-In 13 decerebrate, artificially ventilated cats preganglionic sympathetic outflow to the heart was recorded with ECG and ventilation signal. A novel algorithm was implemented that extracts weighted events representing burst occurrences and their size. A multiple threshold strategy was used to separate bursts. Weighted events yielded count signals. Spectral analysis of the count signal revealed a predominance of a discharge synchronous to heart beat at cardiac frequency (CF≅ ≅ 3 Hz), a ventilation rhythm at the high frequency (HF≅ ≅ 0.3 Hz) of beat-to-beat variability, and in 9 of 13 cats a Mayer's wave lower frequency (LF). The CF component was ∼ ∼50%larger in power than both HF and also LF (when present). Spectral analysis at increasing count levels (i.e., with only the events with a weight ≥ ≥ the considered level) indicated that all rhythms were carried by burst activity and its modulations. A modulation index of HF over CF, MI HF/CF , was extracted from dynamic (i.e., ventilation cycle by ventilation cycle) folded histograms of counts. MIHF/CF was significantly higher in the group without LF (0.65± ±0.20, mean± ±SD, n=4) than in that with LF (0.41± ±0.07, n=9). Burst activity can be a key element in the interactions between cardiovascular variability rhythms.

A patient affected by COVID-19 pneumonia may develop pulmonary hypertension (PH) and secondary right ventricular (RV) involvement, due to lung parenchymal and interstitial damage and altered pulmonary haemodynamics, even in non-advanced phases of the disease. This is a consequence of hypoxic vasoconstriction of the pulmonary circulation, the use of positive end-expiratory pressure (PEEP) in mechanical ventilation, pulmonary endothelial injury, and local inflammatory thrombotic and/or thromboembolic processes. We report the case of a young man admitted with a diagnosis of COVID-19 pneumoniae with PH unrelated to viral infection and in whom partial anomalous pulmonary venous drainage (PAPVD) was eventually diagnosed.