American Heart Association 17-segment Model Research Articles

Accuracy of a novel ECGi system in localising the critical isthmus exit site in scar-dependant re-entrant ventricular tachycardia

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Vision in ventricular onset (VIVO) is a novel, non-invasive, mapping system designed to locate the site of earliest activation in ventricular arrhythmia. VIVO utilises a mathematical algorithm, cross-sectional imaging data (CT or MRI), 3D images of the electrodes on the patient torso, and a 12-lead electrocardiogram (ECG) to identify the site of earliest ventricular activation.(1) The system has been shown to accurately predict earliest activation of focal premature ventricular contractions (PVCs), but its accuracy in scar dependant re-entrant ventricular tachycardia (VT) has not been investigated.(1-3) Objective To assess the accuracy of VIVO in localising the VT exit site for patients with ischaemic cardiomyopathy (ICM) and scar related re-entrant VT. Methods 5 patients with ICM (age 56 ± 19 yrs, male n = 5) were investigated (table 1). All patients had an implantable cardioverter-defibrillator with standard indications for VT ablation. Invasive electro-anatomical mapping was performed with the Advisor HD Grid multipolar catheter and maps were generated using omnipolar electrograms (EGMs). The VT exit site was identified using activation ± pace-maps and the location defined by the primary operator using the American Heart Association (AHA) 17 segment model of the left ventricle.(4) Using the intra-procedural VT ECG recordings, VIVO maps were constructed post-procedure. The VIVO predicted VT exit site was identified using the AHA 17-segment model by a second operator, blinded to the results of the procedure. A "complete match" was defined as exact segment concordance between the two operators, "partial match" as adjacent segments, and "no match" if neither requirements satisfied. Results Mean left ventricular ejection fraction was 30.5 ± 9.0%. Mean procedure time was 233 ± 31 minutes, with a mean ablation time of 24 ± 18 minutes. A total of 11 re-entrant VTs were mapped. The VT exit site was identified in all cases (10 activation-map; 1 pace-map). A complete match was seen in 91% of VTs and partial match in 9% (table 2). None of the cases demonstrated a "no match" between the invasive and VIVO maps. There were no procedural complications. Conclusion The VIVO mapping system can accurately predict the VT exit site in scar dependant re-entrant VT. Further studies to assess the feasibility of VIVO-guided ablation in scar dependant VT are ongoing.

A Single Institution's Experience with Cardiac Radioablation Utilizing the 17-Segment Model for Target Localization

<h3>Purpose/Objective(s)</h3> Ventricular arrhythmias (VT and Vfib) account for most sudden cardiac deaths, killing 300,000 per year in the US. Cardiac radioablation (CRA) utilizes SBRT to ablate foci that cannot be otherwise managed with anti-arrhythmics (AAs) or catheter ablation. For radiation oncologists, successfully implementing CRA is difficult as there is little formal training in ventricular anatomy. Herein we report our institution's experience treating 11 patients with refractory VT utilizing the American Heart Association (AHA) 17-segment model of left ventricular anatomy. <h3>Materials/Methods</h3> Patients were considered for treatment with CRA if they had refractory VT despite AAs and either 1) had undergone unsuccessful catheter ablation(s), or 2) were unable to tolerate catheter ablation for medical/technical reasons. All CRA cases were planned by a multidisciplinary team (MDT) including electrophysiologists (EPs), radiation oncologists, and radiation physicists. The targets were determined by EP based on available diagnostic testing and their locations were defined as including part/all of several segments in the AHA 17-Segment model (patient 7′s target included the right ventricular outflow track, see table). Axial images from 4D CT simulation were reoriented to the cardiac-specific coordinate system employed in AHA 17-segment model, utilizing our published protocol. Targets were delineated by the MDT with appropriate expansions to account for respiratory motion and uncertainty. CRA was delivered with 25 Gy in a single fraction. Follow up included H&P and interrogation of patients' Automatic Implantable Cardioverter Defibrillators (AICDs), which provided data on instances of anti-tachycardia pacing (ATPs), shock therapy and total burden. To assess treatment efficacy, AICD interventions/month were compared prior to and after CRA using the Wilcoxon matched pairs sign rank test. <h3>Results</h3> Between 1/2020 and 12/2021, 11 patients underwent CRA at our institution, 9 of whom had at least 2 months of follow up before and after treatment as recorded by their AICD (median follow up 12 months and 12 months, respectively). Four patients also underwent cardiac sympathetic denervation prior to CRA. Prior to CRA, median ATP/month, shocks/month, total burden/month were 1.15, 0.56, and 2.31, which significantly decreased to 0.11, 0.00, and 0.11 after CRA (p < 0.05, p < 0.01, p < 0.05, respectively). Except one, all patients had a decrease in ATP and total burden. All 9 patients experienced a decrease in shock burden, and 6 remain shock-free since CRA. In the 11 patients treated, there were no CTCAE grade >1 toxicities that were attributable to CRA. <h3>Conclusion</h3> In our relatively large singe-institution CRA experience, the AHA 17-segment model has proven to be an effective means of communicating target location, facilitating excellent clinical outcomes with most patients remaining shock-free after treatment.

