Prediction Of Myocardial Ischemia Research Articles

Value of QT dispersion in prediction of myocardial ischemia and its severity detected by stress imaging

Value of QT dispersion in prediction of myocardial ischemia and its severity detected by stress imaging

Clinical values of resting electrocardiography in patients with known or suspected chronic coronary artery disease: a stress perfusion cardiac MRI study

BackgroundElectrocardiography (ECG) is an essential investigation in patients with chronic coronary artery disease (CAD). However, evidence regarding the diagnostic and prognostic value of ECG in this population is limited. Therefore, we sought to determine whether baseline ECG abnormalities were associated with myocardial ischemia and cardiac events in patients with known or suspected chronic CAD.MethodsConsecutive patients with known (n = 146) or suspected chronic CAD (n = 349) referred for adenosine stress cardiac magnetic resonance (CMR) between 2011 and 2014 were enrolled. Resting ECGs were classified as major, minor, and no abnormalities. Predictors of myocardial ischemia on CMR and major adverse cardiac events (MACE) including cardiac death, nonfatal myocardial infarction, hospitalization for heart failure and late revascularization (> 180 days after CMR) were evaluated.ResultsAverage age was 69 ± 11 years (51% men). One hundred and eighty-five patients (37.4%) had major and 154 (31.1%) had minor ECG abnormalities. In patients with suspected CAD, myocardial ischemia was presented in 83 patients (23.8%). Multivariable analysis demonstrated major ECG abnormality as the strongest predictor of myocardial ischemia (HR 2.51; 95% CI 1.44–4.36; p = 0.001). Adding ECG to clinical pretest probability models improved the prediction of myocardial ischemia in ROC analyses (p = 0.04). In the whole cohort (n = 495), 91 MACE occurred during the median follow-up period of 4.8 years. Multivariable analysis showed that diabetes mellites, history of heart failure, prior revascularization, left ventricular ejection fraction, ischemia, and major ECG abnormality were independent predictors of MACE.ConclusionAbnormal resting ECG is common in patients with known or suspected chronic CAD. ECG had important diagnostic and prognostic values in this population.

Can QT dispersion improve the accuracy of stress ECG TMT in detecting myocardial ischemia in chronic stable CAD patients? A stress myocardial perfusion imaging study

BackgroundQT dispersion (QTd) is related to regional variations in myocardial repolarization. Our study aims to assess the value of QTd in prediction of myocardial ischemia and its severity during stress imaging.We enrolled one hundred patients having stable coronary artery disease (CAD) and fulfilling the “Appropriateness criteria for cardiac radionuclide imaging” (MPI). They were divided into group I including patients with MPI-detected ischemia (50 patients) and group II including patients with normal perfusion scan (50 patients). We excluded unstable CAD and all other causes affecting QTd. During isotope scan, ECGs were taken and QTd was calculated at rest and at maximum heart rate.ResultsQTd was significantly higher in the ischemic group both at rest and exercise (P = 0.000). QTd difference, the difference between QTd at rest and stress, was calculated. QTd difference was significantly lower in normal than in ischemic group (P = 0.003). There was a significant positive correlation between QTd difference and defect size (P = 0.04).ConclusionQTd increases in ischemia and the QTd difference (between rest and stress) correlates positively with severity of ischemia.QTd and QTd difference could be used to improve the accuracy of stress imaging test.

Can QT dispersion improves stress imaging accuracy in detecting ischemia?

Background and Aims: QT dispersion (QTd) is related to regional variations in myocardial repolarization. As exercise-induced ischemia causes heterogeneity in the ventricular repolarization, QTd could be used to assess the resulting ischemia. Aim: To assess the value of QTd in prediction of myocardial ischemia and its severity during stress imaging.

