Normal Cardiovascular Magnetic Resonance Research Articles

Prognostic impact of artificial intelligence-based fully automated global circumferential strain in patients undergoing stress CMR

To determine whether fully automated artificial intelligence-based global circumferential strain (GCS) assessed during vasodilator stress cardiovascular magnetic resonance (CMR) can provide incremental prognostic value. Between 2016 and 2018, a longitudinal study included all consecutive patients with abnormal stress CMR defined by the presence of inducible ischaemia and/or late gadolinium enhancement (LGE). Control subjects with normal stress CMR were selected using a propensity score-matching. Stress-GCS was assessed using a fully automatic machine learning algorithm based on featured-tracking imaging from short-axis cine images. The primary outcome was the occurrence of major adverse clinical events (MACE) defined as cardiovascular mortality or nonfatal myocardial infarction. Cox regressions evaluated the association between stress-GCS and the primary outcome after adjustment for traditional prognosticators. In 2670 patients [65 ± 12 years, 68% men, 1:1 matched patients (1335 with normal and 1335 with abnormal CMR)], stress-GCS was associated with MACE [median follow-up 5.2 (4.8–5.5) years] after adjustment for risk factors in the propensity-matched population (adjusted hazard ratio [HR]: 1.12 [95% CI: 1.06–1.18]) and patients with normal CMR (HR: 1.43 [95% CI: 1.30–1.57], both P < 0.001), but not in patients with abnormal CMR (P = 0.33). In patients with normal CMR, an increased stress-GCS > −10% showed the best improvement in model discrimination and reclassification above traditional and stress CMR findings (C-statistic improvement: 0.27; NRI = 0.538; IDI = 0.108, all P < 0.001; LR-test P < 0.001). Stress-GCS is independently associated with MACE in patients undergoing stress CMR, with an incremental prognostic value over traditional risk factors and stress CMR findings in the group of patients with normal CMR. Prognostic value of AI-based Stress-GCS (Fig. 1).

Prognostic impact of artificial intelligence-based fully automated global circumferential strain in patients undergoing stress CMR.

To determine whether fully automated artificial intelligence-based global circumferential strain (GCS) assessed during vasodilator stress cardiovascular (CV) magnetic resonance (CMR) can provide incremental prognostic value. Between 2016 and 2018, a longitudinal study included all consecutive patients with abnormal stress CMR defined by the presence of inducible ischaemia and/or late gadolinium enhancement. Control subjects with normal stress CMR were selected using a propensity score-matching. Stress-GCS was assessed using a fully automatic machine-learning algorithm based on featured-tracking imaging from short-axis cine images. The primary outcome was the occurrence of major adverse clinical events (MACE) defined as CV mortality or nonfatal myocardial infarction. Cox regressions evaluated the association between stress-GCS and the primary outcome after adjustment for traditional prognosticators. In 2152 patients [66 ± 12 years, 77% men, 1:1 matched patients (1076 with normal and 1076 with abnormal CMR)], stress-GCS was associated with MACE [median follow-up 5.2 (4.8-5.5) years] after adjustment for risk factors in the propensity-matched population [adjusted hazard ratio (HR), 1.12 (95% CI, 1.06-1.18)], and patients with normal CMR [adjusted HR, 1.35 (95% CI, 1.19-1.53), both P < 0.001], but not in patients with abnormal CMR (P = 0.058). In patients with normal CMR, an increased stress-GCS showed the best improvement in model discrimination and reclassification above traditional and stress CMR findings (C-statistic improvement: 0.14; NRI = 0.430; IDI = 0.089, all P < 0.001; LR-test P < 0.001). Stress-GCS is not a predictor of MACE in patients with ischaemia, but has an incremental prognostic value in those with a normal CMR although the absolute event rate remains low.

Reference data for left ventricular filling and atrial function in children using cardiovascular magnetic resonance

BackgroundDiastolic dysfunction is associated with morbidity and mortality in multiple pediatric disease processes. Cardiovascular magnetic resonance (CMR) provides a non-invasive method of studying left ventricular (LV) diastolic dysfunction through the assessment of LV filling curves and left atrial (LA) volume and function. However, there are no normative data for LV filling curves and the standard method is time-intensive. This study aims to compare an alternate, more rapid method of obtaining LV filling curves to standard methodology and report normative CMR diastolic function data for LV filling curves and LA volumes and function. MethodsNinety-six healthy pediatric subjects (14.3 ± 3.4 years) with normal CMR defined by normal biventricular size and systolic function without late gadolinium enhancement were included. LV filling curves were generated by removing basal slices without myocardium present throughout the cardiac cycle and apical slices with poor endocardial delineation (compressed method), then re-generated including every phase of myocardium from apex to base (standard method). Indices of diastolic function included peak filling rate and time to peak filling. Systolic metrics included peak ejection rate and time to peak ejection. Both peak ejection and peak filling rates were indexed to end-diastolic volume. LA maximum, minimum and pre-contraction volumes were calculated using a biplane method. Inter-and intra-observer variability were assessed with intraclass correlation coefficient. Multivariable linear regression was used to assess the effects of body surface area (BSA), gender and age on metrics of diastolic function. ResultsBSA had the largest effect on LV filling curves. Normal LV filling data are reported for both compressed and standard methods. The time to perform the compressed method was significantly shorter than the standard method (median 6.1 min vs. 12.5 min, p < 0.001). Both methods had strong to moderate correlation for all metrics. Intra-observer reproducibility was moderate to high for all LV filling and LA metrics except for time to peak ejection and peak filling. ConclusionsWe report reference values for LV filling metrics and LA volumes. The compressed method is more rapid and produces similar results to standard methodology, which may facilitate the use of LV filling in clinical CMR reporting.

