[Clinical significance of Q-Tc dispersion after exercise in aged patients with old myocardial infarction].
OBJECTIVE
This study was aimed to evaluate clinical significance of Q-Tc dispersion after exercise in aged patients with old myocardial infarction.


METHODS
Sixty-four aged patients with old myocardial infarction(infarction group) were examined by treadmill exercise, dynamic electrocardiography, echocardiography, and were followed up for average of 24.12 +/- 7.7 months. 30 healthy aged persons were served as control group.


RESULTS
Compared with that (40.21 +/- 15.21 ms) before exercise, Q-Tc dispersion (59.37 +/- 20.17 ms) was increased significantly after exercise in infarction group(P < 0.01). But no significant difference was found in Q-Tc dispersion of control group before and after exercise(34.70 +/- 12.29 ms vs 38.91 +/- 13.62 ms P > 0.05). In infarction group, occurrence of abnormal contraction of left ventricular wall, aneurysms, NYHA III class and > III class of Lown's ventricular arrhythmia classification was significantly higher in Q-Tcd > 50 ms patients than that in Q-Tcd < 50 ms ones(P < 0.05). It was found that 5 patients died of cardiac sudden death in Q-Tcd > 50 ms patients and no one died of cardiac sudden death in Q-Tcd < 50 ms ones.


CONCLUSIONS
The Q-Tc dispersion after exercise is an important index to predict ventricular arrhythmia and cardiac death in the patients with old myocardial infarction.
Yu
G
G
Department of Griatric Cardiology, Xiangya Hospital, Hunan Medical University, Changsha 410008.
Cheng
G
G
Zhuang
H
H
D000368:Aged; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology*