Cardiologic Manifestations in Omicron-Type Versus Wild-Type COVID-19: A Systematic Echocardiographic Study.

Background Information about the cardiac manifestations of the Omicron variant of COVID-19 is limited. We performed a systematic prospective echocardiographic evaluation of consecutive patients hospitalized with the Omicron variant of COVID-19 infection and compared them with similarly recruited patients were propensity matched with the wild-type variant. Methods and Results A total of 162 consecutive patients hospitalized with Omicron COVID-19 underwent complete echocardiographic evaluation within 24 hours of admission and were compared with propensity-matched patients with the wild-type variant (148 pairs). Echocardiography included left ventricular (LV) systolic and diastolic, right ventricular (RV), strain, and hemodynamic assessment. Echocardiographic parameters during acute infection were compared with historic exams in 62 patients with the Omicron variant and 19 patients with the wild-type variant who had a previous exam within 1 year. Of the patients, 85 (53%) had a normal echocardiogram. The most common cardiac pathology was RV dilatation and dysfunction (33%), followed by elevated LV filling pressure (E/e' ≥14, 29%) and LV systolic dysfunction (ejection fraction <50%, 10%). Compared with the matched wild-type cohort, patients with Omicron had smaller RV end-systolic areas (9.3±4 versus 12.3±4 cm2; P=0.0003), improved RV function (RV fractional-area change, 53.2%±10% versus 39.7%±13% [P<0.0001]; RV S', 12.0±3 versus 10.7±3 cm/s [P=0.001]), and higher stroke volume index (35.6 versus 32.5 mL/m2; P=0.004), all possibly related to lower mean pulmonary pressure (34.6±12 versus 41.1±14 mm Hg; P=0.0001) and the pulmonary vascular resistance index (P=0.0003). LV systolic or diastolic parameters were mostly similar to the wild-type variant-matched cohort apart from larger LV size. However, in patients who had a previous echocardiographic exam, these LV abnormalities were recorded before acute Omicron infection, but not in the wild-type cohort. Numerous echocardiographic parameters were associated with higher in-hospital mortality (LV ejection fraction, stroke volume index, E/e', RV S'). Conclusions In patients with Omicron, RV function is impaired to a lower extent compared with the wild-type variant, possibly related to the attenuated pulmonary parenchymal and/or vascular disease. LV systolic and diastolic abnormalities are as common as in the wild-type variant but were usually recorded before acute infection and probably reflect background cardiac morbidity. Numerous LV and RV abnormalities are associated with adverse outcome in patients with Omicron.

Systematic lung ultrasound in Omicron-type vs. wild-type COVID-19.

AIMS: Preliminary data suggested that patients with Omicron-type-Coronavirus-disease-2019 (COVID-19) have less severe lung disease compared with the wild-type-variant. We aimed to compare lung ultrasound (LUS) parameters in Omicron vs. wild-type COVID-19 and evaluate their prognostic implications. METHODS AND RESULTS: One hundred and sixty-two consecutive patients with Omicron-type-COVID-19 underwent LUS within 48 h of admission and were compared with propensity-matched wild-type patients (148 pairs). In the Omicron patients median, first and third quartiles of the LUS-score was 5 [2-12], and only 9% had normal LUS. The majority had either mild (≤5; 37%) or moderate (6-15; 39%), and 15% (≥15) had severe LUS-score. Thirty-six percent of patients had patchy pleural thickening (PPT). Factors associated with LUS-score in the Omicron patients included ischaemic-heart-disease, heart failure, renal-dysfunction, and C-reactive protein. Elevated left-filling pressure or right-sided pressures were associated with the LUS-score. Lung ultrasound-score was associated with mortality [odds ratio (OR): 1.09, 95% confidence interval (CI): 1.01-1.18; P = 0.03] and with the combined endpoint of mortality and respiratory failure (OR: 1.14, 95% CI: 1.07-1.22; P < 0.0001). Patients with the wild-type variant had worse LUS characteristics than the matched Omicron-type patients (PPT: 90 vs. 34%; P < 0.0001 and LUS-score: 8 [5, 12] vs. 5 [2, 10], P = 0.004), irrespective of disease severity. When matched only to the 31 non-vaccinated Omicron patients, these differences were attenuated. CONCLUSION: Lung ultrasound-score is abnormal in the majority of hospitalized Omicron-type patients. Patchy pleural thickening is less common than in matched wild-type patients, but the difference is diminished in the non-vaccinated Omicron patients. Nevertheless, even in this milder form of the disease, the LUS-score is associated with poor in-hospital outcomes.

Cross-neutralisation of Australian brown snake, taipan and death adder venoms by monovalent antibodies.

An understanding of the cross-neutralisation of snake venoms by antibodies is important for snake antivenom development. We investigated the cross-neutralisation of brown snake (Pseudonaja textilis) venom, taipan (Oxyuranus scutellatus) venom and death adder (Acanthophis antarcticus) with commercial antivenoms and monovalent anti-snake IgG, using enzyme immunoassays, in vitro clotting and neurotoxicity assays. Each commercial antivenom bound all three venoms, and neutralised clotting activity of brown snake and taipan venoms and neurotoxicity of death adder venom. The 'in-house' monovalent anti-snake venom IgG raised against procoagulant brown snake and taipan venoms, did not neutralise the neurotoxic effects of death adder venom. However, they did cross-neutralise the procoagulant effects of both procoagulant venoms. This supports the idea of developing antivenoms against groups of snake toxins rather than individual snake venoms.