Abstract 11734: Myocardial Perfusion Reserve Quantified by Stress Cardiovascular Magnetic Resonance Imaging is Reduced in Long COVID Patients Presenting With Chest Pain

Introduction: Chest pain is common in patients with Post-acute Sequelae of SARS-CoV-2 (PASC), also known as long COVID, but the mechanism is unknown. Hypothesis: We hypothesized that PASC patients with chest pain have impaired myocardial perfusion reserve (MPR) measured by stress perfusion cardiovascular magnetic resonance (CMR) imaging. Methods: We retrospectively identified the first 30 consecutive patients who underwent clinically ordered adenosine stress perfusion CMR for chest pain persisting &gt;4 weeks after SARS-CoV-2 infection (PASC). Patients with a history of coronary artery disease (CAD) or left ventricular ejection fraction (LVEF) &lt;50% were excluded. Patients without a history of SARS-CoV-2 infection who had a normal clinically ordered perfusion CMR served as controls. A previously-described automated pixel-wise quantitative perfusion tool was used to calculate stress and rest myocardial blood flow (MBF) in mL/min/g, and MPR as the ratio of stress MBF/rest MBF. The cutoff for reduced MPR was &gt;2 SD below mean MPR for controls. Results: In 30 PASC (67% female, age 43±13) and 13 controls (54% female, age 50±12), with LVEF (61±6% vs 59±8%), native T1 (1001±49 vs 992±57 ms), T2 (49.5±3.7 vs 48.0±3.3 ms), and ECV (24.6±2.9 vs 24.6±2.6%) were similar (p&gt;0.2 for all). Prior pericarditis (n=2) or prior myocarditis (n=3) were infrequent, with no acute disease by CMR. PASC patients had significantly lower global MPR than controls (1.54±0.25 vs. 2.20±0.36, p&lt;0.001), and 16/30 (53%) PASC patients had reduced MPR (&lt;1.49). Clinical ischemia evaluation revealed obstructive CAD in only 2 PASC patients. Conclusions: In PASC patients with chest pain undergoing stress perfusion CMR, global MPR is frequently reduced and is significantly lower than in patients with normal clinical perfusion CMR and no history of SARS-CoV-2 infection. This study raises the possibility that microvascular dysfunction is an important cause of chest pain in patients with long COVID.

Timing of cardiovascular magnetic resonance imaging and diagnostic yield in patients with acute myocardial infarction with nonobstructive coronary arteries

Abstract Background Accurate diagnosis of the underlying cause of myocardial infarction (MI) without obstructive coronary artery disease (MINOCA) is crucial. Cardiovascular magnetic resonance (CMR) plays an important role in the work up of patients with MINOCA. However, the timing of performance of CMR may impact on the diagnosis yield. Purpose To establish the diagnostic yield of CMR in a large cohort of patients admitted with MINOCA based on the timing of referral to CMR. Methods All patients referred to CMR from January 2009 to February 2022 with MINOCA were included. Studies were performed on a 1.5 T or 3T scanners. SSFP cines, T2-weighted black-blood fat-sat images and DE-segmented GE IR images 10–15 minutes after iv gadolinium-DTPA administration (0.15mmol/kg) were performed in 3 long-axis and 11–15 parallel short-axis views. All images were reviewed and analyzed off-line with specialized post-processing software. Results A total of 203 patients (median age 49 years, 60% men) with MINOCA diagnosis were included. Main ECG alterations were ST-segment elevation (STE) (57%) and T wave inversion (19%). Mean peak high sensitivity (HS)-TnI levels were 3706pg/mL. Median time to CMR was 7 days (5–9 days). Mean LVEF was 58% (range 18–83%) and mean LVEDVi 77 mL/m2 (range 35–210 mL/m2). Regional wall abnormalities were present in 123 patients (62%). High signal in T2w images was detected in 153 cases (75%) and late gadolinium enhancement (LGE) in 143cases (71%). Final CMR diagnosis resulted in myocarditis in 46%, MI in 20%, Takotsubo in 18%, and other cardiomyopathies in 6.4%. CMR was normal in 15 patients and not conclusive in 1. When CMR was performed within 7 days of admission (median: 5 days (4–6 days); n: 116 patients), the distribution of diagnoses was myocarditis in 53%, MI in 20%, Takotsubo in 16%, other cardiomyopathies in 6% and normal CMR in 4%. Whereas, if CMR was performed after 7 days (median: 10 days (8–12 days); n: 87 patients), the diagnoses were as flows: myocarditis in 36%, MI in 22%, Takotsubo 20%, cardiomyopathies in 7%, not conclusive in 1% and normal CMR in 13% (Table 1). Conclusions CMR led to the underlying diagnosis of MINOCA in 92% of patients. Myocarditis was the most frequent diagnosis. The final diagnosis of myocarditis was more frequent when CMR was performed within 7 days with a lesser percentage of normal CMR. Funding Acknowledgement Type of funding sources: None.

