Occurrence Of ST-segment Depression Research Articles

Quantification of coronary artery disease using different modalities of cardiopulmonary exercise testing

BackgroundThis study examined the accuracy of cardiopulmonary exercise testing (CPET) on a treadmill (TM) and recumbent ergometry (RE) in the predicting coronary artery disease (CAD) severity and prognosis. MethodsForty Caucasian subjects, mean age 63.5 ± 7.6, with significant coronary artery lesions (≥50%) were included. Within two months of coronary angiography, TM and RE CPET were performed on two visits 2–4 days apart and subsequently followed up to 32 ± 10 months. ResultsMean left ventricular ejection fraction was 56.7 ± 9.6%. TM CPET exhibited a higher occurrence of ST segment depression ≥ 1 mm (71.05% vs 28.95%, p = 0.04). Subjects with 1–2 stenotic coronary arteries (SCA) demonstrated a better CPET response compared to those with 3-SCA. ROC analysis revealed a high predictive value for the ventilation/carbon dioxide production (VE/VCO2) slope obtained on TM (area 0.84, p = 0.003, Sn 88.9%, Sp 72%) in distinguishing between 1 and 2-SCA and 3-SCA. Among all CPET parameters, work efficiency (∆VO2/∆WR) during RE predicted cumulative cardiac events (p < 0.01). ConclusionsCPET parameters hold predictive value for CAD severity and prognosis. CPET on a TM appears to be more reliable in the quantification of CAD compared to RE.

Waveform analysis of the fetal ECG in labor in patients with intrahepatic cholestasis of pregnancy.

Intrahepatic cholestasis of pregnancy (ICP) is reported to be associated with an increased risk of sudden fetal death. The possible mechanism is thought to be cardiac arrhythmia. Prolonged QT interval of the electrocardiogram (ECG) is associated with arrhytmogenic events. The aim of the study was to compare the fetal ECG QT interval during labor in pregnancies complicated with ICP to healthy controls. The fetal ECG and QT interval was reviewed retrospectively. The intrapartum QT interval was measured in 61 fetuses born to mothers with ICP and in a control group of similar size. The corrected QT interval (QTc) was calculated using Bazett's formula: QT/√RR. The occurrence of ST segment depression was also included in the analysis. The groups were similar regarding to maternal age, parity, BMI, gestational age and smoking habits. The rate of labor induction was significantly higher in ICP patients (P < 0.001). The QTc at the beginning and the end of recording was analyzed and there were no significant differences in these values between the ICP patients and healthy controls (P = 0.467). Most ICP patients used ursodeoxycholic acid (UDCA) for mediation. We analyzed separately patients who had elevated liver enzymes before labor. No significant differences in the QTc were noted in these patients either. Nor were there any significant ST depressions in ICP patients. The etiology of adverse perinatal outcome and even sudden fetal death in ICP is still controversial. No differences in QTc intervals and ST waveforms during labor were found in our study material.

Ambulatory recorded ST segment depression on ECG is associated with lower cognitive function in healthy elderly men.

ST segment depression (STDE) has been found to be associated with cardiovascular disease in the elderly. Studies of the relation of ambulatory STDE to cognitive function in elderly persons aged 80 years or above is lacking. To study the association between STDE and cognition. A cross-sectional cohort study of 88 81-year-old men from the population study "Men born in 1914" investigated in an outpatient research clinic. Measurements included ambulatory 24-hour electrocardiogram (ECG) monitoring and a cognitive test battery of six tests. Proportion of lower cognitive function was calculated for each test in relation to STDE during the day and at night-time. Fifty-eight percent of the men had STDE and a higher proportion with low visuospatial cognitive function was found among those with STDE compared to the others (84% vs 59%; p = 0.014). A significant trend was noted for subjects without STDE compared to STDE night-time less than 60 minutes and night-time more than 60 minutes for spatial and verbal cognitive functions (p = 0.022). No trends were noted for STDE daytime. Maximal STDE during night showed similar association to spatial function (Benton Visual Retention test, r = -0.26; p = 0.028). Even when seven subjects with a history of stroke were excluded, the occurrence of STDE was associated to lower visuospatial cognitive function compared to those without STDE (87% vs 57%; p = 0.004). ST segment depression on ECG is common among elderly men and might be a vascular risk factor for cognitive deterioration.

