for echocardiography. During a face-to-face meeting, consensus about the final rating was reached by open discussion for each indication. For reasons of simplicity, the scores were reduced from a 9-point scale to a 3-point scale (indicating an appropriate, uncertain or inappropriate echo indication, respectively).

Results

Nine cardiologist members of the WGE reported their judgment on the echo cases (n = 153). Seventy-one indications were rated as appropriate, 35 were rated as uncertain, and 47 were rated as inappropriate. In 5% of the cases the rating was opposite to that in the original (appropriate compared with inappropriate and vice versa), whereas in 20% judgements differed by 1 level of appropriateness. After the consensus meeting, the appropriateness of 7 (5%) cases was judged differently compared with the original paper.

Conclusions

Echocardiography was rated appropriate when it is applied for an initial diagnosis, a change in clinical status or a change in patient management. However, in about 5% of the listed clinical scenarios, members of the Dutch WGE rated the AUC for echocardiography differently as compared with their American counterparts. Further research is warranted to analyse this decreased external validity.

Electronic supplementary material

The online version of this article (doi: 10.1007/s12471-017-0960-9) contains supplementary material, which is available to authorized users.

Prognostic Benefit of Cardiac Magnetic Resonance Over Transthoracic Echocardiography for the Assessment of Ischemic and Nonischemic Dilated Cardiomyopathy Patients Referred for the Evaluation of Primary Prevention Implantable Cardioverter–Defibrillator Therapy

Background—

The aim of this study was to determine the prognostic benefit of cardiac magnetic resonance (CMR) over transthoracic echocardiography (TTE) in ischemic cardiomyopathy and nonischemic dilated cardiomyopathy patients evaluated for primary prevention implantable cardioverter–defibrillator therapy.

Methods and Results—

We enrolled 409 consecutive ischemic and dilated cardiomyopathy patients (mean age: 64±12 years; 331 men). All patients underwent TTE and CMR, and left ventricle end-diastolic volume, left ventricle end-systolic volume, and left ventricle ejection fraction (LVEF) were evaluated. In addition, late gadolinium enhancement was also assessed. All patients were followed up for major adverse cardiac events (MACE) defined as a composite end point of long runs of nonsustained ventricular tachycardia, sustained ventricular tachycardia, aborted sudden cardiac death, or sudden cardiac death. The median follow-up was 545 days. CMR showed higher left ventricle end-diastolic volume (mean difference: 43±22.5 mL), higher left ventricle end-systolic volume (mean difference: 34±20.5 mL), and lower LVEF (mean difference: −4.9±10%) as compared to TTE ( P <0.01). MACE occurred in 103 (25%) patients. Patients experiencing MACE showed higher left ventricle end-diastolic volume, higher left ventricle end-systolic volume, and lower LVEF with both imaging modalities and higher late gadolinium enhancement per-patient prevalence as compared to patients without MACE. At multivariable analysis, CMR-LVEF ≤35% (hazard ratio=2.18 [1.3–3.8]) and the presence of late gadolinium enhancement (hazard ratio=2.2 [1.4–3.6]) were independently associated with MACE ( P <0.01). A model based on CMR-LVEF ≤35% or CMR-LVEF ≤35% plus late gadolinium enhancement detection showed a higher performance in the prediction of MACE as compared to TTE-LVEF resulting in net reclassification improvement of 0.468 (95% confidence interval, 0.283–0.654; P <0.001) and 0.413 (95% confidence interval, 0.23–0.63; P <0.001), respectively.

Conclusions—

CMR provides additional prognostic stratification as compared to TTE, which may have direct impact on the indication of implantable cardioverter–defibrillator implantation.

Three-dimensional speckle tracking echocardiography and cardiac magnetic resonance for left ventricular chamber quantification and identification of myocardial transmural scar

Background

We compared three-dimensional speckle tracking echocardiography (3DSTE) and its strain to cardiac magnetic resonance (CMR) with delayed contrast enhancement for left ventricular (LV) chamber quantification and transmurality of myocardial scar. Furthermore, we examined the ability of 3DSTE strain to differentiate between ischaemic and non-ischaemic LV dysfunction.

Methods

In 80 consecutive patients with ischaemic and 40 patients with non-ischaemic LV dysfunction, the correlations between LV volumes and ejection fraction were measured using 3DSTE and CMR. Global and regional 3DSTE strains and total or percentage enhanced LV mass were evaluated.

