ST-segment Depression In ECG Research Articles

Significance of ST-segment Depression during Paroxysmal Supraventricular Tachycardia

Background: ST-segment depression in ECG is a common finding during paroxysmal supraventricular tachycardia. The exact mechanism and etiology of this ST-segment depression is not always evident. In this study we have tried to evaluate the significance of ST-segment depression during supraventricular tachycardia. Methods: Hospitalized patients for elective electrophysiological study with previous (EPS) history of supraventricular tachycardia with or without ST-segment depression were evaluated clinically, by coronary angiogram and EPS. Data were analyzed by appropriate statistical methods and comparison made between groups with ST-segment depression (Group A) and without ST-segment depression (Group B). Results: Total number of patients was 66. Equal number of patients (33) was in each group. The mean age of patients was 43.8 years. There was female predominance (M:F ratio 2:3). The mean heart rate during supraventricular tachycardia was 161 beats/min. Age, sex, coronary artery disease risk factors and heart rate during an episode of supraventricular tachycardia did not have any significant influence on ST-segment depression. Significant coronary artery disease was found in two patients in Group A and one patient in Group B. Electrophysiological study revealed that Atrio ventricular reentry tachycardia (AVRT) and AV nodal reentry tachycardia (AVNRT) were present in 28 (42.4%) and 38 (57.6%) cases respectively. Patients of group A exhibit AVRT significantly more than patients of group B.The sensitivity of ST-segment depression in correctly diagnosing coronary artery disease (CAD) was 66.7% while the specificity was 50.8%. The sensitivity of ST-segment depression in correctly differentiating AVRT was 83.3% while the specificity was 66.7%. The positive predictive value (PPV) and Negative predictive value (NPV) of the test were 75% and 76.9% respectively. Conclusion: ST-segment depression during episode of supraventricular tachycardia is a poor indicator of coronary artery disease. Presence of ST-segment depression can differentiate AVRT from AVNRT. However, >2 mm ST-segment depression was proved to be an excellent predictor of AVRT. DOI: http://dx.doi.org/10.3329/cardio.v7i2.22249 Cardiovasc. j. 2015; 7(2): 93-97

Attenuated NOx responses and myocardial ischemia, a possible risk for structural vascular disease in African men: the SABPA study

Chronically elevated blood pressure has been associated with impaired NO-mediated vasodilation and structural vascular disease risk. This study aimed to determine whether significant associations exist regarding NO metabolite (NOx) responses, cardiovascular function and structural vascular disease in a cohort of African and Caucasian men. The study included 81 African and 94 Caucasian male teachers stratified via median splits into low and high NOx ethnic groups. Ambulatory blood pressure, electrocardiogram monitoring and ultrasound carotid intima-media thickness (CIMT) images were obtained. Cardiovascular measurements and fasting blood for NOx responses were measured during rest and on challenging the cardiovascular system with the Stroop colour-word conflict test. African men displayed significantly higher resting NOx as well as higher number of 24 h silent ischemic events than their Caucasian counterparts. Low NOx African men displayed enhanced α-adrenergic and ECG ST segment depression acute mental stress responses as well as 24 h silent ischemic events associated with CIMT (adjusted R(2) = 0.47; β = 0.25; confidence interval (CI) = 0.13, 0.41). African men demonstrated a vulnerable cardiovascular profile. Novel findings revealed α-adrenergic-driven blood pressure responses and less NO bioavailability during acute stress. The association between myocardial ischemia and CIMT in this group emphasized their risk for future coronary artery disease and cerebrovascular events.

