Independent prognostic significance of ischemic ST-segment response limited to recovery from treadmill exercise in asymptomatic subjects

Cardiotoxicity from Capecitabine Chemotherapy: Prospective Study of Incidence at Rest and During Physical Exercise

BACKGROUND

Physical activity may increase the risk of cardiotoxicity (myocardial ischemia, major arrhythmias) of 5-Fluorouracil, but this risk has never been investigated for its prodrug capecitabine.

PATIENTS AND METHODS

One hundred and ninety-two consecutive patients undergoing capecitabine chemotherapy from December 1, 2010 through July 31, 2016 were prospectively evaluated. The baseline evaluation included electrocardiography (ECG) and echocardiography (2DE); a follow-up evaluation, including ECG and exercise stress testing (2DE in case of ECG abnormalities), was done after ≥10 days of treatment. Cardiotoxicity was suspected from ischemic ECG changes, new kinetic abnormalities at 2DE, Lown classification ≥2 ventricular arrhythmia, symptomatic arrhythmias, or positive stress test, and confirmed by a negative stress test after capecitabine washout.

RESULTS

Cardiotoxicity was diagnosed in 32 patients (16.7%): six at rest and 26 during exercise. All 32 patients had ECG abnormalities: ST-segment changes (24 patients), negative T-waves (2) and/or arrhythmias: ventricular arrhythmias (14 cases), supraventricular tachycardia (2), complete heart block (1). Eight patients had typical symptoms, 6 had atypical symptoms, 1 had syncope, 17 (53%) were asymptomatic. Cardiotoxicity was more common in patients with atypical symptoms during daily life (OR = 15.7) and in those on a therapeutic schedule of 5 days/week (OR = 9.44).

CONCLUSION

Capecitabine cardiotoxicity is frequent, and often elicited by physical effort. Oncologists, cardiologists, and general practitioners should be aware of this risk. Active cardiotoxicity surveillance with ECG (and echocardiogram and/or stress testing in suspected cases) during therapy is recommended.

CLINICAL TRIALS REGISTRATION NUMBER

CRO-2010-17.

Exercise-Induced Ventricular Ectopy and Cardiovascular Mortality in Asymptomatic Individuals

BACKGROUND

The prognosis of exercise-induced premature ventricular contractions (PVCs) in asymptomatic individuals is unclear.

OBJECTIVES

This study sought to investigate whether high-grade PVCs during stress testing predict mortality in asymptomatic individuals.

METHODS

A cohort of 5,486 asymptomatic individuals who took part in the Lipid Research Clinics prospective cohort had baseline interview, physical examination, blood tests, and underwent Bruce protocol treadmill testing. Adjusted Cox survival models evaluated the association of exercise-induced high-grade PVCs (defined as either frequent (>10 per minute), multifocal, R-on-T type, or ≥2 PVCs in a row) with all-cause and cardiovascular mortality.

RESULTS

Mean baseline age was 45.4 ± 10.8 years; 42% were women. During a mean follow-up of 20.2 ± 3.9 years, 840 deaths occurred, including 311 cardiovascular deaths. High-grade PVCs occurred during exercise in 1.8% of individuals, during recovery in 2.4%, and during both in 0.8%. After adjusting for age, sex, diabetes, hypertension, lipids, smoking, body mass index, and family history of premature coronary disease, high-grade PVCs during recovery were associated with cardiovascular mortality (hazard ratio [HR]: 1.82; 95% CI: 1.19-2.79; P = 0.006), which remained significant after further adjusting for exercise duration, heart rate recovery, achieving target heart rate, and ST-segment depression (HR: 1.68; 95% CI: 1.09-2.60; P = 0.020). Results were similar by clinical subgroups. High-grade PVCs occurring during the exercise phase were not associated with increased risk. Recovery PVCs did not improve 20-year cardiovascular mortality risk discrimination beyond clinical variables.

