Exercise-induced ST-segment Depression Research Articles

FREQUENCY OF SIGNIFICANT CORONARY ARTERY DISEASE IN CASES WITH ST SEGMENT DEPRESSION DURING RECOVERY PHASE OF EXERCISE

Coronary Artery Disease (CAD) imposes physical, social, and economic burden. It is amongst the leading causes of mortality and morbidity. Exercise-induced ST segment depression is considered reliable ECG finding for the diagnosis of obstructive coronary atherosclerosis. Exercise testing has an excellent safety record. The aim of the study is to determine the frequency of significant coronary artery disease in cases with ST-segment depression during recovery phase of exercise tolerance test. This descriptive case series was carried out at the Department of Cardiology, Rehmatul-Lil-Alamin Institute of Cardiology, Lahore, from 11-01-2021 to 10-07-2021. A total of 89 patients were taken in this study. Conventional coronary angiography via femoral or radial route was performed. Lesions were quantified by QCA technique in addition to visual assessment. Significant CAD was labelled as per operational definition. Patients ranged between 30-70 years of age with mean age of 51.8±10.8 years. There were 56 males (62.9%) while remaining 33 (37.1%) were females. History of diabetes mellitus was reported in 31 patients (34.8%), hypertension in 38 patients (42.7%) and smoking 51 (57.3%). Family history of CAD found in 46 patients (51.7%). Hyperlipidemia reported in 38 patients (42.7%). Significant CAD was observed in 76 patients (85.4%). Stratification for age, gender, diabetes mellitus, hypertension and smoking were carried out and found no association with significant CAD. In conclusion, 85.4% frequency rate of significant coronary artery disease in cases with ST segment depression during recovery phase of exercise tolerance test was observed. Thus, careful evaluation of ST segment depression occurring in recovery phase may add significantly to the clinical information derived from the results of ETT.

Significance of Rate-Pressure Product and Duke Treadmill Score in Predicting Disease Severity in Patients with Coronary Artery Disease: A Cross-sectional Study

Introduction: Exercise electrocardiography is a well-established and cost-effective investigation for evaluating Coronary Artery Disease (CAD). The Rate-pressure Product (RPP), which is the product of maximal Systolic Blood Pressure (SBP) and peak Heart Rate (HR) during exercise, is a widely accepted parameter reflecting cardiac work and evaluating ventricular function. The use of Duke Treadmill Score (DTS) improves the diagnostic accuracy of exercise-induced ST-segment depression and has been observed to provide independent prognostic information. It has been shown that DTS provides information about the complexity of coronary artery lesions assessed by invasive coronary artery testing. Aim: To determine the significance of RPP and DTS in predicting the severity and complexity of angiographic lesions in patients with Stable Ischemic Heart Disease (SIHD) and a positive Treadmill Test (TMT). Materials and Methods: This study involved 100 consecutive patients with a positive TMT but no prior history of Acute Coronary Syndrome (ACS) who underwent coronary angiography at Government Medical College, Kottayam, Kerala, India, between March 2018 and March 2019 after obtaining ethical clearance from the Institutional Review Board. The DTS and RPP were calculated for these patients. All patients then underwent coronary angiography, and their SYNTAX scores were calculated. Correlation analysis was performed to assess the relationship between DTS, RPP, and SYNTAX score using Spearman's correlation coefficient. The Kruskall-Wallis test was used to compare risk factors among groups. Results: A total of 100 patients were evaluated, ranging in age from 40 to 74 years with an average age of 57 years. The average SYNTAX score was 15, ranging from 2 to 56. The average Duke TMT score was -5.2, ranging from 6 to -22. There was a significant negative correlation between DTS and angiographic severity determined by SYNTAX score (r=-0.702, p=0.001). The average RPP was 22174, ranging from 14000 to 37620. The study showed a significant negative correlation between RPP and SYNTAX score (r=-0.201, p=0.04). Diabetic patients had a significantly higher SYNTAX score compared to non-diabetics (r=-0.602, p=0.013). Additionally, a significant negative correlation was observed between the Metabolic Equivalents (METs) attained, duration of exercise, and the SYNTAX score. Conclusion: DTS and RPP derived from the exercise treadmill test have a significant negative correlation with the severity and complexity of CAD as determined by the SYNTAX score in coronary angiography.

