Circadian analysis of myocardial infarction incidence in an Argentine and Uruguayan population.

Background: The occurrence of variations in the spectrum of cardiovascular disease between different regions of the world and ethnic groups have been the subject of great interest. This study report the 24-h variation of myocardial infarction (MI) occurrence in patients recruited from CCU located in Argentina and Uruguay.

Method: A cohort of 1063 patients admitted to the CCU within 24 h of the onset of symptoms of an acute MI was examined.

Circadian periodicity of heart rate variability in hospitalized angor patients.

The relationship between unstable angor (angina) and circadian periodicity of heart rate variability (HRV) was explored in a group of patients hospitalized in a coronary care unit (CCU). Patients were classified as normal (whose symptoms had non-cardiovascular origin, n=8), moderate angor (n=13) and severe angor (n=11). A fourth group of ambulatory healthy volunteers (n=12) was included.

Low urinary 6-sulfatoxymelatonin levels in patients with severe congestive heart failure.

Objective: To assess urinary 6-sulfatoxymelatonin excretion in patients admitted to the hospital because of congestive heart failure (CHF).

Methods: Urinary 6-sulfatoxymelatonin was measured by a specific radioimmunoassay in 33 hospitalized patients with CHF and in 146 healthy ambulatory volunteers. Individuals with hepatic or renal failure were excluded from the sample.