CONCLUSIONS

High-grade PVCs occurring during recovery were associated with long-term risk of cardiovascular mortality in asymptomatic individuals, whereas PVCs occurring only during exercise were not associated with increased risk.

Significance of 'recovery ST-segment depression' in exercise stress test

Objective

To study the significance of ST-segment depression during ‘recovery’ compared to that ‘during stress’ and ‘both the phases’ in exercise stress test.

Methods

Patients with positive exercise stress test who underwent coronary angiography (CAG) from 1st January 2017 to 31st December 2018 were studied. Patients were divided into 3 groups- Group A with ST-depression restricted to recovery phase, group B with ST-depression restricted to stress phase and group C with ST-depression seen both during exercise and recovery. All patients underwent CAG. Sensitivity, specificity, and predictive values of each of these groups in diagnosis of significant coronary artery disease (CAD) were analysed and compared.

Results

Total 300 patients were studied. Mean age of the study population was 48.77 ± 7.94 years. 78.3% of patients with positive exercise stress test had significant CAD. 96% of patients in group A had significant CAD, which was higher than in group B (88.9%) & group C (70.1%). The specificity, positive predictive value and negative predictive value of ST-segment depression in group A (96.92%, 96% and 25.2% respectively) were higher than that of ST-depression in group B (89.23%, 88.89% and 24.47% respectively) and group C (13.85%, 70.05% and 7.96% respectively). Sensitivity and accuracy of ST-depression in group A were lower (20.43% and 37% respectively), compared to other 2 groups.

Conclusion

Patient with ST-depression restricted to recovery phase had highest specificity, positive predictive value, and negative predictive value. However, accuracy was highest in group with both stress phase and exercise ST-segment depression.

Incremental Diagnostic Performance of Combined Parameters in the Detection of Severe Coronary Artery Disease Using Exercise Gated Myocardial Perfusion Imaging

Purpose

Myocardial perfusion imaging (MPI) using gated single-photon emission tomography (gSPECT) may underestimate the severity of coronary artery disease (CAD). This study aimed to evaluate the significance of combined parameters derived from gSPECT, as well as treadmill stress test parameters, in the detection of severe CAD.

Methods

A total of 211 consecutive patients referred for exercise MPI between June 2011 and June 2013 (who received invasive coronary angiography within six months after MPI) were retrospectively reviewed. Exercise MPI was performed with Bruce protocol and ²⁰¹Tl injected at peak exercise. Gated SPECT was performed using a cadmium-zinc-telluride camera and processed by QPS/QGS software. Perfusion defect abnormalities such as sum stress score (SSS); sum difference score, algorithm-derived total perfusion deficits, transient ischemic dilatation ratios of end-diastolic volumes and end-systolic volumes, post-stress changes in ejection fraction, and lung/heart ratio (LHR) were calculated. Treadmill parameters, including ST depression (STD) at the 1st and 3rd minutes of recovery stage (1’STD and 3’STD), maximal STD corrected by heart rate increment (ST/HR), heart rate decline in 1^st and 3^rd minutes of recovery stage, recovery heart rate ratio (HR ratio), systolic and mean blood pressure ratios (SBP ratio and MAP ratio) during recovery phase were recorded. Diagnostic performances of these parameters were analyzed with receiver operating characteristic (ROC) analysis and logistic regression for detection of left main (≥ 50%) or 3-vessel disease (all ≥ 70% luminal stenosis) on invasive angiography.

Results

Among various MPI and treadmill parameters used for detection of severe CAD, SSS and ST/HR had the highest AUC (0.78, 0.73, p = NS) and best cut-off values (SSS > 6, ST/HR > 17.39 10^-2mV/bpm), respectively. By univariate logistic regression, all parameters except 1’HRR, 3’HRR, SBP and MAP ratios increased the odds ratio of severe CAD. Only increased L/H ratio, 3’STD, and HR ratio remained significant after multivariate regression. The predicted values of combined MPI and treadmill parameters (LHR, 3’STD, and HR ratio) gave the best ROC (AUC: 0.91) than any individual parameter or parameter combination.

