Bois, John P.

BACKGROUND: Technetium-based cardiac amyloid radionuclide imaging enables noninvasive diagnosis of transthyretin amyloid cardiomyopathy (ATTR-CM), but conventional planar and visual semiquantitative approaches have important limitations. We developed the quantitative 3-dimensional Mayo 3D Score, defined as the ratio of mean left ventricular myocardial radiotracer uptake to right atrial blood-pool uptake using computed tomography (CT)-fused single-photon emission CT (SPECT) volumes of interest, and sought to validate its diagnostic performance against myocardial pathology. METHODS: Consecutive patients who underwent 99m Tc-pyrophosphate SPECT/CT at Mayo Clinic for suspected ATTR-CM between June 2017 and January 2025 with archived myocardial tissue were included. Baseline characteristics, including demographics, echocardiogram, biomarkers, visual semiquantitative, and Mayo 3D Score metrics, were collected. Myocardial specimens underwent histopathologic confirmation of amyloid, with amyloid subtype determination and further semiquantitative grading of amyloid burden and deposition patterns. RESULTS: Among 230 patients (median age, 72 years; 78% male), 107 (47%) had ATTR-CM, of whom 9 had hereditary ATTR-CM. The Mayo 3D Score showed excellent discrimination against pathology (area under the receiver operating characteristic curve, 0.92 [0.88–0.96]), exceeding planar Perugini (0.87 [0.83–0.92]; P =0.006), and heart-to-contralateral lung ratio (0.86 [0.81–0.91]; P =0.004) and comparable to SPECT Perugini (0.90 [0.86–0.94]; P =0.12). A cutoff ≥1.0 yielded 86.0% sensitivity, 92.7% specificity, 91.1% positive predictive value, and 88.4% negative predictive value. Among ATTR-positive cases, the Mayo 3D Score correlated strongly with semiquantitative amyloid burden (Spearman ρ=0.69), was higher in pericellular than nodular deposition patterns ( P <0.001), and was not associated with vascular involvement ( P =0.42). CONCLUSIONS: In patients with suspected ATTR-CM undergoing 99m Tc-pyrophosphate SPECT/CT, the Mayo 3D Score demonstrated superior diagnostic performance compared with planar metrics and comparable to SPECT Perugini, while correlating with myocardial ATTR burden and deposition patterns on pathology. These findings support its integration as a quantitative adjunct within clinical diagnostic ATTR-CM workflows.

Abstract Background Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment and are increasingly associated with cardiovascular toxicities, including myocarditis and accelerated atherosclerosis. While ICI myocarditis has received substantial attention, thrombotic complications remain underrecognized and may be difficult to distinguish from immune-mediated cardiac inflammation and cancer-related hypercoagulable state. We present a case of non-bacterial thrombotic endocarditis (NBTE) and myocardial microthrombi mimicking ICI myocarditis. Case summary A 76-year-old woman with metastatic adenosquamous lung carcinoma presented with progressive dyspnoea 3 weeks after initiating pembrolizumab. Pulmonary arterial and coronary imaging were unremarkable, but cardiac magnetic resonance imaging (MRI) showed late gadolinium enhancement (LGE) and myocardial oedema suggestive of ICI myocarditis. Chest computed tomography revealed inflammatory lung changes, and empirical corticosteroids were initiated with initial clinical improvement. One week later, brain MRI showed multifocal infarcts, and Doppler ultrasound identified bilateral lower extremity deep vein thromboses. Transoesophageal echocardiography showed thickened mitral and aortic valves with moderate regurgitation. Non-bacterial thrombotic endocarditis with embolic phenomena was suspected. Anticoagulation was escalated from apixaban to therapeutic enoxaparin, followed by warfarin. Despite initial stabilization, the patient died 2 months later. Post-mortem examination revealed fibrin-rich valvular vegetations consistent with NBTE, widespread intramyocardial thrombi, and no histopathologic evidence of myocarditis. Discussion This case underscores how microthrombotic complications of ICI therapy may closely mimic myocarditis on imaging. Nonspecific cardiac MRI findings, such as LGE and T2 signal elevation, can result from thrombotic or ischaemic injury alike. Histopathologic confirmation may be required for accurate diagnosis, as misclassification can lead to suboptimal treatment.

