Reproducibility assessment of rapid strains in cardiac MRI: Insights and recommendations for clinical application

PURPOSE

Studies have shown the incremental value of strain imaging in various cardiac diseases. However, reproducibility and generalizability has remained an issue of concern. To overcome this, simplified algorithms such as rapid atrioventricular strains have been proposed. This multicenter study aimed to assess the reproducibility of rapid strains in a real-world setting and identify potential predictors for higher interobserver variation.

METHODS

A total of 4 sites retrospectively identified 80 patients and 80 healthy controls who had undergone cardiac magnetic resonance imaging (CMR) at their respective centers using locally available scanners with respective field strengths and imaging protocols. Strain and volumetric parameters were measured at each site and then independently re-evaluated by a blinded core lab. Intraclass correlation coefficients (ICC) and Bland-Altman plots were used to assess inter-observer agreement. In addition, backward multiple linear regression analysis was performed to identify predictors for higher inter-observer variation.

RESULTS

There was excellent agreement between sites in feature-tracking and rapid strain values (ICC ≥ 0.96). Bland-Altman plots showed no significant bias. Bi-atrial feature-tracking and rapid strains showed equally excellent agreement (ICC ≥ 0.96) but broader limits of agreement (≤18.0 % vs. ≤3.5 %). Regression analysis showed that higher field strength and lower temporal resolution (>30 ms) independently predicted reduced interobserver agreement for bi-atrial strain parameters (ß = 0.38, p = 0.02 for field strength and ß = 0.34, p = 0.02 for temporal resolution).

CONCLUSION

Simplified rapid left ventricular and bi-atrial strain parameters can be reliably applied in a real-world multicenter setting. Due to the results of the regression analysis, a minimum temporal resolution of 30 ms is recommended when assessing atrial deformation.

Feasibility of Reduced Iodine Loads for Vascular Assessment Prior to Transcatheter Aortic Valve Implantation (TAVI) Using Spectral Detector CT

Reduced iodine loads for computed tomography (CT)-based vascular assessment prior to transcatheter aortic valve implantation (TAVI) may be feasible in conjunction with a spectral detector CT scanner. This prospective single-center study considered 100 consecutive patients clinically referred for pre-TAVI CT. They were examined on a dual-layer detector CT scanner to obtain an ECG-gated cardiac scan and a non-ECG-gated aortoiliofemoral scan. Either a standard contrast media (SCM) protocol using 80 mL Iohexol 350 mgI/mL (iodine load: 28 gI) or a body-mass-index adjusted reduced contrast media (RCM) protocol using 40-70 mL Iohexol 350 mgI/mL (iodine load: 14-24.5 gI) were employed. Conventional images and virtual monoenergetic images at 40-80 keV were reconstructed. A threshold of 250 HU was set for sufficient attenuation along the arterial access pathway. A qualitative assessment used a five-point Likert scale. Sufficient attenuation in the thoracic aorta was observed for all patients in both groups using conventional images. In the abdominal, iliac, and femoral segments, sufficient attenuation was observed for the majority of patients when using virtual monoenergetic images (SCM: 96-100% of patients, RCM: 88-94%) without statistical difference between both groups. Segments with attenuation measurements below the threshold remained qualitatively assessable as well. Likert scores were 'excellent' for virtual monoenergetic images 50 keV and 55 keV in both groups (RCM: 1.2-1.4, SCM: 1.2-1.3). With diagnostic image quality maintained, it can be concluded that reduced iodine loads of 14-24.5 gI are feasible for pre-TAVI vascular assessment on a spectral detector CT scanner.

Safety of dobutamine or adenosine stress cardiac magnetic resonance imaging in patients with left ventricular thrombus

BACKGROUND

Left ventricular (LV) thrombus formation is a common but potentially serious complication, typically occurring after myocardial infarction. Due to perceived high thromboembolic risk and lack of safety data, stress cardiac magnetic resonance (CMR) imaging especially with dobutamine is usually avoided despite its high diagnostic yield. This study aimed to investigate the characteristics, safety and outcome of patients with LV thrombus undergoing dobutamine or vasodilator stress CMR.

METHODS

Patients undergoing stress CMR with concomitant LV thrombus were retrospectively included. Risk factors, comorbidities, and previous embolic events were recorded. Periprocedural safety was assessed for up to 48 h following the examination. Major adverse cardiac events (MACE) 12 months before the diagnosis were compared to 12 months after the exam and between patients and a matched control group. Additionally, patients were followed up for all-cause mortality.

RESULTS

95 patients (78 male, 65 ± 10.7 years) were included. Among them, 43 patients underwent dobutamine (36 high-dose, 7 low-dose) and 52 vasodilator stress CMR. Periprocedural safety was excellent with no adverse events. During a period of 24 months, 27 MACE (14.7%) occurred in patients and controls with no statistical difference between groups. During a median follow-up of 33.7 months (IQR 37.6 months), 6 deaths (6.3%) occurred. Type of stress agent, thrombus mobility, or protrusion were not correlated to embolic events or death.

CONCLUSION

The addition of a stress test to a CMR exam is safe and does increase the generally high cardioembolic event rate in LV thrombus patients. Therefore, it is useful to support reperfusion decision-making.

Absence of visible infarction on cardiac magnetic resonance imaging despite the established diagnosis of myocardial infarction by 4th Universal Definition of Myocardial Infarction

AIMS

Myocardial scarring due to acute myocardial infarction (AMI) can be visualized by late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) imaging. However, a recent study revealed a group of Type 1 AMI patients with undetectable myocardial injury on LGE. This study aims to describe these cases in detail and explore possible explanations for this new phenomenon.

METHODS AND RESULTS

A total of 137 patients diagnosed with either ST-elevation myocardial infarction (STEMI) or non-ST-elevation myocardial infarction (non-STEMI) diagnosed according to the 4th Universal Definition of Myocardial Infarction underwent LGE-CMR after invasive coronary angiography. Fourteen of them (10.2%) showed no LGE and were included in the final study population. Most patients presented with acute chest pain, 3 patients were diagnosed as STEMI, and 11 as non-STEMI. Peak high-sensitive cardiac troponin T ranged from 45 to 1173 ng/L. A culprit lesion was identified in 12 patients. Severe coronary stenoses were found in five patients, while seven patients had subtotal to total coronary artery occlusion. Percutaneous coronary intervention was performed in 10 patients, while 2 patients required coronary artery bypass grafting and no intervention was required in 2 patients. Cardiac magnetic resonance was performed 30 (4-140) days after the initial presentation. Most patients showed preserved left ventricular ejection fraction on CMR. No alternative reasons for the rise/fall of high-sensitive cardiac troponin T were found.

CONCLUSION

The absence of LGE on CMR in patients with Type 1 AMI is a new finding. While insufficient spatial resolution of LGE imaging, delayed CMR performance, spontaneous reperfusion, and coronary collaterals may provide some explanations, further investigations are required to fully understand this phenomenon.

Effects of Ionizing Radiation on Cardiac Implantable Electronic Devices (CIEDs) in Patients with Esophageal Cancer Undergoing Radiotherapy: A Pilot Study

(1) Background: The prevalence of cancer patients relying on cardiac implantable electronic device (CIED) is steadily rising. The aim of this study was to evaluate RT-related malfunctions of CIEDs. (2) Methods: We retrospectively analyze sixteen patients with esophageal cancer who were treated with radiotherapy between 2012 and 2022 at the University Hospital Heidelberg. All patients underwent systemic evaluation including pre-therapeutic cardiological examinations of the CIED functionality and after every single irradiation. (3) Results: Sixteen patients, predominantly male (14) with a mean age of 77 (range: 56-85) years were enrolled. All patients received 28 fractions of radiotherapy with a cumulative total dose 58.8 Gy. The mean maximum dose at the CIEDs was 1.8 Gy. Following radiotherapy and during the one-year post-radiation follow-up period, there were no registered events associated with the treatment in this evaluation. (4) Conclusion: The study did not observe any severe CIED malfunctions following each radiation fraction or after completion of RT. Strict selection of photon energy and alignment with manufacturer-recommended dose limits appear to be important. Our study showed no major differences in the measured values of the pacing threshold, sensing threshold and lead impedance after RT.

