Distinct kinetics of viral replication, T cell infiltration, and fibrosis in three phases of myocarditis following Theiler's virus infection.

We established a novel model of myocarditis induced with Theiler's murine encephalomyelitis virus (TMEV), which has been used as a viral model for multiple sclerosis and seizure/epilepsy. Following TMEV infection, C3H mice developed severe myocarditis with T cell infiltration, while C57BL/6 mice had mild lesions and SJL/J mice had no inflammation in the heart. In C3H mice, myocarditis was divided into three phases: acute viral, subacute immune, and chronic fibrotic phases. Using toll-like receptor (TLR) 4-deficient C3H mice, we found that interleukin (IL)-6, IL-17, TLR4, and anti-viral immune responses were associated with myocarditis susceptibility.

Pure Androgen-Secreting Radiologically Suspicious Adrenal Mass: Benign or Malignant?

Pure androgen-secreting adrenocortical tumors (PASATs) are rare entities. Their clinical presentations include virilizing features that vary based on age and gender. The pathogenesis of this tumor is still unclear, with around 50% of such tumors being malignant. Imaging characteristics of the tumor on CT/MRI including size, heterogenicity, and contrast wash-out time are used to predict malignancy. Surgical excision is recommended for all functional adrenal tumors. In this report, we discuss a case of a 68-year-old postmenopausal female presenting with hyperandrogenism and was found to have a 7-cm, PASAT that raised suspicion for malignancy on CT scan, but was determined to be benign on surgical pathology.

Late Gadolinium Enhancement Magnetic Resonance Imaging Evaluation of Post-Atrial Fibrillation Ablation Esophageal Thermal Injury Across the Spectrum of Severity.

Background Esophageal thermal injury (ETI) is a byproduct of atrial fibrillation (AF) ablation using thermal sources. The most severe form of ETI is represented by atrioesophageal fistula, which has a high mortality rate. Late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) allows identification of ETI. Hence, we sought to evaluate the utility of LGE-MRI as a method to identify ETI across the entire spectrum of severity. Methods and Results All AF radiofrequency ablations performed at the University of Utah between January 2009 and December 2017 were reviewed. Patients with LGE-MRI within 24 hours following AF ablation as well as patients who had esophagogastroduodenoscopy in addition to LGE-MRI were identified. An additional patient with atrioesophageal fistula who had AF ablation at a different institution and had MRI and esophagogastroduodenoscopy at the University of Utah was identified. A total of 1269 AF radiofrequency ablations were identified. ETI severity was classified on the basis of esophageal LGE pattern (none, 60.9%; mild, 27.5%; moderate, 9.9%; severe, 1.7%). ETI resolved in most patients who underwent repeat LGE-MRI at 3 months. All patients with esophagogastroduodenoscopy-confirmed ETI had moderate-to-severe LGE 24 hours after ablation MRI. Moderate-to-severe LGE had 100% sensitivity and 58.1% specificity in detecting ETI, and a negative predictive value of 100%. Atrioesophageal fistula was visualized by both computed tomography and LGE-MRI in one patient. Conclusions LGE-MRI is useful in detecting and characterizing ETI across the entire severity spectrum. LGE-MRI exhibits an extremely high sensitivity and negative predictive value in screening for ETI after AF ablation.

Routine DFT testing in patients undergoing ICD implantation does not improve mortality: A systematic review and meta-analysis.

Defibrillation threshold (DFT) testing has been an integral part of implantable cardioverter-defibrillator (ICD) implantation to confirm appropriate sensing of ventricular fibrillation and to establish an adequate safety margin for defibrillation. However, there is a lack of evidence regarding benefits of routine DFT testing. Therefore, we performed a meta-analysis to assess its mortality benefit. We searched MEDLINE for studies comparing mortality outcomes in ICD recipients who underwent DFT testing to those who did not. For the second analysis, studies comparing outcomes in patients with high- vs low-energy DFT were included. Odds ratio and standard errors were calculated, and inverse variance method in a random-effect model was used to combine effect sizes. Fifteen studies with 10,975 subjects comparing outcomes in patients who underwent routine DFT testing during ICD implantation and those who did not were included. There was no difference in the group that did not undergo DFT testing with regards to all-cause mortality (OR 0.935; CI 0.725-1.207; P = 0.606), cardiac mortality (OR 0.709; CI 0.385-1.307; P = 0.271), noncardiac mortality (OR 0.921; CI 0.701-1.210; P = 0.554), and arrhythmic mortality (OR 1.152; CI 0.831-1.596; P = 0.396). Percentage of successful appropriate first shocks among the two groups showed no difference. Five studies with 2278 subjects were included in the second analysis comparing patients with low DFT vs high DFT. Patients with high DFT had no significant increase in all-cause mortality compared to patients with low DFT (OR 0.527; CI 0.034-8.107; P = 0.646). Patients requiring higher DFT had no increased all-cause mortality compared to patients with lower DFT. Routine DFT testing during ICD implantation does not confer any significant benefit.