Conclusions

Of all treadmill and gSPECT parameters, the combination of MPI and treadmill parameters can offer better diagnostic performance for severe CAD.

Pre-exercise participation cardiovascular screening in a heterogeneous cohort of adult cancer patients

BACKGROUND

The purpose of this study was to investigate the extent of pre-exercise participation ("preparticipation") health screening in a heterogeneous cohort of adult cancer patients.

METHODS

Patients (n = 413) with histologically confirmed solid or hematologic malignancy were categorized into preparticipation health screening risk stratification based on American College Sports Medicine (ACSM) recommendations. Risk of an exercise-related event was evaluated during a symptom-limited cardiopulmonary exercise test (CPET) with 12-lead electrocardiography (ECG).

RESULTS

Participant risk was categorized as low risk (n = 59, 14%), moderate risk (n = 217, 53%), and high risk (n = 137, 33%). Mean peak oxygen consumption was 21.7 ± 6.7 mL/kg(-1) per minute(-1) or 19.5 ± 21.7% below age- and sex-predicted sedentary values. No major serious adverse events or fatal events were observed during CPET procedures. A total of 31 positive ECG tests were observed, for an event rate of 8%. ACSM risk stratification did not predict the risk of a positive test. Age, statin use, antiplatelet therapy use, cardiovascular disease, prior treatment with anthracycline or radiation therapy, and being sedentary were predictors of a positive test (all p < .10).

CONCLUSION

The patient risk-stratification profile strongly suggests that the use of formalized preparticipation health screening is required in all oncology scenarios; however, risk of an exercise-induced event is low, suggesting that the use of exercise testing is not required for pre-exercise clearance in the majority of patients.

Evaluation of ST‐segment changes during and after maximal exercise tests in one‐, two‐ and three‐vessel coronary artery disease

OBJECTIVE

To relate ECG and heart rate (HR) variables during and after exercise testing with the presence of one-, two- or three-vessel disease defined by angiography.

DESIGN

Seventy-three male patients with stable angina pectoris and angiographically verified coronary artery disease underwent a maximal exercise test. From 12-lead ECG recordings and computer averaging ST-amplitude and HR data were measured in consecutive 10-s intervals.

RESULTS

In univariate analysis, patients with three-vessel disease had lower maximal exercise capacity, a shorter time to >1 mm ST-depression, more often a clockwise ST/HR recovery loop, more frequently a post-exercise downward ST-segment slope, and a greater ST-deficit at 3.5 min after exercise than patients with one-vessel disease. In multivariate analysis, time to >1 mm ST-depression discriminated between patients with three- and one-vessel disease. In patients with an intermediate time to >1 mm ST-depression a clockwise ST/HR recovery loop and/or a downsloping ST-segment in the post-exercise period were significantly more prevalent in severe vessel disease.

CONCLUSION

Patients with three-vessel disease had a significantly shorter time to >1 mm ST-depression during exercise and more often an abnormal post-exercise ST/HR reaction than those with one-vessel disease.

Asymptomatic ST-segment depression during exercise testing and the risk of sudden cardiac death in middle-aged men: a population-based follow-up study

AIMS

Silent electrocardiographic ST change predicts future coronary events in patients with coronary heart disease (CHD), but the prognostic significance of asymptomatic ST-segment depression with respect to sudden cardiac death in subjects without apparent CHD is not well known.

METHODS AND RESULTS

We investigated the association between silent ST-segment depression during and after maximal symptom-limited exercise test and the risk of sudden cardiac death in a population-based sample of 1769 men without evident CHD. A total of 72 sudden cardiac death occurred during the median follow-up of 18 years. The risk of sudden cardiac death was increased among men with asymptomatic ST-segment depression during exercise [hazard ratio (HR) 2.1, 95% confidence interval (CI) 1.2-3.9] as well as among those with asymptomatic ST-segment depression during recovery period (HR 3.2, 95% CI 1.7-6.0). Asymptomatic ST-depression during exercise testing was a stronger predictor for the risk of sudden cardiac death especially among smokers as well as in hypercholesterolaemic and hypertensive men than in men without these risk factors.

