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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Data from previous studies are debatable regarding whether Holter monitors are a reliable electrocardiographic indicator of ischemia, for which the 12-lead electrocardiogram (ECG) is the standard. Simultaneous 12-lead and Holter ECGs were performed on 30 patients with typical angina pectoris during coronary angiography or exercise testing. ST depression recorded by both methods was directly compared, using the 12-lead ECG as the reference. The Holter tapes were also scanned by two automated ST analysis programs and the results were compared to 12-lead ECGs. Only 66 of the 178 12-lead ECG ST depression events were also present on the Holter recordings (37.1% Holter sensitivity). ST depression was underestimated by the Holter recordings compared to the 12-lead ECGs (p < 0.0001). The majority (67.0%) of ST depression events identified by one computer program were false positive events. The degree of ST depression was overestimated compared to 12-lead ECGs by the second program (p = 0.0033). Holter-detected ST depression may not be a reliable ECG indicator of myocardial ischemia.
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PMID:Comparison of ST depression recorded by Holter monitors and 12-lead ECGs during coronary angiography and exercise testing. 140 18

The results from recent studies suggest that the endogenous opioid beta-endorphin (beta-E) is related to pain modulation. Therefore, plasma beta-E levels were studied in 23 patients with essential hypertension (EH) and in 7 patients with coronary artery disease (CAD) during asymptomatic ischemic events and in 5 patients with CAD during symptomatic ischemic events. Blood samples for beta-E were taken at the moment of silent ST depression, pointed with alarm by the real time ECG monitor "Q Med Monitor" (USA). Control blood samples were taken under the same conditions without ischemic events. Control plasma beta-E levels were significantly higher (p less than 0.01) in patients with EH as compared to that in both groups of patients with CAD (22.9 +/- 4.0 vs 7.0 +/- 1.9 and 4.5 +/- 1.6 pmol/l). At the time of silent ischemia, beta-E showed a significant increase in patients with EH (+10.1 +/- 2.1 pmol/l, p less than 0.01) and in patients with CAD (+10.7 +/- 1.3 pmol/l, p less than 0.05) as compared to the control levels. However, plasma beta-E showed no increase (+1.0 +/- 0.6 pmol/l, p greater than 0.1) during symptomatic ischemia as compared to the control levels. Thus, differences in the circulating levels of beta-E may be associated with the presence or absence of pain during myocardial ischemia.
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PMID:[Plasma beta-endorphin level in "silent" myocardial ischemia during Holter ECG monitoring]. 140 1

The TQ segment depression and the ST segment elevation in the electrocardiogram during acute myocardial ischemia are caused by flow of injury current. This current flows between potential gradients across the ischemic border. The initial change is the TQ segment depression, which is brought about by a positive shift of the resting membrane potential of the ischemic cells. After 1 to 2 minutes ST segment elevation develops as a consequence of the action potential shortening and loss of plateau. The loss of potassium ions and ensuing extracellular K+ accumulation is the major cause of the alterations in action potential. After 15 to 20 minutes of ischemia, electrical cell-to-cell uncoupling occurs and interrupts the flow of injury current (decrease of TQ segment depression and ST segment elevation), producing conduction block.
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PMID:[Elevation of the ST-segment in the electrocardiogram and ischemic injury current]. 141 Sep 97

