Is the change of late potential over time related to enzyme levels? Ischemic burden in acute myocardial infarction.
BACKGROUND
The ventricular late potential (VLP) detected using the technique of signal average electrocardiography (SAECG) interacts with several factors, primarily time.


METHODS
In this study, we examined the interaction, over time, of VLP with the initial ischemic burden and enzyme levels in acute myocardial infarction. Patients diagnosed as having acute myocardial infarction were included in the study. On the first day, the patients underwent enzyme analysis and electrocardiography (ECG) follow-up every 6 hours. A 24-hour ambulatory ECG was performed on the seventh day in order to determine the ischemic burden. SAECG findings (TQRS, RMS, LAS) were obtained on the seventh day, in the first and third months. The study was continued with the patients who did not require angioplasty as decided with angiographic evaluation in the first month.


RESULTS
The study included 30 patients with acute myocardial infarction (mean age 51 +/- 12, 28 males and 2 females). The initial mean CK-MB levels and the mean ischemic burden were 98 +/- 31 U/L and 44 +/- 96 minutes. The TQRS (ms), LAS (ms), and RMS (microV) values (mean +/- SD ) obtained at day 7, month 1, and month 3 are 97 +/- 12, 96 +/- 9, 103 +/- 11, P = 0.01; 31 +/- 10, 31 +/- 11, 32 +/- 10, P = 0.46; 43 +/- 28, 41 +/- 26, 33 +/- 25, P = 0.01, respectively. We observed that the TQRS and RMS values changed significantly with time, but these levels of significance disappeared when adjusted for the initial ischemic burden and CK-MB levels (P = 0.06; P = 0.53). The VLP frequency was 33% at day 7 and 23% at month 3. Unlike the CK-MB level, the initial ischemic burden was significantly different between the patients with and without VLP at month 3 (150.85 +/- 149.28, 12.34 +/- 26.48, P = 0.001 ). When tested together with age and gender, it was found that the high initial ischemic burden increased the possibility of VLP (OR: 24, CI: 2.09-279.52, P = 0.01 ) at month 3.


CONCLUSIONS
SAECG findings in patients with myocardial infarction changed with time; however, this change occurred depending on the initial ischemic burden and CK-MB levels. Of these, only the initial ischemic burden, especially in high levels, was a determinant for the presence of VLP in the late period of myocardial infarction.
Eryol
Namik Kemal
NK
Department of Cardiology, Medical Faculty, Erciyes University, Kayseri, Turkey. nkeryol@erciyes.edu.tr
Topsakal
Ramazan
R
Oguzhan
Abdurrahman
A
Abaci
Adnan
A
Başar
Emrullah
E
Ergin
Ali
A
Cetin
Servet
S
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D004796:Clinical Enzyme Tests; D015331:Cohort Studies; D003402:Creatine Kinase / Q000097:blood / Q000378:metabolism*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000097:blood / Q000378:metabolism; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000201:enzymology*; D017202:Myocardial Ischemia / Q000175:diagnosis / Q000201:enzymology; D011237:Predictive Value of Tests; D011336:Probability; D011379:Prognosis; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013997:Time Factors
D007527:Isoenzymes; D003402:Creatine Kinase