CONCLUSION

Asymptomatic ST-segment depression was a very strong predictor of sudden cardiac death in men with any conventional risk factor but no previously diagnosed CHD, emphasizing the value of exercise testing to identify asymptomatic high-risk men who could benefit from preventive measures.

Significance of QRS duration changes in the evaluation of ST-segment depression presenting exclusively during the postexercise recovery period

BACKGROUND

The aim of this study was to evaluate the contribution of QRS prolongation in the diagnosis of coronary artery disease (CAD) in patients with exercise-induced ST-segment depression exclusively during the recovery period.

METHODS

The study population consisted of 107 patients (90 males and 17 females) aged 39-70 (mean 59 +/- 7) years who underwent a treadmill exercise test using Bruce protocol and presented ST-segment depression limited to the recovery period. Angiographic data were available for all studied patients.

RESULTS

Among studied patients, 74 (69%) were found to have hemodynamically significant CAD, while the remaining 33 (31%) had normal coronary arteries. Concomitant QRS prolongation was revealed in 61 (82%) of the patients with angiographically documented CAD, while in 13 (18%) patients QRS duration remained unchanged. On the contrary, only 4 (12%) of the 33 patients with normal coronary arteries showed prolonged QRS duration during ST depression, while in the remaining 29 (88%) QRS duration remained unchanged.

CONCLUSIONS

The evaluation of the concomitant QRS duration changes may discriminate patients with truly ischemia-induced ST-segment depression limited to the recovery period.

The predictive value of exercise testing for survival among 75-year-old men and women

All 75-year-olds born in 1914 and living in the city of Jyväskylä, central Finland (n=388) were invited to study the predictive value of exercise test for mortality. Subjects who entered the laboratory (n=295) were to have a standard pre-test evaluation and perform a cycle ergometer exercise test. Subjects with complete background, exercise-test status and mortality data (n=282) were divided into three groups according to exercise-test status: a non-exercise test group (n=79), an exercise-test termination group (n=95), and an exercise-test completion group (n=108). Mortality was followed up for 9 years. The multivariate hazard ratio (HR) for death among the non-exercise test group compared with exercise-test completion group was 1.87 (CI 1.19-2.94). The multivariate HR for death among the exercise-test termination group compared with the exercise-test completion group was 0.95 (CI 0.58-1.54). High cycling power (W/kg body weight) in the exercise-test completion group was associated with a decreased risk for death with a multivariate HR 0.14 (CI 0.05-0.38). Performing an exercise test serves information on the risk of death that is incremental to clinical data and traditional risk factors of death in elderly people.

Comparison of prognostic value of stress echocardiography versus stress electrocardiography in patients with suspected coronary artery disease

