Ventricular tachycardia substrate mapping with cardiac computed tomography and cardiac magnetic resonance imaging: Head-to-head comparison of two clinically available postprocessing platforms.

Although multi-detector computed tomography (MDCT) and cardiac magnetic resonance (CMR) can assess the structural substrate of ventricular tachycardia (VT) in ischemic cardiomyopathy (ICM), non-ICM (NICM), and arrhythmogenic right ventricular cardiomyopathy (ARVC), the usefulness of systematic image integration during VT ablation remains undetermined. A total of 116 consecutive patients (67 ICM; 30 NICM; 19 ARVC) underwent VT ablation with image integration (MDCT 91%; CMR 30%; both 22%). Substrate was defined as wall thinning on MDCT and late gadolinium-enhancement on CMR in ICM/NICM, and as myocardial hypo-attenuation on MDCT in ARVC. This substrate was compared to mapping and ablation results with the endpoint of complete elimination of local abnormal ventricular activity (LAVA), and the impact of image integration on procedural management was analyzed. Imaging-derived substrate identified 89% of critical VT isthmuses and 85% of LAVA, and was more efficient in identifying LAVA in ICM and ARVC than in NICM (90% and 90% vs. 72%, P < 0.0001), and when defined from CMR than MDCT (ICM: 92% vs. 88%, P = 0.026, NICM: 88% vs. 72%, P < 0.001). Image integration motivated additional mapping and epicardial access in 57% and 33% of patients. Coronary and phrenic nerve integration modified epicardial ablation strategy in 43% of patients. The impact of image integration on procedural management was higher in ARVC/NICM than in ICM (P < 0.01), and higher in case of epicardial approach (P < 0.0001). Image integration is feasible in large series of patients, provides information on VT substrate, and impacts procedural management, particularly in ARVC/NICM, and in case of epicardial approach.

PURPOSE:The pathophysiological mechanism of cardiac troponin (cTn) elevation after marathon running is still not clear. It is discussed controversially whether (especially a prolonged) elevation reflects rather physiological than pathological processes. We hypothesized that a prolonged elevation of cTn (pecTn) post-marathon is associated with late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR) imaging as a sign of myocardial damage. METHODS: We examined cTn T values in 162 healthy male marathon runner (age: 42.1 ± 10.9 yrs) before (V2) and immediately (V3), 24 hrs (V4), and 72 hrs (V5) after a marathon race. A pecTn was defined as follows: a high-sensitive cTnT > 25 ng/L at V4 or > 14 ng/L at V5. The participants with pecTn were compared to controls without pecTn which were similar with respect to age and previous finished long-distance races. Both groups were examined with CMR in the days post-race and those with LGE in the first CMR also with a second CMR approximately 3 month post-race. RESULTS: We examined in total 22 out of 162 runners (13.6%). 12 of 162 (7.4%, age 38.7 ± 10.4 yrs) had prolonged elevated cTn T values. 7 in the pecTn group (58.3%) and 2 in the control group (20%, p = 0.099) had a LGE in the first CMR. In the second CMR, 5 participants in the pecTn group (41.7%) and 1 in the control group (10%, p = 0.162) presented LGE. In the ROC analyses, cTnT values immediately post-race were not associated with LGE (1st CMR: AUC = 0.671, p = 0.182, 2nd CMR: AUC = 0.474, p = 0.854). However, LGE in first CMR was significantly associated with cTnT at V4 (AUC = 0.769, p = 0.035) and LGE in second MRI with cTnT at V5 (AUC = 0.807, p = 0.030), however not reaching level of significance for V4 (AUC = 0.750, p = 0.077). Regarding mean cTn values at V4 and V5, LGE in both CMRs were significantly associated with cTn values (first CMR: AUC = 0.752, p = 0.049; second CMR: AUC = 0.828, p = 0.020). An optimal cut-point regarding LGE at the first MRI determined by maximizing the Youden index for a cTn value at 24 hrs post-race was found at 23.5 ng/L (estimated sensitivity: 66.7 %, specificity: 84.6 %). CONCLUSIONS: Prolonged elevation of cTn after marathon running is associated with LGE in CMR and therefore, seems to be a sign for myocardial damage. Furthermore, high-sensitive cTnT values ≥ 24 ng/L 24 hrs post-race are highly suspicious for a pathological process.

