Institutional experience report on the target contouring workflow in the radiotherapy department for stereotactic arrhythmia radioablation delivered on conventional linear accelerators.

PURPOSE: In stereotactic arrhythmia radioablation (STAR), the target is defined using multiple imaging studies and a multidisciplinary team consisting of electrophysiologist, cardiologist, cardiac radiologist, and radiation oncologist collaborate to identify the target and delineate it on the imaging studies of interest. This report describes the workflow employed in our radiotherapy department to transfer the target identified based on electrophysiology and cardiology imaging to the treatment planning image set. METHODS: The radiotherapy team was presented with an initial target in cardiac axes orientation, contoured on a wideband late gadolinium-enhanced (WB-LGE) cardiac magnetic resonance (CMR) study, which was subsequently transferred to the computed tomography (CT) scan used for treatment planning-i.e., the average intensity projection (AIP) image set derived from a 4D CT-via an axial CMR image set, using rigid image registration focused on the target area. The cardiac and the respiratory motion of the target were resolved using ciné-CMR and 4D CT imaging studies, respectively. RESULTS: The workflow was carried out for 6 patients and resulted in an internal target defined in standard anatomical orientation that encompassed the cardiac and the respiratory motion of the initial target. CONCLUSION: An image registration-based workflow was implemented to render the STAR target on the planning image set in a consistent manner, using commercial software traditionally available for radiation therapy.

Massive Mysteries.

Papillary fibroelastomas are benign masses often originating from the endocardium of the aortic and mitral valves. Rarely, these neoplasms are found in areas of the heart embryonically distinct from the aortic and mitral valves. Diagnosis of a papillary fibroelastoma relies on multimodal imaging as well as histologic assessment. A case series of papillary fibroelastomas in unusual locations is presented, highlighting the role of multimodal imaging techniques in identifying these intra-cardiac masses. Differential diagnoses, imaging characteristics, histopathology, and preferred management strategies for cardiac masses are reviewed. The unique imaging qualities of cardiac masses are discussed.

Right Atrial Compression From Biodebris Associated With Long-Term Left Ventricular Assist Device Support.

Biodebris surrounding HVAD (Medtronic) intrapericardial centrifugal-flow left ventricular assist device outflow cannulas is common and appears to accumulate over time. We recently encountered 2 patients on long-term HVAD support with right atrial compression from such biodebris, prompting a review of our institution's HVAD cohort to better understand this phenomenon. (Level of Difficulty: Intermediate.).

Case report: paradoxically reversible perfusion defects on vasodilator stress imaging in a case of metastatic coronary compression.

Background: Patients with malignancy who experience metastasis to cardiac structures may exhibit ST-segment elevations and acute coronary syndrome (ACS) through poorly understood pathophysiologic mechanisms. We present a case in which vasodilator stress cardiovascular magnetic resonance provides unique insight into one such patient who suffered from recurrent episodes resembling ACS. Case summary: A 58-year-old male with metastatic lung adenocarcinoma presented with refractory angina and dynamic inferior electrocardiogram changes. The patient was referred for adenosine stress cardiovascular magnetic resonance, revealing multiple territories of abnormal perfusion during rest with improvement during adenosine infusion. Subsequent computed tomography displayed tumour encasement of the right coronary artery. Taken together, vasodilator-responsive extrinsic compression of multiple epicardial coronary arteries was suspected. Outpatient oncology follow-up for chemoimmunotherapy initiation was arranged with the hope that reducing tumour burden might alleviate coronary compression. However, in the ensuing months, the patient's disease advanced beyond the point of which his symptoms could be controlled medically, and he was ultimately enrolled in hospice care. Discussion: Encasement of coronary arteries can result in anginal symptoms if their position impairs coronary arterial flow. The presented case highlights the unique manner in which these lesions might behave on stress cardiac magnetic resonance imaging. Clinicians who encounter such unusual findings on vasodilator stress imaging should consider metastatic lesions to the cardiac structures on the differential diagnosis.

Cardiac MRI of Hereditary Cardiomyopathy.