Performance of artificial intelligence for biventricular cardiovascular magnetic resonance volumetric analysis in the clinical setting

Cardiovascular magnetic resonance (CMR) derived ventricular volumes and function guide clinical decision-making for various cardiac pathologies. We aimed to evaluate the efficiency and clinical applicability of a commercially available artificial intelligence (AI) method for performing biventricular volumetric analysis. Three-hundred CMR studies (100 with normal CMR findings, 50 dilated cardiomyopathy, 50 hypertrophic cardiomyopathy, 50 ischaemic heart disease and 50 congenital or valvular heart disease) were randomly selected from database. Manual biventricular volumetric analysis (CMRtools) results were derived from clinical reports and automated volumetric analyses were performed using short axis volumetry AI function of CircleCVI42 v5.12 software. For 20 studies, a combined method of manually adjusted AI contours was tested and all three methods were timed. Clinicians` confidence in AI method was assessed using an online survey. Although agreement was better for left ventricle than right ventricle, AI analysis results were comparable to manual method. Manual adjustment of AI contours further improved agreement: within subject coefficient of variation decreased from 5.0% to 4.5% for left ventricular ejection fraction (EF) and from 9.9% to 7.1% for right ventricular EF. Twenty manual analyses were performed in 250 min 12 s whereas same task took 5 min 48 s using AI method. Clinicians were open to adopt AI but concerns about accuracy and validity were raised. The AI method provides clinically valid outcomes and saves significant time. To address concerns raised by survey participants and overcome shortcomings of the automated myocardial segmentation, visual assessment of contours and performing manual corrections where necessary appears to be a practical approach.

The Diagnostic and Prognostic Utility of Contemporary Cardiac Magnetic Resonance in Suspected Acute Myocarditis.

Cardiovascular magnetic resonance (CMR) is used to investigate suspected acute myocarditis, however most supporting data is retrospective and few studies have included parametric mapping. We aimed to investigate the utility of contemporary multiparametric CMR in a large prospective cohort of patients with suspected acute myocarditis, the impact of real-world variations in practice, the relationship between clinical characteristics and CMR findings and factors predicting outcome. 540 consecutive patients we recruited. The 113 patients diagnosed with myocarditis on CMR performed within 40 days of presentation were followed-up for 674 (504–915) days. 39 patients underwent follow-up CMR at 189 (166–209) days. CMR provided a positive diagnosis in 72% of patients, including myocarditis (40%) and myocardial infarction (11%). In multivariable analysis, male sex and shorter presentation-to-scan interval were associated with a diagnosis of myocarditis. Presentation with heart failure (HF) was associated with lower left ventricular ejection fraction (LVEF), higher LGE burden and higher extracellular volume fraction. Lower baseline LVEF predicted follow-up LV dysfunction. Multiparametric CMR has a high diagnostic yield in suspected acute myocarditis. CMR should be performed early and include parametric mapping. Patients presenting with HF and reduced LVEF require closer follow-up while those with normal CMR may not require it.

Prognostic impact of cardiac MRI in acute myocardial injury with non-obstructive coronary arteries: The role of 2D speckle-tracking echocardiography and CMR imaging

Acute myocardial injury with non-obstructive coronary arteries (aMINOCA), broader term than MINOCA, including ischemic and non-ischemic causes, represents a diagnostic dilemma, and the prognostic markers have not been clarified. this study sought to assess the prognostic impact of cardiovascular magnetic resonance (CMR) in patients with aMINOCA. Prospective study including patients presenting aMINOCA, admitted from June 2019 to September 2020, undergoing 2D STE Echocardiography and CMR assessment at admission. A 1.5-T CMR was performed using a comprehensive protocol (cines, T2-STIR and late gadolinium enhancement sequences). CMR (performed at an average of 3.22 days from presentation) was able to identify the cause for the troponin rise in 82% (24/29) of the patients (41% myocarditis, 35% MI, and 7% Takotsubo cardiomyopathy), whereas a normal CMR was identified in 17%. 2D LV Global longitudinal systolic myocardial strain (2D GLS) correlated significantly with the amount of LGE (r 2 = 0.230; P = 0.021). Pick troponin level was significantly higher in groups of patients with LGE (18.6 vs. 1.6; P = 0.012) and with myocardial edema (24.4 vs. 4.1; P = 0.026). At follow-up, we found that both LVEF assessed by CMR and amount of myocardial edema were significantly correlated with the absence of recovery of the GLS at 6 months-follow-up echocardiography (r 2 = 0.243; P = 0.032 and r 2 = 0.410; P = 0.003). In contrast, no significant correlation between echography LVEF, 2D GLS and recovery of the GLS at follow-up was founded (r 2 = 0.07; P = 0.71 and r 2 = 0.185; P = 0.06). In a prospective study including 29 patients with non-obstructive coronary myocardial injury, CMR identified a final diagnosis in 82% of patients. 2D speckle-tracking echocardiography was a useful tool in the diagnostic process and follow-up. Presence of myocardial oedema assessed by CMR at admission is a strong predictive factor of absence of LV systolic function recovery.

