Atrial arrhythmia related outcomes in critically ill COVID-19 patients.

RATIONALE: Coronavirus disease 2019 (COVID-19) is associated with many clinical manifestations including respiratory failure and cardiovascular compromise. OBJECTIVES: We examine outcomes in critically ill individuals with COVID-19 who develop atrial tachyarrhythmias. METHODS: We collected data from electrocardiograms and the electronic medical record of COVID-19 positive (COVID+ ) and negative (COVID- ) individuals admitted to our medical intensive care unit between February 29 and June 28, 2020. We compared clinical and demographic characteristics, new onset atrial tachyarrhythmia, hemodynamic compromise following atrial tachyarrhythmia, and in-hospital mortality in COVID+ versus COVID- . Hemodynamic compromise was defined as having a new or increased vasopressor requirement or the need for direct current cardioversion for hemodynamic instability within 1 hour of atrial tachyarrhythmia onset. RESULTS: Of 300 individuals included, 200 were COVID+ and 100 were COVID- . Mean age was 60 ± 16 years, 180 (60%) were males, and 170 (57%) were African American. New onset atrial tachyarrhythmia occurred in 16% of COVID+ and 19% of COVID- individuals (P = .51). When compared to COVID- participants without atrial tachyarrhythmia, COVID+ individuals with new onset atrial tachyarrhythmia had higher mortality after multivariable adjustment (OR 5.0, 95% CI 1.9-13.5). New onset atrial tachyarrhythmia was followed by hemodynamic compromise in 18 COVID+ but no COVID- participants (P = .0001). COVID+ individuals with hemodynamic compromise after atrial tachyarrhythmia required increased ventilatory support at the time of atrial tachyarrhythmia onset. CONCLUSIONS: Atrial tachyarrhythmia is associated with increased mortality in critically ill individuals with COVID-19, especially those mechanically ventilated. Recognition of this could assist with clinical care for individuals with COVID-19.

Significant Discrepancy Between Estimated and Actual Longevity in St. Jude Medical Implantable Cardioverter-Defibrillators.

BACKGROUND: Real-time estimated longevity has been reported in pacemakers for several years, and was recently introduced in implantable cardioverter-defibrillators (ICDs). OBJECTIVE: We sought to evaluate the accuracy of this longevity estimate in St. Jude Medical (SJM) ICDs, especially as the device battery approaches depletion. METHODS: Among patients with SJM ICDs who underwent generator replacements due to reaching elective replacement indicator (ERI) at our institution, we identified those with devices that provided longevity estimates and reviewed their device interrogations in the 18 months prior to ERI. Significant discrepancy was defined as a difference of more than 12 months between estimated and actual longevity at any point during this period. RESULTS: Forty-six patients with Current/Promote devices formed the study group (40 cardiac resynchronization therapy [CRT] and 6 single/dual chamber). Of these, 34 (74%) had significant discrepancy between estimated and actual longevity (28 CRT and all single/dual). Longevity was significantly overestimated by the device algorithm (mean maximum discrepancy of 18.8 months), more in single/dual than CRT devices (30.5 vs. 17.1 months). Marked discrepancy was seen at voltages ≥2.57 volts, with maximum discrepancy at 2.57 volts (23 months). The overall longevity was higher in the discrepant group of CRT devices than in the nondiscrepant group (67 vs. 61 months, log-rank P = 0.03). CONCLUSIONS: There was significant overestimation of longevity in nearly three-fourths of Current/Promote SJM ICDs in the last 18 months prior to ERI. Longevity estimates of SJM ICDs may not be reliable for making clinical decisions on frequency of follow-up, as the battery approaches depletion.

Left atrial appendage electrical isolation and concomitant device occlusion: A safety and feasibility study with histologic characterization.

BACKGROUND: Left atrial appendage (LAA) electrical isolation is reported to improve atrial fibrillation ablation outcomes. However, loss of mechanical function may increase thromboembolic risk. OBJECTIVE: The aim of this study was to evaluate the feasibility and safety of LAA occlusion after electrical isolation in a canine model. METHODS: Nine canines underwent LAA isolation with irrigated radiofrequency ablation after pulmonary vein (PV) isolation. Entrance and exit block were confirmed with intravenous adenosine after 30 minutes. The LAA was then occluded with a Watchman device. Device position was assessed at 10 days by using transthoracic echocardiography. At 45 days, LAA isolation was assessed epicardially. Hearts were then examined macroscopically and histologically. RESULTS: All 36 PVs and 8 of 9 LAAs (89%) were electrically isolated. Acute LAA reconnection occurred in 4 of 8 LAAs (50%). All were reisolated. The mean ablation time was 51 ± 19 minutes, including 24 ± 18 minutes for LAA isolation. LAA occlusion was successful in all cases. One animal died of a primary intracranial bleed due to anticoagulant hypersensitivity 36 hours after the procedure. Transthoracic echocardiography at 10 days confirmed satisfactory device positions and no pericardial effusion. At 45 days, 7 of 8 (88%) had persistent LAA electrical isolation. All devices were stable without evidence of erosion. Microscopy revealed complete device-tissue apposition and a mature connective tissue layer overlying the device surface in all cases. CONCLUSION: LAA electrical isolation and mechanical occlusion can be performed concomitantly in this animal model, with no displacement or mechanical erosion of the appendage at 45 days. This technique can potentially improve success rates and obviate the need for chronic anticoagulation. Future studies should address efficacy, safety, and feasibility in humans.