Digoxin Is Associated With Increased Shock Events and Electrical Storms in Patients With Implantable Cardioverter Defibrillators.

AIM: Recently, digoxin use has been found to associate with higher mortality. Yet, potential mechanisms by which digoxin use increases mortality remain unclear. Increased arrhythmogenicity from digoxin use is one possibility. Thus, we aimed to evaluate the relation between digoxin and shock events in patients with implantable cardioverter defibrillators (ICDs). METHODS: We performed a retrospective chart review of all patients with ICDs and at least 1 device interrogation at our institution between January 1, 2012, and January 1, 2015. We aimed to cover 1 year of interrogation period. Patients with heart failure, atrial fibrillation, or both were included in the analysis. Patients were divided into 2 groups based on digoxin use, defined as use of digoxin for any period of time during ICD interrogation period. Incidence of ICD shock events and electrical storms and hospitalizations were compared between the 2 groups. RESULTS: The study included 202 patients. Of those, 55 patients were on digoxin and 147 were not on digoxin. Patients on digoxin were more likely to receive ICD shocks (odds ratio [OR] = 2.5, 95% confidence interval [95% CI] = 1.01-6.18, P = .04) and have increased risk of electrical storms ( P = .02). Moreover, total hospitalizations were higher in digoxin users ( P = .02). Multivariate logistic regression analysis also showed that digoxin use was an independent predictor of shock events (OR = 4.07, 95% CI = 1.43-11.58, P = .009). CONCLUSION: Digoxin is associated with increased shock events and electrical storms in patients with ICDs; however, large randomized controlled studies are needed to confirm our findings.

High-Power Radiofrequency Catheter Ablation of Atrial Fibrillation: Using Late Gadolinium Enhancement Magnetic Resonance Imaging as a Novel Index of Esophageal Injury.

OBJECTIVES: This study retrospectively evaluated the feasibility and esophageal thermal injury (ETI) patterns of high-power short-duration (HPSD) radiofrequency atrial fibrillation (AF) ablation. BACKGROUND: ETI following AF ablation can lead to serious complications. Little consensus exists on the optimal radiofrequency power setting or on the optimal strategy to assess ETI. METHODS: A total of 687 patients undergoing first-time AF ablation with either HPSD ablation (50 W for 5 s, n = 574) or low-power long-duration ablation (LPLD, ≤35 W for 10 to 30 s, n = 113) were analyzed. ETI was assessed by late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) within 24 h post-ablation. Patients with moderate or severe esophageal LGE had a follow-up MRI within 24 h to 1 week, and esophagogastroduodenoscopies were performed when significant gastrointestinal symptoms or persistent LGE on repeat MRI was present. AF recurrence adjusted for potential confounders was analyzed. RESULTS: The average age was 69.0 ± 11.8 years in the group undergoing HPSD ablation versus 68.3 ± 11.6 years in the LPLD group (p = 0.554), with 67.1% versus 59.3% male (p = 0.111). Esophageal LGE patterns were similar (64.8% vs. 57.5% none, 21.0% vs. 28.3% mild, 11.5% vs. 11.5% moderate, 2.8% vs. 2.7% severe for HPSD vs. LPLD, respectively; p = 0.370) with no atrioesophageal fistulas. Mean procedure length was significantly shorter in the HPSD group (149 ± 65 min vs. 251 ± 101 min; p < 0.001). AF recurrence rates were similar in the 2 groups for the mean 2.5-year follow-up period (adjusted, 42% vs. 41%; p = 0.571). CONCLUSIONS: HPSD ablation results in similar ETI patterns, as assessed by same-day LGE MRI, compared with the LPLD setting but with significantly shorter procedure times. Recurrence rates at 2.5-year follow-up are similar.