Myocardial infarction and nocturnal hypoxaemia

There is an increased risk of cardiovascular morbidity and mortality in patients with nocturnal intermittent hypoxaemia. The aim of this study was to evalute the influence of nocturnal hypoxaemia on ventricular arrhythmias and myocardial ischaemia in patients with myocardial infarction (MI). We studied 77 patients (55.8 +/- 7.9 years) with MI free of complications, chronic pulmonary diseases, abnormal awake blood gases tension. All patients underwent overnight pulse oximetry and 24-hour electrocardiography. Patients were divided into two groups according to nocturnal hypoxaemia. Total number of ventricular premature complex (VPC); maximal VPC/h; incidence of VPC Lown class > 2 and occurrence of ST-segment depression were analysed for nocturnal (10 PM to 6 AM), daytime (6 AM to 22 PM) periods and for the entire 24 hours. Both groups were similar in age, gender, standard risk factors, myocardial infarction size and did not differ in VPC during the analysed periods. The number of nocturnal maximal VPC/h was insignificantly greater in group 1 (with hypoxaemia) compared to group 2 (without hypoxaemia), (p = 0.084). Maximal VPC/h did not differ significantly either for daytime or for 24 hours among the groups. Nocturnal VPC Lown > 2 were significantly more frequent in group 1 (25% vs 0%, p = 0.002). The incidence of VPC Lown > 2 was similar during the daytime, and during 24 hrs in both groups. Occurrence of ST-segment depression did not differ between groups 1 and 2. Nocturnal hypoxaemia was associated with complex nocturnal ventricular arrhythmias in patients with MI.

The prognostic and therapeutic implications of increased troponin T levels and ST depression in unstable coronary artery disease: The FRISC II invasive troponin T electrocardiogram substudy

Background In unstable coronary artery disease, both increased troponin T level and occurrence of ST-segment depression are associated with a worse prognosis. In the Fast Revascularisation in InStability in Coronary disease trial II invasive study, we evaluated whether the troponin T level, alone and combined with ST depression, identified more severe coronary artery disease or a greater efficacy of an early invasive strategy. Methods In the study, 2457 patients with unstable coronary artery disease were randomized to early invasive or noninvasive strategy. Troponin T value and admission electrocardiogram results were available in 2286 patients. Results In the noninvasive cohort, death or myocardial infarction occurred in 16.6% with troponin T level ≥0.03 μg/L versus 8.5% with troponin T level <0.03 μg/L (P <.001). In the invasive group, 49% of patients with both ST depression and troponin T level ≥0.03 μg/L had 3-vessel or left main disease compared with 17% if neither finding was present (P <.001). The invasive strategy reduced death/myocardial infarction at 12 months in the cohort with both ST depression and troponin T level ≥0.03 μg/L from 22.1% to 13.2% (risk ratio, 0.60; 95% confidence interval, 0.43 to 0.82; P =.001). In the cohort with either ST depression or troponin T level ≥0.03 μg/L or neither of these findings, the absolute gain of the invasive strategy was smaller and more uncertain. Conclusion Patients with unstable coronary artery disease with the combination of troponin T level ≥0.03 μg/L and ST depression have a poor prognosis and, in half of the cases, 3-vessel or left main disease. In these patients, an early invasive strategy will substantially reduce death/myocardial infarction. (Am Heart J 2002;143:760-7.)