Stress electrocardiographic (ECG) ST-segment depression is a prognostic marker of adverse cardiac outcomes in coronary artery disease. However, use of concurrent stress echocardiography (ECHO) has lead to concordant and discordant findings on stress electrocardiogram during stress studies. The prognostic value of stress ECHO in the setting of these stress ECG findings has not been previously evaluated. Outcomes of 1,268 patients (60 +/- 12 years old, 48% women) who had normal electrocardiograms and underwent stress ECHO were analyzed. ST-segment depression > or =1.5 mm in 2 contiguous leads on stress electrocardiogram and a wall motion score index of >1 on peak stress echocardiogram were considered abnormal. Events of nonfatal myocardial infarction (n = 18) and cardiac death (n = 32) were analyzed during follow-up (2.8 +/- 0.9 years). In 91 patients (7%) who had abnormal findings on stress electrocardiogram, 38 (41%) had an abnormal finding on stress echocardiogram and 4 had cardiac events (0.6% per year), and all who had a normal finding on stress echocardiogram had no events (n = 53, 59%, p = 0.01). Among 46 events (92%) with a normal finding on stress electrocardiogram, 30 (60%) showed a discordantly abnormal finding on stress echocardiogram (3.2% per year, p <0.01). Overall, the cohort that had normal findings on stress echocardiogram showed a lower event rate (72%, 16 events, 1.1% per year) compared with the cohort that had abnormal findings on stress echocardiogram (28%, 34 events, 3.6% per year, p <0.001), independent of stress ECG response. Peak wall motion score index (hazard ratio 2.55, p <0.001) and left ventricular ejection fraction (hazard ratio 0.99, p <0.001) were independent and incremental (global chi-square, p <0.001) prognostic markers by stress ECHO. In conclusion, a normal finding on stress echocardiogram confers a benign prognosis independent of the type of stress ECG response during stress studies. In addition, peak wall motion score index and ejection fraction by ECHO are stronger prognostic markers over stress electrocardiography in patients who are evaluated for coronary artery disease.

Role of exercise stress test in master athletes

BACKGROUND

The effectiveness of cardiovascular screening in minimising the risk of athletic field deaths in master athletes is not known.

OBJECTIVE

To evaluate the prevalence and clinical significance of ST segment depression during a stress test in asymptomatic apparently healthy elderly athletes.

METHODS

A total of 113 male subjects aged over 60 were studied (79 trained and 34 sedentary); 88 of them (62 trained and 26 sedentary) were followed up for four years (mean 2.16 years for athletes, 1.26 years for sedentary subjects), with a resting 12 lead electrocardiogram (ECG), symptom limited exercise ECG on a cycle ergometer, echocardiography, and 24 hour ECG Holter monitoring.

RESULTS

A significant ST segment depression at peak exercise was detected in one athlete at the first evaluation. A further case was seen during the follow up period in a previously "negative" athlete. Both were asymptomatic, and single photon emission tomography and/or stress echocardiography were negative for myocardial ischaemia. The athletes remained symptom-free during the period of the study. One athlete died during the follow up for coronary artery disease: he showed polymorphous ventricular tachycardia during both the exercise test and Holter monitoring, but no significant ST segment depression.

CONCLUSIONS

The finding of false positive ST segment depression in elderly athletes, although still not fully understood, may be related to the physiological cardiac remodelling induced by regular training. Thus athletes with exercise induced ST segment depression, with no associated symptoms and/or complex ventricular arrhythmias, and no adverse findings at second level cardiological testing, should be considered free from coronary disease and safe to continue athletic training.

Diagnostic and prognostic value of ST segment depression limited to the recovery phase of exercise stress test

OBJECTIVES

To investigate the diagnostic and prognostic value of ST segment depression limited to the recovery phase of an exercise stress test, as compared with that of ST segment depression appearing during exercise.

SETTING

Exercise stress test laboratory of a university hospital.

PATIENTS AND DESIGN

Clinical and angiographic data were compared for 574 consecutive patients who developed ST segment depression during the active phase of an exercise test (group 1) and for 79 patients who developed ST segment depression only during the recovery phase of the exercise test (group 2).

RESULTS

There were no differences between the two groups in major clinical features. Significant coronary artery stenoses were found in 488 group 1 patients (85%) and in 62 group 2 patients (78%, p = 0.14). Three vessel or left main disease was found in 166 (29%) group 1 and in 14 (18%) group 2 patients (p = 0.045). At a median follow up of 55.3 months of 321 group 1 and 54 group 2 patients, there were no significant differences in major cardiac events between the groups (univariate relative risk 0.81, 95% confidence interval 0.25 to 2.68, p = 0.72).

CONCLUSION

The diagnostic and prognostic power of ST segment depression limited to the recovery phase of an exercise test is largely similar to that of ST segment depression induced during effort; thus, assessing ST segment depression during recovery can significantly improve the clinical information derived from exercise stress tests.

