Surpoint algorithm for improved guidance of ablation for ventricular tachycardia (SURFIRE-VT): A pilot study.

INTRODUCTION: The utility of ablation index (AI) to guide ventricular tachycardia (VT) ablation in patients with structural heart disease is unknown. The aim of this study was to assess procedural characteristics and clinical outcomes achieved using AI-guided strategy (target value 550) or conventional non-AI-guided parameters in patients undergoing scar-related VT ablation. METHODS: Consecutive patients (n = 103) undergoing initial VT ablation at a single center from 2017 to 2022 were evaluated. Patient groups were 1:1 propensity-matched for baseline characteristics. Single lesion characteristics for all 4707 lesions in the matched cohort (n = 74) were analyzed. The impact of ablation characteristics was assessed by linear regression and clinical outcomes were evaluated by Cox proportional hazard model. RESULTS: After propensity-matching, baseline characteristics were well-balanced between AI (n = 37) and non-AI (n = 37) groups. Lesion sets were similar (scar homogenization [41% vs. 27%; p = .34], scar dechanneling [19% vs. 8%; p = .18], core isolation [5% vs. 11%; p = .4], linear and elimination late potentials/local abnormal ventricular activities [35% vs. 44%; p = .48], epicardial mapping/ablation [11% vs. 14%; p = .73]). AI-guided strategy had 21% lower procedure duration (-47.27 min, 95% confidence interval [CI] [-81.613, -12.928]; p = .008), 49% lower radiofrequency time per lesion (-13.707 s, 95% CI [-17.86, -9.555]; p < .001), 21% lower volume of fluid administered (1664 cc [1127, 2209] vs. 2126 cc [1750, 2593]; p = .005). Total radiofrequency duration (-339 s [-24%], 95%CI [-776, 62]; p = .09) and steam pops (-155.6%, 95% CI [19.8%, -330.9%]; p = .08) were nonsignificantly lower in the AI group. Acute procedural success (95% vs. 89%; p = .7) and VT recurrence (0.97, 95% CI [0.42-2.2]; p = .93) were similar for both groups. Lesion analysis (n = 4707) demonstrated a plateau in the magnitude of impedance drops once reaching an AI of 550-600. CONCLUSION: In this pilot study, an AI-guided ablation strategy for scar-related VT resulted in shorter procedure time and average radiofrequency time per lesion with similar acute procedural and intermediate-term clinical outcomes to a non-AI-guided approach utilizing traditional ablation parameters.

Association between number of vasopressors and mortality in COVID-19 patients.

Study objective: Study the clinical outcomes associated with the number of concomitant vasopressors used in critically ill COVID-19 patients. Design: A single-center retrospective cohort study was conducted on patients admitted with COVID-19 to the intensive care unit (ICU) between March and October 2020. Setting: Rush University Medical Center, United States. Participants: Adult patients at least 18 years old with COVID-19 with continuous infusion of any vasopressors were included. Main outcome measures: 60-day mortality in COVID-19 patients by the number of concurrent vasopressors received. Results: A total of 637 patients met our inclusion criteria, of whom 338 (53.1 %) required the support of at least one vasopressor. When compared to patients with no vasopressor requirement, those who required 1 vasopressor (V1) (adjusted odds ratio [aOR] 3.27, 95 % confidence interval (CI) 1.86-5.79, p < 0.01) (n = 137), 2 vasopressors (V2) (aOR 4.71, 95 % CI 2.54-8.77, p < 0.01) (n = 86), 3 vasopressors (V3) (aOR 26.2, 95 % CI 13.35-53.74 p < 0.01) (n = 74), and 4 or 5 vasopressors(V4-5) (aOR 106.38, 95 % CI 39.17-349.93, p < 0.01) (n = 41) were at increased risk of 60-day mortality. In-hospital mortality for patients who received no vasopressors was 6.7 %, 22.6 % for V1, 27.9 % for V2, 62.2 % for V3, and 78 % for V4-V5. Conclusion: Critically ill patients with COVID-19 requiring vasopressors were associated with significantly higher 60-day mortality.

Clinical outcomes of COVID-19 infection in patients with pre-existing cardiovascular disease.

Introduction: Patients with pre-existing cardiovascular disease may carry a higher risk for mortality from COVID-19. This study examined the association between individuals with pre-existing cardiovascular disease admitted for COVID-19 and their clinical outcomes. Methods: A retrospective cohort study was conducted on patients admitted with COVID-19 to Rush University System for Health (RUSH) to identify cardiovascular risk factors associated with increased mortality and major adverse cardiovascular events (MACE; a composite of cardiovascular death, stroke, myocardial injury, and heart failure exacerbation). Multivariable logistic regression was used to adjust for demographic data and comorbid conditions. Results: Of the 1682 patients who met inclusion criteria, the median age was 59. Patients were predominantly African American (34.4 %) and male (54.5 %). Overall, 202 (12 %) patients suffered 60-day mortality. In the multivariable model that assessed risk factors for 60-day mortality, age 60-74 (adjusted odds ratio [aOR] 3.30 [CI: 1.23-10.62]; p < 0.05) and age 75-100 (aOR 4.52 [CI: 1.46-16.15]; p < 0.05) were significant predictors when compared to those aged 19 to 39. This model also showed that those with past medical histories of atrial fibrillation (aOR 2.47 [CI: 1.38-4.38]; p < 0.01) and venous thromboembolism (aOR 2.00 [CI: 1.12-3.50]; p < 0.05) were at higher risk of 60-day mortality. Conclusion: In this cohort, patients over 60 years old with a pre-existing history of atrial fibrillation and venous thromboembolism were at increased risk of mortality from COVID-19.

Soluble Urokinase Plasminogen Activator Receptor and Venous Thromboembolism in COVID-19.

Background Venous thromboembolism (VTE) contributes significantly to COVID-19 morbidity and mortality. The urokinase receptor system is involved in the regulation of coagulation. Levels of soluble urokinase plasminogen activator receptor (suPAR) reflect hyperinflammation and are strongly predictive of outcomes in COVID-19. Whether suPAR levels identify patients with COVID-19 at risk for VTE is unclear. Methods and Results We leveraged a multinational observational study of patients hospitalized for COVID-19 with suPAR and D-dimer levels measured on admission. In 1960 patients (mean age, 58 years; 57% men; 20% Black race), we assessed the association between suPAR and incident VTE (defined as pulmonary embolism or deep vein thrombosis) using logistic regression and Fine-Gray modeling, accounting for the competing risk of death. VTE occurred in 163 (8%) patients and was associated with higher suPAR and D-dimer levels. There was a positive association between suPAR and D-dimer (ß=7.34; P=0.002). Adjusted for clinical covariables, including D-dimer, the odds of VTE were 168% higher comparing the third with first suPAR tertiles (adjusted odds ratio, 2.68 [95% CI, 1.51-4.75]; P<0.001). Findings were consistent when stratified by D-dimer levels and in survival analysis accounting for death as a competing risk. On the basis of predicted probabilities from random forest, a decision tree found the combined D-dimer <1 mg/L and suPAR <11 ng/mL cutoffs, identifying 41% of patients with only 3.6% VTE probability. Conclusions Higher suPAR was associated with incident VTE independently of D-dimer in patients hospitalized for COVID-19. Combining suPAR and D-dimer identified patients at low VTE risk. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT04818866.

Wide area circumferential ablation for pulmonary vein isolation using radiofrequency versus laser balloon ablation.