Hypertension and Silent Myocardial Ischemia: Their Influence on Cardiovascular Mortality and Morbidity

The presence of ST-segment depression during ambulatory electrocardiographic monitoring, in relation to blood pressure treatment and control, was monitored in a non-randomized study in 167 men (49%) from the 'Men born in 1914' Malmö study, who were considered to have hypertension (diastolic blood pressure [DBP], > or = 95 mm Hg or receiving antihypertensive therapy). Men were excluded if they had a history of ischemic heart disease. A high frequency of ST-segment depression (41%) and associated high cardiac event rate (14%) were found in hypertensive elderly men who had inadequately controlled blood pressure (i.e. DBP > or = 95 mm Hg). This was associated with a relative risk of a cardiac event of 9.8 (95% confidence interval: 2.6-36.9), even after adjustment for smoking, blood lipids and alcohol consumption. The lower frequency of ST-segment depression (21%) and lower cardiac event rate (5%) in hypertensive men with adequate blood pressure control suggests that effective antihypertensive treatment leads to a reduced event rate. In conclusion, the occurrence of ST-segment depression during ambulatory electrocardiographic monitoring in this group of subjects may be an expression of silent myocardial ischemia, with or without left ventricular hypertrophy. The incidence of asymptomatic ST-segment depression and the rate of cardiac events in hypertensive patients may be, in part, related to the level of blood pressure control attained.

Transient myocardial ischaemia in hypertensives: missing link with left ventricular hypertrophy.

Hypertensive patients often complain of angina pectoris in spite of a normal coronary angiogram. The aim of this study was to establish whether electrographical signs of transient myocardial ischaemia during 24-h ST Holter monitoring are associated with an increased left ventricular muscle mass. Thirty-five hypertensive patients were studied by 24-h Holter monitoring and M-mode and two-dimensional echocardiography. For control purposes nine normotensives were studied by the same protocol. Hypertensives with and without ST-segment depression did not differ in respect of blood pressure or left ventricular muscle mass (162.9 +/- 80 vs. 162.3 +/- 53 g m-2). Since both groups only showed a borderline left ventricular hypertrophy, the myocardial factor does not seem to be important for the occurrence of ST segment depression. Primary functional and structural alterations at the microcirculation level seem to be responsible for the occurrence of transient episodes of ST segment depression in the Holter electrocardiogram, indicating transient myocardial ischaemia.

Slow-Release Gallopamil Evaluated by Exercise Test and Long-Term Electrocardiography

The effects of slow-release gallopamil (100 mg b.i.d.) were studied on exercise-induced ST-segment depression as well as on spontaneous myocardial ischemia detected by long-term electrocardiography (ECG) monitoring for 48 h in 26 patients with coronary artery disease and angina pectoris. Eight patients had to be excluded (because of paroxysmal atrial fibrillation in four patients, development of unstable angina pectoris in three patients, and frequent ventricular premature beats in one patient). In the remaining 18 patients, gallopamil led to an increase of work load (W x min) evaluated by bicycle ergometry, paralleled by an increase of exercise duration until the occurrence of ST-segment depression of > or = 0.1 mV in the nonblinded part of the trial. The number of spontaneous episodes of myocardial ischemia during long-term ECG recording, ranging from 0 to 14 during control, decreased in patients with two or more episodes during control, paralleled by a decrease in the total duration of ischemic episodes and a decrease in the ischemic score (duration of episodes x maximal ST-segment depression). During long-term ECG monitoring, we observed asymptomatic episodes of spontaneous second degree atrioventricular block of the Wenckebach type in three patients. No other adverse effects of slow-release gallopamil were observed. Therefore, these preliminary results of the non-blinded protocol confirm the anti-ischemic effects of slow-release gallopamil given 100 mg b.i.d.; however, these promising results will have to be confirmed in the consecutive double-blind, placebo-controlled part of the trial.

