Effects of environmental factors on severity and mortality of COVID-19

BackgroundMost respiratory viruses show pronounced seasonality, but for SARS-CoV-2 this still needs to be documented. MethodsWe examined the disease progression of COVID-19 in 6,914 patients admitted to hospitals in Europe and China. In addition, we evaluated progress of disease symptoms in 37,187 individuals reporting symptoms into the COVID Symptom Study application. FindingsMeta-analysis of the mortality risk in eight European hospitals estimated odds ratios per one day increase in the admission date to be 0.981 (0.973-0.988, p<0.001) and per increase in ambient temperature of one degree Celsius to be 0.854 (0.773-0.944, p=0.007). Statistically significant decreases of comparable magnitude in median hospital stay, probability of transfer to Intensive Care Unit and need for mechanical ventilation were also observed in most, but not all hospitals. The analysis of individually reported symptoms of 37,187 individuals in the UK also showed the decrease in symptom duration and disease severity with time. InterpretationSeverity of COVID-19 in Europe decreased significantly between March and May and the seasonality of COVID-19 is the most likely explanation. Mucosal barrier and mucociliary clearance can significantly decrease viral load and disease progression, and their inactivation by low relative humidity of indoor air might significantly contribute to severity of the disease.

Trends in inflammatory biomarkers during atrial fibrillation ablation across different catheter ablation strategies.

INTRODUCTION: Chest pain after atrial fibrillation (AF) ablations is a common complaint with a wide differential diagnosis including coronary events. Elevation of troponins (Trop I) has been shown with radio-frequency (RF) ablation for atrial fibrillation. New devices including cryoballoon and multipolar ablation catheters have been introduced as alternative methods. We aim to compare cardiac injury following AF ablations according to different ablation technologies. METHODS: In consecutive patients undergoing AF ablations with RF ablation, cryoballoon or multipolar ablation catheter (PVAC), Trop I, creatine kinase (CK) and CRP were analyzed immediately prior to and 24h following completion of ablation. Coronary events and symptoms and serial ECGs post procedure were evaluated. RESULTS: A total of 243 patients were included, 18.5% of them females. The mean age was 63 ± 11 years old. Baseline Trop I, CK and CRP levels were within normal range in all patients. After RF ablation Trop I, CK and CRP levels were elevated in 100%, 20% and 91% of patients respectively (Trop I 3.55 pg/ml [range: 0.60-24.01 pg/ml], CK 147 U/l [range: 56-380 U/l] and CRP 2.15 mg/dl [range: 0.28-20.98 mg/dl]). All post-procedure Trop I levels were above the range of myocardial infarction (>0.15 ng/ml). After cryoballoon ablation, Trop I and CK levels were significantly higher than after RF or PVAC ablation (p<0.001). No ischemic ECG changes were documented. CONCLUSIONS: Trop I elevations are not specific for ischemia in the setting of chest pain after AF ablation. Cryoballoon ablation resulted in a higher amount of cardiac injury.