Triple occurrence of Takotsubo cardiomyopathy

A 51 year-old woman after a quarrel with her husband and with no previous cardiovascular history was admitted to hospital with a suspicion of anterior myocardial infarction (MI) in 2005. She was suffering from chest pain; ECG documented ST-segment elevation in the V1–V3 leads and a positive troponin I level (2.8 ng/dL) was documented. An echocardiogram revealed akinesia of apical and mid-wall segments of left ventricular (LV) anterior wall and intraventricular septum with an ejection fraction (EF) of 45% (Fig. 1A, B). An urgent coronary angiography demonstrated no coronary artery disease (CAD). We observed full recovery with no LV contraction abnormalities at one-month follow-up. The subsequent focal type of Takotsubo cardiomyopathy (TTC) was diagnosed. Three years later, she presented with an inverse-type of TTC after knee surgery due to chest pain, ST-segment abnormalities in ECG and an increased troponin level (5.3 ng/dL). An echocardiogram and ventriculography revealed akinesia of all basal and mid-wall LV segments with an EF of 38% (Fig. 1C, D). We observed again a full clinical recovery with no LV wall motion abnormalities. A third hospitalisation, following a panic attack, occurred in 2009. The patient was referred for invasive diagnostics due to chest discomfort, ST-segment depression in ECG and a troponin I level of 1.1 ng/dL. Echocardiography and coronarography results were similar to those from the second episode (Fig. 1E, F). Therefore, a third occurrence of TTC was subsequently recognised. The most recent echocardiography showed normal LV contraction with an EF of 68% and normal longitudinal peak systolic strain for all LV regions (Fig. 1G, H). TTC, first described in 1990, usually affects postmenopausal women and is proceeded by psychological or physical stress. TTC mimics acute MI due to angina chest pain, ST-segment elevation pattern in ECG and a positive troponin level. However, obstructive CAD is in the majority of cases excluded. TTC, which is sometimes also known as apical ballooning syndrome, is predominantly characterised by transient, reversible, regional systolic dysfunction involving the LV apex and mid-ventricle with hyperkinesis of the basal LV segments. Case reports from the last 2 decades have also shown different faces of TTC concerning atypical TTCs such as inverse TTC with basal wall motion abnormalities, mid-segment TTC with akinesia presentation of all LV mid-segment and hyperkinesias of the basal and apical regions of LV, and focal TTC with regional wall motion disturbances. We here present a unique case of three TTC episodes in one patient after different stress events.

110: Non-invasive coronary flow reserve predicts response to exercise in asymptomatic severe aortic stenosis

In patients (pts) with asymptomatic aortic stenosis (AS), exercise stress echocardiography (ESE) provides additional prognostic information beyond baseline. The coronary flow reserve (CFR) is impaired in AS but its link with exertion is missing in this setting. We hypothesize that CFR could predict exercise capacity and an abnormal exercise test in AS. non-invasive CFR and symptom limited semi-supine exercise stress echocardiography (ESE) were performed the same morning in 20 consecutive pts with asymptomatic isolated severe AS (mean age 69±12 years, 30% women, mean aortic valve area 0.8±0.1 cm 2 ;, mean LVEF 70±6%). CFR was performed in the distal part of the left anterior descending artery using intravenous adenosine infusion (140 μg/kg/min over 2 min). An abnormal ESE was defined as onset of symptoms at less than 80% of maximum predicted workload, ECG ST-segment depression ≥2 mm during exercise, rise of systolic blood pressure < 20 mmHg or fall in blood pressure, complex ventricular arrhythmia. when compared to pts with normal ESE, pts with an abnormal ESE (n=9) were older, had higher left atrial volume index (all, ≤0.05), and lower CFR (2.1±0.3 vs. 2.9±0.7, ≤0.01), whereas resting hemodynamic variables assessing AS severity were not significantly different between subgroups. Furthermore, CFR was significantly correlated to age, the change of transvalvular pressure gradient and LVEF with exercise, workload (in watts), and exercise duration (all, p<0.05). After adjusting for age, and sex, CFR remained significantly correlated to exercise duration and workload (all, p<0.05). Using a ROC curve analysis, a CFR < 2.17 was the best cut-off to predict an abnormal ESE with a sensitivity of 67%, a specificity of 90% (AUC=0.8, p<0.01). In pts with asymptomatic severe AS, non-invasive CFR is correlated to exercise duration and workload, and a low CFR predicts an abnormal ESE with a good accuracy.

