High-power short-duration versus standard-power standard-duration settings for repeat atrial fibrillation ablation

Introduction High-power short-duration (HPSD) ablation is a novel strategy using contact force-sensing catheters optimized for radiofrequency ablation for atrial fibrillation (AF). No study has directly compared HPSD versus standard-power standard-duration (SPSD) contact force-sensing settings in patients presenting for repeat ablation with AF recurrence after initial ablation. Methods We studied consecutive cases of patients with AF undergoing repeat ablation with SPSD or HPSD settings after their initial pulmonary vein isolation (PVI) with temperature controlled non-contact force, SPSD or HPSD settings between 6/23/14 and 3/4/20. Procedural data collected included radiofrequency ablation delivery time (RADT). Clinical data collected include sinus rhythm maintenance post-procedure. Results A total of 61 patients underwent repeat ablation (36 SPSD, 25 HPSD). A total of 51 patients (83.6%) were found to have pulmonary vein reconnections necessitating repeat isolation, 10 patients (16.4%) had durable PVI and ablation targeted non-PV sources. RADT was shorter when comparing repeat ablation using HPSD compared to SPSD (22 vs 35 min; p = 0.01). There was no difference in sinus rhythm maintenance by Kaplan–Meier survival analysis (log rank test p = 0.87), after 3 or 12-months between groups overall, and when stratified by AF type, left atrial volume index, CHA2DS2-VASc score, or left ventricular ejection fraction. Conclusion We demonstrated that repeat AF ablation with HPSD reduced procedure times with similar sinus rhythm maintenance compared to SPSD in those presenting for repeat ablation.

541. Comparing Patients with Severe COVID-19 Who Improve to the Point of Discharge Following an Abbreviated Course (< 5 Days) of Remdesivir (RDV) Versus a Standard Course (≥5 Days)

Background The COVID-19 pandemic has negatively affected our healthcare system. Our hospitals have reached maximum capacity on several occasions. Because of the need to make beds available to new patients, some patients with severe COVID-19 who were on low flow O2 supplementation have been discharged home prior to completion of the standard (≥ 5-day) RDV course. To date, data are limited regarding clinical outcomes on these patients. Because of this, we conducted a retrospective study to assess the clinical outcomes of patients who received an abbreviated treatment course of RDV. Methods Retrospective (chart review) study Subject population All nonpregnant adult patients who were hospitalized at Kaiser Permanente Riverside Medical Center and Kaiser Permanente Moreno Valley Medical Center in 2020 with severe COVID-19 who required low flow O2 supplement during hospitalization who received RDV and discharged from hospital alive. Severe COVID-19 = positive SARS-CoV-2 PCR + evidence of lung involvement on lung imaging (X-ray or CT) + O2 saturation ≤ 94% on room air or requirement of O2 supplement. Inclusion criteria Age ≥ 18 years; Hospitalized with severe COVID-19; Given RDV Exclusion criteria Pregnancy; O2 requirement &gt; 6 L including high flow and mechanical ventilation (noninvasive or invasive); discontinuation of RDV due to adverse effects Figure 1. Patient Section. Results Mortality rate: no difference (2.1% vs 1.8%, p=0.84). 30 day post-discharge ED visit: twice more likely in the abbreviated RDV group as compared to the group receiving the standard duration (16.1% vs 8.5%, p=0.03). 30 day readmission: almost 10 times more likely in the abbreviated RDV group as compared to the group receiving the standard duration (11.9% vs 1.2%, p=&lt; 0.001). Table 1. Patient's Characteristics Table 2. Clinical Outcomes. *8 Patients Who Died Within 30-Day from Discharge Were Excluded Conclusion Though there is no difference in 30 day mortality rate, the patients who received the abbreviated RDV course are twice more likely to have ER visit and 10 times more likely to have readmission within 30 day post discharge despite more patients in the abbreviated course receiving steroids. The findings suggest that completing an at least 5-day course of RDV may be beneficial even in patients who demonstrate a clinical response earlier in course. Disclosures All Authors: No reported disclosures

Duration Comparisons for Vision and Touch Are Dependent on Presentation Order and Temporal Context

