In 57 normal subjects (age 20-60 years), we analyzed the spontaneous beat-to-beat oscillation in R-R interval during control recumbent position, 90 degrees upright tilt, controlled respiration (n = 16) and acute (n = 10) and chronic (n = 12) beta-adrenergic receptor blockade. Automatic computer analysis provided the autoregressive power spectral density, as well as the number and relative power of the individual components. The power spectral density of R-R interval variability contained two major components in power, a high frequency at approximately 0.25 Hz and a low frequency at approximately 0.1 Hz, with a normalized low frequency:high frequency ratio of 3.6 +/- 0.7. With tilt, the low-frequency component became largely predominant (90 +/- 1%) with a low frequency:high frequency ratio of 21 +/- 4. Acute beta-adrenergic receptor blockade (0.2 mg/kg IV propranolol) increased variance at rest and markedly blunted the increase in low frequency and low frequency:high frequency ratio induced by tilt. Chronic beta-adrenergic receptor blockade (0.6 mg/kg p.o. propranolol, t.i.d.), in addition, reduced low frequency and increased high frequency at rest, while limiting the low frequency:high frequency ratio increase produced by tilt. Controlled respiration produced at rest a marked increase in the high-frequency component, with a reduction of the low-frequency component and of the low frequency:high frequency ratio (0.7 +/- 0.1); during tilt, the increase in the low frequency:high frequency ratio (8.3 +/- 1.6) was significantly smaller. In seven additional subjects in whom direct high-fidelity arterial pressure was recorded, simultaneous R-R interval and arterial pressure variabilities were examined at rest and during tilt. Also, the power spectral density of arterial pressure variability contained two major components, with a relative low frequency:high frequency ratio at rest of 2.8 +/- 0.7, which became 17 +/- 5 with tilt. These power spectral density components were numerically similar to those observed in R-R variability. Thus, invasive and noninvasive studies provided similar results. More direct information on the role of cardiac sympathetic nerves on R-R and arterial pressure variabilities was derived from a group of experiments in conscious dogs before and after bilateral stellectomy. Under control conditions, high frequency was predominant and low frequency was very small or absent, owing to a predominant vagal tone. During a 9% decrease in arterial pressure obtained with IV nitroglycerin, there was a marked increase in low frequency, as a result of reflex sympathetic activation.(ABSTRACT TRUNCATED AT 400 WORDS)

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Mycotic coronary aneurysm is a rare infective disease of arterial vessel walls. Their development could be linked to the presence of an infective endocarditis or could represent a primary infection at the site of an implanted intracoronary stent. Bacterial agents, particularly Staphylococcus aureus, are the most common etiological agents. Due to an aspecific clinical presentation and examination, diagnosis could be challenging. Multiple imaging techniques (both invasive and noninvasive) are often required to reach the final diagnosis. Prognosis is characterized by high morbidity and mortality rates and, in fact, a tempestive treatment is required, although, to date, scanty data concerning the optimal treatment choice are present in literature.

There is no doubt that in the last 2 months during COVID-19 pandemic a smaller number of ST-elevation Myocardial Infarction (STEMI) and Stroke arrived to cardiological and neurological departments. The pathophysiology of STEMI in COVID-19 women is not fully understood; it could be thrombus recanalization, catecholamine storm or Type 2 Myocardial infarction in case of severe respiratory distress or direct myocardial damage (viral myocarditis). Because most of them have normal coronary arteries an invasive strategy with coronary angiography is important to rule out atherosclerotic severe coronary disease.

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