Circadian Variation of the Onset of Acute Myocardial Infarction in the Osaka Area, 1998-1999

Abstract

he time of onset of acute myocardial infarction (AMI) has a characteristic circadian variation, 1-10 with a definite morning peak and a vague evening peak. [7][8][9][10] Analysis of this circadian variations is important to clarify the triggering mechanisms of AMI.Although the precise underlying mechanisms of the circadian variation of AMI are still unclear, the morning peak appears to be associated with surges of blood pressure, 11-13 neurohumoral factors 14,15 and platelet aggregability; [16][17][18] that is, it appears to be associated with an inherent biologic rhythm. However, the second peak in the evening is more associated with socioeconomic factors, such as the timing of the evening meal, 19 mental stress 20-22 and overtime work, 23 but it is unclear which population is more susceptible to the morning surge or to the nighttime socioeconomic factors.Serious economic recession has existed for several yearsJapanese Circulation Journal Vol.65, July 2001 in Japan and so the circadian variation of AMI, especially the nighttime peak, may have altered in Japan. The present study had 2 aims: (1) to examine the recent circadian variation of AMI in Osaka, Japan and (2) to examine which specific population/s shows the morning peak or nighttime peak predominantly. Methods Organization and SubjectsWe conducted a district based survey named the 'Osaka Acute Coronary Insufficiency Study' (OACIS) to assess the clinical variables, therapeutic procedures and consequent clinical events in patients with AMI in the Osaka area. The study group comprised 1,609 consecutive patients with AMI who were admitted to 25 collaborating hospitals within 1 week of onset between April 1998 and January 2000. The diagnosis of definite AMI required 2 of the following 3 criteria: (1) a clinical history of central chest pressure, pain, or tightness lasting for 30 min or more, (2) ST-segment elevation greater than 0.1 mV in at least one standard or 2 precordial leads, and (3) a rise in serum creatine kinase concentration to greater than twice the normal laboratory value. Standard clinical variables, including the timing of the onset of AMI, therapeutic procedures and clinical events, were assessed during the patient's stay in hospital. When written informed consent for entering the OACIS study was obtained from the patient, all in-hospital data were transmitted to the OACIS office located at the The onset of acute myocardial infarction (AMI) shows characteristic circadian variations; that is, a definite morning peak related to biologic rhythms and a vague nighttime peak related to socioeconomic factors. The recent economic recession in Japan may change the circadian variation, especially the nighttime peak. This study evaluated the recent circadian variation of AMI in Osaka and specified the patient subgroups showing either a morning or nighttime peak predominantly. Of 1,609 consecutive patients with AMI registered from April 1998 to January 2000, 1,252 whose onset of AMI was definitely identified were studied. The day was divided into six 4-...

Predictors of Length of Hospital Stay After Acute Myocardial Infarction in Japan

“…However, the subjects registered in the study can be considered representative of the AMI population in the Osaka area, because more than one-third of all AMI patients in Osaka were registered at the participating hospitals distributed throughout the region. 31 Therefore, our results may at least be generalized to the length of hospital stay after AMI and its predictors in the Osaka region.…”

Periodic Variation and Its Effect on Management and Prognosis of Korean Patients With Acute Myocardial Infarction

“…Kinjo et al suggested socioeconomic factors related to work and lifestyle as an explanation for the secondary peak, especially in young male workers. 19 Because our data did not include such information, we could not analyze the effect of socioeconomic factors.…”

Prevalence of Helicobacter Pylori Infection and Its Link to Coronary Risk Factors in Japanese Patients With Acute Myocardial Infarction

“…The case subjects were 618 patients with AMI who had been enrolled in the Osaka Acute Coronary Insufficiency Study (OACIS; a detailed description of this study has been published elsewhere 20 ). Briefly, we conducted a prospective, multicenter observational study in which 25 collaborating hospitals in the Osaka area recorded demographic, procedural and outcome data on patients with AMI, beginning in April 1998.…”