Integrating visual and tactile information in the temporal domain is critical for active perception. To accomplish this, coordinated timing is required. Here, we study perceived duration within and across these two modalities. Specifically, we examined how duration comparisons within and across vision and touch were influenced by temporal context and presentation order using a two-interval forced choice task. We asked participants to compare the duration of two temporal intervals defined by tactile or visual events. Two constant standard durations (700 ms and 1,000 ms in ‘shorter’ sessions; 1,000 ms and 1,500 ms in ‘longer’ sessions) were compared to variable comparison durations in different sessions. In crossmodal trials, standard and comparison durations were presented in different modalities, whereas in the intramodal trials, the two durations were presented in the same modality. The standard duration was either presented first (&lt;sc&gt;) or followed the comparison duration (&lt;cs&gt;). In both crossmodal and intramodal conditions, we found that the longer standard duration was overestimated in &lt;cs&gt; trials and underestimated in &lt;sc&gt; trials whereas the estimation of shorter standard duration was unbiased. Importantly, the estimation of 1,000ms was biased when it was the longer standard duration within the shorter sessions but not when it was the shorter standard duration within the longer sessions, indicating an effect of temporal context. The effects of presentation order can be explained by a central tendency effect applied in different ways to different presentation orders. Both crossmodal and intramodal conditions showed better discrimination performance for &lt;sc&gt; trials than &lt;cs&gt; trials, supporting the Type B effect for both crossmodal and intramodal duration comparison. Moreover, these results were not dependent on whether the standard duration was defined using tactile or visual stimuli. Overall, our results indicate that duration comparison between vision and touch is dependent on presentation order and temporal context, but not modality.

Response rates in acute myeloid leukemia patients treated with attenuated durations of venetoclax in combination with hypomethylating agents.

e19008 Background: The combination of the Bcl-2 inhibitor, venetoclax, with hypomethylating agents (HMA) recently emerged as an efficacious treatment for older adults with acute myeloid leukemia (AML) who are not eligible for intensive induction therapy. In a phase III randomized controlled trial of HMA +/- venetoclax, DiNardo et al demonstrated impressive composite complete response rate and complete response with incomplete recovery (CR+CRi) of 66% in the venetoclax arm as compared to 28% in the placebo arm. Despite HMA/Venetoclax being lower intensity, 83% of patients developed grade 3 hematologic adverse events, and 42% of patients experienced febrile neutropenia in the venetoclax arm, as compared to 19% in the placebo arm. In the trial, venetoclax was given continually for 28 day cycles, with some patients receiving shortened durations of venetoclax (21 days) due to toxicity. To reduce toxicity, some institutions have further limited the duration of venetoclax in cycle 1. Here, we report response rates with attenuated durations of venetoclax with HMA. Methods: We conducted a retrospective study of AML patients who received venetoclax in combination with HMA, excluding those with prior chemotherapy for AML or MDS, or previous exposure to HMA or venetoclax. Demographic, cytogenetic, pathology, and outcome data were collected including bone marrow biopsy results at diagnosis and after cycle 1 (day +28) or cycle 2 (day +56). The primary outcome was composite response rate (CR+CRi) following cycle 1 or cycle 2 defined by 2017 ELN criteria. Results: 25 patients were identified with median age of 73 (range 63-82). 9 patients received 14 or less days of venetoclax (attenuated duration): < 8 days in 1 patient and 8-14 days in 8 patients. 16 patients received 21 days or more (standard duration): 21 days in 14 patients, and 28 days in 2 patients. Of the patients who received an attenuated duration, the median age was 74 (68-82), 22% had either a TP53 mutation or deletion, 56% had complex karyotype, and 44% had received prior cytotoxic chemotherapy. Of the patients who received standard duration therapy, the median age was 71 (63-81), 44% had either a TP53 mutation or deletion, 75% had complex karyotype, and 6% had received prior cytotoxic chemotherapy. The composite response rate was 78% in the attenuated duration group and 75% in the standard duration group (p > 0.99). Conclusions: Though a limited sample size, this data suggests high response rates can be observed with attenuated courses of venetoclax. With appropriately selected patients, the feasibility of attenuated venetoclax courses could be further explored in larger prospective studies.[Table: see text]

The effect of pain on reference memory for duration

Previous research has consistently reported that pain related stimuli are perceived as lasting longer than non-pain related ones, suggesting that pain lengthens subjective time. However, to date, the investigation has been limited to the immediate effects of pain on time perception. The current study aims to investigate whether pain affects how a duration is recalled after a period of delay. In two experiments, participants were asked to complete four temporal generalisation tasks, where they were required first to remember the duration of a standard tone (learning phase) and then to compare the standard duration to a series of comparison durations (testing phase). Using a 2 × 2 design, the four tasks differed in terms of whether participants were exposed to a painful or non-painful stimulus during the learning phase, and whether the testing phase started immediately or 15 min after the learning phase. Participants were exposed to low pain in Experiment 1 and high pain in Experiment 2. Two possible results were expected: pain could decrease temporal accuracy, because pain disrupts cognitive processes required for accurate timing, or pain could increase temporal accuracy, because pain facilitates memory consolidation. Contrary to expectations, results from both Experiments indicated that participants’ temporal performances were similar in the pain and no-pain conditions when testing occurred 15 min after the learning phase. Findings, therefore, suggest that pain neither disrupts nor enhances long-term memory representations of duration.