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J Am Coll Cardiol. 1996 Mar 15;27(4):774-8.

Circadian variations of onset of acute myocardial infarction and efficacy of thrombolytic therapy.

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1
Osaka Mishima Critical Care Medical Center, Osaka Medical College, Takatsuki, Japan.

Abstract

OBJECTIVES:

The present study investigated whether the onset of acute myocardial infarction and resistance to thrombolysis have similar circadian variations.

BACKGROUND:

Circadian variations of the onset of acute myocardial infarction and resistance to thrombolysis in the early morning have been reported. Some studies have also reported a secondary peak incidence in late evening; however, it is not known whether the resistance to thrombolysis has a similar circadian variation in these patients.

METHODS:

Six hundred eight Japanese patients with an acute myocardial infarction were the subjects of the study. Two hundred forty-four of the 608 patients were treated with thrombolysis within 12 h of the onset of symptoms. One hundred thirteen patients received urokinase, and 131 patients received tissue-type plasminogen activator (t-PA) over 60 min. Patency of the infarct-related artery, the primary end point of the study, was evaluated at 60 min after the initiation of thrombolytic therapy, and Thrombolysis in Myocardial Infarction (TIMI) grade 0, 1 or 2 was defined as resistant to thrombolysis.

RESULTS:

The onset of acute myocardial infarction and resistance to thrombolysis showed circadian variations with early morning and late evening peaks (p<0.001 and p<0.05, respectively). These circadian patterns showed similar distributions as evaluated with Spearman's method (r=0.70, p<0.05), although resistance to thrombolysis showed a phase difference of about 2 h earlier than the infarction incidence. The circadian variation of the resistance to thrombolysis was independent of the types of thrombolytic agents (urokinase or t-PA).

CONCLUSIONS:

These findings suggest that adjustment of treatment based on the time of the onset of symptoms may be warranted for the patients with acute myocardial infarction.

PMID:
8613602
DOI:
10.1016/0735-1097(95)00552-8
[Indexed for MEDLINE]
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