Diagnostic Ability of 384-Slice Computed Tomographic Angiography in Prediction of Myocardial Ischemia in Patients with Myocardial Bridging (MB) as Compared to SPECT-MPI Examination

Background: During the past decade, coronary computed tomographic angiography (CCTA) has become the primary non-invasive imaging technique for the assessment of myocardial bridging (MB). Objectivs: The aim of this study was to evaluate the ability of CCTA to predict myocardial ischemia in patients with MB. Patients and Methods: A total of 32 MB patients (21 males and 11 females) participated in this study. Eleven MB parameters were measured to assess the ability of CCTA to predict MB patients with ischemia. In order to evaluate ischemia, all the patients underwent single positron emission computed tomography-myocardial perfusion imaging (SPECT-MPI) examination. Results: Ischemia was observed in 17 patients (53.1%), while 15 patients (46.9%) did not show signs of ischemia. Out of the 32 patients, superficial MB was observed in 15 patients while deep MB was identified in 12, and borderline was observed in five patients. All MB examined parameters were found to be significantly different between ischemic and non-ischemic patients, except for the location and tunnel artery diameter in diastole. Moreover, a cut-off value of 0.65 mm was able to discriminate ischemia with a sensitivity of 100%, specificity of 93%, and yield area under the receiver operating characteristic (ROC) curve (AUC) of 0.996. Also, by considering the depth cut-off value of 1.75 mm, ischemia can be distinguished with sensitivity and specificity of 100%. MB length had a lower discrimination power, with a cut off value of 22.5 mm yield, 76% sensitivity, 67% specificity, and AUC = 0.810 in the diagnosis of ischemia. Conclusion: CCTA was a reliable modality with high accuracy to depict MB, identify high risk MB, and prevent unnecessary SPECT-MPI examination.

Gender Difference in Albuminuria and Ischemic Heart Disease in Type 2 Diabetes

The value of urinary albumin excretion in the prediction of myocardial ischemia in men and women with type 2 diabetes is not well understood. We questioned whether gender influences the albuminuria-ischemic heart disease relationship in patients with type 2 diabetes. We designed a matched case-control study of 926 patients with albuminuria (cases) and 926 age and body mass index matched patients without albuminuria (controls). Ischemic heart disease was defined as the presence of (1) history of angina pectoris or angina equivalent symptoms and critical care unit admission, (2) myocardial infarction and/or electrocardiographic evidence of Q-wave myocardial infarction, (3) coronary revascularization and/or stenting, (4) positive myocardial single-photon emission computed tomography scan, (5) ischemic ST-segment or T-wave changes, and (6) positive stress testing. Patients with albuminuria had a lower glomerular filtration rate and a longer diabetes duration than patients without albuminuria. In the group of cases, there were a greater number of men with ischemic heart disease (120 of 370; 32.4%) compared to women (97 of 559; 17.4%) (P<0.001). The odds ratio of having ischemic heart disease according to the presence or absence of albuminuria was 1.25 [95% CI: 1.01-1.56] (P<0.05) in all studied populations, 0.79 [95% CI: 0.51-1.21] (P=0.14) in women, and 2.84 [95% CI: 1.68-4.79] (P<0.001) in men. We showed that diabetes duration, high-density lipoprotein, low-density lipoprotein, and hemoglobin A(1c) influence albuminuria in women, while diabetes duration, fasting blood sugar, and diastolic blood pressure influence albuminuria in men. Men with albuminuria are at increased risk of ischemic heart disease compared to women. This may be related to the role of high-density lipoprotein on the albuminuria-gender relationship.