Layer-specific fast strain-encoded cardiac magnetic resonance imaging aids in the identification and discrimination of acute myocardial injury: a prospective proof-of-concept study

BACKGROUND

Acute myocardial injury is a common diagnosis in the emergency department and differential diagnoses are numerous. Cardiac magnetic resonance (CMR) strain sequences, such as fast strain ENCoded (fSENC), are early predictors of myocardial function loss. This study assessed the potential diagnostic and prognostic benefits of a layer-specific approach.

METHODS

For this prospective study, patients in the emergency department fulfilling rule-in criteria for non-ST-elevation myocardial infarction (NSTEMI) received an ultra-fast fSENC CMR. Volunteers without cardiac diseases (controls) were recruited for comparison. Measurements were performed in a single heartbeat acquisition to measure global longitudinal strain (GLS) and segmental longitudinal strain and dysfunctional segments. The GLS was measured in two layers and a difference (GLSdifference = GLSepicardial - GLSendocardial) was calculated. The performance of those strain features was compared to standard care (physical examination, cardiac biomarkers, electrocardiogram). According to the final diagnosis after discharge, patients were divided into groups and followed up for 2 years.

RESULTS

A total of 114 participants, including 50 controls, were included. The 64 patients (51 male) were divided into a NSTEMI (25), myocarditis (16), and other myocardial injury group (23). GLS served as a potent predictor of myocardial injury (area under the curve (AUC) 91.8%). The GLSdifference provided an excellent diagnostic performance to identify a NSTEMI (AUC 83.2%), further improved by including dysfunctional segments (AUC 87.5%, p = 0.01). An optimal test was achieved by adding fSENC to standard care (AUC 95.5%, sensitivity 96.0%, specificity 86.5%, p = 0.03). No death occurred in 2 years for patients with normal GLS and ≤5 dysfunctional segments, while three patients died that showed abnormal GLS or >5 dysfunctional segments.

CONCLUSIONS

Layer-specific strain is a potential new marker with high diagnostic performance in the identification and differentiation of acute myocardial injuries.

Prognostic value of negative stress cardiac magnetic resonance imaging in patients with moderate-severe coronary artery stenosis

Objective

This study aims to evaluate the prognostic value of stress cardiac magnetic resonance (CMR) without inducible ischemia in a real-world cohort of patients with known severe coronary artery stenosis.

Background

The prognosis of patients with severe coronary artery stenosis and without inducible ischemia using stress CMR remains uncertain, even though its identification of functionally significant coronary artery disease (CAD) is excellent.

Materials and methods

Patients without inducible ischemia and known CAD who underwent stress CMR between February 2015 and December 2016 were included in this retrospective study. These patients were divided into two groups: group 1 with stenosis of 50%-75% and group 2 with stenosis of >75%. The primary endpoint was defined as the occurrence of a major adverse cardiovascular event (MACE) [cardiac death, non-fatal myocardial infarction (MI), percutaneous coronary intervention (PCI), or coronary artery bypass grafting (CABG)].

Results

Real-world data collected from 169 patients with a median age of 69 (60-75) years were included. The median follow-up was 5.5 (IQR 4.1-6.6) years. Events occurred after a mean time of 3.0 ± 2.2 years in group 1 and 3.7 ± 2.0 years in group 2 (p = 0.35). Sixteen (18.8%) patients in group 1 and 23 (27.4%) patients in group 2 suffered from MACE without a significant difference between the two groups (p = 0.33). In group 2, one cardiac death (1.2%), seven non-fatal MI (8.3%), 15 PCI (17.9%), and one CABG (1.2%) occurred.

Conclusion

The findings of this pilot study suggest that long-term outcomes in a real-world patient cohort with known severe and moderate coronary artery stenosis but without inducible ischemia were similar. Stress CMR may provide valuable risk stratification in patients with angiographically significant but hemodynamically non-obstructive coronary lesions.

Safety, accuracy, and prediction of prognosis in patients with end-stage chronic kidney disease undergoing dobutamine stress cardiac magnetic resonance imaging

Introduction

Advanced chronic kidney disease (CKD) is an independent risk factor for coronary artery disease (CAD). Due to its unique uremia-derived pathophysiology of atherosclerosis and the limitations of using potentially harmful contrast agents, the best non-invasive approach to assess CAD in these patients remains unclear. We sought to investigate the accuracy, safety, and prognosis of patients with severe CKD undergoing dobutamine stress cardiac magnetic resonance imaging (CMR).

Materials and methods

In this retrospective, single-center study, patients on dialysis or with a glomerular filtration rate of <15 ml/min/1.73 m2 who underwent dobutamine stress CMR were included. A rest and stress wall motion analysis was performed using dobutamine/atropine as stressor. The target heart rate was 85% of the maximum heart rate. Periprocedural adverse events and 1-year follow-up data were obtained.

Results

A total of 176 patients (127 men, 49 women) with a mean age of 60.9 ± 14.7 years were included, of which 156 patients were on permanent dialysis. Short-term symptoms such as angina or shortness of breath during stress CMR were frequent (22.1%), but major complications were rare (one patient with myocardial infarction, 0.6%). The 1-year event rate was high (16.4%) with a significant independent correlation to reduced ejection fraction at rest (p = 0.037) and failure to achieve the target heart rate (p = 0.029). The overall accuracy for predicting significant CAD was good (sensitivity of 71.4%, specificity of 98.4%) and excellent if the target heart rate was achieved (83.3%, 97.9%). A negative stress CMR was highly predictive for the absence of major adverse cardiac event or any coronary revascularization during the 1-year follow-up (negative predictive value of 95.0%).

Discussion

Dobutamine stress CMR is a safe and accurate diagnostic imaging technique in patients at advanced stages of chronic kidney disease. A reduced ejection fraction and the inability to reach the target heart rate are independent predictors of a poor outcome.

Safety of Stress Cardiac Magnetic Resonance in Patients With Moderate to Severe Aortic Valve Stenosis

BACKGROUND

Dobutamine and adenosine stress cardiac magnetic resonance (CMR) imaging is relatively contraindicated in patients with moderate to severe aortic valve stenosis (AS). We aimed to determine the safety of dobutamine and adenosine stress CMR in patients with moderate to severe AS.

METHODS

In this retrospective study patients with AS who underwent either dobutamine or adenosine stress CMR for exclusion of obstructive coronary artery disease were enrolled. We recorded clinical data, CMR and echocardiography findings, and complications as well as minor symptoms. Patients with AS were compared to matched individuals without AS.

RESULTS

A total of 187 patients with AS were identified and compared to age-, gender- and body mass index-matched 187 patients without AS. No severe complications were reported in the study nor the control group. The reported frequency of non-severe complications and minor symptoms were similar between the study and the control groups. Nineteen patients with AS experienced non-severe complications or minor symptoms during dobutamine stress CMR compared to eighteen patients without AS (p = 0.855). One patient with AS and two patients without AS undergoing adenosine stress CMR experienced minor symptoms (p = 0.562). Four examinations were aborted because of chest pain, paroxysmal atrial fibrillation and third-degree atrioventricular block. Inducible ischaemia, prior coronary artery bypass grafting, prior stroke and age were associated with a higher incidence of complications and minor symptoms.

CONCLUSIONS

Moderate to severe AS was not associated with complications during CMR stress test. The incidence of non-severe complications and minor symptoms was greater with dobutamine.