Myocardial Fibrosis in Competitive Triathletes Detected by Contrast-Enhanced CMR Correlates With Exercise-Induced Hypertension and Competition History

Myocardial Deformation Imaging by Two-Dimensional Speckle-Tracking Echocardiography in Comparison to Late Gadolinium Enhancement Cardiac Magnetic Resonance for Analysis of Myocardial Fibrosis in Severe Aortic Stenosis

Myocardial Deformation Imaging by Two-Dimensional Speckle-Tracking Echocardiography for Prediction of Global and Segmental Functional Changes after Acute Myocardial Infarction: A Comparison with Late Gadolinium Enhancement Cardiac Magnetic Resonance

Relationship Between Fibrosis Detected on Late Gadolinium-Enhanced Cardiac Magnetic Resonance and Re-Entrant Activity Assessed With Electrocardiographic Imaging in Human Persistent Atrial Fibrillation.

Cardiac magnetic resonance to predict recurrences after ventricular tachycardia ablation: septal involvement, transmural channels, and left ventricular mass.

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Long-term prognostic value of scar characteristics in cardiac magnetic resonance to predict appropriate therapies in primary prevention

Percutaneous coronary intervention (PCI) in acute myocardial infarction (AMI) is sometimes complicated by microvascular damage and hemorrhage. Hemoglobin degradation products have magnetic susceptibility effects which help in detecting hemorrhagic AMI by T₂ -weighted cardiac magnetic resonance (CMR) images. To investigate the possibility to detect intramyocardial hemorrhage after AMI and to assess its contribution to the delayed hypoenhanced core on late gadolinium enhancement (LGE) CMR, a feature traditionally referred to as microvascular obstruction. Consecutive patients with AMI who underwent PCI and CMR were investigated. Hypointense zones T₂ -weighted images were labelled as "hemorrhagic" AMI. Areas of late hypoenhancement on LGE CMR were considered as regions of persistent microvascular damage (PMD). Only transmural AMI were considered. A total number of 108 transmural AMI patients were eventually enrolled and divided into two groups according to the presence of hypoenhancement on T₂ images. Thirty-two patients showed an hypointense stria within the high signal intensity zone on T₂ -weighted images; all these patients showed midmural PMD on LGE. Among the remaining 76 patients, only 14 (18.4%) showed PMD in the subendocardial region. The angiographic outcome was worse in patients with hemorrhagic AMI, with a lower prevalence of TIMI 3 (65.6% vs. 96.1%, P = 0.017) and higher prevalence of myocardial blush grade 0 (84.4% vs. 13.2%, P < 0.001) post-PCI. T₂ -weighted CMR in reperfused AMI allows identification of hemorrhage, related to PMD areas on LGE images and to a worse reperfusion profile on angiography. These features open new avenues of investigation for prognostic assessment of reperfused AMI.