CMRSegTools: An open-source software enabling reproducible research in segmentation of acute myocardial infarct in CMR images.

In the last decade, a large number of clinical trials have been deployed using Cardiac Magnetic Resonance (CMR) to evaluate cardioprotective strategies aiming at reducing the irreversible myocardial damage at the time of reperfusion. In these studies, segmentation and quantification of myocardial infarct lesion are often performed with a commercial software or an in-house closed-source code development thus creating a barrier for reproducible research. This paper introduces CMRSegTools: an open-source application software designed for the segmentation and quantification of myocardial infarct lesion enabling full access to state-of-the-art segmentation methods and parameters, easy integration of new algorithms and standardised results sharing. This post-processing tool has been implemented as a plug-in for the OsiriX/Horos DICOM viewer leveraging its database management functionalities and user interaction features to provide a bespoke tool for the analysis of cardiac MR images on large clinical cohorts. CMRSegTools includes, among others, user-assisted segmentation of the left-ventricle, semi- and automatic lesion segmentation methods, advanced statistical analysis and visualisation based on the American Heart Association 17-segment model. New segmentation methods can be integrated into the plug-in by developing components based on image processing and visualisation libraries such as ITK and VTK in C++ programming language. CMRSegTools allows the creation of training and testing data sets (labeled features such as lesion, microvascular obstruction and remote ROI) for supervised Machine Learning methods, and enables the comparative assessment of lesion segmentation methods via a single and integrated platform. The plug-in has been successfully used by several CMR imaging studies.

Reducing cardiac implantable electronic device–induced artefacts in cardiac magnetic resonance imaging

ObjectivesCardiac implantable electronic device (CIED)–induced metal artefacts possibly significantly diminish the diagnostic value of magnetic resonance imaging (MRI), particularly cardiac MR (CMR). Right-sided generator implantation, wideband late-gadolinium enhancement (LGE) technique and raising the ipsilateral arm to the generator during CMR scanning may reduce the CIED-induced image artefacts. We assessed the impact of generator location and the arm-raised imaging position on the CIED-induced artefacts in CMR.MethodsWe included all clinically indicated CMRs performed on patients with normal cardiac anatomy and a permanent CIED with endocardial pacing leads between November 2011 and October 2019 in our institution (n = 171). We analysed cine and LGE sequences using the American Heart Association 17-segment model for the presence of artefacts.ResultsRight-sided generator implantation and arm-raised imaging associated with a significantly increased number of artefact-free segments. In patients with a right-sided pacemaker, the median percentage of artefact-free segments in short-axis balanced steady-state free precession LGE was 93.8% (IQR 9.4%, n = 53) compared with 78.1% (IQR 20.3%, n = 58) for left-sided pacemaker (p < 0.001). In patients with a left-sided implantable cardioverter-defibrillator, the median percentage of artefact-free segments reached 87.5% (IQR 6.3%, n = 9) using arm-raised imaging, which fell to 62.5% (IQR 34.4%, n = 9) using arm-down imaging in spoiled gradient echo short-axis cine (p = 0.02).ConclusionsArm-raised imaging represents a straightforward method to reduce CMR artefacts in patients with left-sided generators and can be used alongside other image quality improvement methods. Right-sided generator implantation could be considered in CIED patients requiring subsequent CMR imaging to ensure sufficient image quality.Key Points• Cardiac implantable electronic device (CIED)–induced metal artefacts may significantly diminish the diagnostic value of an MRI, particularly in cardiac MRIs.• Raising the ipsilateral arm relative to the CIED generator is a cost-free, straightforward method to significantly reduce CIED-induced artefacts on cardiac MRIs in patients with a left-sided generator.• Right-sided generator implantation reduces artefacts compared with left-sided implantation and could be considered in CIED patients requiring subsequent cardiac MRIs to ensure adequate image quality in the future.

A clinical study on relationship between visualization of cardiac fibroblast activation protein activity by Al18F-NOTA-FAPI-04 positron emission tomography and cardiovascular disease.