Correlation of serial high-sensitivity cardiac Troponin T values to infarct mass determined by cardiac magnetic resonance imaging: a validation study

Aim

To validate correlations between contrast-enhanced magnetic resonance imaging (CE-MRI) infarct mass and high-sensitivity cardiac Troponin T (hs-cTnT) values at different time points in patients with confirmed acute myocardial infarction (AMI).

Methods and results

Patients presenting with AMI and with available CE-MRI between 1 January 2018 and 31 December 2020 were included. Correlation coefficients between hs-cTnT on admission, after 24, 48, 72, and 96 h, and peak hs-cTnT values and CE-MRI infarct mass were calculated. Correlations between hs-cTnT and CE-MRI infarct mass were compared with those of a third generation cTnT assay from a previously published study of our group. A total of 137 patients were included for the present analysis. Median CE-MRI infarct mass was 12,5 g [95% confidence interval (CI): 9.8–16.2 g]. Hs-cTnT values and infarct mass correlated well at all time points including admission (r = 0.474, 95% CI: 0.331–0.560, P &lt; 0.0001), 24 h (r = 0.508, 95% CI: 0.370–0.625, P &lt; 0.0001), 48 h (r = 0.547, 95% CI: 0.404–0.664, P &lt; 0.0001), 72 h (r = 0.489, 95% CI: 0.320–0.628, P &lt; 0.0001), 96 h (r = 0.509, 95% CI: 0.330–0.653, P &lt; 0.001) including peak hs-cTnT values (r = 0.547, 95% CI: 0.416–0.656, P &lt; 0.0001), and maximum absolute delta changes within 96 h (r = 0.507, 95% CI: 0.369–0.622, P &lt; 0.001). Correlations of the third generation assay could be confirmed for hs-cTnT at all time points. A superior correlation with CE-MRI infarct mass was observed for hs-cTnT values on admission.

Conclusion

Hs-cTnT values at different time points correlate well with CE-MRI infarct mass. Correlations of admission hs-cTnT values are superior to those of a third generation assay.

A head-to-head comparison of fast-SENC and feature tracking to LV long axis strain for assessment of myocardial deformation in chest pain patients

BACKGROUND

Myocardial strain imaging has gained importance in cardiac magnetic resonance (CMR) imaging in recent years as an even more sensitive marker of early left ventricular dysfunction than left-ventricular ejection fraction (LVEF). fSENC (fast strain encoded imaging) and FT (feature tracking) both allow for reproducible assessment of myocardial strain. However, left-ventricular long axis strain (LVLAS) might enable an equally sensitive measurement of myocardial deformation as global longitudinal or circumferential strain in a more rapid and simple fashion.

METHODS

In this study we compared the diagnostic performance of fSENC, FT and LVLAS for identification of cardiac pathology (ACS, cardiac-non-ACS) in patients presenting with chest pain (initial hscTnT 5-52 ng/l). Patients were prospectively recruited from the chest pain unit in Heidelberg. The CMR scan was performed within 1 h after patient presentation. Analysis of LVLAS was compared to the GLS and GCS as measured by fSENC and FT.

RESULTS

In total 40 patients were recruited (ACS n = 6, cardiac-non-ACS n = 6, non-cardiac n = 28). LVLAS was comparable to fSENC for differentiation between healthy myocardium and myocardial dysfunction (GLS-fSENC AUC: 0.882; GCS-fSENC AUC: 0.899; LVLAS AUC: 0.771; GLS-FT AUC: 0.740; GCS-FT: 0.688), while FT-derived strain did not allow for differentiation between ACS and non-cardiac patients. There was significant variability between the three techniques. Intra- and inter-observer variability (OV) was excellent for fSENC and FT, while for LVLAS the agreement was lower and levels of variability higher (intra-OV: Pearson > 0.7, ICC > 0.8; inter-OV: Pearson > 0.65, ICC > 0.8; CoV > 25%).

CONCLUSIONS

While reproducibility was excellent for both FT and fSENC, it was only fSENC and the LVLAS which allowed for significant identification of myocardial dysfunction, even before LVEF, and therefore might be used as rapid supporting parameters for assessment of left-ventricular function.

Abstract P2104: Adeno-associated Virus Serotype 5 Is A Suitable Vector For S100a1-based Gene Therapy Of Post-ischemic Chronic Cardiac Dysfunction

Introduction: For S100A1-based heart failure gene therapies, AAV9 and 6 have shown efficacy in pre-clinical large animal studies. As AAV9 has shown concerning signs of toxicity in clinical studies and AAV6 displays poor production yields, there is need for a novel safe and cardiac-specific AAV serotype.

Hypothesis: We hypothesized that in a pig model the safety proven and scalably manufacturable AAV5 may be a suitable vector for S100A1-based gene therapy of post-ischemic cardiac dysfunction.

Methods: AAV production, 2h balloon-occlusion of the LCX, retrograde cardiac gene delivery, cardiac MRI, late gadolinium enhancement (LGE), global T1 relaxation, qPCR, RNA-Seq, WGCNA, KEGG, Reactome, LAD-ligation mouse model

Results: In a comparative study of AAV5-, 6- and 9-luciferase (luc) in healthy farm pigs (n=5 each; 1x10 13 vgc/pig), AAV5 achieved a more homogeneous cardiac apical-basal transduction pattern than AAV6 with a higher luc activity than AAV9. In a clinically relevant endpoint driven study, we demonstrated a significant improvement in EF (+19 ± 5 %) 12 weeks after retrograde AAV5- S100A1 gene delivery compared to AAV5-luc in infarcted pigs (n=4 each; 1x10 13 vgc/pig). Moreover, S100A1 -treated pigs showed significantly less infarct extension (-0.5 ± 0.3 g vs. 5 ± 1.3 g (luc)) measured by cardiac MRI. There were no unfavorable alterations in blood chemistry or ECG. S100A1 expression was predominantly contained to the heart. The WGCNA unveiled a significant correlation between the improved EF and a suppression of inflammatory and immunological pathways (r=-0.96, p < 0.01) and between the absent infarct extension and enhanced activity of cardioprotective signaling (r=-0.82, p < 0.05). With injections of 2х10 11 vgc of AAV5- S100A1 or AAV5-gfp (n=4 each) into the remote myocardium in the mouse model, we confirmed a significant improvement in FS (+43.8 ± 8.8 %, vs. gfp) and suppression of inflammatory gene expression including i.e., IL1b or TNFa by S100A1.

Conclusion: We conclude that AAV5 is suitable for S100A1-based gene therapy of post-ischemic cardiac dysfunction and that this vector/target combination can help accelerating the way towards a clinical trial. We also found novel signaling pathways that may be involved in S100A1’s therapeutic actions.

Dual-Layer Spectral CTA for TAVI Planning Using a Split-Phase Protocol and Low-keV Virtual Monoenergetic Images: Improved Image Quality in Comparison with Single-Phase Conventional CTA

PURPOSE

 Adaptation of computed tomography protocols for transcatheter aortic valve implantation (TAVI) planning is required when a first-generation dual-layer spectral CT scanner (DLCT) is used. The purpose of this study was to evaluate the objective image quality of aortic CT angiography (CTA) for TAVI planning using a split-phase technique with reconstruction of 40 keV virtual monoenergetic images (40 keV-VMI) obtained with a DLCT scanner. CT angiography obtained with a single-phase protocol of a conventional single-detector CT (SLCT) was used for comparison.

MATERIALS AND METHODS

 75 CTA scans from DLCT were retrospectively compared to 75 CTA scans from SLCT. For DLCT, spiral CTA without ECG-synchronization was performed immediately after a retrospectively ECG-gated acquisition covering the heart and aortic arch. For SLCT, spiral CTA with retrospective ECG-gating was performed to capture the heart and the access route simultaneously in one scan. Objective image quality was compared at different levels of the arterial access route.