Increased occurrence of arrhythmias in men with ischaemic type ST‐segment depression during long‐term ECG recording. Prognostic impact on ischaemic heart disease: results from the prospective population study ‘Men born in 1914’, Malmö, Sweden

The objective of this long-term ECG (LTER) study in 394 68-year-old men, selected at random from the general population of Malmö, Sweden, was to determine the prevalence and occurrence of cardiac arrhythmias and their impact on morbidity and mortality from IHD. According to Lown classification, 29.4% (116 men) had ventricular arrhythmia (VA) group 4-5. Serious ventricular arrhythmia (Lown group 4-5) was more common in men with asymptomatic ischaemic type ST-segment depression (STD) than in those without it (37.8% vs. 26.7%: P less than 0.05). During the mean follow-up period of 53.1 months there were seven IHD deaths (6%) among the 116 patients with VA, Lown 4-5, and nine IHD deaths (3.2%) among the 278 patients without serious VA, Lown 0-3, (P = 0.26). Six and three of these deaths, respectively, were considered to be sudden (P = 0.022). The increased cardiac event rate (fatal or non-fatal MI or deaths due to chronic IHD) associated with a serious ventricular arrhythmia disappeared when history of IHD at baseline and occurrence of STD during LTER were taken into account. The study did not provide any evidence to suggest that ventricular arrhythmia was triggered by myocardial ischaemia. Five of 9 (56%) deaths due to IHD in men with STD occurred among the 38% (37/98) of patients who belonged to Lown class 4-5. It is concluded that the prognostic information derived from LTER can be improved by combined monitoring of STD and ventricular arrhythmias.

Effect of diltiazem on symptomatic and asymptomatic episodes of ST segment depression occurring during daily life and during exercise.

Silent myocardial ischemia is an adverse prognostic marker in patients with coronary disease; however, controlled data on the effect of treatment are sparse and contradictory, and the relations among the occurrence of ST segment depression, drug efficacy, and heart rate are unclear. Sixty patients with stable coronary artery disease, a positive treadmill exercise test and asymptomatic ST segment depression on ambulatory electrocardiographic recording were assessed in a multicenter, double-blind, placebo-controlled, cross-over trial. Treadmill exercise tests and 72-hour electrocardiographic recordings were obtained at the end of two 2-week treatment periods with sustained-release diltiazem 180 mg b.i.d. or equivalent placebo. Episodes of asymptomatic ST depression decreased by 50% or more in 70% of the patients from a median number of 4.5 (range, 0-19) to 1.5 (range, 0-13) (p = 0.0001); their cumulative duration also decreased from 78.5 (range, 0-60) to 24.5 (range, 0-411) minutes (p = 0.001). No circadian variation was found in the efficacy of diltiazem. The occurrence of ischemic type ST segment depression was modulated by changes in heart rate rather than by absolute heart rate. Diltiazem also improved exercise test end points but to a lesser extent. Time to ST segment depression increased to 341 +/- 148 from 296 +/- 154 seconds (p = 0.005). Although less frequent with diltiazem administration (45 versus 54 patients, p less than 0.03), exercise-induced ST depression was more often asymptomatic (98% versus 72% of patients, p less than 0.0001). Diltiazem reduces the frequency and severity of ischemic type ST depression in patients with stable coronary artery disease.

Prevalence and prognostic significance of silent myocardial ischaemia detected by exercise test and continuous ECG monitoring after acute myocardial infarction

The incidence and prognostic significance of silent myocardial ischaemia in 165 patients who survived a first acute myocardial infarction were assessed by means of maximal exercise stress test and 24 h continuous ECG monitoring performed before discharge. During the 1 year follow-up period 10 cardiac deaths occurred; moreover seven patients suffered a fatal myocardial re-infarction and 14 developed unstable angina. Cardiac death occurred in five of 40 patients (12.5%) with ST segment depression on stress test by in only three of 117 (2.6%) without ST segment changes (P less than 0.01). One-hundred-and-three of 117 patients (88.0%) without angina or ST segment depression on stress testing survived 1 year without cardiac events, compared with 24 of 40 patients (60.0%) with ST segment depression whether or not associated with angina (P less than 0.001). Cardiac death occurred in five of 25 patients (20.0%) with ST segment depression on continuous ECG monitoring, compared with five of 140 (3.6%) without (P less than 0.01). One-hundred-and-seventeen out of 140 patients (83.6%) without angina or ST segment depression survived 1 year follow-up without cardiac events, compared with 13 of 25 (52.0%) with ST segment depression with or without angina (P less than 0.01). Classifying patients in a 2 x 5 contingency table according to the occurrence of ST segment depression on exercise testing and/or ECG ambulatory monitoring, the Yates corrected chi-square test showed a significant pattern when cardiac deaths and cardiac events were considered together (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