Results

LV end-diastolic and end-systolic volumes and ejection fraction correlated well between 3DSTE and CMR (r: 0.83, 0.88 and 0.89, respectively). However, 3DSTE significantly underestimated volumes. Correlation for LV mass was modest (r = 0.59). All 3DSTE regional strain values except for radial strain were lower in segments with versus segments without transmural enhancement. However, strain parameters could not identify the transmurality of scar. No significant difference between ischaemic and non-ischaemic LV dysfunction was observed in either global or regional 3DSTE strain except for twist, which was lower in the non-ischaemic group (4.9 ± 3.3 vs. 6.4 ± 3.2°, p = 0.03).

Conclusion

3DSTE LV volumes are underestimated compared with CMR, while LV ejection fraction revealed excellent accuracy. Functional impairment by 3DSTE strain does not correlate well with scar localisation or extent by CMR. 3DSTE strain could not differentiate between ischaemic and non-ischaemic LV dysfunction. Future studies will need to clarify if 3DSTE strain and CMR delayed contrast enhancement can provide incremental value to the prediction of future cardiovascular events.

Cardiac sympathetic activity in chronic heart failure: cardiac 123I-mIBG scintigraphy to improve patient selection for ICD implantation

Heart failure is a life-threatening disease with a growing incidence in the Netherlands. This growing incidence is related to increased life expectancy, improvement of survival after myocardial infarction and better treatment options for heart failure. As a consequence, the costs related to heart failure care will increase. Despite huge improvements in treatment, the prognosis remains unfavourable with high one-year mortality rates. The introduction of implantable devices such as implantable cardioverter defibrillators (ICD) and cardiac resynchronisation therapy (CRT) has improved the overall survival of patients with chronic heart failure. However, after ICD implantation for primary prevention in heart failure a high percentage of patients never have appropriate ICD discharges. In addition 25–50 % of CRT patients have no therapeutic effect. Moreover, both ICDs and CRTs are associated with malfunction and complications (e. g. inappropriate shocks, infection). Last but not least is the relatively high cost of these devices. Therefore, it is essential, not only from a clinical but also from a socioeconomic point of view, to optimise the current selection criteria for ICD and CRT. This review focusses on the role of cardiac sympathetic hyperactivity in optimising ICD selection criteria. Cardiac sympathetic hyperactivity is related to fatal arrhythmias and can be non-invasively assessed with ¹²³I-meta-iodobenzylguanide (¹²³I-mIBG) scintigraphy. We conclude that cardiac sympathetic activity assessed with ¹²³I-mIBG scintigraphy is a promising tool to better identify patients who will benefit from ICD implantation.

Impact of the papillary muscles on cardiac magnetic resonance image analysis of important left ventricular parameters in hypertrophic cardiomyopathy

PURPOSE

The use of cardiac magnetic resonance (CMR) analysis has increased in patients with hypertrophic cardiomyopathy (HCM). Quantification of left ventricular (LV) measures will be affected by the inclusion or exclusion of the papillary muscles as part of the LV mass, but the magnitude of effect and potential consequences are unknown.

METHODS

We performed Cine-CMR in (1) clinical HCM patients (n = 55) and (2) subclinical HCM mutation carriers without hypertrophy (n = 14). Absolute and relative differences in LV ejection fraction (EF) and mass were assessed between algorithms with and without inclusion of the papillary muscles.

RESULTS

Papillary muscle mass in group 1 was 6.6 ± 2.5 g/m(2) and inclusion of the papillary muscles resulted in significant relative increases in LVEF of 4.5 ± 1.8 % and in LV mass of 8.7 ± 2.6 %. For group 2 these figures were 4.0 ± 0.9 g/m(2), 3.8 ± 1.0 % and 9.5 ± 1.8 %, respectively. With a coefficient of variation of 4 %, this 9 % difference in LV mass during CMR follow-up will be considered a change, while in fact the exact same mass may have been assessed according to two different algorithms.

CONCLUSIONS

In clinical HCM patients, CMR quantification of important LV measures is significantly affected by inclusion or exclusion of the papillary muscles. In relative terms, the difference was similar in subjects without hypertrophy. This underscores a general need for a uniform approach in CMR image analysis.

Echocardiography and cardiac resynchronisation therapy, friends or foes?