Clinicians often fail to detect intraoperative ischemic electrocardiographic (ECG) changes when viewing oscilloscopes. Automated ST-segment monitors promise to increase the detection of such ECG changes. We investigated the capacity of two commercially available ST-segment monitors to detect intraoperative myocardial ischemia in patients at high risk for developing intraoperative myocardial ischemia during vascular and other noncardiac procedures. The ST-segment monitors were compared with two reference monitors: (a) printed eight-lead ECGs, as interpreted by a cardiologist, and (b) the presence of segmental wall motion abnormalities and thickening abnormalities detected by transesophageal echocardiography (TEE). We also examined the capacity of the printed ECG to diagnose myocardial ischemia when compared with TEE. We studied 44 patients who underwent TEE, printed multilead ECG, oscilloscope monitoring of leads V5 and II, and measurement of ST-segment deviation from the baseline using an automated Hewlett Packard ST-segment device. The sensitivities for the Hewlett Packard system were 40% for TEE-diagnosed myocardial ischemia and 75% for ECG-diagnosed ischemia. Comparison of the printed ECG with TEE revealed that ST-segment changes in the printed ECG, as analyzed by a cardiologist, were 25% sensitive and 62% specific for the detection of TEE-diagnosed myocardial ischemia. When T-wave inversions were added to ST-segment depression as a criterion for the diagnosis of myocardial ischemia by the printed ECG, the sensitivity of ECG for the detection of intraoperative myocardial ischemia, as determined by TEE, was 40% and specificity was 58%. Twenty-three of the 44 patients were simultaneously monitored in leads I, II, and V5 with an automated Marquette ST-segment monitor.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:A comparison of methods for the detection of myocardial ischemia during noncardiac surgery: automated ST-segment analysis systems, electrocardiography, and transesophageal echocardiography. 141 32

ECG changes suggestive of myocardial ischemia are common during cesarean delivery under regional anesthesia. To determine the time course, duration, and significance of these ECG changes, we monitored 111 parturients with continuous ambulatory ECG (Holter) during and after cesarean delivery. Twenty-two parturients undergoing vaginal delivery were similarly monitored. ST segment depression was present in 25% of patients undergoing cesarean delivery but was not found in those patients delivering vaginally. ST segment elevation was not detected in either group. The incidence of ST segment depression during cesarean delivery was similar with epidural (29%), spinal (17%), and general (18%) anesthesia, occurring most commonly in the 30 min following delivery (P less than 0.001). Transthoracic echocardiographic imaging was performed in 23 patients undergoing cesarean section. Five of the 23 patients had seven episodes of intraoperative ST segment depression. Regional wall motion abnormalities were not present in any patient. A decrease in ejection fraction area greater than 15% from baseline or from previous interval ejection fraction area was present during four episodes of ST change. Three episodes of ST depression were not associated with significant decreases in ejection fraction area. Precordial Doppler monitoring for detection of venous air embolism in 25 patients revealed no association between the occurrence of venous air embolism and ST segment depression. We conclude that although significant myocardial impairment during cesarean delivery does not occur, episodes of ST depression may not all be merely an artifact of parturition.
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PMID:ST segment depression during labor and delivery. 848 79

From a total of 81 patients on maintenance hemodialysis who underwent coronary angiography, 8 patients fulfilled the criteria: significant coronary artery disease, hematocrit less than 27%, reproducible (ECG) positive treadmill test, no disturbance of repolarization in ECG at rest. Exercise stress testing was performed at a hematocrit of 25 +/- 2% and following erythropoietin therapy at a hematocrit of 34 +/- 0.5%. Symptom-limited exercise performance increased in all patients (1.10 +/- 0.3 W/kg b.w. vs. 1.44 +/- 0.31 W/kg b.w., p less than 0.01) as well as exercise duration (489 vs. 362 s, p +/- 0.01). ST segment depression during maximal exercise was reduced from a mean of 2.1 to 0.4 mm (p less than 0.01). It is concluded that amelioration of renal anemia by erythropoietin in dialysis patients with significant coronary artery disease reduces exercise-induced myocardial ischemia.
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PMID:Effect of erythropoietin on ischemia tolerance in anemic hemodialysis patients with confirmed coronary artery disease. 143 8

Twenty patients with stable ischemic heart disease in functional capacity Class II-IV underwent dental treatment. Scaling was performed in seven patients without local anesthesia. In the remaining 13 patients, pain control for restoration placement was obtained by local anesthesia: in seven patients, the anesthetics contained epinephrine, while in six this drug was omitted. Heart rate, blood pressure, and electrocardiograph were continuously monitored during the dental session. All patients had elevated systolic blood pressure and rate pressure product during treatment. In the patients who received plain local anesthetics only, the elevation in systolic blood and rate pressures was, however, significantly lower than the ischemic threshold. Arrhythmia or ST segment depression of > or = 1 millimeter were not recorded in any of the subjects. In severely compromised ischemic heart disease patients undergoing routine dental procedures of limited chair time, plain local anesthesia seems to be the preferred analgesic modality.
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PMID:Perioperative hemodynamic changes in ischemic heart disease patients undergoing dental treatment. 144 Jan 25