RESULTS

 40 keV virtual monoenergetic images of DLCT showed a significantly higher mean vessel attenuation, SNR, and CNR at all levels of the arterial access route. With 40 keV-VMI of DLCT, the overall mean aortic attenuation of all six measured regions was 589.6 ± 243 HU compared to 492.7 ± 209 HU of SLCT (p < 0.01). A similar trend could be observed for SNR (23.6 ± 18 vs. 18.6 ± 9; p < 0.01) and CNR (21.1 ± 18 vs. 16.4 ± 8; p < 0.01). No deterioration was observed for vascular noise (27.8 ± 9 HU vs. 28.1 ± 8 HU; p = 0.599).

CONCLUSION

 Using a DLCT scanner with a split-phase protocol and 40 keV-VMI for TAVI planning, higher objective image quality can be obtained compared to a single-phase protocol of a conventional CT scanner.

KEY POINTS

  · Adaption of TAVI planning CT protocols may be required when using a first-generation dual-layer CT scanner.. · Reconstruction of virtual monoenergetic images at 40 keV improves image quality.. · With a split-phase protocol, the radiation dose is lower compared to a single-phase ECG-gated CT acquisition..

CITATION FORMAT

· Mangold D, Salatzki J, Riffel J et al. Dual-Layer Spectral CTA for TAVI Planning Using a Split-Phase Protocol and Low-keV Virtual Monoenergetic Images: Improved Image Quality in Comparison with Single-Phase Conventional CTA. Fortschr Röntgenstr 2022; DOI: 10.1055/a-1717-2542.

Dynamic Handgrip Exercise: Feasibility and Physiologic Stress Response of a Potential Needle-Free Cardiac Magnetic Resonance Stress Test

Background: Cardiac magnetic resonance (CMR) pharmacological stress-testing is a well-established technique for detecting myocardial ischemia. Although stressors and contrast agents seem relatively safe, contraindications and side effects must be considered. Substantial costs are further limiting its applicability. Dynamic handgrip exercise (DHE) may have the potential to address these shortcomings as a physiological stressor. We therefore evaluated the feasibility and physiologic stress response of DHE in relation to pharmacological dobutamine-stimulation within the context of CMR examinations.

Methods: Two groups were prospectively enrolled: (I) volunteers without relevant disease and (II) patients with known CAD referred for stress-testing. A both-handed, metronome-guided DHE was performed over 2 min continuously with 80 contractions/minute by all participants, whereas dobutamine stress-testing was only performed in group (II). Short axis strain by fast-Strain-ENCoded imaging was acquired at rest, immediately after DHE and during dobutamine infusion.

Results: Eighty middle-aged individuals (age 56 ± 17 years, 48 men) were enrolled. DHE triggered significant positive chronotropic (HR_rest: 68 ± 10 bpm, HR_DHE: 91 ± 13 bpm, p < 0.001) and inotropic stress response (GLS_rest: −19.4 ± 1.9%, GLS_DHE: −20.6 ± 2.1%, p < 0.001). Exercise-induced increase of longitudinal strain was present in healthy volunteers and patients with CAD to the same extent, but in general more pronounced in the midventricular and apical layers (p < 0.01). DHE was aborted by a minor portion (7%) due to peripheral fatigue. The inotropic effect of DHE appears to be non-inferior to intermediate dobutamine-stimulation (GLS_DHE= −19.5 ± 2.3%, GLS_Dob= −19.1 ± 3.1%, p = n.s.), whereas its chronotropic effect was superior (HR_DHE= 89 ± 14 bpm, HR_Dob= 78 ± 15 bpm, p < 0.001).

Conclusions: DHE causes positive ino- and chronotropic effects superior to intermediate dobutamine-stimulation, suggesting a relevant increase of myocardial oxygen demand. DHE appears to be safe and timesaving with broad applicability. The data encourages further studies to determine its potential to detect obstructive CAD.

The diagnostic accuracy of truncated cardiovascular MR protocols for detecting non-ischemic cardiomyopathies

Cardiovascular magnetic resonance imaging is one of the most important diagnostic modalities in the evaluation of cardiomyopathies. However, significant limitations are the complex and time-consuming workflows and the need of contrast agents. The aim of this multi-center retrospective study was to assess workflows and diagnostic value of a short, contrast agent-free cardiac magnetic resonance protocol. 160 patients from Heidelberg, Germany and 119 patients from Montreal, Canada with suspected cardiomyopathy and 20 healthy volunteers have been enrolled. Scans were performed at a 1.5Tesla or 3Tesla scanner in Heidelberg and at a 3Tesla scanner in Montreal. We used single-slice T1 map only. A stepwise analysis of images has been performed. The possible differential diagnosis after each step has been defined. T1-values and color-encoded T1 maps significantly contributed to the differential diagnosis in 54% of the cases (161/299); the final diagnosis has been done without late gadolinium enhancement images in 83% of healthy individuals, in 99% of patients with dilated cardiomyopathy, in 93% of amyloidosis patients, in 94% of patients with hypertrophic cardiomyopathy and in 85% of patients with hypertensive heart disease, respectively. Comparing the scan time with (48 ± 7 min) vs. without contrast agent (23 ± 5 min), significant time saving could be reached by the short protocol. Subgroup analysis showed the most additional diagnostic value of T1 maps in amyloidosis and hypertrophic cardiomyopathy or in confirmation of normal findings. In patients with unclear left ventricular hypertrophy, a short, non-contrast protocol can be used for diagnostic decision-making, if the quality of the T1 map is diagnostic, even if only one slice is available.

Presence of dysfunction and myocardial remodeling in patients with premature ventricular complex-induced cardiomyopathy - a cardiovascular MR study

Funding Acknowledgements

Type of funding sources: None.

Background

Premature ventricular complexes (PVCs) in the absence of underlying structural heart disease are considered to be benign. However, cardiac dysfunction has been observed in patients with a high PVC burden. The characterization of a PVC-induced cardiomyopathy with structural remodeling including myocardial fibrosis and the determination of a specific PVC burden leading to subclinical cardiac dysfunction remains to be determined.

Objectives

We aimed to evaluate cardiac function, remodeling and myocardial fibrosis patterns in patients with PVCs using cardiac magnetic resonance imaging (CMR). Additionally, we aimed to determine a PVC cut-off value leading to subclinical cardiac dysfunction.

Methods

Patients who underwent CMR and 24-hour, 12-lead ECG monitoring (Holter ECG) within six months were retrospectively studied. Patients with evidence of structural heart disease were excluded. The cohort was subdivided based on the number of PVCs in Holter ECG; Group-1 = 0-100, Group-2 = 100-5000 and Group-3 &gt; 5000 PVCs. CMR parameters were extracted from our local databank. Myocardial strain was measured using feature tracking. For quantification of myocardial fibrosis, T1 mapping and late gadolinium enhancement (LGE) were investigated. Z-scores were calculated in order to combine T1 values from a 1.5 and 3Tesla CMR vendor.

Results

443 patients (52 ± 20 years, 45% females) were included in the study. Compared to Group-1, Group-3 revealed a significantly reduced LV-EF, an increased indexed LV-EDV and increased indexed LV-ESV, indicating cardiac dysfunction and LV enlargement. PVCs frequency was inversely correlated with LV-EF (r=-0.23, p &lt; 0.001) and positively correlated with indexed LV-EDV (r = 0.13; p &lt; 0.01). Feature tracking showed significantly higher global circumferential strain (GCS) indicating subclinical dysfunction. Global T1 times were significantly prolonged in Group-3. Elevated global T1 Z-scores were found in Group-2 and Group-3 compared to Group-1. Significantly more intramural LGE was present in Group-2. The PVC cut-off value characterized by reduced GCS was defined by 216 PVCs (AUC = 0.61, p = 0.02). 