Significance of ST-segment morphology noted on electrocardiography during the recovery phase after exercise in patients with ischemic heart disease as analyzed with simultaneous dual-isotope single photon emission tomography

BACKGROUND

The significance of differences in electrocardiographic morphology that occur during the recovery phase after exercise has not been clarified. We investigated the relationship between postexercise electrocardiographic morphology and the pattern of residual ischemia measured at that time.

METHODS

Exercise dual-isotope single photon emission computed tomography was performed on 171 consecutive patients with chest pain syndrome. After injection of technetium-99m tetrofosmin at peak exercise and thallium-201 at 3 minutes after exercise, dual-isotope single photon emission computed tomographic images were obtained simultaneously. After cross-talk compensation, the extent of ischemia and its localization were measured at both peak exercise and after exercise.

RESULTS

When 64 patients with angiographically and scintigraphically proven ischemic heart disease were grouped by morphology of ST-segment depressions at 3 minutes after exercise, 38 patients with the downsloping type had ischemia localized mainly to the middle and basal levels as compared with the more rapid resolution of ischemia in 12 patients with horizontal type and 14 patients with no ischemic electrocardiographic response (apical level 18.4% [7/38], 8.3% [1/12], and 0% [0/14], P = not significant, middle level 47.4% [18/38], 16.7% [2/12], and 7.1% [1/14], P <.01, basal level 57.9% [22/38], 33.3% [4/12], and 14.3% [2/14], P <.02, respectively) independent of the extent or localization of any ischemia noted during exercise (all levels, P = not significant).

CONCLUSION

Electrocardiographic morphology during the recovery phase of exercise reflects the extent and localization of residual ischemia at that time independent of ischemic changes noted during exercise.

Exercise stress testing for detection of silent myocardial ischemia in human immunodeficiency virus-infected patients receiving antiretroviral therapy

The prevalence of silent myocardial ischemia (SMI) and the factors associated with SMI were evaluated in patients infected with human immunodeficiency virus (HIV) who had been receiving highly active antiretroviral therapy (HAART) for > or =12 months and did not have known coronary artery disease or cardiac symptoms. Patients prospectively underwent exercise stress testing. The prevalence of SMI was 11% (11 of 99 patients). Patients who had SMI were significantly older than were patients who did not (mean+/-SD, 51+/-8 years vs. 42+/-9 years; P=0.001) and were more likely to have trunk obesity (54% of patients vs. 17%; P=.004). A significant correlation was found between a positive exercise test result and obesity (correlation,.006), waist-to-hip ratio (.007), and glucose and cholesterol levels (.04; P=.03). In multivariate analysis, age, central fat accumulation, and cholesterol level were independent variables associated with the detection of SMI. Exercise testing might be recommended for patients with HIV who have central fat accumulation and hypercholesterolemia.

Assessing patients with possible heart disease using scores

Multivariable analysis of clinical and exercise test data has the potential to become a useful tool for assisting in the diagnosis of coronary artery disease, assessing prognosis, and reducing the cost of evaluating patients with suspected coronary disease. Since general practitioners are functioning as gatekeepers and decide which patients must be referred to the cardiologist, they need to use the basic tools they have available (i.e. history, physical examination and the exercise test), in an optimal fashion. Scores derived from multivariable statistical techniques considering clinical and exercise data have demonstrated superior discriminating power compared with simple classification of the ST response. In addition, by stratifying patients as to probability of disease and prognosis, they provide a management strategy. While computers, as part of information management systems, can run complicated equations and derive these scores, physicians are reluctant to trust them. Thus, these scores have been represented as nomograms or simple additive tables so physicians are comfortable with their application. Their results have also been compared with physician judgment and found to estimate the presence of coronary disease and prognosis as well as expert cardiologists and often better than nonspecialists. However, the discriminating power of specific variables from the medical history and exercise test remains unclear because of inadequate study design and differences in study populations. Should expired gases be substituted for estimated metabolic equivalents (METs)? Should ST/heart rate (HR) index be used instead of putting these measurements separately into the models? Should right-sided chest leads and HR in recovery be considered? There is a need for further evaluation of these routinely obtained variables to improve the accuracy of prediction algorithms especially in women. The portability and reliability of these equations must be demonstrated since access to specialised care must be safe-guarded. Hopefully, sequential assessment of the clinical and exercise test data and application of the newer generation of multivariable equations can empower the clinician to assure the cardiac patient access to appropriate and cost-effective cardiological care.