Abstract Background Cardiac masses encompass a broad differential, including benign tumours, malignancies, and pseudotumours. Accurate diagnosis requires integration of clinical context, patient characteristics, lesion location, and imaging features. In select cases, tissue characterization is necessary. We describe a case of a rapidly enlarging interatrial mass following transcatheter aortic valve implantation (TAVI). Case summary A 70-year-old man underwent TAVI for severe low-flow, low-gradient aortic stenosis. Preprocedural imaging revealed an incidental interatrial mass consistent with lipomatous hypertrophy of the atrial septum (LHAS). Six months later, the mass showed significant interval growth, raising concern for malignancy. Multimodality imaging, including cardiac magnetic resonance imaging and FDG positron emission tomography yielded indeterminate results. An echocardiography-guided biopsy was performed, and histopathologic analysis confirmed LHAS with intralesional haemorrhage likely incurred during the TAVI procedure. Discussion While LHAS is typically benign and stable or slowly progressive, rare cases may present with atypical features and rapid growth, mimicking malignant cardiac tumours. This case represents the first reported instance of LHAS with haemorrhagic expansion.

BACKGROUND: Guidelines recommend 3-hour cardiac amyloid radionuclide imaging (CARI) for transthyretin amyloid cardiomyopathy. Citing rapid blood clearance of 99m Tc-hydroxymethylene-diphosphonate (HMDP) and efficient laboratory throughput, 1-hour imaging is increasingly practiced despite limited supporting evidence. We sought to compare diagnostic performance and interpreter experience of 1-hour versus 3-hour HMDP-CARI. METHODS: Consecutive patients with suspected transthyretin amyloid cardiomyopathy (n=114) underwent both 1-hour and 3-hour HMDP single photon emission computed tomography (CT)/CT. Two cardiologist-radiologist reader teams, blinded to imaging timepoint (1 versus 3 hours), assessed overall interpretation, single photon emission CT–based Perugini grade, interpretation difficulty, interpreter confidence, and need for CT-fused images for anatomic localization. Discordant, equivocal, and difficult cases were arbitrated by a third tie-breaking team. The myocardial-to-blood-pool radiotracer uptake ratio (3-dimensional Score) was measured as a surrogate of contrast resolution. RESULTS: Interinterpreter agreement was high at both time points (κ≥0.81), with more cases requiring arbitration at 3 hours versus 1 hour (22% versus 13%; P =0.049). Overall interpretation and Perugini grades were concordant between time points in 111/114 (97%) and 106/114 (93%) patients, respectively. Three patients (3%) were negative at 1 hour but equivocal at 3 hours, all of which were clinically ruled out for transthyretin amyloid cardiomyopathy. Interpreter confidence was comparable at both timepoints (97% versus 95%; P =0.317). Compared with 3-hour imaging, contrast resolution was inferior (lower 3-dimensional score, P <0.001) and CT fusion was more frequently needed (57% versus 31%, P <0.001) at 1-hour imaging. CONCLUSIONS: In a prospective, blinded comparison of 1-hour versus 3-hour HMDP-CARI, diagnostic performance and interpreter experience were similar, with readers requesting CT fusion more frequently at 1 hour to optimize myocardial-to-blood pool discrimination.

Case Description: Immune checkpoint inhibitors (ICIs) have transformed cancer therapy but are associated with immune-related adverse events, including cardiovascular toxicity. While ICI-myocarditis is rare but potentially fatal, thrombotic complications—such as venous thromboembolism, arterial occlusion, and non-bacterial thrombotic endocarditis (NBTE)—are underrecognized. These raise questions about the roles of malignancy-associated hypercoagulability versus ICI-induced effects. We present a case of NBTE and myocardial microthrombi mimicking ICI-myocarditis. A 76-year-old woman with metastatic adenosquamous lung cancer and recent DVT (on apixaban and aspirin) presented with worsening dyspnea three weeks after starting pembrolizumab (Image 1). One week earlier, CT pulmonary angiography and coronary angiography were unrevealing. On presentation, she was stable but had peripheral edema, a late diastolic murmur, and elevated hs troponin (706→657→656 ng/L). NT-proBNP was 11,500 pg/mL. Cardiac MRI showed mid-wall late gadolinium enhancement (LGE), myocardial edema, and elevated T2 values—findings concerning for ICI-myocarditis. She initially improved on intravenous methylprednisolone. A week later, brain MRI showed multifocal embolic infarcts. Doppler ultrasound revealed a new left-sided DVT. TEE showed no intracardiac thrombus but identified a thickened aortic valve with moderate-to-severe regurgitation, a thickened mitral A2 segment with moderate regurgitation, and a patent foramen ovale (PFO) with left-to-right shunting. Findings raised concern for NBTE with systemic embolism or paradoxical embolism. Anticoagulation was transitioned to heparin, then warfarin. She was discharged on oral prednisone without further cancer therapy. Two months later, she died suddenly. Autopsy revealed fibrin-rich vegetations on the mitral valve consistent with NBTE and thromboembolic infarcts in small myocardial arteries, without inflammatory infiltrates or myocardial scarring (Image 2 and 3). Conclusion: This case highlights NBTE and microthrombi as important mimics of ICI-myocarditis. Despite MRI features suggestive of inflammation, pathology confirmed ischemic injury. ICIs have been suggested to promote thrombosis through elevated factor VIII, von Willebrand factor, reduced protein S, and systemic inflammation. Clinicians should consider thrombotic mimics in ICI-treated patients with cardiac symptoms and abnormal imaging. Tissue diagnosis may be necessary to guide management.