Cardiac magnetic resonance strain and mechanical dispersion assessment in patients with chronic total coronary artery occlusion

Abstract Background Chronic total occlusions (CTO) are a frequent angiographic finding. Viability of CTO-subtended myocardium is dependent on the presence of an adequate collateral circulation. At rest, collateral supply may be sufficient to avert ischaemia and maintain normal systolic function. However, it remains unclear whether CTO-subtended myocardium may be considered truly normal, or whether subtle functional abnormalities may be present at rest. Purpose To determine whether, in the absence of infarction and hibernation, CTO-subtended myocardium remains functionally normal or whether abnormalities of strain and/or mechanical dispersion may be present at rest. Methods In a retrospective, single centre, observational study, we studied patients with ≥1 angiographically-diagnosed CTO referred for clinical stress perfusion cardiovascular magnetic resonance (CMR), and compared healthy volunteers (HVs) with a normal stress CMR scan. CMR imaging comprised functional and scar assessment with qualitative [visual] evaluation of infarction and segmental wall motion. Patients with infarction and/or wall motion score index (WMSI) ≥1 were excluded from further analysis. In remaining CTO subjects and HVs, segmental peak systolic longitudinal strain and circumferential strain were analysed (in 3 long-axis planes and 3 short-axis planes, respectively) and mechanical dispersion for both orientations was computed. Image analysis was performed using Medis (QStrain) software blinded to all clinical information. Results From a total of 389 patients with ≥1 angiographically-diagnosed CTO, 68 had normal WMSI and no infarction (63.0±11.7 years, 79.4% male, LVEF 62.6±4.5%). Fifty HVs (61.1±7.0 years, 74.0% males, LVEF 61.1±5.3%) were also studied. The majority of CTO patients had concomitant coronary artery disease in at least one non-CTO vessel (n=37, 54.4%). GLS was lower in CTO patients than HVs (−21.8%±1.5% versus −24.0±1.1%; p&amp;lt;0.0001; Figure 1). By contrast, GCS was greater in CTO patients (−32.7±2.5% versus −28.8±2.1%; p&amp;lt;0.0001). Mechanical dispersion was increased in CTO patients (Figure 2), both longitudinally (90.3±14.6 ms in CTO patients versus 68.6±11.1 ms in HVs; p&amp;lt;0.0001) and circumferentially (66.7±9.1 ms versus 55.3±6.6 ms, respectively; p=0.02). Conclusion Subclinical changes in left ventricular dynamics are present at rest in CTO patients with fully viable myocardium and no evidence of resting regional wall abnormality. Further study is warranted to evaluate the potential association between mechanical dispersion and arrhythmic events in CTO. Funding Acknowledgement Type of funding sources: Other. Main funding source(s): NIHR Clinician Scientist Award (CS-2018-18-ST2-007 to J.R.A.) and Research Professorship award (RP-2017-08-ST2-007 to G.P.M.). Figure 1. Strain analysis. CTO vs HVFigure 2. Mechanical dispersion. CTO vs HV

Serum Anti-Heart and Anti-Intercalated Disk Autoantibodies: Novel Autoimmune Markers in Cardiac Sarcoidosis.