ObjectiveFAP plays a vital role in myocardial injury and fibrosis. Although initially used to study imaging of primary and metastatic tumors, the use of FAPI tracers has recently been studied in cardiac remodeling after myocardial infarction. The study aimed to investigate the application of FAPI PET/CT imaging in human myocardial fibrosis and its relationship with clinical factors.Materials and methodsRetrospective analysis of FAPI PET/CT scans of twenty-one oncological patients from 05/2021 to 03/2022 with visual uptake of FAPI in the myocardium were applying the American Heart Association 17-segment model of the left ventricle. The patients’ general data, echocardiography, and laboratory examination results were collected, and the correlation between PET imaging data and the above data was analyzed. Linear regression models, Kendall’s TaU-B test, the Spearman test, and the Mann–Whitney U test were used for the statistical analysis.Results21 patients (60.1 ± 9.4 years; 17 men) were evaluated with an overall mean LVEF of 59.3 ± 5.4%. The calcific plaque burden of LAD, LCX, and RCA are 14 (66.7%), 12 (57.1%), and 9 (42.9%). High left ventricular SUVmax correlated with BMI (P < 0.05) and blood glucose level (P < 0.05), and TBR correlated with age (P < 0.05). A strong correlation was demonstrated between SUVmean and CTnImax (r = 0.711, P < 0.01). Negative correlation of SUVmean and LVEF (r = −0.61, P < 0.01), SUVmax and LVEF (r = −0.65, P < 0.01) were found. ROC curve for predicting calcified plaques by myocardial FAPI uptake (SUVmean) in LAD, LCX, and RCA territory showed AUCs were 0.786, 0.759, and 0.769.ConclusionFAPI PET/CT scans might be used as a new potential method to evaluate cardiac fibrosis to help patients’ management further. FAPI PET imaging can reflect the process of myocardial fibrosis. High FAPI uptakes correlate with cardiovascular risk factors and the distribution of coronary plaques.

Standardizing the cardiac radioablation targeting workflow: enabling semi-automated angulation and segmentation of the heart according to the American Heart Association segmented model

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Dutch Heart Foundation Purpose Cardiac radioablation has evolved as a potential treatment modality for therapy-refractory ventricular tachycardia. To standardize cardiac radioablation treatments, promote accurate communication and target identification, and to assess toxicity, robust and reproducible methods for angulation and cardiac segmentation are paramount. In this study, we developed and evaluated a workflow for semi-automated angulation and segmentation according to the American Heart Association (AHA) 17-segment model. Methods and materials The workflow for semi-automated angulation and segmentation of the planning-CT was based on an in-house developed tool requiring placement of only 4 point-markers and a rotation matrix. For angulation, 2 markers defining the cardiac long-axis were placed: at the cardiac apex and at the center of the mitral valve (figure A). A rotation matrix was derived that angulates the CT-volume, resulting in the cardiac short axis (figure B). Segmentation was subsequently performed based on marking the two left ventricular hinge points (figure BC). To evaluate reproducibility, 5 observers independently placed markers in planning-CTs of 6 patients. Results The Root-Mean-Square of the standard deviation for the angulation and segmentation marker positions were all below 0.52cm. The 17-segments were subsequently generated and compared between the observers resulting in a median dice coefficient of 0.8 [0.70;0.87] and a median of the mean Hausdorff distance of 0.09cm [0.05;0.17]. Figure D shows the heat maps of two illustrative segments indicating the percentage agreement per voxel between the 5 observers. The interquartile ranges of Euler angles α and β, determined by the angulation markers, was less than 30 for all patients except one. For the γ angle, determined by the hinge point markers, the interquartile range was up to 120. Conclusion In this study, a workflow for cardiac radioablation is presented that enables reproducible semi-automatic cardiac angulation and segmentation of the planning-CT according to the AHA 17-segment model. This workflow can be easily implemented and be used to promote communication between radiation oncology and cardiology, enables cardiology-oriented targeting and permits focused toxicity evaluations.

Standardizing the Cardiac Radioablation Targeting Workflow: Enabling Semi-Automated Angulation and Segmentation of the Heart According to the American Heart Association Segmented Model

PurposeCardiac radioablation has evolved as a potential treatment modality for therapy-refractory ventricular tachycardia. To standardize cardiac radioablation treatments, promote accurate communication and target identification, and to assess toxicity, robust, and reproducible methods for angulation and cardiac segmentation are paramount. In this study, we developed and evaluated a tool for semiautomated angulation and segmentation according to the American Heart Association 17-segment model. Methods and MaterialsThe semiautomated angulation and segmentation of the planning-computed tomography (CT) was based on an in-house developed tool requiring placement of only 4 point-markers and a rotation matrix. For angulation, 2 markers defining the cardiac long-axis were placed: at the cardiac apex and at the center of the mitral valve. A rotation matrix was derived that angulates the CT volume, resulting in the cardiac short axis. Segmentation was subsequently performed based on marking the 2 left ventricular hinge points. To evaluate reproducibility, 5 observers independently placed markers in planning CTs of 6 patients. ResultsThe root mean square of the standard deviation for the angulation and segmentation marker positions were ≤0.5 cm. The 17 segments were subsequently generated and compared between the observers resulting in a median Dice coefficient of 0.8 (interquartile range: 0.70-0.87) and a median of the mean Hausdorff distance of 0.09 cm (interquartile range: 0.05-0.17). The interquartile ranges of Euler angles α and β, determined by the angulation markers, was less than 3 degrees for all patients except one. For the γ angle, determined by the hinge point markers, the interquartile range was up to 12 degrees. ConclusionsIn this study a method for semiautomatic angulation and segmentation of the heart for cardiac radioablation according to the American Heart Association Segmented Model is presented and evaluated. Based on our results we believe that the segmentation is reproducible and that it can be used to promote communication between radiation oncology and cardiology, enables cardiology-oriented targeting and permits focused toxicity evaluations.

