Silent myocardial ischemia in patients with stable coronary artery disease receiving conventional antianginal drug therapy.
BACKGROUND
Few data are available on the behavior of myocardial ischemia during daily activities in patients with coronary artery disease receiving antianginal drug therapy.


OBJECTIVE
To study the mechanism generating myocardial ischemia by evaluating blood pressure and heart rate changes in patients with stable atherosclerotic disease receiving drug therapy and with evidence of myocardial ischemia.


METHODS
Fifty non-hospitalized patients (40 males) underwent 24-hour electrocardiographic monitoring synchronized with blood pressured monitoring.


RESULTS
Thirty five episodes of myocardial ischemia were detected in 17 patients, with a total duration of 146.3 minutes; angina was reported in five cases. Twenty nine episodes (100.3 minutes) occurred during wakefulness, with 11 episodes (35.3 + 3.7 min) in the period from 11 a.m. to 3 p.m. Blood pressure and heart rate evaluation in the three ten-minute intervals following the ischemic episodes showed a statistically significant difference (p< 0.05), unlike that shown for the three intervals preceding the episodes. However, during the ischemic episode, a higher than 10-mmHg elevation in blood pressure and 5 beats per minute in heart rate were observed when compared with the time interval between 20 and 10 minutes before the episode. The mean heart rate at the onset of ischemia during the exercise test performed before the study was 118.2 + 14.0, and 81.1 + 20.8 beats per minute on the 24-hour electrocardiogram (p < 0.001).


CONCLUSIONS
The incidence of silent myocardial ischemia is high in stable coronary artery disease and is related to alterations in blood pressure and heart rate, with different thresholds for ischemia for the same patient.
Ferreira
João Fernando Monteiro
JF
Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina de São Paulo, São Paulo, SP, Brasil. jfmf@cardiol.br
César
Luiz Antonio Machado
LA
Gruppi
César J
CJ
Giorgi
Dante M A
DM
Hueb
Whady A
WA
Mansur
Antonio P
AP
Ramires
José A F
JA
D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000787:Angina Pectoris / Q000503:physiopathology / Q000517:prevention & control; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001795:Blood Pressure Determination; D003324:Coronary Artery Disease / Q000188:drug therapy* / Q000503:physiopathology; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D000960:Hypolipidemic Agents / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000517:prevention & control; D017202:Myocardial Ischemia / Q000175:diagnosis* / Q000503:physiopathology
D000959:Antihypertensive Agents; D000960:Hypolipidemic Agents