Hereditary cardiomyopathy comprises a heterogeneous group of diseases of the cardiac muscle that are characterized by the presence of genetic mutations. Cardiac MRI is central to evaluation of patients with cardiomyopathy owing to its ability to allow evaluation of many different tissue properties in a single examination. For example, cine MRI is the standard of care for assessment of myocardial structure and function. It clearly shows regions of asymmetric wall thickening that are typical of hypertrophic cardiomyopathy and allows it to be differentiated from other hereditary disorders such as Fabry disease or transthyretin cardiac amyloidosis that produce concentric hypertrophy. Late gadolinium enhancement provides a different tissue property and allows these latter two causes of concentric hypertrophy to be distinguished on the basis of their enhancement appearances (Fabry disease shows midwall basal inferolateral enhancement, and amyloidosis shows global subendocardial enhancement). Native T1 mapping may similarly allow differentiation between Fabry disease and amyloidosis without the use of contrast material. T2*-weighted MRI is important in the detection and quantification of iron overload cardiomyopathy. Other hereditary entities for which comprehensive MRI has proven essential include Danon disease, familial dilated cardiomyopathy, hereditary muscular dystrophy, arrhythmogenic right ventricular cardiomyopathy, and ventricular noncompaction. As a result of the diagnostic power of cardiac MRI, cardiac MRI examinations are being requested with increasing frequency, not only in academic centers but also in community practices. The genetic background, pathophysiologic characteristics, and clinical presentation of patients with hereditary cardiomyopathy are described; the characteristic cardiac MRI features of hereditary cardiomyopathy are discussed; and the role of MRI in risk stratification, treatment, and prognostication in patients with cardiomyopathy is reviewed. ©RSNA, 2022 Online supplemental material is available for this article.

Influence of extracellular volume fraction on peak exercise oxygen pulse following thoracic radiotherapy.

BACKGROUND: Radiation-induced myocardial fibrosis increases heart failure (HF) risk and is associated with a restrictive cardiomyopathy phenotype. The myocardial extracellular volume fraction (ECVF) using contrast-enhanced cardiac magnetic resonance (CMR) quantifies the extent of fibrosis which, in severe cases, results in a noncompliant left ventricle (LV) with an inability to augment exercise stroke volume (SV). The peak exercise oxygen pulse (O2Pulse), a noninvasive surrogate for exercise SV, may provide mechanistic insight into cardiac reserve. The relationship between LV ECVF and O2Pulse following thoracic radiotherapy has not been explored. METHODS: Patients who underwent thoracic radiotherapy for chest malignancies with significant incidental heart dose (≥5 Gray (Gy), ≥10% heart) without a pre-cancer treatment history of HF underwent cardiopulmonary exercise testing to determine O2Pulse, contrast-enhanced CMR, and N-terminal pro-brain natriuretic peptide (NTproBNP) measurement. Multivariable-analyses were performed to identify factors associated with O2Pulse normalized for age/gender/anthropometrics. RESULTS: Thirty patients (median [IQR] age 63 [57-67] years, 18 [60%] female, 2.0 [0.6-3.8] years post-radiotherapy) were included. The peak VO2 was 1376 [1057-1552] mL·min- 1, peak HR = 150 [122-164] bpm, resulting in an O2Pulse of 9.2 [7.5-10.7] mL/beat or 82 (66-96) % of predicted. The ECVF, LV ejection fraction, heart volume receiving ≥10 Gy, and NTproBNP were independently associated with %O2Pulse (P < .001). CONCLUSIONS: In patients with prior radiotherapy heart exposure, %-predicted O2Pulse is inversely associated markers of diffuse fibrosis (ECVF), ventricular wall stress (NTproBNP), radiotherapy heart dose, and positively related to LV function. Increased LV ECVF may reflect a potential etiology of impaired LV SV reserve in patients receiving thoracic radiotherapy for chest malignancies.

Evidence-based cardiovascular magnetic resonance cost-effectiveness calculator for the detection of significant coronary artery disease.

BACKGROUND: Although prior reports have evaluated the clinical and cost impacts of cardiovascular magnetic resonance (CMR) for low-to-intermediate-risk patients with suspected significant coronary artery disease (CAD), the cost-effectiveness of CMR compared to relevant comparators remains poorly understood. We aimed to summarize the cost-effectiveness literature on CMR for CAD and create a cost-effectiveness calculator, useable worldwide, to approximate the cost-per-quality-adjusted-life-year (QALY) of CMR and relevant comparators with context-specific patient-level and system-level inputs. METHODS: We searched the Tufts Cost-Effectiveness Analysis Registry and PubMed for cost-per-QALY or cost-per-life-year-saved studies of CMR to detect significant CAD. We also developed a linear regression meta-model (CMR Cost-Effectiveness Calculator) based on a larger CMR cost-effectiveness simulation model that can approximate CMR lifetime discount cost, QALY, and cost effectiveness compared to relevant comparators [such as single-photon emission computed tomography (SPECT), coronary computed tomography angiography (CCTA)] or invasive coronary angiography. RESULTS: CMR was cost-effective for evaluation of significant CAD (either health-improving and cost saving or having a cost-per-QALY or cost-per-life-year result lower than the cost-effectiveness threshold) versus its relevant comparator in 10 out of 15 studies, with 3 studies reporting uncertain cost effectiveness, and 2 studies showing CCTA was optimal. Our cost-effectiveness calculator showed that CCTA was not cost-effective in the US compared to CMR when the most recent publications on imaging performance were included in the model. CONCLUSIONS: Based on current world-wide evidence in the literature, CMR usually represents a cost-effective option compared to relevant comparators to assess for significant CAD.

Cardiovascular magnetic resonance imaging in suspected cardiac tumour: a multicentre outcomes study.

AIMS: Cardiovascular magnetic resonance (CMR) imaging is a key diagnostic tool for the evaluation of patients with suspected cardiac tumours. Patient management is guided by the CMR diagnosis, including no further testing if a mass is excluded or if only a pseudomass is found. However, there are no outcomes studies validating this approach. METHODS AND RESULTS: In this multicentre study of patients undergoing clinical CMR for suspected cardiac tumour, CMR diagnoses were assigned as no mass, pseudomass, thrombus, benign tumour, or malignant tumour. A final diagnosis was determined after follow-up using all available data. The primary endpoint was all-cause mortality. Among 903 patients, the CMR diagnosis was no mass in 25%, pseudomass in 16%, thrombus in 16%, benign tumour in 17%, and malignant tumour in 23%. Over a median of 4.9 years, 376 patients died. Compared with the final diagnosis, the CMR diagnosis was accurate in 98.4% of patients. Patients with CMR diagnoses of pseudomass and benign tumour had similar mortality to those with no mass, whereas those with malignant tumour [hazard ratio (HR) 3.31 (2.40-4.57)] and thrombus [HR 1.46 (1.00-2.11)] had greater mortality. The CMR diagnosis provided incremental prognostic value over clinical factors including left ventricular ejection fraction, coronary artery disease, and history of extracardiac malignancy (P < 0.001). CONCLUSION: In patients with suspected cardiac tumour, CMR has high diagnostic accuracy. Patients with CMR diagnoses of no mass, pseudomass, and benign tumour have similar long-term mortality. The CMR diagnosis is a powerful independent predictor of mortality incremental to clinical risk factors.

An interventional approach to left ventricular assist device outflow graft obstruction.

BACKGROUND: LVADs provide life-sustaining treatment for patients with heart failure, but their complexity allows for complications. One complication, LVAD outflow graft obstruction, may be misdiagnosed as intraluminal thrombus, when more often it is extraluminal compression from biodebris accumulation. It can often be treated endovascularly with stenting. This case series describes diagnostic and procedural techniques for the treatment of left ventricular assist device (LVAD) outflow graft obstruction. METHODS: We present four patients with LVADs who developed LVAD outflow graft obstruction within the bend relief-covered segment. All were initially diagnosed with computed tomographic angiography (CTA). All underwent invasive evaluation with intravascular ultrasound (IVUS), then were treated with stenting. After misdiagnosing a twist, we developed the technique of balloon "graftoplasty" to ensure suitability for stent delivery in subsequent cases. RESULTS: All patients presented with low-flow alarms and symptoms of low output, and were diagnosed with outflow graft obstruction by CTA. In all four, IVUS confirmed an extraluminal etiology. Patient 1 was treated with stenting and had a good outcome. Patient 2's obstruction was from twisting, rather than biodebris accumulation, and had sub-optimal stent expansion and ultimately required surgery. Balloon "graftoplasty" was used in subsequent cases to ensure subsequent stent expansion. Patients 3 and 4 were successfully stented. All improved after treatment. CONCLUSIONS: In patients with LVAD outflow graft obstruction, IVUS can distinguish intraluminal thrombus from extraluminal compression. Balloon "graftoplasty" can ensure that the outflow graft will respond to stenting. Many cases of LVAD outflow graft obstruction should be amenable to endovascular treatment.

Management of Acute and Recurrent Pericarditis: JACC State-of-the-Art Review.

Pericarditis refers to the inflammation of the pericardial layers, resulting from a variety of stimuli triggering a stereotyped immune response, and characterized by chest pain associated often with peculiar electrocardiographic changes and, at times, accompanied by pericardial effusion. Acute pericarditis is generally self-limited and not life-threatening; yet, it may cause significant short-term disability, be complicated by either a large pericardial effusion or tamponade, and carry a significant risk of recurrence. The mainstay of treatment of pericarditis is represented by anti-inflammatory drugs. Anti-inflammatory treatments vary, however, in both effectiveness and side-effect profile. The objective of this review is to summarize the up-to-date management of acute and recurrent pericarditis.

Determinants of Cardiorespiratory Fitness Following Thoracic Radiotherapy in Lung or Breast Cancer Survivors.

We measured peak oxygen consumption (VO2) in previous recipients of thoracic radiotherapy and assessed the determinants of cardiorespiratory fitness with an emphasis on cardiac and pulmonary function. Cancer survivors who have received thoracic radiotherapy with incidental cardiac involvement often experience impaired cardiorespiratory fitness, as measured by reduced peak VO2, a marker of impaired cardiovascular reserve. We enrolled 25 subjects 1.8 (0.1 to 8.2) years following completion of thoracic radiotherapy with significant heart exposure (at least 10% of heart volume receiving at least 5 Gray). All subjects underwent cardiopulmonary exercise testing, Doppler echocardiography, and circulating biomarkers assessment. The cohort included 16 Caucasians (64%), 15 women (60%) with a median age of 63 (59 to 66) years. The peak VO2 was 16.8 (13.5 to 21.9) ml·kg-1·min-1 or moderately reduced at 62% (50% to 93%) of predicted. The mean cardiac radiation dose was 5.4 (3.7 to 14.7) Gray, and it significantly correlated inversely with peak VO2 (R = -0.445, p = 0.02). Multivariate regression analysis revealed the diastolic functional reserve index and the N-terminal pro-brain natriuretic peptide (NTproBNP) serum levels were independent predictors of peak VO2 (ß = +0.813, p <0.01 and ß = -0.414, p = 0.04, respectively). In conclusion, patients who had received thoracic radiation display a dose-dependent relation between the cardiac radiation dose received and the impairment in peak VO2, the reduction in diastolic functional reserve index, and elevation of NTproBNP.

Left Ventricular Assist Device Outflow Graft Compression: Incidence, Clinical Associations and Potential Etiologies.

BACKGROUND: Left ventricular assist devices (LVADs) have revolutionized the treatment of advanced heart failure, but proliferation of device therapy has unmasked potential complications. Reports have emerged of outflow graft narrowing due to extrinsic compression. METHODS AND RESULTS: The records of patients with LVADs that had been implanted at our institution were reviewed. Those who had postimplantation computed tomography angiographies sufficient to analyze the outflow graft lumen were identified, and the studies were analyzed to characterize the outflow graft lumen. We identified 241 patients; 110 (46%) had suitable computed tomography angiographies. Of those, 15 (14%) had evidence of outflow graft lumen narrowing, all in HeartMate devices and all within the portion covered by the bend relief. Of the 15, 3 underwent invasive examination, all without intraluminal thrombus but, rather, with biodebris between the bend relief and the outflow graft. Patients with HeartWare devices had a wide range of biodebris accumulation surrounding the outflow graft but no cases of lumen narrowing. On multivariable analysis, 1) time from device implant to scan, 2) nonischemic cardiomyopathy and 3) age at implant were significantly associated with higher risk of graft narrowing. CONCLUSION: Outflow graft narrowing can be seen in a number of patients with HeartMate LVADs within the portion covered by the bend relief. In the limited number of patients who underwent invasive evaluation, the narrowing was found to arise from extrinsic compression rather than intraluminal thrombus. The clinical significance of this requires further investigation.

Sources of variability in quantification of cardiovascular magnetic resonance infarct size - reproducibility among three core laboratories.

BACKGROUND: Acute myocardial infarct (AMI) size depicted by late gadolinium enhancement cardiovascular magnetic resonance (CMR) is increasingly used as an efficacy endpoint in randomized trials comparing AMI therapies. Infarct size is quantified using manual planimetry (MANUAL), visual scoring (VISUAL), or automated techniques using signal-intensity thresholding (AUTO). Although AUTO is considered the most reproducible, prior studies did not account for the subjective determination of endocardial/epicardial borders, which all methods require. For MANUAL and VISUAL, prior studies did not address how to treat intermediate signal intensities due to partial volume. METHODS: To assess sources of variability, AMI size was measured in 30 patients and 12 controls by 3 core-laboratories using 8 methods, each separated by more than 2 months time (n = 720 evaluations). The methods were: (1,2) AUTOSegment, AUTOFWHM (using Segment software or the full-width-at-half-maximum algorithm, respectively); (3,4) AUTO-UCSegment, AUTO-UCFWHM (user correction for endocardial border pixels, no-reflow, etc.); (5) MANUAL; (6) MANUAL-ISI (adjustment for intermediate signal-intensities); (7) VISUAL; (8) VISUAL-ISI. RESULTS: Mean infarct size varied between 16.8% and 27.2% of LV mass depending on method. Even automated techniques with no user interaction for infarct borders resulted in significant within-patient variability given the need to subjectively trace endocardial/epicardial contours. The coefficient-of-variation (CV) was 10.6% and 14.6% for AUTOSegment and AUTOFWHM, respectively. For manual and visual categories, reproducibility was improved when intermediate signal-intensities were considered (MANUAL-ISI vs MANUAL: CV = 8.3% vs 14.4%; p = 0.03; VISUAL-ISI vs VISUAL: CV = 8.4% vs 10.9%; p = 0.01). For AUTO-UCSegment, MANUAL-ISI, and VISUAL-ISI (best technique in each category) within-patient variability due to the quantification method was less than 10% of total variability, and the required sample sizes for detecting a 5% absolute difference in infarct size were 62, 63, and 62 patients, respectively. CONCLUSION: Among CMR core-laboratories, an important source of variability in infarct size quantification is the subjective delineation of endocardial/epicardial borders. When intermediate signal intensities are considered in manual planimetry and visual scoring, reproducibility and impact on sample size are similar to automated techniques.

Prospective Evaluation of Implantable Cardioverter-Defibrillator Lead Function During and After Left Ventricular Assist Device Implantation.

OBJECTIVES: This study investigated the mechanism of lead malfunction by monitoring lead parameters throughout left ventricular assist device (LVAD) implantation. BACKGROUND: Implantable cardioverter-defibrillator (ICD) lead malfunction can occur after LVAD implantation. METHODS: ICD lead data were prospectively evaluated during and after LVAD implantation and at 12 pre-specified intraoperative time points. RESULTS: We prospectively evaluated 32 patients with ICDs who underwent LVAD implantation, of whom 20 patients underwent serial testing at 12 intraoperative steps. Post-operative right ventricle (RV) sensing had decreased by >50% from baseline in 7 patients (22%), with RV sensing improving at 1 to 7 weeks in 2 patients (28.6%). Nine patients (28.1%) had >10-ohm (Ω) high-voltage (HV) impedance changes from baseline to final impedance. In all 5 patients with >50% decrease in RV sensing and all 7 patients with a >10-Ω HV impedance change who underwent intraoperative testing, changes were not detected until after weaning from cardiopulmonary bypass. Patients with decreased RV lead sensing >50% (n = 7) had lower glomerular filtration rates (48.7 ± 21.9 ml/min/1.73 m2 vs. 68.4 ± 22.5 ml/min/1.73 m2, respectively, p = 0.0489), were more likely to have undergone concomitant RVAD placement (42.9% vs. 0%, respectively, p = 0.0071), concomitant tricuspid valve surgery (57.1% vs. 16%, p = 0.0469), or to have had cardiac tamponade or unplanned return to the operating room (57.1% vs. 12%, p = 0.0258). CONCLUSIONS: ICD lead malfunction can occur following LVAD implantation but may improve over time. Intraoperative RV sensing and HV impedance changes were not detected until after weaning from cardiopulmonary bypass, suggesting the mechanism of RV lead malfunction may be related to LV unloading and concomitant leftward septal shift. A conservative approach is warranted in many patients with ICD parameter changes after LVAD implantation because parameter abnormalities may improve over time. (Implantable Cardioverter Defibrillator (ICD) Function During Ventricular Assist Device (VAD) Implantation; NCT01576562).