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Open AccessResearch article

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

Carlos E D'Negri1 email, Leonardo Nicola-Siri1,2,3 email, Daniel E Vigo1,4 email, Luis A Girotti2 email and Daniel P Cardinali1,4 email

1Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina

2División de Cardiología, Hospital Ramos Mejía, Buenos Aires, Argentina

3Laboratorio de Bioelectricidad, Escuela de Ingeniería – Bioingeniería, Universidad Nacional de Entre Ríos, Argentina

4Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, Argentina

author email corresponding author email

BMC Cardiovascular Disorders 2006, 6:1doi:10.1186/1471-2261-6-1

Published: 9 January 2006

Abstract

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.

Methods

A cohort of 1063 patients admitted to the CCU within 24 h of the onset of symptoms of an acute MI was examined. MI incidence along the day was computed in 1 h-intervals.

Results

A minimal MI incidence between 03:00 and 07:00 h and the occurrence of a first maximum between 08:00 and 12:00 h and a second maximum between 15:00 and 22:00 h were verified. The best fit curve was a 24 h cosinor (acrophase ~ 19:00 h, accounting for 63 % of variance) together with a symmetrical gaussian bell (maximum at ~ 10:00 h, accounting for 37 % of variance). A similar picture was observed for MI frequencies among different excluding subgroups (older or younger than 70 years; with or without previous symptoms; diabetics or non diabetics; Q wave- or non-Q wave-type MI; anterior or inferior MI location). Proportion between cosinor and gaussian probabilities was maintained among most subgroups except for older patients who had more MI at the afternoon and patients with previous symptoms who were equally distributed among the morning and afternoon maxima.

Conclusion

The results support the existence of two maxima (at morning and afternoon hours) in MI incidence in the Argentine and Uruguayan population.


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