Frequency and Influence of Exercise-Induced Artifact in Electrocardiograms During Exercise Treadmill Testing for Detection of Myocardial Ischemia.

Exercise treadmill testing (ETT) is frequently utilized for noninvasive detection of myocardial ischemia and coronary artery disease. The frequency of electrocardiogram (ECG) artifacts (ECGA) during ETT and their influence on the identification of exercise-induced ischemia are not known. We reviewed all ETTs with ST segment depression in the University of California, Davis, Medical Center treadmill database during each of the years 2012 and 2016 to identify tests with exercise-induced ST segment depression in the inferior and inferolateral leads. We identified cases with ECGA during progressive phases of the test, and we assessed the influence of comorbidities and the impact of ECGA on the diagnosis of coronary artery disease. Tests were considered false or true positive based on the result of confirmatory tests. Of 2,100 tests, we identified 123 patients with exercise-induced ST segment depression in inferior or inferolateral leads (men, 43%; mean age, 59 ± 10 years; white, 59%). Tests were symptom-limited: maximum heart rate, 153 ± 18; peak METs (metabolic equivalents of resting total oxygen consumption), 9.4 ± 2.7; ECGA occurred in 91% of tests at peak exercise with earlier occurrence among females. Tests were less likely to be true positive with peak ECGA than those without ECGA (13% vs. 50%, p = 0.05). ECGA at peak exercise are frequent and related to peak heart rate and peak metabolic equivalents of resting total oxygen consumption, suggesting a motion effect. ECGA affected the diagnostic accuracy of ETT examinations, indicating that algorithms to reduce artifact for improved diagnosis of ETT require further investigation.

False-positive stress testing: Does endothelial vascular dysfunction contribute to ST-segment depression in women? A pilot study.

The utility of exercise-induced ST-segment depression for diagnosing ischemic heart disease (IHD) in women is unclear. Based on evidence that IHD pathophysiology in women involves coronary vascular dysfunction, we hypothesized that coronary vascular dysfunction contributes to exercise electrocardiography (Ex-ECG) ST-depression in the absence of obstructive coronary artery disease, so-called false positive results. We tested our hypothesis in a pilot study evaluating the relationship between peripheral vascular endothelial function and Ex-ECG. Twenty-nine asymptomatic women without cardiac risk factors underwent maximal Bruce protocol exercise treadmill testing and peripheral endothelial function assessment using peripheral arterial tonometry (Itamar EndoPAT 2000) to measure reactive hyperemia index (RHI). The relationship between RHI and Ex-ECG ST-segment depression was evaluated using logistic regression and differences in subgroups using 2-tailed t tests. Mean age was 54 ± 7 years, body mass index 25 ± 4 kg/m2 , and RHI 2.51 ± 0.66. Three women (10%) had RHI <1.68, consistent with abnormal peripheral endothelial function, whereas 18 women (62%) met criteria for positive Ex-ECG based on ST-segment depression in contiguous leads. Women with and without ST-segment depression had similar baseline and exercise vital signs, metabolic equivalents achieved, and RHI (all P > 0.05). RHI did not predict ST-segment depression. Our pilot study demonstrates high prevalence of exercise-induced ST-segment depression in asymptomatic, middle-aged, overweight women. Peripheral vascular endothelial dysfunction did not predict Ex-ECG ST-segment depression. Further work is needed to investigate the utility of vascular endothelial testing and Ex-ECG for IHD diagnostic and management purposes in women.

Cardiorespiratory fitness and exercise-induced ST segment depression in assessing the risk of sudden cardiac death in men

ObjectiveThe aim of this study was to investigate whether information on both cardiorespiratory fitness (CRF) and exercise-induced ST segment depression improves the prediction of sudden cardiac death (SCD) in men.MethodsThe...

The Relation of Arm Exercise Peak Heart Rate to Stress Test Results and Outcome.