Is ATP-sensitive K + channel (K +ATP) recruitment a common mechanism for ECG-ST segment depression and elevation?

ATP sensitive (K + ATP) potassium cardiac channels are recruited when ATP levels are low as in ischemic injury and acute trauma. Such activation results in ECG-ST elevation and cardiac arrhythmias. K + ATP channel recruitment may be blocked by the sulfonylurea glibenclamide, permitting a wide variety of animal experimentation designed to test the genesis of ECG-ST segment elevations and depressions in diverse conditions including digitalis effect, acute arterial occlusion, tachycardias, and acute pericarditis. A specific series of animal experiments designed to test this hypothesis is proposed. Clinical implications are discussed.

Valor pronóstico del fibrinógeno en pacientes ingresados con sospecha de angina inestable o infarto de miocardio sin onda Q

In recent years, the relation between biological markers of inflammation and prognosis in patients suffering from acute coronary syndromes has been investigated. The aim of this study was to evaluate the association between baseline fibrinogen concentrations and the development of clinical events in patients admitted with suspicion of unstable angina and non-Q-wave myocardial infarction. Levels of fibrinogen at enrollment were analyzed in 325 consecutive patients with acute coronary syndromes. Fibrinogen values were divided into tertiles and the incidence of clinical events was evaluated at each level. The combination of death and/or myocardial infarction was the main endpoint. Fibrinogen levels were significantly higher in patients who subsequently had myocardial infarction, cardiac death, or both during follow up. The probabilities of death and/or myocardial infarction were 6%, 13%, and 29% (p < 0.0001), respectively, in patients grouped by fibrinogen tertiles (304, 305-374 and 375 mg/dl). Multivariate predictors of combined events were age, previous angina, ST-segment depression in the admission ECG, and fibrinogen into tertiles. The adjusted hazard ratio (95% CI) for patients in the upper tertile was 4.8 (1.6-14; p = 0.004). High fibrinogen levels were related to a less favorable long-term or short-term outcome in patients admitted for suspicion of unstable angina and non-Q-wave myocardial infarction. This association persists after adjustment for other classical risk factors such as age, prior angina, and ST-segment depression in the ECG.

Angiographic and hemodynamic determinants of myocardial ischemia during adenosine thallium-201 scintigraphy in coronary artery disease.

Myocardial ischemia attributed to coronary steal may occur in some patients receiving pharmacological coronary vasodilation. ECG ST-segment depression is a marker of myocardial ischemia in these patients, but the factors determining the presence or absence of ischemia are not well known. To examine the angiographic, hemodynamic, and scintigraphic determinants of adenosine-induced ischemic ST-segment depression in patients with coronary artery disease, we studied 65 consecutive patients (45 men and 20 women; mean age, 65 +/- 12 years) who showed reversible perfusion defects during adenosine (140 micrograms.kg-1.min-1 for 6 minutes) 201Tl single-photon emission computed tomography. Patients with prior myocardial infarction were excluded. Ischemic ST depression occurred in one third of the whole cohort (22 of 65 patients). The presence of coronary collateral vessels (p = 0.001), systolic blood pressure at baseline (p = 0.006), and adenosine-induced anginal chest pain (p = 0.011) were the only significant independent predictors of ischemic ST-segment depression by stepwise logistic regression analysis. Rate-pressure product at baseline, systolic blood pressure, heart rate, rate-pressure product, increase in heart rate, and rate-pressure product during adenosine infusion and maximal percent stenosis were variables also significantly related to ischemic ST depression by univariate analysis but were not predictive after the three primary variables were included in the regression model. Perfusion defect size, number of diseased vessels, and age did not correlate with ST-segment depression. The presence of collaterals, which may predispose to coronary collateral steal, is the most significant correlate of ischemic ST-segment depression during adenosine infusion. Systolic blood pressure at baseline, which may affect the myocardial oxygen supply/demand ratio and anginal chest pain induced by adenosine, are additional variables related to ischemic ST-segment depression during adenosine infusion.

