Noninvasive electrocardiographic findings and plasma norepinephrine levels in patients with post-myocardial infarction receiving anti-anginal agents.
OBJECTIVE
The aim of this study was to investigate the effects of anti-anginal agents on plasma norepinephrine (NE) levels and the autonomic nerve functions evaluated by advanced noninvasive electrocardiographic (ECG) tests in post-myocardial infarction (PMI) patients.


METHODS
The subjects were 89 PMI patients who had suffered myocardial infarction (MI) at least 2 months before they participated in this study, and who had been taking anti-anginal agent mono-therapy (typical Japanese doses) for at least 6 months. Subjects were classified into the following 3 groups, based on type of anti-anginal agent: calcium antagonists (n=31, 60+/-12 years), nitrates (n=29, 56+/-11 years) and beta-blockers (n=29, 63+/-14 years). Left ventricular late potentials (LP), heart rate variability (HRV), T wave alternans (TWA), QT dispersion (QTd), and plasma NE levels of all subjects were assessed. There were no significant differences in age, gender, MI location or coronary risk factors between the 3 groups.


RESULTS
There were no significant differences in the number of subjects who satisfied criteria for LP, TWA, and QTd between the 3 groups. Mean high frequency power of HRV of the calcium antagonist group was significantly (p<0.05) lower than those of the nitrate and beta-blocker groups. All 3 groups had similar LF/HF, TWA microvoltage and QTd values, but mean plasma NE level of the calcium antagonist group was significantly (p<0.01) higher than those of the nitrate and beta-blocker groups.


CONCLUSIONS
These results indicate that calcium antagonist therapy in PMI patients lowers parasympathetic tone and elevates plasma NE levels. However, in the present study, these values remained within normal ranges.
Kurita
Akira
A
Department of Biomedical Engineering and Cardiology, National Defense Medical College, Tokorozawa, Saitama, Japan. kurita@res.ndmc.ac.jp
Matsui
Takemi
T
Ishizuka
Toshiaki
T
Takase
Bonpei
B
Satomura
Kimio
K
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000368:Aged; D000787:Angina Pectoris / Q000188:drug therapy*; D001341:Autonomic Nervous System / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000494:pharmacology; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy*; D005996:Nitroglycerin / Q000494:pharmacology; D009638:Norepinephrine / Q000097:blood*; D014665:Vasodilator Agents / Q000494:pharmacology* / Q000627:therapeutic use
D000319:Adrenergic beta-Antagonists; D002121:Calcium Channel Blockers; D014665:Vasodilator Agents; D005996:Nitroglycerin; D009638:Norepinephrine