Arm exercise is an alternative to pharmacologic stress testing for >50% of patients unable to perform treadmill exercise, but no data exist regarding the effect of attained peak arm exercise heart rate on test sensitivity. Thus, the purpose of this investigation was to characterize the relationship of peak arm exercise heart rate responses to abnormal stress test findings, coronary revascularization, and mortality in patients unable to perform leg exercise. From 1997 until 2002, arm cycle ergometer stress tests were performed in 443 consecutive veterans age 64.1 yr (11.0 yr) (mean (SD)), of whom 253 also underwent myocardial perfusion imaging (MPI). Patients were categorized by frequency distributions of quartiles of percentage age-predicted peak heart rate (APPHR), heart rate reserve (HRR), and peak heart rate-systolic blood pressure product (PRPP). Exercise-induced ST-segment depression, abnormal MPI findings, coronary revascularization, and 12.0-yr (1.3 yr) Kaplan-Meier all-cause and cardiovascular mortality plots were then characterized by quartiles of APPHR, HRR, and PRPP. A reduced frequency of abnormal arm exercise ECG results was associated only with the lowest quartile of APPHR (≤69%) and HRR (≤43%), whereas higher frequency of abnormal MPI findings exhibited an inverse relationship trend with lower APPHR (P = 0.10) and HRR (P = 0.12). There was a strong inverse association of APPHR, HRR, and PRPP with all-cause (all P ≤ 0.01) and cardiovascular (P < 0.05) mortality. The frequency of coronary revascularization was unrelated to APPHR or HRR. Arm exercise ECG stress test sensitivity is only reduced at ≤69% APPHR or ≤43% HRR, whereas arm exercise MPI sensitivity and referral for coronary revascularization after arm exercise stress testing are not adversely affected by even a severely blunted peak heart rate. However, both all-cause mortality and cardiovascular mortality are strongly and inversely related to APPHR and HRR.

The value of cardiorespiratory fitness and exercise-induced ST segment depression in predicting death from coronary heart disease

a Lapland Central Hospital, Rovaniemi, Finland b Rovaniemi Health Center, Finland c Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Finland d Kuopio Research Institute of Exercise Medicine, Kuopio, Finland e Division of Cardiology, Department of Internal Medicine, Oulu University Hospital, Finland f The Department of Clinical Physiology and Nuclear Medicine, University of Eastern Finland, Finland g Department of Physiology, Institute of Biomedicine, University of Eastern Finland, Kuopio Campus, Finland h Central Finland Central Hospital, Jyvaskyla, Finland

Clinical Usefulness of Exercise-Induced ST-Segment Depression Occurring or Increasing during the Recovery Phase

Background Despite the current availability of diagnostic image tests with excellent diagnostic and prognostic accuracy, exercise stress testing (EST) remains as the procedure most commonly used for the evaluation, diagnosis and risk stratification of patients with coronary artery disease (CAD). Objectives 1) To investigate the clinical usefulness of significant exercise-induced ST-segment depression (ST-d) occurring or increasing during the recovery phase of exercise stress test and to compare it with significant ST-segment depression presenting during the active phase of exercise; 2) to evaluate the clinical data and the information provided by EST and coronary angiography. Material and Methods Clinical and EST data from 147 patients with positive stress test were analyzed. All patients had significant ST-segment depression and were divided into three groups: GI, 94 patients with ST-d during exercise; GII, 29 patients with ST-d only during the recovery phase; and GIII, 24 patients with borderline ST-d during exercise which became significant during the recovery phase. The results of the EST were correlated with the coronary angiography findings in each group. Results A diagnosis of significant CAD was made in 78 patients in GI (82.9%), in 22 in GII (75.8%) and in 21 in GIII (87.5%) (p = 0.52). Patients in GIII were older, with high prevalence of dyslipemia, history of previous infarction and three-vessel and/or left main coronary artery disease. GII presented the higher number of asymptomatic patients with one-vessel disease and high prevalence of CAD. Conclusions There were no statistical differences in the percentage of patients with significant CAD among the groups. Patients in GIII had high prevalence of significant and severe CAD. A proper evaluation of ST-d occurring or becoming significant during the recovery phase provided additional clinical information to the results of the EST.