Background: Sarcoidosis is an immune-mediated disease. Cardiac involvement, a granulomatous form of myocarditis, is under-recognized and prognostically relevant. Anti-heart autoantibodies (AHAs) and anti-intercalated disk autoantibodies (AIDAs) are autoimmune markers in nonsarcoidosis myocarditis forms. Objective: The aim was to assess serum AHAs and AIDAs as autoimmune markers in cardiac sarcoidosis. Methods: This is a cross-sectional study on AHA and AIDA frequency in: 29 patients (aged 46 ± 12, 20 male) with biopsy-proven extracardiac sarcoidosis and biopsy-proven or clinically suspected and confirmed by 18-fluorodeoxyglucose positron emission tomography and/or cardiovascular magnetic resonance (CMR) cardiac involvement; 30 patients (aged 44 ± 11, 12 male) with biopsy-proven extracardiac sarcoidosis without cardiac involvement (no cardiac symptoms, normal 12-lead electrocardiogram, echocardiography and CMR), and control patients with noninflammatory cardiac disease (NICD) (n = 160), ischemic heart failure (IHF) (n = 141) and normal blood donors (NBDs) (n = 270). Sarcoidosis patients were recruited in two recruiting tertiary centers in the USA and Italy. AHAs and AIDAs were detected by indirect immunofluorescence on the human myocardium and skeletal muscle. Results: AHA and AIDA frequencies were higher in sarcoidosis with cardiac involvement (86%; 62%) than in sarcoidosis without cardiac involvement (0%; 0%), NICD (8%; 4%), IHF (7%; 2%) and NBD (9%; 0%) (p = 0.0001; p = 0.0001, respectively). Sensitivity and specificity for cardiac sarcoidosis were 86% and 92% for positive AHAs and 62% and 98% for positive AIDAs, respectively. AIDAs in cardiac sarcoidosis were associated with a higher number of involved organs (p = 0.04). Conclusions: Serum AHAs and AIDAs provide novel noninvasive diagnostic autoimmune markers for cardiac sarcoidosis.

Myocardial extracellular volume by T1 mapping: a new marker of arrhythmia in mitral valve prolapse

ObjectivesWe aimed to evaluate the relationship between mitral annular disjunction (MAD) severity and myocardial interstitial fibrosis at the left ventricular (LV) base in patients with mitral valve prolapse (MVP), and to assess the association between severity of interstitial fibrosis and the occurrence of ventricular arrhythmic events.BackgroundIn MVP, MAD has been associated with myocardial replacement fibrosis and arrhythmia, but the importance of interstitial fibrosis remains unknown.MethodsIn this retrospective study, 30 patients with MVP and MAD (MVP–MAD) underwent cardiovascular magnetic resonance (CMR) with assessment of MAD length, late gadolinium enhancement (LGE), and basal segments myocardial extracellular volume (ECVsyn). The control group included 14 patients with mitral regurgitation (MR) but no MAD (MR-NoMAD) and 10 patients with normal CMR (NoMR-NoMAD). Fifteen MVP–MAD patients underwent 24 h-Holter monitoring.ResultsLGE was observed in 47% of MVP–MAD patients and was absent in all controls. ECVsyn was higher in MVP–MAD (30 ± 3% vs 24 ± 3% MR-NoMAD, p < 0.001 and vs 24 ± 2% NoMR-NoMAD, p < 0.001), even in MVP–MAD patients without LGE (29 ± 3% vs 24 ± 3%, p < 0.001 and vs 24 ± 2%, p < 0.001, respectively). MAD length correlated with ECVsyn (rho = 0.61, p < 0.001), but not with LGE extent. Four patients had history of out-of-hospital cardiac arrest; LGE and ECVsyn were equally performant to identify those high-risk patients, area under the receiver operating characteristic (ROC) curve 0.81 vs 0.83, p = 0.84). Among patients with Holter, 87% had complex ventricular arrhythmia. ECVsyn was above the cut-off value in all while only 53% had LGE.ConclusionIncrease in ECVsyn, a marker of interstitial fibrosis, occurs in MVP–MAD even in the absence of LGE, and was correlated with MAD length and increased risk of out-of-hospital cardiac arrest. ECV should be includedin the CMR examination of MVP patients in an effort to better assess fibrous remodelling as it may provide additional value beyond the assessment of LGE in the arrhythmic risk stratification.

Cardiovascular magnetic resonance imaging in children after recovery from symptomatic COVID-19 or MIS-C: a prospective study

BackgroundCardiac evaluations, including cardiovascular magnetic resonance (CMR) imaging and biomarker results, are needed in children during mid-term recovery after infection with SARS-CoV-2. The incidence of CMR abnormalities 1–3 months after recovery is over 50% in older adults and has ranged between 1 and 15% in college athletes. Abnormal cardiac biomarkers are common in adults, even during recovery.MethodsWe performed CMR imaging in a prospectively-recruited pediatric cohort recovered from COVID-19 and multisystem inflammatory syndrome in children (MIS-C). We obtained CMR data and serum biomarkers. We compared these results to age-matched control patients, imaged prior to the SARS-CoV-2 pandemic.ResultsCMR was performed in 17 children (13.9 years, all ≤ 18 years) and 29 age-matched control patients without SARS-CoV-2 infection. Cases were recruited with symptomatic COVID-19 (11/17, 65%) or MIS-C (6/17, 35%) and studied an average of 2 months after diagnosis. All COVID-19 patients had been symptomatic with fever (73%), vomiting/diarrhea (64%), or breathing difficulty (55%) during infection. Left ventricular and right ventricular ejection fractions were indistinguishable between cases and controls (p = 0.66 and 0.70, respectively). Mean native global T1, global T2 values and segmental T2 maximum values were also not statistically different from control patients (p ≥ 0.06 for each). NT-proBNP and troponin levels were normal in all children.ConclusionsChildren prospectively recruited following SARS-CoV-2 infection had normal CMR and cardiac biomarker evaluations during mid-term recovery. Trial Registration Not applicable.

