Dr.S.VenkatesanDr.S.Venkatesan

Madras Medical College. ChennaiMadras Medical College. Chennai

CardiologicalCardiological society of India . New Delhi .1999society of India . New Delhi .1999

CIRCADIAN PHENOMENON IN CARDIOLOGY

Acute myocardial infarction (AMI),

Sudden cardiac death,

Silent ambulatory ischemia,

Recently Circadian variations in the efficacy tothrombolysis have been reported.

STUDY POPULATION445patients with AMI between Jan 98 -June 99Mean age and range 48(24-68)Male female ratio 6.5 :1Methods

AMI was diagnosed and treated as per the GUSTOcriteria

All received thrombolysis with streptokinase

mean symptom needle time 4.6 h(30mts -12hr)

late thrombolysis >12 hrs were excluded

Successful thrombolysis was defined by clinical andECG criteria

STUDY GROUPS

The patients were divided in to 4 groupswith reference to time of thrombolysis

Group 1 6am-12 am

Group 2 12am-6pm

Group 3 6pm-12pm

Group 4 12pm-6am

Group16-12AM

group 212-6PM

group36-12PM

group412-6AM

P value2vs 43vs4

No of patientsThrombolysed

156 144 140 128 -

Successfulthrombolysis

80( 51%)

91(63%)

83( 59%)

52(40%)

< .001

In hospitalMortality

24(12.3%)

12(8.3%)

15(10.7%)

22(17.1%)

<.001

0

20

40

60

80

%

SUCCESSFUL THROMBOLYSIS

6 -12AM 12-6PM 6 -12PM 12-6AM

There is a circadian variation in theability of streptokinase to open up thecoronary arteries, with highest efficacybetween noon and midnight. and it’sleast effective in the early hours ofmorning

CLINICAL IMPLICATION

Relative resistance to thrombolysis inmorning.

Favorable fibrinolytic profile in theevening.

Adjustment of treatment based on thetiming of thrombolysis may be warranted.

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

Circadian variations of onset of acutemyocardial infarction and efficacy ofthrombolytic therapy.

Kono T,, Fujiwara A

MECHANISM IN THE CIRCADIAN RHYTHM

INCREASED FIBRINOGEN

CATECHOLAMINES

CORTISOL

C- REACTIVE PROTIEN

WORLD BY DAY

WORLD BY NIGHT