Elevated baseline hs-cTnT levels predict exercise-induced myocardial ischemia in patients with peripheral arterial disease

IntroductionDue to the systemic nature of atherosclerosis, the prevalence of coronary artery disease (CAD) is high in patients with peripheral arterial disease (PAD). A biochemical assay for assessing cardiac risk might improve clinical evaluation of PAD patients. The aim of this study was to investigate whether a new high-sensitivity cardiac Troponin T (hs-cTnT) assay can predict exercise-induced myocardial ischemia in PAD patients without clinical signs of CAD. MethodsSixty-eight ambulatory patients with Fontaine stage II PAD underwent treadmill stress testing to maximum walking distance. Myocardial ischemia was assessed using a 2-lead Holter ECG and ST-segment depression of ≥0.2mV was considered significant. Hs-cTnT was measured from serum samples taken at baseline as well as 5, 10 and 30min after exercise. ResultsHs-cTnT baseline levels were significantly higher (19.3ng/L (5.0; 20.2ng/L) vs. 6.6ng/L (4.4; 9.4ng/L); p=0.037) and increase of serum levels 5min after cessation of exercise was more pronounced (1.09ng/L (0.23; 1.80ng/L) vs. 0.22ng/L (−0.1; 0.65ng/L), p=0.032) in ECG positive patients compared to individuals with normal ECG. Logistic regression analysis identified the baseline hs-cTnT serum level as an independent risk factor for developing significant exercise-induced ST-segment depression (odds ratio 1.2 per 1-unit increase, p=0.015). ConclusionsIn patients with PAD, exercise-induced myocardial ischemia is associated with elevated baseline levels and a significant early increase of hs-cTnT serum levels.

Coronary Microvascular Function and Cortical Pain Processing in Patients With Silent Positive Exercise Testing and Normal Coronary Arteries

ST-segment depression during exercise stress testing in asymptomatic subjects showing normal coronary arteries is considered a "false-positive" result. Coronary microvascular dysfunction, however, might be a possible cause of ST-segment depression in these cases. We assessed the coronary blood flow response to adenosine and to cold pressor test in the left anterior descending artery, using transthoracic Doppler echocardiography in 14 asymptomatic subjects with exercise-induced ST-segment depression and normal coronary arteries (group 1), 14 patients with microvascular angina (group 2), and 14 healthy subjects (group 3). Flow-mediated dilation was assessed in the brachial artery. Central pain processing was assessed using cortical laser evoked potentials during chest and right hand stimulation with 3 sequences of painful stimuli. The coronary blood flow response to adenosine was 1.8 ± 0.4, 1.9 ± 0.5, and 3.1 ± 0.9 in groups 1, 2, and 3, respectively (p <0.001). The corresponding coronary blood flow responses to the cold pressor test were 1.74 ± 0.4, 1.53 ± 0.3, and 2.3 ± 0.6 (p <0.001). The flow-mediated dilation was 5.5 ± 2.3%, 4.6 ± 2.4%, and 9.8 ± 1.2% in the 3 groups, respectively (p <0.001). The laser evoked potential N2/P2 wave amplitude decreased throughout the 3 sequences of stimulation in groups 1 and 3 but not in group 2 (chest, -19 ± 22%, +11 ± 42% and -36 ± 12%, p <0.001; right hand, -22 ± 25%, +12 ± 43% and -30 ± 20%, p = 0.009; in groups 1, 2, and 3). In conclusion, exercise stress test-induced ST-segment depression in asymptomatic subjects with normal coronary arteries cannot be considered as a simple false-positive result, because it can be related to coronary microvascular dysfunction. The different symptomatic state compared to patients with microvascular angina can, at least in part, be explained by differences in cortical processing of neural pain stimuli.