Conclusion

CMR revealed cardiac dysfunction, left ventricular enlargement and diffuse myocardial fibrosis in patients with PVC in the absence of structural heart disease. These changes indicate the development of a PVC-induced cardiomyopathy depending on the PVC burden. Interestingly, subclinical myocardial dysfunction was determined at already low PVC frequencies. Further investigations are necessary in order to examine the influence of different origins of PVCs and the development of structural remodeling.

The impact of Wilson disease on myocardial tissue and function: a cardiovascular magnetic resonance study

BACKGROUND

Systemic effects of altered serum copper processing in Wilson Disease (WD) might induce myocardial copper deposition and consequently myocardial dysfunction and structural remodeling. This study sought to investigate the prevalence, manifestation and predictors of myocardial tissue abnormalities in WD patients.

METHODS

We prospectively enrolled WD patients and an age-matched group of healthy individuals. We applied cardiovascular magnetic resonance (CMR) to analyze myocardial function, strain, and tissue characteristics. A subgroup analysis of WD patients with predominant neurological (WD-neuro+) or hepatic manifestation only (WD-neuro-) was performed.

RESULTS

Seventy-six patients (37 years (27-49), 47% women) with known WD and 76 age-matched healthy control subjects were studied. The prevalence of atrial fibrillation in WD patients was 5% and the prevalence of symptomatic heart failure was 2.6%. Compared to healthy controls, patients with WD had a reduced left ventricular global circumferential strain (LV-GCS), and also showed abnormalities consistent with global and regional myocardial fibrosis. WD-neuro+ patients presented with more severe structural remodeling and functional impairment when compared to WD-neuro- patients.

CONCLUSIONS

In a large cohort, WD was not linked to a distinct cardiac phenotype except CMR indexes of myocardial fibrosis. More research is warranted to assess the prognostic implications of these findings.

TRIAL REGISTRATION

This trial is registered at the local institutional ethics committee (S-188/2018).

Feasibility of fast cardiovascular magnetic resonance strain imaging in patients presenting with acute chest pain

Background

Cardiovascular magnetic resonance (CMR) is the current reference standard for the quantitative assessment of ventricular function. Fast Strain-ENCoded (fSENC)-CMR imaging allows for the assessment of myocardial deformation within a single heartbeat. The aim of this pilot study was to identify obstructive coronary artery disease (oCAD) with fSENC-CMR in patients presenting with new onset of chest pain.

Methods and results

In 108 patients presenting with acute chest pain, we performed fSENC-CMR after initial clinical assessment in the emergency department. The final clinical diagnosis, for which cardiology-trained physicians used clinical information, serial high-sensitive Troponin T (hscTnT) values and—if necessary—further diagnostic tests, served as the standard of truth. oCAD was defined as flow-limiting CAD as confirmed by coronary angiography with typical angina or hscTnT dynamics. Diagnoses were divided into three groups: 0: non-cardiac, 1: oCAD, 2: cardiac, non-oCAD. The visual analysis of fSENC bull´s eye maps (blinded to final diagnosis) resulted in a sensitivity of 82% and specificity of 87%, as well as a negative predictive value of 96% for identification of oCAD. Both, global circumferential strain (GCS) and global longitudinal strain (GLS) accurately identified oCAD (area under the curve/AUC: GCS 0.867; GLS 0.874; p<0.0001 for both), outperforming ECG, hscTnT dynamics and EF. Furthermore, the fSENC analysis on a segmental basis revealed that the number of segments with impaired strain was significantly associated with the patient´s final diagnosis (p<0.05 for all comparisons).

Conclusion

In patients with acute chest pain, myocardial strain imaging with fSENC-CMR may serve as a fast and accurate diagnostic tool for ruling out obstructive coronary artery disease.

Hyperventilation/Breath-Hold Maneuver to Detect Myocardial Ischemia by Strain-Encoded CMR: Diagnostic Accuracy of a Needle-Free Stress Protocol

OBJECTIVES

The purpose of this study was to evaluate the diagnostic accuracy of a fast, needle-free test for myocardial ischemia using fast Strain-ENCoded (fSENC) cardiovascular MR (CMR) after a hyperventilation/breath-hold maneuver (HVBH).

BACKGROUND

Myocardial stress testing is one of the most frequent diagnostic tests performed. Recent data indicate that CMR first-pass perfusion outperforms other modalities. Its use, however, is limited by the need for both, a vasodilatory stress and the intravenous application of gadolinium. Both are associated with added cost, safety concerns, and patient inconvenience. The combination of 2 novel CMR approaches, fSENC, an ultrafast technique to visualize myocardial strain, and HVBH, a physiological vasodilator, may overcome these limitations.

METHODS

Patients referred for CMR stress testing underwent an extended protocol to evaluate 3 different tests: 1) adenosine-perfusion; 2) adenosine-strain; and 3) HVBH-strain. Diagnostic accuracy was assessed using quantitative coronary angiography as reference.

RESULTS

A total of 122 patients (age 66 ± 11years; 80% men) suspected of obstructive coronary artery disease were enrolled. All participants completed the protocol without significant adverse events. Adenosine-strain and HVBH-strain provided significantly better diagnostic accuracy than adenosine-perfusion, both on a patient level (adenosine-strain: sensitivity 82%, specificity 83%; HVBH-strain: sensitivity 81%, specificity 86% vs. adenosine-perfusion: sensitivity 67%, specificity 92%; p < 0.05) and territory level (adenosine-strain: sensitivity 67%, specificity 93%; HVBH-strain: sensitivity 63%, specificity 95% vs. adenosine-perfusion: sensitivity 49%, specificity 96%; p < 0.05). However, these differences in diagnostic accuracy disappear by excluding patients with history of coronary artery bypass graft or previous myocardial infarction. The response of longitudinal strain differs significantly between ischemic and nonischemic segments to adenosine (ΔLS_ischemic = 0.6 ± 5.4%, ΔLS_nonischemic = -0.9 ± 2.7%; p < 0.05) and HVBH (ΔLS_ischemic = 1.3% ± 3.8%, ΔLS_nonischemic = -0.3 ± 1.8%; p = 0.002). Test duration of HVBH-strain (t = 64 ± 2 s) was significantly shorter compared with adenosine-strain (t = 184 ± 59 s; p < 0.0001) and adenosine-perfusion (t = adenosine-perfusion: 172 ± 59 s; p < 0.0001).

CONCLUSIONS

HVBH-strain has a high diagnostic accuracy in detecting significant coronary artery stenosis. It is not only significantly faster than any other method but also neither requires contrast agents nor pharmacological stressors.

Presence of contractile impairment appears crucial for structural remodeling in idiopathic left bundle-branch block

BACKGROUND

To differentiate effects of ventricular asynchrony from an underlying hypocontractile cardiomyopathy this study aimed to enhance the understanding of functional impairment and structural remodeling in idiopathic left bundle-branch block (LBBB). We hypothesize, that functional asynchrony with septal flash volume effects alone might not entirely explain the degree of functional impairment. Hence, we suggest the presence of a superimposed contractile cardiomyopathy.

METHODS

In this retrospective study, 53 patients with idiopathic LBBB were identified and matched to controls with and without cardiovascular risk factors. Cardiovascular magnetic resonance (CMR) was used to evaluate cardiac function, volumes and myocardial fibrosis using native T1 mapping and late gadolinium enhancement (LGE). Septal flash volume was assessed by CMR volumetric measurements and allowed to stratify patients with systolic dysfunction solely due to isolated ventricular asynchrony or superimposed contractile impairment.

RESULTS

Reduced systolic LV-function, increased LV-volumes and septal myocardial fibrosis were found in patients with idiopathic LBBB compared to healthy controls. LV-volumes increased and systolic LV-function declined with prolonged QRS duration. Fibrosis was typically located at the right ventricular insertion points. Subgroups with superimposed contractile impairment appeared with pronounced LV dilation and increased fibrotic remodeling compared to individuals with isolated ventricular asynchrony.

