Chronobiological Patterns of Acute Aortic Syndrome : Comparison with Those of Acute Myocardial Infarction

BACKGROUND AND OBJECTIVES: Chronobiological rhythms have been shown to influence the occurrence of a variety of cardiovascular disorders, including acute myocardial infarction (AMI). The present study investigated whether the onset of acute aortic syndrome (AAS) has unique chronobiological rhythms in Korean populations.

SUBJECTS AND METHODS: The clinical data of 371 consecutive AAS patients, admitted between 1993 and 2003, were retrospectively analyzed; 310 AMI patients, who underwent primary percutaneous angioplasty in the hyperacute phase between 1998 and 2001, were also selected.

RESULTS: In the AAS group, the final diagnoses were aortic dissection (AD) and aortic intramural hematoma (AIH) in 212 and 159 patients, respectively Similar to AMI, AAS showed a significantly higher occurrence from 6 AM to noon compared with other time periods (p=0.0013). AAS showed a second peak occurrence from 6 PM to midnight, which was not observed in the AMI group. A subgroup analysis revealed that younger patients (age < 60 years) and those with a past medical history of hypertension had the highest occurrence from 6 PM to midnight, which was quite different compared to the AAS patients. No significant variation was found for the day of the week in either group. Although no significant seasonal variation was observed in the frequency of AMI, the frequency of AAS was significantly higher during winter (p<0.001). The circadian and seasonal variations in the frequency of AIH were similar to those of AD.

CONCLUSION: AAS shows unique circadian and seasonal variations in Korean populations. Our findings may have implications for the prevention of AAS by tailoring treatment strategies to ensure maximal benefits during the vulnerable periods.