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BACKGROUND Radiofrequency (RF) ablation with half-normal saline (HNS) has shown promise as a bail-out strategy following failed ventricular tachycardia ablation using standard approaches. OBJECTIVE To use a novel infrared thermal imaging (ITI) model to evaluate biophysical and lesion characteristics during RF ablation using normal saline (NS) and HNS irrigation. METHODS Left ventricular strips of myocardium were excised from fresh porcine hearts. RF ablation was performed using an open-irrigated ablation catheter (Thermocool ST/SF) with NS (n = 75) and HNS (n = 75) irrigation using different power settings (40/50 W), RF durations (30/60 s), contact force of 10-15 g, and flow rate of 15 ml/min. RF lesions were recorded using an infrared thermal camera and border zone, lethal, 100° isotherms were matched with necrotic borders after 2% triphenyltetrazolium chloride staining. Lesion dimensions and isotherms (mm2 ) were measured. RESULTS In total, 150 lesions were delivered. HNS lesions were deeper (6.4 ± 1.1 vs. 5.7 ±0.8 mm; p = .03), and larger in volume (633 ± 153 vs. 468 ± 107 mm3 ; p = .007) than NS lesions. Steam pops (SPs) occurred during 19/75 lesions (25%) in the NS group and 32/75 lesions (43%) in the HNS group (p = .34). Lethal (57.8 ± 6.5 vs. 36.0 ± 3.9 mm2 ; p = .001) and 100°C isotherm areas (16.9 ± 6.9 vs. 3.8 ± 4.2 mm2 ; p = .003) areas were larger and were reached earlier in the HNS group. CONCLUSIONS RFA using HNS created larger lesions than NS irrigation but led to more frequent SPs. The presence of earlier lethal isotherms and temperature rises above 100°C on ITI suggest a potentially narrower therapeutic-safety window with HNS.

Introduction: Vasopressor use has been associated with higher mortality rates in patients with COVID-19, the association between the maximum number of concurrent vasopressors with mortality has not yet been studied. Methods: A retrospective cohort study was conducted on patients admitted with COVID-19 to the intensive care unit (ICU) at Rush University System for Health in Illinois between March and October 2020. Multivariable logistic regression, adjusted for age, BMI, history of CAD and diabetes, was used to determine if an increasing number of vasopressors is associated with higher 60-day mortality. Results: A total of 637 patients met the inclusion criteria. Composite 60-day mortality was 28.6%. Of the 637 patients who met inclusion criteria, 338 (53.1%) required the support of at least one vasopressor. When compared to patients with no vasopressor requirement, those who required 1 (adjusted OR [aOR] 3.27, p Conclusion: In this cohort, each additional vasopressor added was associated with escalating 60-day mortality. Identifying these high-risk patients can help determine prognostic outcomes and guide decision-making. .

Ablation Index (AI) is a multiparametric quality marker to assess the durability of radiofrequency (RF) lesions. The comparative effectiveness and safety of AI versus time-based energy dosing for ablation of ventricular arrhythmias are unknown.We compared AI and time-based RF dosing strategies in the left ventricles (LVs) of freshly harvested porcine hearts.Ablation was performed in vitro with an open-irrigated ablation catheter (Thermocool ST/SF), 40 W, contact force 10-15 g. Tissue samples were stained in triphenyltetrazolium chloride for the measurement of lesion dimensions.A total of 560 lesions were performed (AI-group: [n = 360]; time-group: [n = 200]). Using normal saline (NS) (n = 280), growth in lesion depth slowed after 30 s and AI 550 in comparison to width, volume, and magnitude of impedance drops which continued to increase with longer RF duration. Risk of steam pop (SP) was higher for RF 30 s (RF 30 s:1 SP [2.5%] vs. RF 30 s: 15 SP [25%]; p = .002) or AI targets550 (AI: 350-550: 2 SP [2%] vs. AI 600-750: 15 SP [19%]; p = .001). Using half-normal saline (HNS) (n = 280), lesion dimension and impedance drops were larger and growth in lesion depth slowed earlier (AI: 500). Risk of SPs was higher above AI 550 (AI: 350-550: 7 [7%] SPs vs. AI 600-750: 28 [35%] SPs; p .00001). While codependent variables, correlation between AI and time was modest-to-strong but decreased with longer RF duration.In this ex vivo study, AI was a better predictor of lesion dimensions than ablation time and magnitude of impedance drop in the LV using NS and HNS irrigation. AI targets above 550 led to a higher risk of SPs. Future trials are required to verify these findings.