Enabling Best Practices for Cardiac Radioablation Through a Remote Education and Peer Review Program

<h3>Purpose/Objective(s)</h3> Noninvasive cardiac radioablation (CRA) is increasingly used for treatment of high-risk ventricular tachycardia (VT). In an effort to promote consistency and disseminate best practices learned from our experience and that of other centers, we developed a remote education and peer review program via our Center for Noninvasive Cardiac Radioablation (CNCR). We report structure and international engagement via the CNCR program. <h3>Materials/Methods</h3> Centers that contacted CNCR with interest in starting a CRA program were provided with a digital packet of relevant literature on CRA, as well as brief guidance documents for optimizing simulation, image reorientation, and targeting. An introductory video call was scheduled with representatives from electrophysiology and radiation oncology between the site and CNCR. A consistent set of topics was discussed with each center in light of their local capabilities, including general principles of patient selection, targeting, simulation, motion management, treatment planning, delivery, and follow-up, and when appropriate, regulatory and billing issues. To facilitate consistent approaches to discussion of targeting, the American Heart Association 17-segment model construct was employed. For centers with a potential CRA case(s), interactive peer review was accomplished for targeting and planning, with the final decision for treatment at the discretion of the treating centers. <h3>Results</h3> From 2019 to present, 50 centers have engaged with CNCR through our program, representing 11 countries across 5 continents. Following initial engagement, 35/50 (70%) have treated at least one patient (range, 1-7), with 82 patients treated to date. Ninety-seven percent (34/35) of centers have maintained active engagement with CNCR following initial treatment of their first patient. Subsequently, three of those centers have develop prospective IDE trials through the FDA. All centers have committed to engagement in a newly established international registry and enrollment on developing clinical trials. <h3>Conclusion</h3> Cardiac radioablation is undergoing rapid uptake as a potential treatment for patients with high-risk VT, with the potential for wide variability in implementation. The CNCR remote education and peer review program has enabled rapid engagement with centers around the world, with a focus on best practices, establishing relationships for mutual sharing and collaboration, and encouraging prospective evaluation of safety and efficacy for CRA.

A novel algorithm for 3-D visualization of electrogram duration for substrate-mapping in patients with ischemic heart disease and ventricular tachycardia.

BackgroundMyocardial slow conduction is a cornerstone of ventricular tachycardia (VT). Prolonged electrogram (EGM) duration is a useful surrogate parameter and manual annotation of EGM characteristics are widely used during catheter-based ablation of the arrhythmogenic substrate. However, this remains time-consuming and prone to inter-operator variability. We aimed to develop an algorithm for 3-D visualization of EGM duration relative to the 17-segment American Heart Association model.MethodsTo calculate and visualize EGM duration, in sinus rhythm acquired high-density maps of patients with ischemic cardiomyopathy undergoing substrate-based VT ablation using a 64-mini polar basket-catheter with low noise of 0.01 mV were analyzed. Using a custom developed algorithm based on standard deviation and threshold, the relationship between EGM duration, endocardial voltage and ablation areas was studied by creating 17-segment 3-D models and 2-D polar plots.Results140,508 EGMs from 272 segments (n = 16 patients, 94% male, age: 66±2.4, ejection fraction: 31±2%) were studied and 3-D visualization of EGM duration was performed. Analysis of signal processing parameters revealed that a 40 ms sliding SD-window, 15% SD-threshold and >70 ms EGM duration cutoff was chosen based on diagnostic odds ratio of 12.77 to visualize rapidly prolonged EGM durations. EGMs > 70 ms matched to 99% of areas within dense scar (<0.2 mV), in 95% of zones within scar border zone (0.2–1.0 mV) and detected ablated areas having resulted in non-inducibility at the end of the procedure. Ablation targets were identified with a sensitivity of 65.6% and a specificity of 94.6% avoiding false positive labeling of prolonged EGMs in segments with healthy myocardium.ConclusionThe novel algorithm allows rapid visualization of prolonged EGM durations. This may facilitate more objective characterization of arrhythmogenic substrate in patients with ischemic cardiomyopathy.

