[Cardiovascular risk factors in the circadian rhythm of acute myocardial infarction].
OBJECTIVE
The aim of this study was to analyze the influence of modifiable cardiovascular risk factors on the circadian rhythm of acute myocardial infarction.


METHODS
We analyzed a retrospective cohort of 54,249 patients from a multicenter study of acute myocardial infarction (the Spanish ARIAM study). The variables were time of onset of symptoms, age, sex, previous ischemic heart disease, coronary unit discharge status, previous stroke, familial antecedents of ischemic heart disease, hypertension, diabetes, dyslipidemia, smoking, and reinfarction. To verify the presence of circadian rhythm, we developed a simple test of equality of time series based on cosinor analysis of multiple sinusoid curves. Three sinusoids (24, 12 and 8 hour periods) were used.


RESULTS
The time of onset of pain showed a circadian rhythm (P< .01), with a peak at 10:07 am and a trough at 4:46 am. All subgroups categorized according to the presence of the variables analyzed here showed a circadian rhythm, with a sinusoid curve after adjustment. In patients with diabetes or reinfarction or who were smokers, the sinusoid curve was bimodal.


CONCLUSIONS
Time of onset of symptoms in patients with acute myocardial infarction follows a circadian rhythm. Diabetes, smoking and reinfarction can modify the standard circadian rhythm of onset of myocardial infarction.
López Messa
Juan B
JB
Unidad de Cuidados Intensivos, Hospital Río Carrión, Palencia, Spain. jlomessa@telefonica.net
Garmendia Leiza
José R
JR
Aguilar García
María D
MD
Andrés de Llano
Jesús M
JM
Alberola López
Carlos
C
Ardura Fernández
Julio
J
D000368:Aged; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D008297:Male; D009203:Myocardial Infarction / Q000503:physiopathology*; D012189:Retrospective Studies; D012307:Risk Factors; D013030:Spain
Factores de riesgo cardiovascular en el ritmo circadiano del infarto agudo de miocardio.