Acute hydralazine overdose: Marked ECG abnormalities in a young adult

Although hydralazine is a commonly prescribed antihypertensive agent, reports of acute human poisoning are uncommon. Most of the literature focuses on chronic toxicity, most notably, the drug-induced systemic lupus erythematosus syndrome. A case of acute hydralazine overdose associated with marked ECG ST segment depression in a young adult is presented. Although the patient also had mild hypotension, acidemia, and ethanol intoxication, the ECG abnormality was alarming and suggestive of myocardial ischemia. The patient was managed conservatively in an ICU setting, and the metabolic and ECG abnormalities resolved. No reports of such marked ECG changes associated with acute hydralazine poisoning in a young adult could be found. Clinical and experimental data on acute hydralazine exposure suggest that the possibility of direct drug effects, including positive inotropic and chronotropic effects and myocardial cell injury, should be considered.

Superiority of selected treadmill exercise protocols predischarge and six weeks postinfarction for detecting ischemic abnormalities

We evaluated 29 uncomplicated post-myocardial infarction patients with heart rate-limited and symptom-limited modified naughton treadmill exercise tests predischarge and 31 similar patients with symptom-limited modified Naughton and standard Bruce stress tests at 6 weeks following infarction to determine their comparative value for detecting unsuspected ischemic abnormalities. Predischarge, the symptom-limited modified Naughton test identified a significantly greater number of patients with ECG ST segment depression or angina than did the heart rate-limited test (21 vs 13 patients, p < 0.05). This resulted from a significantly longer average maximal exercise duration (10.5 ± 4.9 vs 7.9 ± 4.2 minutes, p < 0.001) and higher maximal rate-pressure product (21.9 ± 5.8 vs 19.2 ± 4.6 × 10 3, p < 0.001) during the symptom-limited test. At 6 weeks following infarction, the standard Bruce stress test identified a significantly higher frequency of ischemic abnormalities than did the symptom-limited modified Naughton test (20 vs 13 patients, p < 0.05). This resulted from a higher average maximal rate-pressure product (23.1 ± 7.3 vs 21.0 ± 6.2 × 10 3, p < 0.02), despite a shorter maximal exercise duration (6.9 ± 1.2 vs 10.7 ± 4.4 minutes, p < 0.001) during the Bruce stress test. We conclude that: (1) symptom-limited exercise is superior to heart rate-limited exercise predischarge and (2) the standard Bruce stress test is superior to the symptom-limited modified Naughton exercise test at 6 weeks following infarction for the detection of unsuspected ischemic abnormalities in uncomplicated postinfarction patients.

Angina Pectoris in a Child With Sickle Cell Anemia

A 7-year-old black boy with sickle cell disease, Wolff-Parkinson-White syndrome, mild left ventricular dysfunction, and normal coronary arteries developed angina pectoris five months after cessation of hypertransfusion therapy. Exercise-induced ECG ST segment depression associated with angina disappeared following transfusion therapy.

Blood viscosity factors in evaluation of submaximal work output and cardiac activity in men.

Sixty-two male subjects, including patients with postmyocardial infarction, angina, other disorders, and normals, were studied by exercise testing on the bicycle ergometer, including exercise ECG, and by in vitro determination of blood viscosity, plasma viscosity, aggregation of red cells, and other factors. Significant correlations were found between the blood viscosity factors on the one hand, and different terms describing physical fitness and cardiac functions on the other. In all correlations an elevation of blood viscosity factors led to lower fitness or lower cardiac efficiency; and a decrease of blood viscosity (or plasma viscosity, or compound viscosity product) was associated with better fitness and higher cardiac efficiency. Similarly, ECG ST-segment depression was proportional to increase of blood viscosity factors. All these highly significant correlations were found within a very narrow range of hematocrits, while the hematocrit value itself was not significant in this study.