A 63-year-old female with mixed connective tissue disease on long-term immunosuppression (prednisone, azathioprine, hydroxychloroquine (HCQ)) was referred to a tertiary care center for evaluation of progressive dyspnea and exertional chest discomfort. Cardiac history included transient complete heart block and ventricular tachycardia with dual-chamber AICD, and severe aortic stenosis with bicuspid aortic valve. Laboratory evaluation was notable for NT pro-BNP > 5000 pg/mL and elevated but adynamic troponin (300-500 ng/L). Electrocardiogram revealed atrial pacing with first degree atrioventricular block. Echocardiogram confirmed severe aortic stenosis, elevated filling pressures, abnormal left ventricular longitudinal strain and LV hypertrophy. Cardiac MRI, sarcoid PET, and PYP SPECT/CT were without any evidence of edema, scar, inflammation or amyloid deposition. Catheterization revealed severe pulmonary hypertension and elevated filling pressures, without significant coronary disease. Medical treatment included empagliflozin (discontinued due to urosepsis), bumetanide, spironolactone, and metoprolol succinate. Neither TAVR nor transition to biventricular pacing improved LV function. Ultimately, endomyocardial biopsy was performed, revealing histologic features of HCQ-induced cardiotoxicity, including myocyte hypertrophy and interstitial fibrosis. HCQ was discontinued. She was referred to Rheumatology for alternative treatments. HCQ induced cardiomyopathy represents <2% of adverse events of patients treated with HCQ, presenting as hypertrophic or restrictive cardiomyopathy with conduction abnormalities. Mean treatment duration in HCQ cardiomyopathies is approximately 12.7 years. Confirmation of diagnosis requires endomyocardial biopsy, as imaging findings are often non-specific. Management involves discontinuing the offending agent and optimizing heart failure therapy. Around 45% of patients with HCQ cardiomyopathy exhibit resolution of cardiac function following medication discontinuation. This case emphasizes the importance of a systematic approach to unexplained heart failure, particularly in patients with long-term HCQ use. Infiltrative or toxic cardiomyopathies should be considered when imaging suggests myocardial dysfunction. Multimodal imaging and biopsy are crucial for diagnosis. Early recognition is essential to prevent irreversible myocardial damage and improve long-term outcomes.

Introduction: Cardiovascular risks following SARS-CoV-2 infection are incompletely defined. We evaluated evolving cardiovascular outcomes across COVID-19 variant eras using a large community-based cohort to inform risk stratification and clinical care. Methods: We conducted a retrospective cohort study of 162,471 adults with COVID-19 between March 2020 and December 2023 using the Rochester Epidemiology Project. Patients were stratified by variant era (Pre-Delta, Delta, and Omicron). Cardiovascular outcomes included major adverse cardiovascular events (MACE: myocardial infarction, stroke, death), ischemic and inflammatory heart disease, thrombotic events, and dysrhythmias. Diagnoses were identified using ICD-10 codes and validated in a subset. Cumulative incidence was estimated using Kaplan-Meier and competing risk models. Cox proportional hazards regression was used to assess differences by era and age. Results: MACE occurred in 4,922 patients, primarily in those ≥80 (2-year incidence: 17%). Event rates peaked within 30 days post-infection, with marked variation by variant. In patients ≥80, 30-day MACE risk was highest in the Pre-Delta (HR 3.85; 95% CI, 3.14–4.71) and Delta (HR 2.72; 95% CI, 2.13–3.47) eras versus Omicron. After 30 days, event rates fell and era differences narrowed. Thrombotic events (n=2,090; 1.4%) decreased across eras. Ischemic and inflammatory heart disease rates were stable. Myocarditis/pericarditis were rare (0.1%) without age trends. Dysrhythmias affected 6,765 patients (2-year incidence: 4.9%) and rose with age (2.0% in <40 vs. 19.9% in ≥80). Within 30 days, risk was higher in the Pre-Delta and Delta eras for age ≥40, especially ≥80 (Delta HR 3.08; 95% CI, 2.08–4.56) and 60–79 (HR 2.23; 95% CI, 1.75–2.85). Among those 40–59, Delta posed the highest risk (HR 2.74; 95% CI, 1.94–3.86 vs. Pre-Delta HR 1.77; 95% CI, 1.26–2.49). No differences were observed in <40. Beyond 30 days, risk converged across variants. Conclusion: Cardiovascular risk after SARS-CoV-2 infection was concentrated in the first 30 days, with attenuation thereafter. While MACE and thrombotic event rates declined over time, early dysrhythmia risk varied by variant and age, especially in older adults. These findings define a time-sensitive, variant-specific risk window and support short-term, risk-stratified post-COVID monitoring. This work informs targeted follow-up protocols by infection era and age, with implications for quality improvement, resource use, and equitable care.