Role of Dual-layer Detector Energy Spectral CT in Resting Myocardial Perfusion Imaging for Patients with Normal Coronary Artery

Objective To investigate the role of dual-layer detector energy spectral CT in resting myocardial perfusion imaging for patients with normal coronary artery. Methods One hundred and fifty-six patients with suspected coronary heart disease underwent dual-layer detector energy spectral CT coronary angiography,and resting myocardial perfusion imaging was performed for 28 patients with normal coronary artery.According to American Heart Association's 17-segmentmodel,the iodine density and effective atomic number(Zeff value)of each myocardial segment(except for apical segment)were measured and normalized to those of the aorta.All the data were quantitatively evaluated using ANOVA or Friedman test. Results Iodine density and Zeff value of myocardial segments in middle plane were significantly different(all P<0.001).The iodine density and Zeff value showed no significant difference between segments in basal and apical plane(all P > 0.05). Conclusions Iodine density and Zeff value of myocardial segments can be quantitatively evaluated using dual-layer detector energy spectral CT.Resting myocardial perfusion of segments in middle plane are significantly different in patients with normal coronary artery.

Late gadolinium enhancement location assessed by magnetic resonance and arrhythmogenic risk in hypertrophic cardiomyopathy

Introduction and ObjectivesLate gadolinium enhancement (LGE) extent has emerged as a predictor of sudden cardiac death (SCD) in patients with hypertrophic cardiomyopathy (HCM), however little is known about the arrhythmogenic relevance of its specific location in the left ventricle. Our aim was to analyze the influence of LGE location on the occurrence of ventricular arrhythmias (VA) and SCD in patients with HCM. MethodsWe performed a retrospective analysis of clinical and Holter records of HCM patients who underwent cardiac magnetic resonance at our center. LGE extent and distribution were assessed using the American Heart Association 17-segment model. VA was defined as non-sustained or sustained ventricular tachycardia, ventricular fibrillation or SCD. ResultsSixty-one patients (age 57.0±16.7 years) were included and VA occurred in 24.6% (n=15). Patients with VA showed greater LGE extent than those without (7.40±5.3 vs. 3.52±3.0 segments, p=0.007). Analyzing the distribution of LGE, a set of arrhythmogenic segments (apex/basal inferior/basal anterolateral/mid inferoseptal) was found. The extent of LGE involvement in these segments was also greater in patients with VA (2.07±1.03 vs. 0.65±0.71 segments, p<0.001; area under the curve 0.861 for VA) and this difference remained significant after adjustment for potentially confounding variables. ConclusionsThe extent of LGE involvement of a set of segments with an apparent relation to cardiac areas of increased mechanical stress was significantly and independently associated with the occurrence of VA, suggesting that not only the extent but also the location of LGE is important for the assessment of SCD risk in HCM patients.

Relationship Between Cardiac Fibroblast Activation Protein Activity by Positron Emission Tomography and Cardiovascular Disease.

FAP (fibroblast activation protein) plays an important role in cardiac wound healing and remodeling. Although initially developed as a theranostic ligand for metastasized cancer, FAPI (FAP inhibitor) tracers have recently been used to study cardiac remodeling following myocardial infarction in small-animal models. The aim of the study was to evaluate the activity of FAP via FAPI-positron emission tomography-computed tomography scans in human hearts. FAPI-positron emission tomography-computed tomography scans of 229 patients of 2 consecutive cohorts (modeling cohort: n=185; confirmatory cohort: n=44) suffering from metastasized cancer were analyzed applying the American Heart Association 17-segment model of the left ventricle. Logistic regression models were created using data from the modeling cohort. Multivariate regression models were established using Akaike information criterion in a step-down approach. Fourteen percent of patients had preexisting coronary artery disease (n=31), 33% arterial hypertension (n=75), and 12% diabetes mellitus type II (n=28). Forty-three percent had been treated with platin derivatives (n=100), 14% with anthracyclines (n=32), and 10% had a history of prior radiation to the chest (n=23). High left ventricular FAPI signals correlated with the presence of cardiovascular risk factors (odds ratio [OR], 4.3, P=0.0029), a focal myocardial signal pattern (OR, 3.9, P=0.0068), diabetes mellitus type II (OR, 4.1, P=0.046), and beta-blocker use (OR, 3.8, P=0.049) in univariate regression models. In a multivariate analysis, increased signal intensity was significantly higher in patients with cardiovascular risk factors (overweight [OR, 2.6, P=0.023], diabetes mellitus type II [OR, 2.9, P=0.041], certain chemotherapies [platinum derivatives; OR, 3.0, P=0.034], and a history of radiation to the chest [OR, 3.5, P=0.024]). A focal enrichment pattern was more frequently observed in patients with known cardiovascular risk factors (P<0.0001). FAPI-positron emission tomography-computed tomography scans represent a new imaging modality to investigate cardiac FAP. High signal intensities correlate with cardiovascular risk factors and metabolic disease.

