CAN 24-HOURS ECG MONITORING RECOGNIZE ISCHEMIC PRECONDITIONING IN PATIENTS WITH ISCHEMIC HEART DISEASE








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CAN 24-HOURS ECG MONITORING RECOGNIZE ISCHEMIC PRECONDITIONING IN PATIENTS WITH ISCHEMIC HEART DISEASE
V. A. Kuznetsov, V. V. Todosiychuk
Institute of Clinical and Preventive Cardiology, Tyumen, Russia

It has been shown that brief episodes of myocardial ischemia can render the heart more resistant to a subsequent ischemic episode. This phenomenon, called "preconditioning", has been described in human beings during coronary angioplasty and repeated stress tests with the use of clinical, electrocardiographic (ECG) or metabolic parameters. The aim of this study was to assess this phenomenon with the use of 24-hours ECG monitoring.
By 24-hours ECG monitoring 31 patients with ischemic heart disease (IHD) and severe angina pectoris were examined. The ECG parameters describing ischemia were estimated in three subsequently selected episodes of SST-segment depression (more than 1mm) at minimal time interval between the 1st and the 2nd episodes (but not more than 60 min) and at time interval between the 2nd and the 3rd episodes more than 60min.
RESULTS (M± 1 SE).


ECG parameters

1st episode

2nd episode

3rd episode

P 1-2

P 2-3

P 1-3


Duration of ST depression (min)

5,29±
1,03

3,45±
1,51

7,74±
1,84

0,0012

0,0071

0,7194


Level of ST depression (mcV)

155,0±
9,7

127,5±
9,3

155,4±
17,7

0,0012

0,2087

0,106


Integral of ST depression (mcV*min)

468,0±
91,4

265,1±
97,1

702,7±
214,8

<0,0001

0,0071

0,8575


Maximal heart rate (beats/min)

92,9±
3,2

91,7±
3,0

90.7±
3,6

0,7194

0,4725

0,2812



There were registered from 6 to 23 ischemic episodes in each patient. Significant decrease of the ischemic episode duration, amplitude and integral of ST-segment depression were revealed at the 2nd episode in comparsion with the 1st and restoration of parameters at the 3rd ischemic episode. At the 2nd episode compared with the 1st the reduction of ST-segment depression integral was established in 28 (90%) patients, reduction of ST-segment level and decrease of ischemia duration were revealed in 23 (74%) patients.
Our data suggest the presence of spontaneous ischemic preconditioning in the most patients with IHD. This phenomenon can be registered by 24-hour ECG monitoring.


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