Background Dilated cardiomyopathy (DCM) is defined as the presence of left ventricular or biventricular dilatation and systolic dysfunction in the absence of abnormal loading conditions or significant coronary heart disease. The diagnostic work-up for patients with DCM includes cardiac imaging and cardiac magnetic resonance (CMR) is the gold-standard method for detailed morphological caracterization. Although there is a limited diagnostic role for radionuclide imaging in DCM, myocardial perfusion single-photon emission computed tomography (SPECT) is commonly performed to exclude ischemic etiology. Purpose The aim of this study was to compare the findings of myocardial perfusion SPECT (MPS) and CMR in non-ischemic DCM. Methods We included 35 patients that had been diagnosed with DCM and underwent MPS and CMR for etiological diagnosis in our institution between January 2020 and December 2023. We evaluated left ventricular motility, thickening and perfusion defects in MPS, the presence of late gadolinium enhancement (LGE) in CMR and the values of left ventricular ejection fraction (LVEF), end-systolic and end-diastolic volumes in both exams. Results 24 patients were male (69%), with a median age of 65,9 ± 11,8 years. Ischemic etiology for DCM was excluded based on CMR in 25 patients, 6 patients were diagnosed with alcoholic DCM, 3 patients with familial DCM and 1 with chemotherapy-induced cardiotoxicity. In 23 patients (66%), MPS showed diffuse motility and thickening abnormalities. In MPS, 34 patients (97%) had perfusion defects and 17 (50%) had reversible defects. 14 patients (41%) had only one perfusion defect while 20 (59%) patients had 2 or more. The septal wall was the most affected (24 patients - 69%). In 24 patients (69%), CMR showed LGE suggestive of fibrosis and in 88% of these patients the fibrosis was seen in the septal wall. A moderate correlation (0,508) was found between LVEF in MPS and CMR. 8 patients (33%) presented LGE in CMR and had non-reversible perfusion defects in the same myocardial wall in MPS while 12 patients (50%) presented with reversible perfusion defects in the same LGE location. Of the 12 patients that presented with LGE in CMR and reversible defects in MPS, 7 (58%) had total or parcial but significant reversibility and 5 (42%) had partial but non-significant reversibility. Conclusions The presence of perfusion defects is common in non-ischemic DCM. In most patients the perfusion defects (MPS) and fibrosis (CMR) were seen in the septal wall. Reversible defects may be explained by microvascular dysfunction known to play a role in DCM pathogenesis. These findings should be taken into account in the interpretation of MPS results in the etiological diagnosis of DCM.

Electrocardiographic imaging to guide VT ablation in structural heart disease

Relation of Fragmented QRS Complex to Right Ventricular Fibrosis Detected by Late Gadolinium Enhancement Cardiac Magnetic Resonance in Adults With Repaired Tetralogy of Fallot

Scar characteristics analyzed by late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) are related with ventricular arrhythmias. Current guidelines are based only on the left ventricular ejection fraction to recommend an implantable cardioverter-defibrillator (ICD) in primary prevention. Our study aims to analyze the role of imaging to stratify arrhythmogenic risk in patients with ICD for primary prevention. From 2006 to 2017, we included 200 patients with LGE-CMR before ICD implantation for primary prevention. The scar, border zone, core, and conducting channels (CCs) were automatically measured by a dedicated software. The mean age was 60.9 ± 10.9 years; 81.5% (163) were men; 52% (104) had ischemic cardiomyopathy. The mean left ventricular ejection fraction was 29% ± 10.1%. After a follow-up of 4.6 ± 2 years, 46 patients (22%) reached the primary end point (appropriate ICD therapy). Scar mass (36.2 ± 19 g vs 21.7 ± 10 g; P < .001), border zone mass (26.4 ± 12.5 g vs 16.0 ± 9.5 g; P < .001), core mass (9.9 ± 8.6 g vs 5.5 ± 5.7 g; P < .001), and CC mass (3.0 ± 2.6 g vs 1.6 ± 2.3 g; P < .001) were associated with appropriate therapies. Scar mass > 10 g (25.31% vs 5.26%; hazard ratio 4.74; P = .034) and the presence of CCs (34.75% vs 8.93%; hazard ratio 4.07; P = .003) were also strongly associated with the primary end point. However, patients without channels and with scar mass < 10 g had a very low rate of appropriate therapies (2.8%). Scar characteristics analyzed by LGE-CMR are strong predictors of appropriate therapies in patients with ICD in primary prevention. The absence of channels and scar mass < 10 g can identify patients at a very low risk of ventricular arrhythmias in this population.

An optimized multisource acquisition and registration workflow for imaging guided ventricular tachycardia ablation