Effects of long-term statin-treatment on coronary atherosclerosis in patients with inflammatory joint diseases.

BackgroundThe effect of statins over time on coronary atherosclerosis in patients with inflammatory joint diseases (IJD) is unknown. Our aim was to evaluate the change in coronary plaque morphology and volume in long-term statin-treated patients with IJD.MethodsSixty-eight patients with IJD and carotid artery plaque(s) underwent coronary computed tomography angiography before and after a mean of 4.7 (range 4.0–6.0) years of statin treatment. The treatment target for low density lipoprotein cholesterol (LDL-c) was ≤1.8 mmol/L. Changes in plaque volume (calcified, mixed/soft and total) and coronary artery calcification (CAC) from baseline to follow-up were assessed using the 17-segment American Heart Association-model.ResultsMedian (IQR) increase in CAC after statin treatment was 38 (5–236) Agatston units (p<0.001). Calcified and total plaque volume increased with 5.6 (0.0–49.1) and 2.9 (0.0–23.5) mm3, respectively (p<0.001 for both). The median (IQR) change in soft/mixed plaque volume was -10 (-7.1–0.0), p = <0.001. Patients who had obtained the LDL-c treatment target at follow-up, experienced reduced progression of both CAC and total plaque volume compared to patients with LDL-c >1.8mmol/L (21 [2–143] vs. 69 [16–423], p = 0.006 and 0.65 [-1.0–13.9] vs. 13.0 [0.0–60.8] mm3, p = 0.019, respectively).ConclusionsA progression of total atherosclerotic plaque volume in statin-treated patients with IJD was observed. However, soft/mixed plaque volume was reduced, suggesting an alteration in plaque composition. Patients with recommended LDL-c levels at follow-up had reduced atherosclerotic progression compared to patients with LDL-c levels above the treatment target, suggesting a beneficial effect of treatment to guideline-recommended lipid targets in IJD patients.

P5270Impaired myocardial deformation assessed by cardiac magnetic resonance is associated with increased arrhythmic risk in hypertrophic cardiomyopathy

Abstract Background Strain techniques, such as feature tracking cardiac magnetic resonance (FT-CMR), have emerged as a promise for more accurate evaluation of cardiac function compared to ejection fraction. In hypertrophic cardiomyopathy (HCM) patients, impaired myocardial deformation measured by FT-CMR has been associated with severity of hypertrophy and presence of late gadolinium enhancement (LGE) but associations with clinical severity and prognosis are scarce. Purpose To analyse the association between left ventricular strain measured by FT-CMR, morphologic features and prognostic markers in patients with HCM. Methods Retrospective analysis of clinical, echocardiography, Holter and CMR data of HCM patients aged ≥16 years followed at two referral centres. Ventricular arrhythmias (VA) were defined as non-sustained or sustained ventricular tachycardia or sudden cardiac arrest. Sudden cardiac death (SCD) risk was evaluated using the score proposed by the European Society of Cardiology. LGE extension was evaluated using the American Heart Association 17-segment model. FT-CMR was used to evaluate global peak systolic longitudinal (GLS), radial (GRS) and circumferential (GCS) strains - GLS was averaged from three standard longitudinal views while GRS and GCS were averaged from the basal, mid and apical LV short-axis planes. Results A total of 109 HCM patients (59.2±16.2 years old; 60.6% males) were included; mean follow-up was 39±25 months. Mean LV mass was 170.6±70.3g, LVEF was 63.7±10.0% and the number of segments with LGE was 3.14±3.32. Mean GLS, GRS and GCS were −14.8±4.0%, 34.4±13.3% and −17.5±4.8%, respectively. Impaired strain was associated with higher LV mass (GLS: r=0.46, GRS: r=−0.46, GCS: r=0.47, p&lt;0.001 for all), reduced LVEF (GLS: r=−0,33, GRS: r=0,44, GCS: r=−0.41, p&lt;0.003 for all) and LGE extension (GLS: r=0.26, GRS: r=−0.38, GCS: r=0.38, p&lt;0.01 for all). SCD risk score was 3.12%±2.98 (8 patients scored as high risk) and VA were documented in 26 patients (26%). Patients with VA had worse strain values than those without (GLS −13.2±4.12 vs −15.5±3.71, p=0.011; GCS −15,8±5.22 vs −18.3±4.24, p=0.017). Patients with high estimated risk of SCD also had worse strain values than those at low/intermediate risk (GLS −12.2±3.57 vs −15.1±3.83, p=0.048; GCS −14.5±4.26 vs −17.9±4.54, p=0.047). A correlation between SCD risk and GLS and GCS was observed (r=0.32, p=0.004; r=0.23, p=0.03, respectively). Conclusions In our population, worse strain measurements were associated with a more severe HCM phenotype, presence of VA and a higher estimated risk of SCD. Strain assessed by FT-CMR may improve risk stratification in HCM patients.