Nitrate monotherapy was assessed by treadmill exercise stress testing in 18 patients with significant but relatively asymptomatic myocardial ischemia who were receiving no other antianginal therapy. In addition, prolonged ambulatory electrocardiographic monitoring was performed in 7 patients with demonstrable ischemia during baseline monitoring. After baseline assessment, 5 treatment periods were used in a random order (each of 1 week duration), incorporating 2 dose levels of transdermal nitrate (10 and 20 mg/24 hours) and isosorbide dinitrate (ISDN) (30 and 60 mg/day in divided doses) with a 10-hour nitrate-free interval every 24 hours, as well as a placebo period using a double-blind technique. All treatment periods (including placebo) showed a significant (p < 0.01) 45 to 69% prolongation in the time to 1 mm ST depression during exercise. Paired baseline times of 231 +/- 28 and 233 +/- 30 seconds increased to 367 +/- 37 seconds with 30 mg/day of ISDN, 393 +/- 37 seconds with 60 mg/day of ISDN, 381 +/- 31 seconds with 10 mg/day of transdermal nitrate, and 372 +/- 33 seconds with 20 mg/day of transdermal nitrate. The value for placebo was 342 +/- 29 seconds, which was not significantly different from active treatment (p > 0.1). Some patients appeared to individually respond to > or = 1 nitrate preparation significantly more than to placebo, but this appeared to be unpredictable and largely independent of dosage level and route of administration. There was a qualitatively similar but statistically insignificant reduction in total ischemic time during ambulatory monitoring.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Placebo effect of nitrate monotherapy for myocardial ischemia. 144 72

The role of myocardial oxygen demand in the pathogenesis of silent ambulatory myocardial ischemia was evaluated by reviewing and assessing the methods and results of recent studies. The performance of simultaneous ambulatory electrocardiographic and blood pressure monitoring in 25 men with proven coronary artery disease (CAD) revealed significant increases in heart rate and blood pressure (p < 0.001) preceding most silent ischemic events. By plotting the mean heart rate obtained at 5-minute intervals during the 30 minutes before an ischemic event, the ischemic heart rate was shown to be significantly higher (95 +/- 15 vs 74 +/- 11 beats per minute [bpm]; p < 0.01) than the nonischemic heart rate. The evaluation of heart rate changes during ambulatory ischemia (in patients with CAD and ischemia induced by an exercise test using gradual work load increments) showed a significant heart rate increase (> 10 bpm) at 1-5 minutes preceding the onset of ST-segment depression. Heart rate increases during exercise testing according to the gradual work load increments of the National Institutes of Health protocol were compared with the heart rate preceding ischemic events during daily life monitored by ambulatory electrocardiography and were found to be closely related. In contrast, heart rate increases that occurred during exercise testing using the standard Bruce protocol were higher and correlated less with those preceding ischemia in daily life. Heart rate and blood pressure increased significantly in most silent ischemic episodes, indicating that increased myocardial oxygen demand plays a significant role in the pathogenesis of myocardial ischemia during daily life.
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PMID:Role of myocardial oxygen demand in the pathogenesis of silent ischemia during daily life. 144 97

The prevalence and prognostic significance of transient myocardial ischemia after coronary artery bypass grafting (CABG) were evaluated. In 3 studies, ischemia was found in an average of 24% of patients by ambulatory electrocardiographic monitoring at 3-12 months after CABG. An average of 36% of patients in 3 other studies experienced ischemic ST-segment depression during exercise testing at 4-50 months after CABG. Of the ischemic episodes, 77% were silent during exercise testing. In the Coronary Artery Surgery Study (CASS) randomized patient subsets, survival at 12 years was significantly lower for patients who had either silent or symptomatic ischemia during exercise testing at 6 months after CABG compared with those who had no ischemia.
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PMID:Significance of silent myocardial ischemia after coronary artery bypass surgery. 144


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