CONCLUSIONS

The presence of superimposed contractile impairment in idiopathic LBBB is crucial to identify patients with enhanced structural remodeling. This finding suggests an underlying cardiomyopathy. Future studies are needed to assess a possible prognostic impact of this entity and the development of heart failure.

TRIAL REGISTRATION

This study was retrospectively registered.

Hyperventilation-breath-hold maneuver to detect ischemia by strain-encoded CMR: a pilot study to evaluate a needle-free stress protocol

Funding Acknowledgements

Type of funding sources: None.

Background

Safety concerns for gadolinium-containing contrast agents and pharmacological stressors, together with tremendous costs and inconsistent reimbursement modalities are still limiting a widespread application of CMR stress testing despite proven benefits. Like the effect of adenosine, hyperventilation-breath-hold-maneuver (HVBH) has demonstrated to induce myocardial vasodilation and might serve as a stressor to induce coronary steal with consecutive hypokinesia. 

Purpose

To evaluate the diagnostic accuracy of a needle-free, ultrafast stress test to detect myocardial ischemia by strain-encoded CMR (fSENC) after HVBH.

Methods

Patients referred for CMR stress testing underwent an extended protocol in order to evaluate three different stress forms: (1) Adenosine first-pass perfusion (Ad-FPP), (2) Adenosine-fSENC (Ad-fSENC) and (3) HVBH-fSENC. Diagnostic accuracy was assessed using quantitative coronary angiography as reference. 

Results

One-hundred-twenty-two predominantly male patients (age 66 ± 11years; 80% men) suspected for obstructive CAD were enrolled. Ad-fSENC and HVBH-fSENC provided significantly better diagnostic accuracy than Ad-FPP, both on a patient-level (Ad-fSENC: sensitivity 82%[65-93], specificity 83%[73-90], p &lt; 0.05; HVBH-fSENC: sensitivity 81%[64-93], specificity 86%[77-93], p &lt; 0.05) and territory-level (Ad-fSENC: sensitivity 67%[52-80], specificity 93%[90-96], p &lt; 0.05; HVBH-fSENC: sensitivity 63%[47-76], specificity 95%[91-97], p &lt; 0.05). The stress response of longitudinal strain differs significantly between ischemic and non-ischemic segments to Adenosine (LSischemic = 0.6 ± 5.4%, LSnon-ischemic = 0.9 ± 2.7%, p &lt; 0.05) and HVBH (LSischemic = 1.3 ± 3.8%, LSnon-ischemic=-0.3 ± 1.8%, p = 0.002). Stress test duration of HVBH-fSENC (t = 64 ± 2s) was significantly shortened compared to Ad-fSENC (t = 184 ± 59s, p &lt; 0.0001) or Ad-FPP (t = Ad-FPP: 172 ± 59s, p &lt; 0.0001). 

Conclusions

Stress testing by HVBH-fSENC provides promising diagnostic accuracy to detect myocardial ischemia and is faster than established methods without the necessity to apply contrast agent or pharmacological stressors.

Contrast-agent free evaluation of cardiomyopathies with T1 mapping and the new fast strain-encoded (fSENC) magnetic resonance imaging

Background

Cardiomyopathies (CMP) may cause impairment of cardiac function and structure. Cardiac Magnetic Resonance Imaging (CMR) is used for analysis and risk stratification of CMP by Late Gadolinium Enhancement (LGE). However, T1 mapping (T1) and fast strain encoded (f-SENC) sequences allow contrast-free and faster exams. The aim of this study was to characterize CMP by T1 and f-SENC to develop a faster and safer CMR protocol (fast-CMR).

Methods

CMP scans from our CMR database were retrospectively analyzed. All patients were scanned at 1.5T/3T scanner. Study groups were divided as follows: Patients with normal findings, dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), hypertensive heart disease (HHD) and cardiac amyloidosis. Global T1 times, longitudinal (GLS) and circumferential (GCS) strain using f-SENC of study groups were compared to healthy individuals (controls). Scan time and amount of gadolinium-based contrast agent (CA) in CMR-protocol with LGE were compared to fast-CMR.

Results

174 patients and 31 controls were recruited. T1 times, GLS and GCS were similar between controls and normal individuals. T1 times were significantly increased (p&lt;0.05), while GLS and GCS were significantly reduced (p&lt;0.05) in all CMR study groups compared to controls (Table 1). Using fast-CMR 21 (±6) min of scan time were saved, about 47%, and 9 (±2) ml of CA were saved per patient.

Conclusion

Normal findings could be identified by fast-CMR without contrast agent. Fast CMR might also be a useful tool to identify different forms of CMP.

Funding Acknowledgement

Type of funding source: None

Spatial relationship between the pulmonary trunk and the left coronaries: Systematic risk assessment based on automated three-dimensional distance measurements

Background

Catheter ablation of right ventricular outflow tract ventricular arrhythmias from above the pulmonary valve is being increasingly reported.

Objective

The purpose of this study was to systematically analyze the spatial relationship between the pulmonary trunk and the left coronaries.

Methods

Contrast-enhanced computed tomographic scans from 58 patients were analyzed. After segmentation of the pulmonary trunk and the proximal left coronaries, 3-dimensional geometries were generated. Minimal distance between the pulmonary trunk and the coronaries was automatically determined using a newly developed mathematical algorithm.

Results

The minimal distance between the pulmonary trunk and the coronaries was 1.4 ± 0.11 mm. Closest relationship was detected 13.8 ± 0.87 mm above the pulmonary valve annulus. Considering a safety margin of 5 mm to render coronary damage unlikely, 84% of patients were found to be at potential risk within the bottom 10 mm of the left sinus cusp. In contrast, positions within or above the right and anterior cusps were less likely to exhibit a close relationship. We identified the anterior aspect of the left cusp as the most critical region. Positions 10–20 mm above the left cusp were found to be critical in 97% of patients. Clinical parameters such as gender, age, height, weight, and body mass index were not predictive of a close spatial relationship.

Conclusion

Our data provide evidence for a close spatial relationship between the pulmonary trunk and coronary arteries. These results should be considered when performing catheter ablation from above the pulmonary valve.

P5259Evaluation of functional impairment and cardiac remodelling in isolated left branch bundle block using magnetic resonance imaging

Introduction

Left bundle-branch block (LBBB) is associated with underlying cardiovascular abnormalities, such as dilated cardiomyopathy and coronary heart disease. However, an isolated LBBB can be found in individuals without detectable cardiovascular disease. Echocardiographic studies demonstrated a reduced left ventricular (LV) ejection fraction (EF) and an increased LV cavity volume and mass in patients with isolated LBBB. Recent studies have shown larger cavity volumes (end-diastolic volume – EDV; end-systolic volume – ESV) and lower LVEF using CMR. However, there is still limited data on cardiac function, volumes and mass and the correlation between the parameters and the QRS duration (QRS) in patients with isolated LBBB.

Purpose

In this retrospective study LV function, volume, mass, T1-values and myocardial strain were measured and correlation between QRS duration in patients with isolated LBBB was identified using CMR.

Methods

Potential cases were identified from our local database, who underwent CMR during 2015–2018. We excluded patients with echocardiographic abnormalities besides abnormal septal motion or greater than a mild valve disease, known cardiovascular disease (coronary artery disease, cardiomyopathy or arrhythmia), history of potential cardiotoxic chemotherapy. We could identify 26 adults, who underwent CMR in a 1.5- or 3-Tesla scanner. LBBB was confirmed by ECG prior to CMR by a cardiologist. T1-values (MOLLI) were available in 19 patients. Myocardial strain (tissue tracking) could be performed in 23 patients. Associations were tested using Pearson's correlation analysis.

Results

26 patients (age 61.5±9.6 years, 19 women, BMI 25.4 (18.2–38.1)) with isolated LBBB were included (QRS duration: 138±12ms). CMR results in the cohort revealed a reduced LVEF (53.4±3,8%) and slightly enlarged LV cavity when corrected to body-surface area (BSA) (LV-EDV/BSA: 83.7±13.8ml/m2; LV-ESV/BSA: 39.3±8.6ml/m2), when compared to normal values from the study center. There is a negative correlation between LVEF and QRS duration (r=−0.550, p<0.05) and a positive correlation between QRS duration and LV-EDV/BSA (r=0.627, p<0.05) as well as between QRS and LV-ESV/BSA (r=0.661, p<0.05). In addition, there is a positive correlation between QRS duration and myocardial mass (r=0.645, p<0.05), septal myocardial thickness (r=0.405, p<0.05) and lateral wall thickness (r=0.495, p<0.05). In addition, there is a positive correlation between LV longitudinal strain and QRS (r=0.449, p<0.05). T1-values were in normal range. There is no correlation between QRS and T1-values.

Conclusion

Using CMR a negative correlation between LV function and QRS duration and the positive correlation between LV volumes and QRS duration in patients with isolated LBBB could be identified. The absence of significant myocardial fibrosis with normal T1-values indicates an electromechanical dissociation rather than an underlying myocardial abnormality as an explanation for the reduced LVEF.

P5267Cardiac tissue characterization in patients with wilsons disease using magnetic resonance imaging

Introduction

Wilson's disease (WD) is a rare autosomal recessive copper disorder with limited excretion of excess copper into the bile. Primary symptoms are hepatic or neurological. However, the clinical range of WD is wide and can result in cardiac symptoms as well. Previous studies revealed a higher incidence of heart failure in WD patients compared to the rest of the population.

Purpose

Cardiac magnetic resonance imaging (CMR) is used to identify the typical features of several systemic disorders with excessive myocardial deposition of substrates. The aim of this study was to perform a cardiac tissue characterization in WD patients by using CMR and to identify subgroups of WD patients with reduced ejection fraction (EF).

Methods

Patients with known WD using Ferenci-Score were included in this prospective study. WD patients were referred to 1.5 Tesla CMR. The following CMR protocol was performed; Cine-images, T1-, T2- and T2*-Mapping, fast-SENC strain and late gadolinium enhancement (LGE). Fast-SENC strain measurements were compared with values from healthy individuals scanned at the center.

Results

43 patients (age 38.7±12.8 years, 20 female, BMI 23.80 (17.4–33.1)) with WD could be identified and were evaluated with CMR. CMR revealed normal left ventricular (LV) EF (62.4±5.4%) and right ventricular (RV) EF (64.4±7.1%) overall. However, three patients (7%), who suffered primarily from neurological symptoms, were found to have mildly reduced LV-EF (46.5%, 51%, and 53.5%). Strain analysis revealed significantly reduced LV global circumferential strain (GCS) overall compared to healthy individuals (WD (%): −19.2 2.7; control (%): −20.71±1.5, p<0.05). Patients with primarily hepatic symptoms (WD-h) did not show reduced strain measurements compared to the control group. Patients suffering from primarily neurological symptoms (WD-n) showed significantly reduced LV GCS compared to healthy individuals (WD-n (%): −18.3±3.1; control (%): −20.7±1.5, p<0.05) and RV GCS (WD-n (%): −17.5±3.0; control (%): −19.2±1.8, p<0.05). Also, LV GCS in WD-n was significantly reduced compared to WD-h (WD-n (%): −18.3±3.1; WD-h (%): −20.0±2.0). Furthermore, there were no significant differences between the two subgroups, besides a significant thicker lateral wall in patients with WD-n (WD-n (mm): 7 (5–9); WD-h (mm): 6 (5–8), p<0.05). T1-, T2- and T2*-Mapping did not show any pathological pattern and were overall in the normal range (T1: 1020±30ms; T2: 52.9±3.0ms; T2*: 38.4±5.6ms). Epicardial LGE was present in 1 patient.

Conclusion

Cardiac tissue characterization was performed in WD patients using CMR. Reduced EF, LV and RV GCS have been detected in patients with primarily neurological symptoms. Cardiovascular autonomic dysfunction in this subgroup could be a reason for the reduced biventricular strain. It is unknown if reduced circumferential strain influences the prognosis of WD patients, which should be investigated in further studies.

P2718Interim study: analysis of myocardial deformation using fSENC-CMR on patients with chest pain

Background

In acute situations such as non-ST-elevation infarction (NSTEMI) or relevant coronary artery disease (CAD) CMR does not yet play a key role due to its lengthy protocols. fSENC is a new CMR technique which may detect subclinical signs of myocardial damage by measuring myocardial strain (change in length/ unit length). A whole-heart coverage is generated in 6 heart-beats and the information obtained is converted into a colour-coded map. fSENC does not require major post-processing, long breath-holds and the administration of contrast agents/medication.

Purpose

In this observational study fSENC is assessed in patients with chest pain and its capability to differentiate between an ischemic cause (NSTEMI, significant CAD), an underlying non-ischemic cardiac disease and non-cardiac chest pain. Additionally, we aim to identify the affected coronary arteries in the ischemic cohort. With fSENC it could be possible to successfully diagnose patients with suspected AMI in <1h after admission and also gain diagnostic information regarding the underlying pathology.

Methods

Patients with chest pain and an initial hscTnT level between 5pg/ml and 52 pg/ml are recruited. These patients then undergo an fSENC-CMR before 2nd hscTnT measurement. Additionally, a stress-induced fSENC-image is acquired (1-minute hyperventilation, followed by a single breath-hold). This breathing manoeuvre leads to an increase in oxygenation through vasodilation, therefore identifying ischemic areas. The fSENC analysis is later compared to the patient's final diagnosis and therapy.

Results

So far 50 patients have been analysed by fSENC in this observational study (26 female, aged 57±18). fSENC correctly identified 7 patients suffering from NSTEMI or significant CAD and their affected coronary arteries. 42 other patients were safely ruled-out by fSENC which was consistent with the serial hscTnT results. In 11 patients fSENC was able to detect generalized impaired myocardial deformation, implying an underlying cardiac disease (hypertrophic cardiomyopathy, myocarditis). fSENC currently exhibits a sensitivity of 100% and specificity of 97,7% for correct rule-in/-out of an ischemic cause.

Conclusions

At this stage fSENC allows correct identification of patients suffering from myocardial infarction and their affected coronary arteries. Additionally, fSENC can safely rule-out patients with chest pain but no underlying ischemic cause. This novel technique is a rapid additional diagnostic tool which assesses myocardial function non-invasively without radiation exposure.

Factors influencing return for maintenance treatment with percutaneous tibial nerve stimulation for the management of the overactive bladder

OBJECTIVES

To identify factors influencing return for maintenance percutaneous tibial nerve stimulation (PTNS) treatment after successful completion of a 12-week course of treatment for overactive bladder (OAB).

PATIENTS AND METHODS

Patients with OAB symptoms referred for PTNS treatment underwent 12 sessions of weekly PTNS treatment and were evaluated at baseline and week 12 using the International Consultation on Incontinence Questionnaire on OAB, the International Consultation on Incontinence Questionnaire on lower urinary tract symptom-related quality of life (ICIQ-LUTSqol) and a bladder diary (BD). Responders to treatment, evaluated using two patient-reported outcome measures, were invited to return for maintenance treatment when symptoms returned. A PTNS Service Evaluation Questionnaire was used to evaluate factors influencing return for maintenance treatment.