Background: Persistent atrial fibrillation (AF) is associated with high recurrence rates of AF and atypical atrial flutters or tachycardia (AFT) postablation. Laser balloon (LB) ablation of the pulmonary vein (PV) ostia has similar efficacy as radiofrequency wide area circumferential ablation (RF-WACA); however, an approach of LB wide area circumferential ablation (LB-WACA) may further improve success rates. Objective: To evaluate freedom from atrial tachyarrhythmia (AFT/AF) recurrence postablation using RF-WACA versus LB-WACA in persistent AF patients. Methods: This was a retrospective multicenter study. Patients were followed for up to 24 months via office visits, Holter, and/or device monitoring. The primary endpoint was freedom from AFT/AF after a single ablation procedure. Secondary endpoints included freedom from AF, freedom from AFT, first-pass isolation of all PVs, and procedural complications. Results: Two hundred and four patients were studied (LB-WACA: n = 103; RF-WACA: n = 101). Patients' baseline characteristics were similar except patients in the RF-WACA group were older (64 vs. 68, p = .03). First-pass isolation was achieved more often during LBA (LB-WACA: 88% vs. RF-WACA 75%; p = .04). Procedure (p = .36), LA dwell (p = .41), and fluoroscopy (p = .44) time were similar. The mean follow-up was 506 ± 279 days. Sixty-six patients had arrhythmic events including 24 AFT and 59 AF recurrences. LB-WACA group had higher arrhythmia-free survival (p = .009) after single ablation procedures. In the multivariate Cox regression model, RF-WACA was associated with a higher recurrence of AFT compared with LB-WACA (Adjusted HR 3.16 [95% CI: 1.13-8.83]; p = .03). Conclusions: LB-WACA was associated with higher freedom from atrial arrhythmias mostly driven by the lower occurrence of AFT compared with RF-WACA.

Comparison of ablation index versus time-guided radiofrequency energy dosing using normal and half-normal saline irrigation in a porcine left ventricular model.

BACKGROUND: 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. OBJECTIVE: We compared AI and time-based RF dosing strategies in the left ventricles (LVs) of freshly harvested porcine hearts. METHODS: 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. RESULTS: 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 targets >550 (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. CONCLUSION: 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.

Cardiovascular findings on chest computed tomography associated with COVID-19 adverse clinical outcomes.

STUDY OBJECTIVE: Chest computed tomography (chest CT) is routinely obtained to assess disease severity in COVID-19. While pulmonary findings are well-described in COVID-19, the implications of cardiovascular findings are less well understood. We evaluated the impact of cardiovascular findings on chest CT on the adverse composite outcome (ACO) of hospitalized COVID-19 patients. SETTING/PARTICIPANTS: 245 COVID-19 patients who underwent chest CT at Rush University Health System were included. DESIGN: Cardiovascular findings, including coronary artery calcification (CAC), aortic calcification, signs of right ventricular strain [right ventricular to left ventricular diameter ratio, pulmonary artery to aorta diameter ratio, interventricular septal position, and inferior vena cava (IVC) reflux], were measured by trained physicians. INTERVENTIONS/MAIN OUTCOME MEASURES: These findings, along with pulmonary findings, were analyzed using univariable logistic analysis to determine the risk of ACO defined as intensive care admission, need for non-invasive positive pressure ventilation, intubation, in-hospital and 60-day mortality. Secondary endpoints included individual components of the ACO. RESULTS: Aortic calcification was independently associated with an increased risk of the ACO (odds ratio 1.86, 95% confidence interval (1.11-3.17) p < 0.05). Aortic calcification, CAC, abnormal septal position, or IVC reflux of contrast were all significantly associated with 60-day mortality and major adverse cardiovascular events. IVC reflux was associated with in-hospital mortality (p = 0.005). CONCLUSION: Incidental cardiovascular findings on chest CT are clinically important imaging markers in COVID-19. It is important to ascertain and routinely report cardiovascular findings on CT imaging of COVID-19 patients as they have potential to identify high risk patients.

Use of infrared thermography to delineate temperature gradients and critical isotherms during catheter ablation with normal and half normal saline: Implications for safety and efficacy.

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.

Admission respiratory status predicts mortality in COVID-19.

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.

Sex Differences in COVID-19 Hospitalization and Mortality.

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.

Clinical Applications of Laser Technology: Laser Balloon Ablation in the Management of Atrial Fibrillation.

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.