Long-term clinical outcomes of troponin-positive chest pain and unobstructed coronary arteries assessed by cardiovascular magnetic resonance imaging

Abstract Background and introduction Troponin-positive chest pain with unobstructed coronary arteries is a distinct entity with different pathophysiological causes. We have previously reported on the incremental diagnostic capability of cardiovascular magnetic resonance (CMR) in this cohort. However, there is paucity of literature on the long-term clinical outcomes of these patients assessed with CMR. Objectives Using the unique cohort of patients previously studied, we sought to assess the long-term clinical outcomes in patients with troponin-positive chest pain and unobstructed coronary arteries, as graded by their acute CMR presentation. Methods A total of 122 consecutive patients with troponin-positive chest pain and unobstructed coronary arteries undergoing CMR assessment during the acute admission (2010–2014) were studied. The primary endpoint was major adverse cardiac event (MACE), defined as a composite of all-cause mortality and cardiovascular readmissions (heart failure, acute myocardial infarction [AMI], atrial or ventricular arrhythmia and stroke). Patients were grouped into 4 categories based on their initial CMR findings: AMI, acute myocarditis, Takotsubo cardiomyopathy and normal CMR. Results The mean age of the study cohort was 55.6±16.5 years and 56.5% were women. CMR (performed at a median of 6 days from presentation) provided a diagnosis in 87% of the patients (38% myocarditis, 28% Takotsubo cardiomyopathy and 21% AMI). Patients with a diagnosis of AMI were prescribed guideline recommended medical therapy. Over a median follow-up of 2524 days (6.9 years), 32 (26.2%) patients experienced a MACE. The all-cause mortality was 2.5%. The most common indication for cardiovascular readmissions in this cohort was heart failure (12.3%) and AMI (9%). In multivariate analysis, a CMR diagnosis of AMI (hazard ratio = 2.6; 95% confidence interval = 1.2, 5.7; p=0.019) and peak troponin (hazard ratio = 1.0003; 95% confidence interval = 1.00003, 1.0006; p=0.028) were significantly associated with MACE after adjusting for age and gender. In addition, CMR diagnosis of AMI was significantly associated with a lower event-free survival rate compared with a diagnosis of non-AMI (adjusted hazard ratio = 2.57, p=0.019) (Figure). Conclusions The long-term prognosis of patients with troponin-positive chest pain and unobstructed coronary arteries is not benign. CMR diagnosis of AMI is a significant predictor of MACE even in the absence of significant coronary artery obstruction and despite guideline recommended post AMI therapy. Figure 1 Funding Acknowledgement Type of funding source: None

Prognosis of incidental left bundle branch block.

Incidental left bundle branch block (iLBBB) is a frequent cause for cardiology referrals. In such instances, there is uncertainty as to its prognosis. We sought to determine the utility of cardiovascular magnetic resonance (CMR) in the risk stratification of patients with iLBBB. Clinical events were collected in patients with iLBBB who had CMR. Controls had no cardiac symptoms or cardiac disease, a normal CMR scan and electrocardiogram. Amongst patients with iLBBB [n = 193, aged 62.7 ± 12.6 years (mean ± SD)], 110/193 (56.9%) had an abnormal phenotype (iLBBBCMR+) and 83/110 (43.0%) had a normal phenotype (iLBBBCMR-). Over 3.75 years (median; inter-quartile range: 2.7-5.5), iLBBBCMR+ had a higher total mortality [adjusted hazard ratio (aHR) 6.49, 95% confidence interval (CI) 1.91-22.0] and total mortality or major adverse cardiac events (MACEs; aHR 9.15, 95% CI 2.56-32.6) than controls (n = 107). In contrast, iLBBBCMR- had a similar risk of total mortality compared with controls, but total mortality or MACEs was higher (aHR 4.24, 95% CI 1.17-15.4; P = 0.028). Amongst iLBBB patients, both myocardial fibrosis (aHR 5.15, 95% CI 1.53-17.4) and left ventricular ejection fraction (LVEF) ≤ 50% (aHR 3.88, 95% CI 1.67-9.06) predicted total mortality. Myocardial fibrosis plus LVEF ≤50% was associated with the highest risk of total mortality (aHR: 9.87, 95% CI 2.99-32.6) and total mortality or MACEs (aHR 3.98, 95% CI 1.73-9.11). Outcomes in iLBBBCMR+ were poor whereas survival in iLBBBCMR- was comparable with controls. Myocardial fibrosis and LVEF <50% had an additive effect on the risk of clinical outcomes. A CMR scan is pivotal in risk-stratifying patients with iLBBB.

Long-Term Prognostic Value of Stress Perfusion Cardiovascular Magnetic Resonance Imaging.