RESULTS

Seventy-three patients were evaluated (mean age 58.9 [±14.7] years, 72.6% women) and clustered into three groups: group 1 (n = 25) did not respond to 12 weekly sessions of PTNS treatment; group 2 (n = 17) responded to treatment but did not return for maintenance treatment and group 3 (n = 31) responded to treatment and returned for maintenance treatment. There were no significant differences in demographic characteristics, diagnosis, baseline symptom scores and BD variables among the three groups. Patients belonging to groups 2 and 3 experienced a significant improvement from baseline to week 12 in total OAB scores (group 2: -1.54 ± 1.85; group 3: -1.85 ± 2.28; P < 0.05); however, patients returning for maintenance treatment reported significant improvements specifically in nocturia (BD difference = -0.4 ± 0.7 [P < 0.05] and ICIQ-LUTSqol difference -0.48 ± 0.94 [P < 0.05]), and perceived benefits of the treatment with regard to their OAB symptoms compared to those not returning for maintenance treatment (difference between the two groups 25.6%; P = 0.030). Improvements in nocturia and perceived benefits predicted return for maintenance treatment based on a logistic regression analysis. Factors related to the need for repeat clinic visits, such as transportation, distance and time commitment, were not found to differ between the two groups.

CONCLUSIONS

Twelve-session weekly PTNS is a safe and effective treatment for OAB. Responders to treatment returning for maintenance PTNS more often reported significant improvements in nocturia and perceived benefits over time, compared to those not returning for maintenance treatment. The BD provides a more objective assessment of treatment outcome after PTNS treatment.

Adipose Tissue Lipolysis Promotes Exercise-induced Cardiac Hypertrophy Involving the Lipokine C16:1n7-Palmitoleate

Endurance exercise training induces substantial adaptive cardiac modifications such as left ventricular hypertrophy (LVH). Simultaneously to the development of LVH, adipose tissue (AT) lipolysis becomes elevated upon endurance training to cope with enhanced energy demands. In this study, we investigated the impact of adipose tissue lipolysis on the development of exercise-induced cardiac hypertrophy. Mice deficient for adipose triglyceride lipase (Atgl) in AT (atATGL-KO) were challenged with chronic treadmill running. Exercise-induced AT lipolytic activity was significantly reduced in atATGL-KO mice accompanied by the absence of a plasma fatty acid (FA) increase. These processes were directly associated with a prominent attenuation of myocardial FA uptake in atATGL-KO and a significant reduction of the cardiac hypertrophic response to exercise. FA serum profiling revealed palmitoleic acid (C16:1n7) as a new molecular co-mediator of exercise-induced cardiac hypertrophy by inducing nonproliferative cardiomyocyte growth. In parallel, serum FA analysis and echocardiography were performed in 25 endurance athletes. In consonance, the serum C16:1n7 palmitoleate level exhibited a significantly positive correlation with diastolic interventricular septum thickness in those athletes. No correlation existed between linoleic acid (18:2n6) and diastolic interventricular septum thickness. Collectively, our data provide the first evidence that adipose tissue lipolysis directly promotes the development of exercise-induced cardiac hypertrophy involving the lipokine C16:1n7 palmitoleate as a molecular co-mediator. The identification of a lipokine involved in physiological cardiac growth may help to develop future lipid-based therapies for pathological LVH or heart failure.

Abstract 213: Fat Tissue specific Adipose Triglyceride Lipase as a major determinant for the development of pressure overload-induced heart failure

Introduction: Myocardial metabolism undergoes change in response to pathological cardiac hypertrophy (PH), characterized by increased reliance on glucose oxidation, decreased free fatty acid (FFA) oxidation and a loss of metabolic flexibility. Cardiac metabolism is influenced by other organs such as adipose tissue. Hence, we aimed to investigate the effect of Adipose Triglyceride Lipase (ATGL) in adipose tissue on the development of PH and heart failure (HF) in a pressure overload-induced cardiac hypertrophy model in mice.

Methods: Male adipose tissue specific ATGL-knock out (atATGL-KO) and wild type mice (WT) underwent sham surgery (sham) or transverse aortic constriction (TAC). After 11 weeks, mice were sacrificed and organs were harvested.

We performed echocardiography one week before and 11 weeks after surgery. Left ventricular mass (LVM), left ventricular mass/tibia length (LVM/TL) and ejection fraction (EF) were calculated. Beta-myosin heavy chain (β-MyHC) was measured in RNA of hearts. Insulin resistance was assessed by an intraperitoneal glucose tolerance test (GTT) and an insulin tolerance test (ITT). FFAs were measured in serum in total.

Results: LVM and LVM/TL in WT was significantly higher compared to atATGL-KO after TAC (LVM/TL [mg/mm] WT-TAC: 18,0±2,2; atATGL-KO-TAC: 13,1±2,3; p<0,01). The higher increase of LVM in WT was associated with a larger left ventricle internal diameter. Reduction of EF was significantly more pronounced in WT compared to atATGL-KO ([%] WT: 28,81±6,9 atATGL-KO: 42,39±4,5; p<0,01).

Beta-MyHC, a marker for PH, was markedly higher in WT-TAC than in atATGL-KO-TAC (WT-TAC: 11,3±3,6; atATGL-KO-TAC: 1.9±0,6; p<0,01).

While WT-TAC showed higher Serum FFA-levels than atATGL-KO-TAC ([mmol/l] WT-TAC: 0,97±0,086; atATGL-KO-TAC: 0,49±0,032; p<0,001), GTT and ITT revealed a higher insulin sensitivity in atATGL-KO-TAC compared to WT-TAC.

Conclusion: The present study demonstrates that atATGL is a crucial determinant for the development of pressure overload-induced PH and HI. The lack of ATGL in adipose tissue, the associated reduction of fatty acid release in the circulation and subsequent switches in cardiac energy substrates from free fatty acids to glucose are potential underlying mechanisms of this process.

Abstract 007: Effects Of Finerenone - A Novel Non-steroidal Mineralocorticoid Receptor Antagonist In A Model Of Pressure Overload-induced Cardiac Hypertrophy

Activation of mineralocorticoid receptors (MR) by its agonist aldosterone induces several unwanted processes like inflammation, fibrosis, increase of blood pressure and ventricular hypertrophy. Inversely, the blockade of MR is known as a highly efficacious therapy in chronic heart failure and arterial hypertension. Therapy with currently approved MR antagonists is often limited due to side effects. Recently, new highly selective, non-steroidal aldosterone antagonists such as finerenone have been developed.

To investigate the effects of finerenone on progressive cardiac hypertrophy the transverse aortic constriction (TAC) model was used. C57BL/6 male mice underwent a TAC-operation and were treated daily by oral gavage with finerenone (fin; 10 mg/kg/d), eplerenone (200 mg/kg/d) or vehicle (veh). The treatment started one week before the TAC-operation, and was continued 4 weeks postoperative. To examine the efficacy of finerenone on myocardial wall thickening echocardiography was performed one week before and 4 weeks after TAC and left ventricular mass (LVM) was calculated. Furthermore, gene expression analysis in heart and kidney were carried out to investigate molecular mechanisms.

TAC-operated mice treated with finerenone showed a significant lower LVM relative to body weight compared with vehicle-treated mice (fin: 3.89 mg/g; veh: 4.32 mg/g; p<0.05). Also the percentage increase of LVM four weeks after TAC was significantly lower in finerenone-treated animals than in vehicle-treated mice (fin: +37.16 %, veh: +52.9 %, p<0.05). Furthermore, markers of pathological hypertrophy like atrial natriuretic factor (ANF) and β-myosin heavy chain (β-MyHC) were measured in the left ventricle, and showed a higher expression in vehicle-treated than finerenone-treated animals. Treatment with eplerenone did not significantly reduce cardiac hypertrophy after 4 weeks post TAC.

In conclusion, these data show for the first time beneficial effects of the new non-steroidal MR-antagonist finerenone on LVM development in a TAC-model. The distinct actions of finerenone when compared to eplerenone may result from different MR-blocking properties.