Echocardiography is used in cardiac resynchronisation therapy (CRT) to assess cardiac function, and in particular left ventricular (LV) volumetric status, and prediction of response. Despite its widespread applicability, LV volumes determined by echocardiography have inherent measurement errors, interobserver and intraobserver variability, and discrepancies with the gold standard magnetic resonance imaging. Echocardiographic predictors of CRT response are based on mechanical dyssynchrony. However, parameters are mainly tested in single-centre studies or lack feasibility. Speckle tracking echocardiography can guide LV lead placement, improving volumetric response and clinical outcome by guiding lead positioning towards the latest contracting segment. Results on optimisation of CRT device settings using echocardiographic indices have so far been rather disappointing, as results suffer from noise. Defining response by echocardiography seems valid, although re-assessment after 6 months is advisable, as patients can show both continuous improvement as well as deterioration after the initial response. Three-dimensional echocardiography is interesting for future implications, as it can determine volume, dyssynchrony and viability in a single recording, although image quality needs to be adequate. Deformation patterns from the septum and the derived parameters are promising, although validation in a multicentre trial is required. We conclude that echocardiography has a pivotal role in CRT, although clinicians should know its shortcomings.

Echo response and clinical outcome in CRT patients

Background

Change in left ventricular end-systolic volume (∆LVESV) is the most frequently used surrogate marker in measuring response to cardiac resynchronisation therapy (CRT). We investigated whether ∆LVESV is the best measure to discriminate between a favourable and unfavourable outcome and whether this is equally applicable to non-ischaemic and ischaemic cardiomyopathy.

Methods

205 CRT patients (age 65 ± 12 years, 69 % men) were included. At baseline and 6 months echocardiographic studies, exercise testing and laboratory measurements were performed. CRT response was assessed by: ∆LVESV, ∆LV ejection fraction (LVEF), ∆ interventricular mechanical delay, ∆VO₂ peak, ∆VE/VCO₂, ∆BNP, ∆creatinine, ∆NYHA, and ∆QRS. These were correlated to the occurrence of major adverse cardiac events (MACE) between 6 and 24 months.

Results

MACE occurred in 19 % of the patients (non-ischaemic: 13 %, ischaemic: 24 %). ∆LVESV remained the only surrogate marker for CRT response for the total population and patients with non-ischaemic cardiomyopathy, showing areas under the curve (AUC) of 0.69 and 0.850, respectively. For ischaemic cardiomyopathy, ∆BNP was the best surrogate marker showing an AUC of 0.66.

Conclusion

∆LVESV is an excellent surrogate marker measuring CRT response concerning long-term outcome for non-ischaemic cardiomyopathy. ∆LVESV is not suitable for ischaemic cardiomyopathy in which measuring CRT response remains difficult.

Clinical Impact of Cardiac Magnetic Resonance Imaging Versus Echocardiography-Guided Patient Selection for Primary Prevention Implantable Cardioverter Defibrillator Therapy

The main eligibility criterion for primary prevention implantable cardioverter defibrillator (ICD) therapy, that is, left ventricular ejection fraction (LVEF), is based on large clinical trials using primarily 2-dimensional echocardiography (2DE). Presently, cardiac magnetic resonance imaging (MRI) is considered the gold standard for LVEF assessment. It has been demonstrated that cardiac MRI assessment results in lower LVEFs compared with 2DE. Consequently, cardiac MRI-LVEF assessment may lead to more patients eligible for ICD implantation with potential clinical consequences. The aim of this study was to evaluate the clinical impact of cardiac MRI-LVEF versus 2DE-LVEF assessment for ICD eligibility. A total of 149 patients with cardiac MRI-LVEF ≤35% referred for primary prevention ICD implantation who underwent both 2DE and cardiac MRI-LVEF assessment were retrospectively included. 2DE-LVEF was computed by Simpson's biplane method. Cardiac MRI-LVEF was computed after outlining the endocardial contours in short-axis cine images. Appropriate device therapy (ADT) and all-cause mortality were evaluated during 2.9 ± 1.7 years of follow-up. The present study found that cardiac MRI-LVEF was significantly lower compared with 2DE-LVEF (23 ± 8% vs 30 ± 8%, respectively, p <0.001), resulting in 29 (19%) more patients eligible for ICD implantation according to the current guidelines (LVEF ≤35%). Patients with 2DE-LVEF >35% but cardiac MRI-LVEF ≤35% experienced a lower ADT rate compared with patients having 2DE-LVEF ≤35% (2.1% vs 10.4% per year, respectively, p = 0.02). Application of cardiac MRI-LVEF cutoff of 30% resulted in 119 eligible patients experiencing 9.9% per year ADT, comparable with 2DE-LVEF cut-off value of 35%. In conclusion, cardiac MRI-LVEF assessment resulted in more patients eligible for ICD implantation compared with 2DE who showed a relatively low event rate during follow-up. The event rate in patients with cardiac MRI-LVEF ≤30% was comparable with patients having a 2DE-LVEF ≤35%. This study suggests the need for re-evaluation of cardiac MRI-based LVEF cut-off values for ICD eligibility.