A QRS axis–based algorithm to identify the origin of scar-related ventricular tachycardia in the 17-segment American Heart Association model

Previously proposed algorithms to predict the ventricular tachycardia (VT) exit site have been based on diverse left ventricular models, but none of them identify the precise region of origin in the electroanatomic map. Moreover, no electrocardiographic (ECG) algorithm has been tested to predict the region of origin of scar-related VTs in patients with nonischemic cardiomyopathy. The purpose of this study was to validate a simple ECG algorithm to identify the segment of origin (SgO) of VT relative to the 17-segment American Heart Association model in patients with structural heart disease (SHD). The study included 108 consecutive patients with documented VT and SHD [77 (71%) with coronary artery disease]. A novel frontal plane axis-based ECG algorithm (highest positive or negative QRS voltage) together with the polarity in leads V3 and V4 was used to predict the SgO of VT. The actual SgO of VT was obtained from the analysis of the electroanatomic map during the procedure. Conventional VT mapping techniques were used to identify the VT exit. In total, 149 12-lead ECGs of successfully ablated VT were analyzed. The ECG-suggested SgO matched with the actual SgO in 122 of the 149 VTs (82%). In 21 of the 27 mismatched ECG-suggested SgOs (77.8%), the actual SgO was adjacent to the segment suggested by the ECG. There were no differences in the accuracy of the algorithm based on the SgO or the type of SHD. This novel QRS axis-based algorithm accurately identifies the SgO of VT in the 17-segment American Heart Association model in patients with SHD.

Associations between coronary and carotid artery atherosclerosis in patients with inflammatory joint diseases

ObjectiveLow association between cardiac symptoms and coronary artery disease (CAD) in patients with inflammatory joint diseases (IJD) demands for objective markers to improve cardiovascular risk stratification. Our main aim was...

Cardiac PET/CT with Rb-82: optimization of image acquisition and reconstruction parameters

BackgroundOur aim was to characterize the influence of time-of-flight (TOF) and point spread function (PSF) recovery corrections, as well as ordered subset expectation maximization (OSEM) reconstruction parameters, in 82Rb PET/CT quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR).Rest and stress list-mode dynamic 82Rb PET acquisition data from 10 patients without myocardial flow defects and 10 patients with myocardial blood flow defects were reconstructed retrospectively. OSEM reconstructions were performed with Gaussian filters of 4, 6, and 8 mm, different iterations, and subset numbers (2 × 24; 2 × 16; 3 × 16; 4 × 16). Rest and stress global, regional, and segmental MBF and MFR were computed from time activity curves with FlowQuant© software. Left ventricular segmentation using the 17-segment American Heart Association model was obtained.ResultsWhole left ventricle (LV) MBF at rest and stress were 0.97 ± 0.30 and 2.30 ± 1.00 mL/min/g, respectively, and MFR was 2.40 ± 1.13. Concordance was excellent and all reconstruction parameters had no significant impact on MBF, except for the exclusion of TOF which led to significantly decreased concordance in rest and stress MBF in patients with or without perfusion defects on a coronary artery basis and in MFR in patients with perfusion defects.ConclusionsChanges in reconstruction parameters in perfusion 82Rb PET/CT studies influence quantitative MBF analysis. The inclusion of TOF information in the tomographic reconstructions had significant impact in MBF quantification.

Two-dimensional speckle-tracking-derived segmental peak systolic longitudinal strain identifies regional myocardial involvement in patients with myocarditis and normal global left ventricular systolic function.