The purpose of this review is to analyze the long-term prognostic value of stress perfusion cardiovascular magnetic resonance (CMR) in patients with suspected or known coronary artery disease (CAD). Stress perfusion CMR provides high diagnostic accuracy for detection of CAD, with high sensitivity and relatively lower specificity. A normal stress perfusion CMR examination is highly predictive of overall low patient risk. Conversely, abnormal stress perfusion CMR results are associated with mortality and increased risk for adverse cardiac-related events. Stress perfusion CMR is a useful and robust tool for risk reclassification across different CAD risk categories, and most significant for patients of intermediate risk. Stress CMR is reliable for excluding clinically significant coronary artery disease in patients presenting with low-risk acute chest pain. An ischemic burden threshold of less than 1.5 cardiac segments has been found to be most appropriate for safe deferral from revascularization therapy. A stress perfusion CMR-guided strategy has been shown to be noninferior compared to fractional flow reserve (FFR) for revascularization in patients with stable CAD. In clinical practice, CMR offers a multiplicity of useful techniques besides stress perfusion which may add significant prognostic value when combined with the findings of the stress test itself. Stress perfusion CMR is an accurate noninvasive diagnostic test for patients with suspected CAD and provides strong prognostic value across different risk categories.

DIAGNOSTIC YIELD OF CARDIOVASCULAR MAGNETIC RESONANCE (CMR) SCREENING FOR ARRHYTHMOGENIC RIGHT VENTRICULAR CARDIOMYOPATHY (ARVC) STRATIFIED BY BASELINE ECHOCARDIOGRAPHY FINDINGS OF THE RIGHT VENTRICLE

Arrythmogenic right ventricular cardiomyopathy (ARVC) is a rare inherited cardiomyopathy but an important cause of sudden death. Cardiovascular Magnetic Resonance (CMR) imaging is considered the gold-standard for exclusion of its structural phenotype, however, limited availability poses challenge in many communities. We aimed to study the relative diagnostic yield of CMR in patients with versus without abnormal right ventricular (RV) findings by routine 2D echocardiography. 447 patients referred for the screening of ARVC between February 2015 and December 2017 were identified from the Cardiovascular Imaging Registry of Calgary (CIROC). A standardized CMR imaging and analysis protocol was used to assess chamber volumes, function and architectural changes in accordance with the 2010 modified Task Force Criteria (mTFC). All patients having echocardiographic imaging within 12 months prior to CMR were identified and a blinded review of reports was performed. A final clinical diagnosis was derived based on the assimilation of all clinical information, and was classified as meeting or not meeting mTFC for ARVC. Of 447 enrolled patients, 387 (76.6%) had echocardiogram performed and were studied. A final diagnosis of definite ARVC was established in nine (2.3%) patients. Echocardiography reported no RV abnormalities in 283 (73.1%) patients (Group A), while 104 patients (26.9%) had at least one abnormal finding (Group B), defined as; reduced RV function, regional RV wall motion abnormality, global or focal dilatation, aneurysm or “hyper-reflective” trabeculations. In Group A, the yield of any mTFC by CMR was 4 (1.4%) with three patients having a minor and one having a major criterion. Two Group A patients (0.7%) ultimately received a diagnosis of ARVC, neither showing any imaging-based abnormalities. In Group B, the yield of any mTFC by CMR was 13 (12.5%) with nine subjects having a major and 4 having a minor criterion. Seven Group B patients (6.7%) were eventually diagnosed with ARVC, 5 (4.8%) meeting a CMR-based mTFC and 2 (1.9%) with normal CMR. Overall, the sensitivity and specificity of CMR for ARVC was 0% and 98.6% in Group A, and 71.4% and 91.7% in Group B. Among patients without RV abnormality by echocardiography referred to CMR for suspected ARVC, the yield of a CMR-based mTFC was low (1.4%) and did not lead to a diagnosis of ARVC in any subject. In contrast, patients with an RV abnormality had a CMR-based yield of 12.5%, leading to a diagnosis of ARVC in 4.8% of patients.

Diagnostic value of global myocardial perfusion reserve assessment based on coronary sinus flow measurements using cardiovascular magnetic resonance in addition to myocardial stress perfusion imaging.