Background Disease‐causative variants in LMNA ‐encoded lamin A/C cause a genetic cardiomyopathy characterized by atrioventricular block, atrial fibrillation, ventricular arrhythmias, and systolic dysfunction. The influence of LMNA variant type/localization on late gadolinium enhancement (LGE) patterns and clinical outcomes remains unclear. Methods Retrospective analysis of 822 genotype‐positive patients with arrhythmogenic/dilated cardiomyopathy was used to identify those with disease‐causative variants in LMNA . Data on LGE distribution and prevalence of advanced heart failure, thromboembolic and sudden cardiac death/major ventricular arrhythmia events were extracted from the electronic record and analyzed by variant type/localization. Results Among the 72/116 (62%) LMNA variant‐positive patients with cardiac magnetic resonance imaging data, LGE was observed in 40/72 (56%) cases. Most exhibited a nonischemic, midmyocardial or subepicardial pattern (73%), and 6/40 (15%) showed a unique “pseudo‐infarct” transmural pattern, predominantly affecting the apical segments. All 6 patients with this distinct LGE pattern harbored C‐terminal IgD (immunoglobulin‐like domain) variants (p.Arg471His or p.Arg541His). In patients with clinically manifest disease (76/116), those with IgD‐localizing variants had a lower prevalence of atrioventricular block (25% versus 72%, P =0.002) and atrial fibrillation (50% versus 81%, P =0.019) but higher rates of thromboembolic events (42% versus 16%, P =0.038). During a median follow‐up of 37 months, IgD variant presence independently predicted sudden cardiac death/major ventricular arrhythmia (hazard ratio, 2.391 [95% CI, 1.046–5.464]; P =0.039). Conclusions LMNA missense variants localizing to IgD present a distinct apical pseudo‐infarct LGE pattern associated with increased risk of ventricular arrhythmias and thromboembolic events but reduced atrioventricular block and atrial fibrillation. Multicenter studies are warranted to develop variant‐specific risk‐stratification strategies in cardiac laminopathy.

Abstract Aims Catheter ablation is commonly performed in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) for management of ventricular arrhythmias (VAs). The impact of catheter ablation on cardiac function is unknown. The aim is to assess the impact of catheter ablation for VAs on cardiac function in patients with ARVC. Methods and results This retrospective study included consecutive patients with ARVC who underwent catheter ablation for VAs. Cardiac and valvular functions were assessed on pre- and post-procedure cardiac imaging. The severities of tricuspid regurgitation, pulmonic regurgitation, right ventricular (RV) enlargement, and RV systolic dysfunction was graded as absent (=0), mild (=1), mild-moderate (=2), moderate (=3), moderate-severe (=4), or severe (=5). Thirty-four patients were included. Median age at the time of ablation was 49 [inter-quartile range (IQR), 23] years, and 10 (29%) patients were female. After a median follow-up of 1 (IQR, 0) day, 11 (34%) patients had worsening RV function, and 4 (12%) patients had worsening left ventricular ejection fraction (LVEF) &gt;5%. Five (15%) patients required inotropic support. After a median follow-up of 6.5 (IQR, 6.4) months, 20 (59%) patients had repeat transthoracic echocardiograms. Among patients with worsening RV function post-ablation, one-sixth (17%) had improvement in the RV function at follow-up. In contrast, among patients who had an acute drop in LVEF post-ablation, two-thirds (67%) had improvement at follow-up. Conclusion Right ventricular dysfunction following catheter ablation in patients with ARVC is common, affecting one-third of patients. Patients undergoing catheter ablation of VAs should be counselled on the potential negative impact of ablation on cardiac function.