093 Ability of ST/HR index and ST/HR hysteresis during exercise testing to predict significant ischemia assessed by G-SPECT imaging

Heart rate adjustment of exercise-induced ST-segment depression (ST/HR index and ST/HR hysteresis) has been suggested as an accurate predictor of the presence of a coronary artery disease. Its powerful predictive value for proven coronary artery stenosis is now accepted. The objective of our study was to investigate the sentitivity and specificity of computerized ST/HR index and ST/HR hysteresis to detect significant ischemia. We used a cross-sectional analysis of exercise test and myocardial perfusion stress-rest SPECT data. The study population comprised 710 consecutive patients referred for myocardial perfusion imaging. The threshold of significant ischemia was set above 10% reversibility hypoperfusion area from entire surface of left ventricle using gated-SPECT image analysis (QGS). Diagnostic performance of ST/HR index and ST/HR hysteresis was assessed by receiver operating characteristic (ROC) curve. Crude ST/HR hysteresis showed at the same 70% specificity, a sensitivities of 56% and 57%, respectively. Diagnostic performance of ST/HR hysteresis seems slightly better than ST/HR index (AUC = .668 vs .654) with the following cut points .038 mV and 1.625 μV/bpm. Adjusting these variables to body mass index does not improve the diagnostic performance. Combining an independant clinical judgement in the model yields a moderate increase of the diagnostic accuracy the prediction only for ST/HR index as suggested by the AUC (.688). ST/HR index and ST/HR hysteresis have a good capability to detect a significant myocardial ischemia evaluated by SPECT, which has therapeutic implications.

E0367 Effect of treatment of hepatocyte growth-promoting factor on improvement of myocardial ischaemia and cardiopulmonary functional capacity during the exercise in patients with severe coronary heart disease

ObjectiveTo test the hypothesis that the treatment of hepatocyte growth-promoting factors (pHGF) by venous injection improves myocardial ischaemia, kinetics of oxygen uptake (VO2) and cardiopulmonary functional capacity during exercise in...

Corrected QT dispersion improves diagnostic performance of exercise testing in diagnosing coronary artery disease

To determine the best combination of parameters that would improve the diagnostic performance of exercise testing, coronary angiography plus exercise testing were done on 112 patients with angina pectoris and normal electrocardiogram. The univariate predictors of coronary artery disease included: age > or = 40 years, male sex, hypertension, smoking, development of exertional chest pain, decrease in systolic blood pressure (BP) > or = 10 mmHg or systolic BP 3 min post-exercise > 90% of peak, heart rate drop < 12 beats/min 1 min postexercise, exercise-induced ST-segment depression > or = 1 mm. Multivariate logistic regression analysis showed that using either ST depression > or = 1 mm or peak exercise QTDc > 70 ms significantly improved sensitivity and negative predictive value of the test without a significant decrease in specificity.

Interrelation of ST-segment depression during bicycle ergometry and extent of myocardial ischaemia by myocardial perfusion SPECT

The aim of this study was to compare ST-segment depression (STD) during bicycle ergometry and extent of myocardial ischaemia assessed by myocardial perfusion SPECT (MPS) in a large patient cohort. Consecutive patients (n = 955) referred for MPS with bicycle ergometry and interpretable stress ECG were evaluated with respect to ECG and MPS findings of ischaemia. The maximal STD was recorded and exercise ECG was considered ischaemic if STD was horizontal or downsloping (>or=1 mm). MPS was interpreted using a 20-segment model with a scale of 0 to 4. A summed stress (SSS), summed rest (SRS) and summed difference score (SDS = SSS-SRS, e.g. extent of ischaemia) were derived. Ischaemia was defined as an SDS >or= 2. An exercise-induced STD was present in 215 patients (22%) and myocardial ischaemia on MPS was present in 366 patients (38%). The extent of ST-segment depression and the number of ECG leads with significant STD were each strongly and significantly associated with increasing severity of ischaemia and the number of coronary territories involved (p < 0.01 for all correlations). These data demonstrate a strong correlation between the extent of STD, number of ischaemic leads and severity of myocardial ischaemia as assessed by MPS during bicycle ergometry.