Myocardial perfusion reserve (MPR) is defined as the maximal possible increase in myocardial blood flow (MBF) above baseline conditions. Global MBF can be measured non-invasively by means of coronary sinus flow velocity encoded cine (VENC) cardiovascular magnetic resonance (CMR). We aimed to explore the relationship between global MBF/MPR and the extent and severity of coronary artery disease (CAD) in patients referred for CAD work-up by adenosine-stress CMR. Fifty-eight patients with suspected obstructive CAD underwent both adenosine-stress CMR and invasive coronary angiography. In addition to standard cine- and late gadolinium enhancement (LGE)-imaging, first-pass myocardial perfusion imaging (MPI) and coronary sinus flow measurements (VENC) were performed at rest and during peak stress (after 140 µg/kg/min adenosine), respectively. Nineteen young patients with a very low CAD pre-test probability and normal adenosine-stress CMR formed the control group. Fifty-nine percent (n = 34) of the study group showed segmental, adenosine-induced myocardial perfusion defects compared to none of the control group (P < 0.001). Global MPR was lower in the study group compared to the control group: 2.3 (1.5-3.1) vs. 3.1 (2.0-4.3), P = 0.016. The SYNTAX score was higher in the study group patients with an impaired MPR (<2) compared to those with a preserved MPR (3.0 vs. 16.0, P = 0.01)-mainly due to higher prevalence of proximal epicardial stenoses (60% vs. 27%, P = 0.02) and multi-vessel disease (56% vs. 24%, P = 0.017). The diagnostic yield of stress CMR for the diagnosis of CAD (>50% stenosis) increased from 65to 88% when global MPR assessment was considered in addition to MPI (P = 0.025). Global MBF and MPR values correlate with the anatomical extent and complexity of CAD and increase the diagnostic yield of non-invasive stress CMR in the work-up of CAD. CMR-based MBF and MPR measurements may play a future role in the evaluation of the total ischaemic burden-particularly in patients with multi-vessel disease.

Role of Perfusion at Rest in the Diagnosis of Myocardial Infarction Using Vasodilator Stress Cardiovascular Magnetic Resonance

In clinical practice, perfusion at rest in vasodilator stress single-photon emission computed tomography is commonly used to confirm myocardial infarction (MI) and ischemia and to rule out artifacts. It is unclear whether perfusion at rest carries similar information in cardiovascular magnetic resonance (CMR). We sought to determine whether chronic MI is associated with abnormal perfusion at rest on CMR. We compared areas of infarct and remote myocardium in 31 patients who underwent vasodilator stress CMR (1.5 T), had MI confirmed by late gadolinium enhancement (LGE scar), and coronary angiography within 6 months. Stress perfusion imaging during gadolinium first pass was followed by reversal with aminophylline (75 to 125 mg), rest perfusion, and LGE imaging. Resting and peak-stress time-intensity curves were used to obtain maximal upslopes (normalized by blood pool upslopes), which were compared between infarcted and remote myocardial regions of interest. At rest, there was no significant difference between the slopes in the regions of interest supplied by arteries with and without stenosis >70% (0.31 ± 0.16 vs 0.26 ± 0.15 1/s), irrespective of LGE scar. However, at peak stress, we found significant differences (0.20 ± 0.11 vs 0.30 ± 0.22 1/s; p <0.05), reflecting the expected stress-induced ischemia. Similarly, at rest, there was no difference between infarcted and remote myocardium (0.27 ± 0.14 vs 0.30 ± 0.17 1/s), irrespective of stenosis, but significant differences were seen during stress (0.21 ± 0.16 vs 0.28 ± 0.18 1/s; p <0.001), reflecting inducible ischemia. In conclusion, abnormalities in myocardial perfusion at rest associated with chronic MI are not reliably detectable on CMR images. Accordingly, unlike single-photon emission computed tomography, normal CMR perfusion at rest should not be used to rule out chronic MI.

134 Incremental Value of Cardiovascular Magnetic Resonance Imaging in Patients Surviving non Traumatic out of Hospital Cardiac Arrest: A Tertiary UK Centre Experience

BackgroundNon-traumatic out of hospital cardiac arrest (OOHCA) is one of the leading causes of death in western world. Acute coronary syndrome (ACS) is the most common aetiology of OOHCA with...

Prevalence of Inferobasal Myocardial Crypts Among Patients Referred for Cardiovascular Magnetic Resonance

Crypts or clefts in the left ventricular inferobasal myocardium have been detected by cardiovascular magnetic resonance (CMR), but the extent to which they represent prephenotypic markers of hypertrophic cardiomyopathy (HCM) or incidental structural variants remains controversial. We examined retrospectively the routine vertical long-axis cines in 686 consecutive patients (48±20 years, 55% men) referred for CMR. Crypts were identified in 46 (6.7%), 17 being among patients (8.7% of 196) with otherwise normal CMR findings and without a known family history of HCM. Higher percentages were found in patients with HCM (16%), myocarditis (15%), and hypertension (14%) but without reaching statistical significance (P=0.12). Only 1 (5%) of 20 phenotype-negative HCM family members had a visible crypt. Relative to those without, patients with crypts had lower indexed left ventricular end-systolic volumes (P=0.042) and higher indexed left and right ventricular stroke volumes (P=0.007 and P=0.015) and ejection fractions (P=0.003 and P=0.021). Crypts tended to narrow in systole, varying slightly in size, shape- and number, without obvious group-related features. Single or paired inferobasal myocardial crypts were an occasional and by no means rare finding among patients referred for CMR without a pretest suspicion of HCM. This, together with similar previous findings in a cohort of healthy volunteers, supports their being regarded, in such individuals, as incidental variants of local myocardial structure, unlikely to require further investigation. However, a larger registry-type study may be justified to investigate the clinical implications of multiple crypts, especially if associated with HCM family history.