COVID‐19 has significant case fatality. Glucocorticoids are the only treatment shown to improve survival, but only among patients requiring supplemental oxygen. WHO advises patients to seek medical care for “trouble breathing,” but hypoxemic patients frequently have no respiratory symptoms. Our cohort study of hospitalized COVID‐19 patients shows that respiratory symptoms are uncommon and not associated with mortality. By contrast, objective signs of respiratory compromise—oxygen saturation and respiratory rate—are associated with markedly elevated mortality. Our findings support expanding guidelines to include at‐home assessment of oxygen saturation and respiratory rate in order to expedite life‐saving treatments patients to high‐risk COVID‐19 patients.

Background: To investigate sex differences in coronavirus disease 2019 (COVID-19) outcomes in a large Illinois-based cohort. Methods: A multicenter retrospective cohort study compared males versus females with COVID-19 infections from March 1, 2020, to June 21, 2020, in the Rush University System. We analyzed sex differences in rates of hospitalization, intensive care unit (ICU) admission, vasopressor use, endotracheal intubation, and death in this cohort. A multivariable model correcting for age and sum of comorbidities was used to explore associations between sex and COVID-19-related outcomes. Results: There were 8108 positive COVID-19 patients-4300 (53.0%) females and 3808 (47.0%) males. Males had higher rates of hospitalization (19% vs. 13%; p < 0.001), ICU transfer (8% vs. 4%; p < 0.001), vasopressor support (4% vs. 2%; p < 0.001), and endotracheal intubation (5% vs. 2%; p < 0.001). Of those who died, 92 were males and 64 were females (2% vs. 1%; p = 0.003). A multivariable model correcting for age and sum of comorbidities showed a significant association between male sex and mortality in the total cohort (odds ratio, 1.96; 95% confidence interval, 1.34-2.90; p = 0.001). Conclusion: Male sex was independently associated with death, hospitalization, ICU admissions, and need for vasopressors or endotracheal intubation, after correction for important covariates.

Introduction: The novel coronavirus disease 2019 (COVID-19) pandemic has affected millions of people worldwide. Higher COVID-19 mortality in men compared to women seen in many countries is not yet explained. We analyzed sex differences in COVID-19 outcomes in a large Illinois-based cohort. Methods: This is a multicenter retrospective cohort study of confirmed COVID-19 infections from March 1–June 3, 2020 in Rush University System. We compared men and women with COVID-19 infection for the rates of hospitalization, intensive care unit (ICU) admission, vasopressor use, endotracheal intubation, and death. A multivariable model correcting for age, race, and sum of comorbidities (obesity, hypertension, diabetes, coronary artery disease, heart failure, end-stage renal disease, asthma, chronic obstructive pulmonary disease, active smoking) was used to determine independent association with outcomes. Results: Of the 8,086 patients who tested positive, 4,267 (53%) were females, while 3,819 (47%) were males. Males had a higher rate of hospitalization (19% vs. 14%; p Conclusions: There were more women who tested positive for COVID-19 disease. Male sex was independently associated with higher rates of death, hospitalization, ICU admissions, need for vasopressors or endotracheal intubation, after correction for important covariates. The interplay of biological and and behavioral factors is likely responsible for the worse outcomes observed in men with COVID-19 infection. Further investigations into the pathophysiology of sex differences in COVID-19 outcomes responses are needed.

Catheter-based ablation techniques have a well-established role in atrial fibrillation (AF) management. The prevalence and impact of AF is increasing globally, thus mandating an emphasis on improving ablation techniques through innovation. One key area of ongoing evolution in this field is the use of laser energy to perform pulmonary vein isolation during AF catheter ablation. While laser use is not as widespread as other ablation techniques, such as radiofrequency ablation and cryoballoon ablation, advancements in product design and procedural protocols have demonstrated laser balloon ablation to be equally safe and effective compared to these other modalities. Additionally, strategies to improve procedural efficiency and decrease radiation exposure through low fluoroscopy protocols make this technology an increasingly promising and exciting option.