Coronary artery disease is common in asymptomatic patients with signs of myocardial ischemia

Background The incidence of coronary artery disease (CAD) in totally asymptomatic patients with myocardial ischemia during stress testing is unknown. Methods 54 patients with asymptomatic myocardial ischemia participated in the Swiss Interventional Study on Silent Ischemia type I (SWISSI I). Asymptomatic myocardial ischemia was verified by bicycle ergometry and stress imaging (echocardiography or scintigraphy). Findings from coronary angiographies in the course of the study constituted the main outcome. Results Of the 54 study participants, 29 patients (53.7%) underwent coronary angiography. CAD was found in 27 of 29 patients (93.1%). In those 27 patients with CAD, 9 patients (33.3%) suffered from single vessel disease, 9 patients (33.3%) from two vessel disease, and 9 patients (33.3%) from triple vessel disease. Two patients showed left main coronary artery stenosis. Conclusion This study shows a high incidence of relevant CAD among totally asymptomatic patients with myocardial ischemia during stress testing. Previously healthy subjects with exercise-induced ST-segment depression at check-up examinations, even if asymptomatic, should have further diagnostic evaluation.

Exercise-induced ST-segment depression in inferior leads during treadmill exercise testing and coronary artery disease

The exercise electrocardiogram is a commonly used non-invasive and inexpensive method for detection of electrocardiogram (ECG) changes secondary to myocardial ischemia. Reversible ST-segment depression is the characteristic finding associated with exercise-induced, demand-driven ischemia in patients with significant coronary obstruction but no flow limitation at rest. The exercise-induced ST-segment depression in inferior leads has been questioned and it has been reported that lead V5 alone consistently outperforms the inferior leads and the combination of lead V5 with II, because lead II has a high false-positive rate. A review of the 12-lead visual electrocardiographic interpretations confirmed that changes isolated to the inferior leads were rare in patients, who had no diagnostic Q waves. Considering the sum of ST-segment depression or the most depression in the three leads representing the three main areas of the myocardium (II, V2, and V5) did not improve the diagnostic capacity of the test. A case is presented to illustrate how in a patient, the ST-segment depression in inferior leads during exercise testing is related with significant coronary artery disease. We present a case of exercise-induced ST-segment depression in inferior leads in a 52year-old Italian man. This experience demonstrates that ST-segment depression in inferior leads during the exercise testing can have a diagnostic significance.

Effect of Hepatocyte Growth-Promoting Factors on Myocardial Ischemia During Exercise in Patients With Severe Coronary Artery Disease

Hepatocyte growth-promoting factor (pHGF) has the greatest potential as a therapeutic agent for vascular growth factor. The aim of this study was to investigate the effect of pHGF on myocardial ischemia and exercise capacity in patients with severe coronary artery disease (CAD). Forty-nine patients were enrolled for a two week treatment period. Treadmill graded exercise tests with gas analysis were conducted before and after therapy. Serum levels of HGF were significantly elevated after therapy. The degrees of exercise-induced ST segment depression were decreased more significantly in the pHGF group. Similar differences were also found in the maximum heart rate and the maximum heart rate when the ST segment was depressed 1 mm while undergoing the treadmill graded exercise test. Both were increased more significantly in the pHGF group. Total exercise time, systolic blood pressure in the peak of exercise, the length of time that ST segment depression of 1 mm is needed, and total work all were increased in both groups after intervention. Furthermore, total exercise time and total work were increased more significantly in the pHGF group. The levels of HGF increased significantly after pHGF treatment. pHGF could favorably improve exercise-induced myocardial ischemia and enhance exercise capacity in patients with severe CAD.

Transdermale Nitroglycerinsysteme mit kontinuierlicher und diskontinuierlicher Substanzfreisetzung: Vergleich antiischämischer und hämodynamischer Akut- und Langzeitwirkung