"Recovery Only" ST-Segment Depression and the Predictive Accuracy of the Exercise Test

To clarify the predictive value of exercise-induced ST-segment depression occurring in recovery only, and to determine whether the addition of recovery data improves the interpretation of the exercise test. Retrospective analysis of data collected during exercise testing and coronary angiography. A 1000-bed Veterans Affairs Medical Center. The study included 328 male patients who had had both a sign- or symptom-limited treadmill test and coronary angiography. Of the 168 patients who had abnormal ST-segment responses, 26 had such responses only during recovery. The positive predictive value of this pattern for significant angiographic disease (84%) was not statistically different from the predictive value of ST depression occurring during exercise (87%). Inclusion of ST depression during recovery significantly increased the sensitivity of the exercise test from 50% to 59% (P = 0.01) without a change in predictive value. In addition, ST-segment depression occurring only during exercise is usually associated with less-severe angiographic coronary artery disease. The occurrence of ST-segment depression during the recovery period only, does not generally represent a "false-positive" response. The inclusion of findings from this period increases the diagnostic yield of the exercise test. Previously proposed exercise test scores, as well as exercise electrocardiography (ECG) analysis done in conjunction with scintigraphy, have a falsely lowered sensitivity that could be increased by considering ST-segment changes occurring in recovery.

Comparison between manual and computer measurement of ST-segment amplitude during exercise

Several studies have shown that the maximal ST HR slope may be used as a reliable index of myocardial ischemia as assessed by coronary angiography, but this involves laborious training and derivation, particularly with respect to the measurement of ST segment amplitude, which is obtained by averaging values measured in at least 10 cardiac cycles in the steady state. The authors compared manual measurement of ST-segment amplitude with computer-processed beat using cardiac cycles in six consecutive patients with standard 12-lead records obtained over 5 seconds and a beat processed by the recorder to represent each lead (modal beat, over 10 seconds). All recordings were made in the steady state. Two patients had myocardial ischemia, as assessed by means including the maximal ST HR slope and the occurrence of ST-segment depression at the end of exercise. Comparisons were made between measurements in 324 pairs of ST-segment amplitude obtained, respectively, from manually averaged recorded beats (average beat) and the modal beat during each step of the exercise test. The level of the ST-segment, (80 msec after the end of QRS complex) was independently obtained from the two records in a blinded fashion. The group data showed that the modal beat gave significantly lower values of ST-segment amplitude than the average beat. Similar results were obtained when 286 pairs of positive amplitudes were compared in the range of 0–7.25 mm. In the remaining 38 pairs in which ST-segment depression was found, the amplitude in the modal beats was not significantly different from the average beats. When the amplitude was assessed in 10–12 average beats of cardiac cycles in 45 pairs, the protocol for obtaining the maximal ST HR slope, no significant difference was found between average beats of 0.59 mm and modal beats of 0.69 mm. Cardiac cycles less than 10 were assessed to examine the influence of ST-segment amplitude and small numbers of recorded beats. Irrespective of the number of beats, amplitudes of values less than 2.45 mm in average beats were not significantly different from those in modal beats. The results show that the ECG recorder processing accuracy was better in cardiac beats with ST-segments having a low amplitude or a negative value than a highly positive amplitude. This should be useful in assessments of the level of the ST-segment at the end of exercise.