The presence of myocardial late gadolinium enhancement (LGE) by cardiac magnetic resonance (CMR) imaging in concert with electrocardiography and elevated biomarkers helps support the diagnosis of acute myocarditis. Two-dimensional echocardiography is limited to global and qualitative regional function assessment and may not contribute to the diagnosis, especially in the presence of normal LV systolic function. Two-dimensional speckle-tracking (2D-STE)-derived segmental peak systolic (pkS) longitudinal strain (LS) may identify segmental myocardial involvement in myocarditis. We sought to identify an association between segmental pkS, LGE, and troponin levels in patients with myocarditis. Retrospective analysis of myocardial segmental function by 2D-STE segmental strain was compared to the presence of LGE and admission peak troponin levels in patients with acute myocarditis and preserved global LV systolic function. American Heart Association 17-segment model was used for comparison between imaging modalities. Global function was assessed by m-mode-derived shortening fraction (SF). Descriptive statistics and regression analysis were utilized. Forty-four CMRs performed to evaluate for myocarditis were identified. Of the 44, 10 patients, median age 17.5 years (14-18.5 years) and median SF 35 % (28-44 %), had paired CMR and 2D-STE data for analysis, and 161/170 segments could be analyzed by both methods for comparison. PkS LS was decreased in 51 % of segments that were positive for LGE with average pkS of -14.7 %. Segmental pkS LS abnormalities were present in all but one patient who had abnormal pkS circumferential strain. Global pkS LS was decreased in patients with myocarditis. There is a moderate correlation between decreased pkS LS and the presence of LGE by CMR, 2D-STE for myocardial involvement in acute myocarditis can serve as an useful noninvasive adjunct to the existing tests used for the diagnosis of acute myocarditis and might have a role in prognostication.

Normal range and regional heterogeneity of myocardial perfusion in healthy human myocardium: assessment on dynamic perfusion CT using 128-slice dual-source CT

Information about myocardial perfusion in healthy hearts is essential for evaluating patients with ischemic heart disease. The purpose of this study was to determine the range and regional variability of myocardial perfusion in normal volunteers on dynamic perfusion computed tomography (CT). Myocardial perfusion was assessed in 19 healthy volunteers (age 33-60 years; 11 men) at rest and during adenosine-induced hyperemia using a 128-slice dual-source CT scanner. Data were quantified as cc/cc/min for the transmural myocardium based on a 17-segment American Heart Association model. Mean myocardial blood flows (MBF) were 1.73 ± 0.33 cc/cc/min during adenosine-induced hyperemia, 0.83 ± 0.21 cc/cc/min at rest, and perfusion reserve was 2.20 ± 0.53. Regional variability was 17 ± 5% for hyperemic perfusion, 18 ± 7% for resting, and 21 ± 6 % for perfusion reserve. Although statistically insignificant, perfusion in the septum was lower at rest and during hyperemia than in other regions. Women tended to have lower perfusion during hyperemia (1.65 ± 0.40 vs. 1.79 ± 0.28 cc/cc/min, P = 0.40), and higher perfusion at rest than men (0.91 ± 0.27 vs. 0.77 ± 0.15 cc/cc/min, P = 0.23), resulting in lower perfusion reserve (1.86 ± 0.31 vs. 2.45 ± 0.53, P = 0.11). This small cohort of healthy volunteers study reveals normal myocardial perfusion parameter on dynamic perfusion CT as follows: mean MBF is 1.73 ± 0.33 cc/cc/min during hyperemia, 0.83 ± 0.21 cc/cc/min at rest, and perfusion reserve is 2.20 ± 0.53. And the study also demonstrates considerable regional heterogeneity of the myocardial perfusion.

Defining Left Ventricular Noncompaction Using Cardiac Computed Tomography

Left ventricular noncompaction (LVNC) is a cardiomyopathy characterized by a distinctive 2-layered appearance of the myocardium because of increased trabeculation and deep intertrabecular recesses. Echocardiography serves as the initial noninvasive diagnostic test. Currently, magnetic resonance imaging (MRI) is increasingly being used to diagnose LVNC because of its improved temporal and spatial resolution. So far, no criteria have been proposed to define pathologic LVNC with the use of computed tomography (CT). We analyzed CT images using an American Heart Association 17-segment model in 8 patients previously diagnosed with LVNC by clinical diagnosis, echocardiography, and/or MRI, as well as in 11 patients with nonischemic dilated cardiomyopathy, 11 patients with hypertrophic cardiomyopathy, 10 patients with severe aortic stenosis, 9 patients with severe aortic regurgitation, 10 patients with left ventricular hypertrophy due to essential hypertension, and, additionally, in a control group of 20 patients who had normal CT scans without a history of cardiovascular disease. The distribution of LVNC was assessed by qualitative analysis of 17 myocardial segments for the presence or absence of any degree of noncompaction. Each segment was analyzed in each of the 3 end-diastolic long-axis views for the presence or absence of noncompaction, and the most prominent trabeculation was chosen for measurement. The left ventricular apex was excluded. Thickness of noncompacted and compacted myocardium was measured perpendicular to the compacted myocardium. The ratio of noncompacted to compacted (NC:C) myocardium was calculated for each segment. Receiver operating characteristics were used to generate cutoff values with sensitivity and specificity to distinguish the LVNC group from other groups. An end-diastolic NC:C ratio >2.3 distinguished pathologic LVNC with 88% sensitivity and 97% specificity; positive and negative predictive values were 78% and 99%, respectively. CT using the standard MRI NC:C ratio cutoff >2.3 accurately characterizes pathologic LVNC.