The anti-ischaemic and haemodynamic effects of two transdermal nitroglycerin systems, each offering 15 mg of nitroglycerine, the first giving continuous release (group 1) and the other discontinuous release (group 2), were compared in 30 men (mean age 56.5 [33-70] years) with coronary heart disease confirmed by angiography. Resting and exercise haemodynamics together with the degree of exercise-induced ST segment depression were measured on the first day, before and two hours after application of the plaster. After one week's therapy these measurements were repeated 24 hours after the application of the plaster on the previous day and two hours after the last application. Two hours after the first application both groups showed significant reduction (P less than 0.01) in exercise-induced ST segment depression (group 1: -60%, group 2: -50%) and in mean pulmonary artery pressure during exercise (group 1: -10%; group 2: -7%). After one week's therapy the reduction in exercise-induced ST segment depression was still significant in group 1 (-60%; P less than 0.01), but in group 2 (-30%) it was no longer significant. After one week had passed there was no longer any significant reduction in mean pulmonary artery pressure in either group (group 1: -6%; group 2: 0%). The acute anti-ischaemic and haemodynamic efficacy of both transdermal nitroglycerin systems was hence comparable; however, the emergence of nitrate tolerance during long-term use was not prevented even by phased release of the drug.

Heart rate and systolic blood pressure response during the early exercise test and cardiovascular mortality after myocardial infarction

Exercise cardiography still remains the cornerstone of noninvasive evaluation of functional status of cardiovascular system and is almost uniformly performed after myocardial infarction. The patients after myocardial infarction can be divided into relative high- and low-risk groups for subsequent cardiac events if all information available on the exercise test is used. The aim of this study was to evaluate the prognostic significance of the shape of heart rate and systolic blood pressure curves (their dynamic characteristics) during the early exercise testing and after it and to design the prognostic system capable to recognize patients with a high risk of coronary death during 2 years after myocardial infarction. The submaximal exercise testing within 3 weeks of acute myocardial infarction was performed on 894 patients. Cases of noncardiac deaths or patients subjected to coronary bypass surgery were excluded from the further analysis. At the end of 2 years after myocardial infarction, there were 426 survivors and 42 cases of cardiac death. At 2-year follow-up after infarction in the nonsurvivor group, there were only 42.2% of patients with exercise-induced ST segment depression. This shows that prognostic importance of ST depression is insufficient and demands research of more consistent signs. The cardiovascular response to exercise was interpreted as transiting process of self-regulation of cardiovascular system, and the new predictive signs were found based on the curves of heart rate and systolic blood pressure during the exercise and after it. The prognostic value of these signs was established. The combined use of both the new predictive signs and usual data of early exercise test shows the high predictive possibility of test - the early cardiac death was predicted in 80% of cases. The combined use of both, the widely accepted data of early exercise test after myocardial infarction and dynamic characteristics of heart rate and systolic blood pressure, increased the predictive power of the test.

Silent Myocardial Ischemia in Middle-Aged Asymptomatic Patients With Type 2 Diabetes in Turkish Population

The authors investigated silent myocardial ischemia in unselected consecutive middle-aged asymptomatic patients with type 2 diabetes without any evidence of coronary heart disease documented by treadmill exercise test. Ninety asymptomatic patients with type 2 diabetes (48 men; mean age: 49 +/-6 years) were included in the study. Mean duration of diabetes in the study group was 4 +/-4.2 years (range 1 to 21 years); 38% of the study population, diabetes duration was only 1 year). All patients were subjected to treadmill exercise test with Bruce protocol. A positive test was noted in 4 of 90 (4%) study patients. Two male patients (4%) and 2 (4%) women patients developed exercise-induced ST-segment depression, but none had concomitant chest pain. Diabetics with silent myocardial ischemia were older (55 +/-3 years vs 49 +/-6 years, p = 0.04) than those without silent myocardial ischemia. Also, diabetics with silent myocardial ischemia had higher fibrinogen level (372 +/-51 vs 307 +/-71 mg/dL, p = 0.04) than diabetics without silent myocardial ischemia. In treadmill exercise test, diabetics with silent myocardial ischemia had lower total exercise time and peak workload (375 +/-30 vs 474 +/-115 seconds, p = 0.04; 7.3 +/-0.5 vs 8.9 +/-1.9, p = 0.04, respectively) than without silent myocardial ischemia. Insulin resistance is associated with a variety of atherosclerosis risk factors. Exercise test findings show increased cardiac sympathetic activity and parasympathetic withdrawal in increased insulin resistance.