The Usefulness of a Fragmented QRS Complex in Patients with Myocardial Ischemia

Background: Fragmented QRS (fQRS) represents myocardial conduction abnormalities due to myocardial scar in patients with coronary artery disease. However, the implication of the fQRS has not been known in patients with myocardial ischemia without scar. Methods: Electrocardiograms from 97 patients (59.9±8.7 years; 67 males) with myocardial ischemia which was confirmed by both exercise nuclear stress test and coronary angiography and 169 patients (56.8±10.2 years; 76 males) who had negative results of exercise nuclear stress test (the control group) were studies. Patients with myocardial scar in nuclear stress test were excluded. Results: The fQRS was more frequent in patients with myocardial ischemia (n=35, 36.1%) than in the control group (n=37, 21.5%) (p=0.010). The sensitivity, specificity, positive predictive value, and negative predictive value of fQRS for diagnosing myocardial ischemia were 36.1%, 78.5%, 48.6%, and 68.5%, respectively. The fQRS (Odds ratio 3.41, 95% confidence interval 1.54 to 7.55, p=0.002) was associated with myocardial ischemia after adjusting for age, gender, current smoking, histories of hypertension, diabetes and hyperlipidemia. Conclusion: The fQRS is a moderately sensitive and an independent predictor for prediction of myocardial ischemia. Large studies are needed to evaluate the implication of fQRS in patients with myocardial ischemia without scar.

Adenosine Stress 64- and 256-Row Detector Computed Tomography Angiography and Perfusion Imaging

Background— Multidetector computed tomography coronary angiography (CTA) is a robust method for the noninvasive diagnosis of coronary artery disease. However, in its current form, CTA is limited in its prediction of myocardial ischemia. The purpose of this study was to test whether adenosine stress computed tomography myocardial perfusion imaging (CTP), when added to CTA, can predict perfusion abnormalities caused by obstructive atherosclerosis. Methods and Results— Forty patients with a history of abnormal single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) underwent adenosine stress 64-row (n=24) or 256-row (n=16) detector CTP and CTA. A subset of 27 patients had invasive angiography available for quantitative coronary angiography. CTA and quantitative coronary angiography were evaluated for stenoses ≥50%, and SPECT-MPI was evaluated for fixed and reversible perfusion deficits using a 17-segment model. CTP images were analyzed for the transmural differences in perfusion using the transmural perfusion ratio (subendocardial attenuation density/subepicardial attenuation density). The sensitivity, specificity, positive predictive value, and negative predictive value for the combination of CTA and CTP to detect obstructive atherosclerosis causing perfusion abnormalities using the combination of quantitative coronary angiography and SPECT as the gold standard was 86%, 92%, 92%, and 85% in the per-patient analysis and 79%, 91%, 75%, and 92% in the per vessel/territory analysis, respectively. Conclusions— The combination of CTA and CTP can detect atherosclerosis causing perfusion abnormalities when compared with the combination of quantitative coronary angiography and SPECT.

The relationship between coronary artery calcification detected by non-gated multi-detector CT in patients with suspected ischemic heart disease and myocardial ischemia detected by thallium exercise stress testing

To examine whether we could predict myocardial ischemia when coronary artery calcification is detected by non-gated multidetector CT in patients with suspected ischemic heart disease. Eighty-three patients suspected of having ischemic heart disease (55 men, 28 women; age range 36-83 years; mean age 68 years) underwent multidetector CT and T1-201 single photon emission computed tomography. Prediction of myocardial ischemia by coronary arterial calcification detected on CT was evaluated by comparing the coronary artery territories that showed calcification with the area of myocardial ischemia determined by SPECT. The sensitivity, specificity, positive predictive value, and negative predictive value of multidetector CT for predicting myocardial ischemia were calculated. Coronary angiography was also examined and compared with multidetector CT. Risk factors, including hypertension, smoking, hyperlipidemia, diabetes, and family history, were compared for evidence of coronary artery calcification detected by multidetector CT and myocardial ischemia detected by thallium nuclear scans. For analysis by patients, the sensitivity, specificity, positive predictive value, and negative predictive value of coronary artery calcification for myocardial ischemia detection were 65, 63, 56, and 71%, respectively. Similarly, for analysis by coronary arterial territories, those values were 56, 77, 41 and 86%, respectively. Coronary stenosis on CAG was also related to the ischemia determined by SPECT and calcification on multidetector CT. Ischemia was better influenced by risk factors than was coronary arterial calcification. For analysis by coronary arterial territories, the specificity and negative predictive value of coronary arterial calcification seen by multidetector CT are relatively high.