Exercise-induced silent myocardial ischemia and coronary morbidity and mortality in middle-aged men

OBJECTIVES

We investigated the prognostic significance of exercise-induced silent myocardial ischemia in both high and low risk men with no prior coronary heart disease (CHD).

BACKGROUND

Silent ischemia predicts future coronary events in patients with CHD, but there is little evidence of its prognostic significance in subjects free of CHD.

METHODS

We investigated the association of silent ischemia, as defined by ST depression during and after maximal symptom-limited exercise test, with coronary risk in a population-based sample of men with no prior CHD followed for 10 years on average.

RESULTS

Silent ischemia during exercise was associated with a 5.9-fold (95% CI 2.3 to 11.8) CHD mortality in smokers, 3.8-fold (95% CI 1.9 to 7.9) in hypercholesterolemic men and 4.7-fold (95% CI 2.4 to 9.1) in hypertensive men adjusting for other risk factors. The respective relative risks (RRs) of any acute coronary event were 3.0 (95% CI 1.7 to 5.1), 1.9 (95% CI 1.2 to 3.1) and 2.2 (95% CI 1.4 to 3.5). These associations were weaker in men without these risk factors. Furthermore, silent ischemia after exercise was a stronger predictor for the risk of acute coronary events and CHD death in smokers and in hypercholesterolemic and hypertensive men than in men without risk factors.

CONCLUSIONS

Exercise-induced silent myocardial ischemia was a strong predictor of CHD in men with any conventional risk factor, emphasizing the importance of exercise testing to identify asymptomatic high risk men who could benefit from risk reduction and preventive measures.

Long-term outcome in asymptomatic men with exercise-induced premature ventricular depolarizations

BACKGROUND

Exercise testing is widely used in the diagnosis of coronary artery disease, but the long-term outcome for asymptomatic persons with exercise-induced premature ventricular depolarizations remains unclear. We used data from the Paris Prospective Study I to assess the long-term outcome for such persons.

METHODS

A total of 6101 asymptomatic French men (42 to 53 years of age) who were free of clinically detectable cardiovascular disease underwent a standardized graded exercise test between 1967 and 1972. Subjects were prospectively classified as having or not having frequent premature ventricular depolarizations (a run of two or more consecutive premature ventricular depolarizations or premature ventricular depolarizations constituting more than 10 percent of all ventricular depolarizations during any of the 30-second electrocardiographic recordings).

RESULTS

During exercise, 138 subjects had frequent premature ventricular depolarizations. After 23 years of follow-up, these subjects had a higher risk of death from cardiovascular causes than the men without frequent premature ventricular depolarizations during exercise (relative risk, 2.67; 95 percent confidence interval, 1.76 to 4.07). In a multivariate model, with adjustment for age, body-mass index, heart rate at rest, systolic blood pressure, tobacco use, level of physical activity, presence or absence of diabetes, total cholesterol level, and the presence or absence of premature ventricular depolarizations before exercise and during recovery from exercise, both an exercise test that was positive for ischemia and the occurrence of frequent premature ventricular depolarizations during exercise remained independently associated with an increased risk of death from cardiovascular causes, with similar relative risks (2.63 [95 percent confidence interval, 1.93 to 3.59] and 2.53 [95 percent confidence interval, 1.65 to 3.88], respectively).

