The Clinical Use of Nonimaging Exercise Stress Testing

Exercise stress testing is an exceptionally useful cardiovascular test providing a wealth of information that can be used in patient management. It can be used in the diagnosis and/or management of chest pain, hypertension, arrhythmia, and heart failure. Non-imaging exercise stress testing not only helps evaluate the etiology of clinical symptoms but also provides an opportunity to evaluate ECG changes with exercise, total exercise capacity, heart rate response or chronotropic index, blood pressure response, heart rate recovery, and to make estimates of the risk of coronary artery disease using tools such as the Duke Treadmill Score. These parameters, individually and collectively, provide valuable information on the likelihood of disease and an individual’s prognosis. In addition, exercise testing is inexpensive, quick and widely available compared to imaging studies. This review contains 6 figures, 5 tables, and 68 references. Keywords: blood pressure response, chronotropic incompetence, coronary artery disease, Duke Treadmill Score, exercise physiology metabolic equivalents (METs), exercise stress test, exercise treadmill test, exercise-induced hypertension, heart rate recovery, maximal exercise capacity, ST-segment deviation

The Clinical Use of Nonimaging Exercise Stress Testing

Exercise stress testing is an exceptionally useful cardiovascular test providing a wealth of information that can be used in patient management. It can be used in the diagnosis and/or management of chest pain, hypertension, arrhythmia, and heart failure. Non-imaging exercise stress testing not only helps evaluate the etiology of clinical symptoms but also provides an opportunity to evaluate ECG changes with exercise, total exercise capacity, heart rate response or chronotropic index, blood pressure response, heart rate recovery, and to make estimates of the risk of coronary artery disease using tools such as the Duke Treadmill Score. These parameters, individually and collectively, provide valuable information on the likelihood of disease and an individual’s prognosis. In addition, exercise testing is inexpensive, quick and widely available compared to imaging studies. This review contains 6 figures, 5 tables, and 68 references. Keywords: blood pressure response, chronotropic incompetence, coronary artery disease, Duke Treadmill Score, exercise physiology metabolic equivalents (METs), exercise stress test, exercise treadmill test, exercise-induced hypertension, heart rate recovery, maximal exercise capacity, ST-segment deviation

The Duke treadmill score with bicycle ergometer: Exercise capacity is the most important predictor of cardiovascular mortality

Background The Duke treadmill score, a widely used treadmill testing tool, is a weighted index combining exercise time or capacity, maximum ST-segment deviation and exercise-induced angina. No previous studies have investigated whether the Duke treadmill score and its individual components based on bicycle exercise testing predict cardiovascular death. Design Two populations with a standard bicycle testing were used: 3936 patients referred for exercise testing (2371 men, age 56 ± 13 years) from the Finnish Cardiovascular Study (FINCAVAS) and a population-based sample of 2683 men (age 53 ± 5.1 years) from the Kuopio Ischaemic Heart Disease study (KIHD). Methods Cox regression was applied for risk prediction with cardiovascular mortality as the primary endpoint. Results In FINCAVAS, during a median 6.3-year (interquartile range (IQR) 4.5–8.2) follow-up period, 180 patients (4.6%) experienced cardiovascular mortality. In KIHD, 562 patients (21.0%) died from cardiovascular causes during the median follow-up of 24.1 (IQR 18.0–26.2) years. The Duke treadmill score was associated with cardiovascular mortality in both populations (FINCAVAS, adjusted hazard ratio (HR) 3.15 for highest vs. lowest Duke treadmill score tertile, 95% confidence interval (CI) 1.83–5.42, P < 0.001; KIHD, adjusted HR 1.71, 95% CI 1.34–2.18, P < 0.001). However, after progressive adjustment for the Duke treadmill score components, the score was not associated with cardiovascular mortality in either study population, as exercise capacity in metabolic equivalents of task was the dominant harbinger of poor prognosis. Conclusions The Duke treadmill score is associated with cardiovascular mortality among patients who have undergone bicycle exercise testing, but metabolic equivalents of task, a component of the Duke treadmill score, proved to be a superior predictor.

Metabolic Abnormalities and Drugs

The chapter Metabolic Abnormalities and Drugs reviews the changes that affect the electrocardiogram at rest and during exercise. Anticipating these changes often allows the exercise test to remain diagnostic without the need for adjunctive imaging. Changes between rest and exercise occur with metabolic acidosis, alkalosis, hyperthyroidism, hypothyroidism, estrogens, androgens, digoxin, diuretics, nitrates, ranolazine, dipyridamole, beta blockers, calcium channel blockers, anti-hypertensive agents, ivabradine, alcohol, nicotine, catecholamines, amphetamines, selective serotonin reuptake inhibitors, tricyclic antidepressants, lithium, and many anti-arrhythmics including quinidine, disopyramide, sotalol, flecainide, dofetilide, amiodarone, and dronedarone. Careful integration of all clinical variables, aided by the use of tools such as the Duke Treadmill Score, can reduce the need for additional testing including coronary angiography.

Comparison of Predicted Significant Coronary Lesion by Duke Treadmill Score among Coronary Heart Disease Risk Factors in Patients with Positive Ischemic Response Treadmill Test

Background: According to Framingham Study, independent risk factors for coronary heart disease (CHD) are diabetes, hypertension, smoking, dyslipidemia, family history of CHD and obesity. Previous study reported cut-off value of Duke Treadmill Score (DTS) < -0.5 represents a significant coronary lesion with positive predictive value 88.4%. Objective: To compare the incidence of predicted significant coronary lesions by DTS among various risk factors for coronary heart disease. Methods: A cross sectional study was done on 292 patients age 18 to 74 years old who had positive exercise testing for CAD screening during period of June 1st 2016 until May 30th 2017. DTS was calculated from treadmill test as: exercise time - (5 x ST deviation in mm) - (4 x exercise angina). A coronary lesion was predicted significant with DTS cut off value < -0.5. Results: Subjects mean age was 57 years old, male were 60.4%. The risk factors for CHD were found sequentially from the most frequent were hypertension 51.9%, smoking 35.3%, diabetes mellitus 23.1%, dyslipidemia 11.9%, obesity 4.2% and family history of CHD 6.3%. It was found that diabetes was significantly different from its effect on DTS value with p value = 0.021, while hypertension, obesity, dyslipidemia and family history CHD had no significant effect. Logistic regression found consistently that diabetes was significant (p=0.019). Conclusion: Predicted significant coronary lesions by DTS developed more frequent in diabetes compared to, hypertension, smoking, dyslipidemia, obesity and family history of coronary heart disease.