CONCLUSIONS

The occurrence of frequent premature ventricular depolarizations during exercise in asymptomatic middle-aged men is associated with a long-term increase in the risk of death from cardiovascular causes.

Exercise-induced silent myocardial ischemia and future cardiac events in healthy, sedentary, middle-aged and older men

OBJECTIVES

Before men older than age 45 participate in vigorous exercise programs, the American Heart Association and the American College of Sports Medicine recommend they undergo a screening maximal exercise treadmill test. We examined the predictive value for subsequent cardiac events of exercise-induced silent myocardial ischemia (SI) during the exercise treadmill test in healthy, sedentary, obese, middle-aged and older men recruited for research studies.

DESIGN

A cohort study with 7 years of follow-up.

SETTING

Out-patient research at a tertiary hospital.

PARTICIPANTS

170 healthy, sedentary, obese, middle-aged and older (ages 45-79 years) men with no prior history of coronary artery disease (CAD) recruited for research studies.

MEASUREMENTS

Cardiac risk factors, exercise-induced SI (ST segment depression on the electrocardiogram during a maximal exercise treadmill test), maximal aerobic capacity (VO2max), and 7- year follow-up data on incident CAD.

RESULTS

At baseline, 37 of the men (22%) had exercise-induced SI on their treadmill tests. Seven-year follow-up data was obtained in 97% of the patients. In the interim, 31 men had cardiac endpoints (sudden cardiac death, myocardial infarction, angioplasty, coronary artery bypass graft surgery, angina), and four had noncardiac deaths. Seventeen of the 37 men (46%) with exercise-induced SI on their baseline exercise tests had cardiac endpoints compared with 14 of 133 (11%) men with normal exercise tests (P < .001). Compared with the men with no cardiac endpoints, the men with subsequent cardiac endpoints were older (63 +/- 1 vs 58 +/- 1 years, mean +/- SEM, P < .001) and had a lower maximal aerobic capacity (VO2max) (24 +/- 1 vs 29 +/- 1 mL/kg/min, P < .001). In Cox proportional hazards analysis, exercise-induced SI and a low VO2max were independent predictors of subsequent cardiac endpoints.

CONCLUSION

In a healthy population of obese, sedentary, middle-aged and older men, exercise-induced SI and low VO2max were predictors of incident CAD. This suggests that exercise treadmill testing is beneficial in assessing risk for future cardiac events in obese, sedentary individuals.

Significance of exercise QT dispersion in patients with coronary artery disease who do not have exercise-induced ischemic ST-segment changes

The poor sensitivity and the poor predictive value of ST-segment depression have limited the usefulness of the exercise electrocardiogram (ECG) in the diagnosis and evaluation of coronary artery disease (CAD). The QT dispersion (QTD), recorded as the difference between maximal and minimal QT intervals on a 12-lead exercise ECG, is sensitive to myocardial ischemia and may improve the accuracy of exercise testing in patients with CAD who do not show an ST-segment depression. Exercise ECGs were analyzed in 50 subjects who had undergone coronary angiography for clinical indications. None of them showed an ST-segment depression during or after exercise: There were 25 patients with significant coronary artery stenosis and 25 without significant stenosis. The QTD measured before, immediately after, and 1 min after exercise was similar in the 2 groups. The QTD at 3 and 5 min after exercise was significantly greater in patients with CAD than in the controls, and the most marked difference in QTD was observed at 3 min after exercise. A QTD at 3 min after exercise of >60 ms had a sensitivity of 80% and specificity of 88% regarding the diagnosis of CAD. When a deltaQTD (post-exercise QTD minus QTD at rest) at 3 min after exercise of >0 ms was added to a QTD of >60 ms as a condition for positivity, the specificity increased to 96%. QTD measured at 3 min after exercise increases the accuracy of exercise testing in patients with CAD who do not show an ST-segment depression.