Maximal exercise stress testing in evaluation of arrhythmias in children: results and reproducibility.

To assess reproducibility in evaluating arrhythmias in children, two maximal treadmill exercise tests using the Bruce protocol were performed an average of 3.1 months apart in 19 children aged 5 to 16 years (mean 11) with chronic idiopathic ventricular (Group 1) and supraventrlcular (Group II) arrhythmias. The performance of each child during the two tests was not statistically different with regard to maximal heart rate achieved or duration of exertion; all but one child achieved expected maximal heart rates. in Group I, eight of nine children with ventricular premature complexes at rest showed suppression of the arrythmia during exercise at similar heart rates on both tests. In one child, ventricular premature complexes were not diminished in either test. One child with accelerated idioventricular rhythm and one with ventricular parasystole had reproducible arrhythmia suppression during exercise. One child with known episodes of ventricular tachycardia had this arrhythmia induced by exercise on both tests. In Group II, five children with supraventricular or junctional premature complexes at rest showed reproducible arrhythmia suppression on exercise, but one unexpectedly manifested ventricular premature complexes and one manifested runs of ectopic atrial rhythm during both exercise periods. Two children with severe sinus bradycardia achieved expected maximal heart rates. One unexpectedly manifested reproducible supraventricular premature complexes after exercise.Comparison of results of exercise testing with ambulatory electrocardiographic monitoring showed that in four patients testing uncovered arrhythmias not evident on monitoring, whereas in one patient severe sinus bradycardia occurred only during monitoring. These results indicate that maximal treadmill exercise for evaluation of arrhythmias can be performed in children using standard methodology and can yield important data reproducibly.     

Influence of moxaprindine treatment on ventricular arrhythmias occurring during maximal exercise stress testing.

Moxaprindine, a new anti-arrhythmic drug, with characteristics similar to aprindine, has been demonstrated to be highly effective in suppressing ventricular arrhythmias occurring before, during and after maximal exercise stress testing. This effect was obtained both in subjects with clinically normal hearts and in a limited number of patients with ischemic heart disease. These findings demonstrate the efficacy and safety of anti-arrhythmic treatment by drugs prolonging ventricular depolarization for ventricular arrhythmias occurring during exercise.     

Ventricular tachycardia during exercise testing as a predictor of sudden death in patients with chronic chagasic cardiomyopathy and ventricular arrhythmias.

OBJECTIVE--To verify the prognostic value of exercise induced ventricular arrhythmias in patients with chagasic cardiomyopathy. METHODS--69 consecutive patients (37 male, 32 female; age range 21-67 years) with chronic chagasic cardiomyopathy and ventricular arrhythmias (more than 10 ventricular premature complexes per hour) were evaluated during treadmill exercise testing, using the Bruce protocol. Protocol end points were peak heart rate or presence of sustained ventricular tachycardia. MAIN OUTCOME MEASURE--Sudden cardiac death. RESULTS--44 patients (group I) developed ventricular tachycardia during exercise testing (five sustained and 39 non-sustained), and 25 did not (group II). After a follow up of 24 (SD 15) months sudden cardiac death occurred in seven patients in group I and in none in group II (P < 0.05). CONCLUSIONS--Ventricular tachycardia on exercise testing is significantly associated with sudden cardiac death in patients with chronic chagasic cardiomyopathy and ventricular arrhythmias.     

Maximal exercise stress testing in normal and hyperlipidemic children.

Electrocardiographic and cardiovascular responses during maximal exercise were evaluated in 103 normal children and in 82 children with familial hyperlipoproteinemia. The normal and hyperlipidemic children were comparable in regards to age, weight--height index, resting and exercise blood pressures, and maximal working capacity indices. The cohort of 82 hyperlipidemic children included 61 children (29 boys and 32 girls) with well defined "monogenic" familial hyperlipoproteinemia. Segmental ST depression on the exercise electrocardiogram occurred in 8 of these 29 boys (27.6%) as compared to 4 of 55 normal boys (7.3%), P less than 0.025 and in 6 of the 32 girls (19%) as compared to 7 of 48 normal girls (14.6%), P greater than 0.1. Segmental ST depression was present in 14 of 61 (23%) children with "monogenic" hyperlipoproteinemia, as compared to 11 of 103 (10.75%) normal (x2 = 4.47, P less than 0.05). An assessment of the clinical significance of an abnormal exercise electrocardiogram in male children with "monogenic" hyperlipoproteinemia must await the following: (1) two to four decades of observation and study of the development of morbid or mortal coronary disease, or (2) the future development of improved invasive or noninvasive techniques for the early detection of covert coronary occlusive disease. Currently, maximal exercise electrocardiography cannot be contemplated as a useful indicator of eventual premature coronary artery disease in asymptomatic hyperlipidemic children.     

Prevalence and reproducibility of exercise-induced ventricular arrhythmias during maximal exercise testing in normal men.

The occurrence of ventricular arrhythmias at rest or during ordinary daily activities has been implicated as a risk factor for future coronary-related events and sudden death. However, the clerical significance of exercise-induced ventricular arrhythmias remains uncertain. To assess the prevalence and reproducibility of such arrhythmias, two serial maximal treadmill exercise tests were performed in a study population of 543 male Indian State policemen at an average interval of 2.9 years. Four hundred sixty-two subjects were clinically free of evidence of cardiovascular disease, and 81 had evidence of definite or suspected cardiovascular disease. The prevalence of exercise-induced ventricular arrhythmias during the first test was 30% in men aged 25 to 34 years, 32% in those aged 35 to 44 years and 36% in those aged 45 to 54 years. The prevalence rate in these age groups with repeat testing was 36, 38 and 42%, respectively. These differences were not statistically significant. The group with definite or suspected cardiovascular disease had a greater prevalence of exercise-induced ventricular arrhythmias than normal subjects during both tests but the prevalence rate with repeat testing remained constant. The occurrence of exercise-induced ventricular arrhythmias was reproducible in individual subjects during the second test in 55% of 25 to 34 year olds, 58% of 35 to 44 year olds and 62% of 45 to 54 year olds. Thus, individual reproducibility in two consecutive tests was only slightly greater than reproducibility by chance alone. The group with known or suspected cardiovascular disease demonstrated a trend toward greater reproducibility with repeat testing. Exercise-induced ventricular arrhythmias were not reproducible by type or complexity. The marked variability of exercise-induced ventricular arrhythmias during repeat maximal exercise testing in a clinically normal population appears to negate the usefulness of this finding during a single test as a marker of future cardiovascular disease. Nevertheless, subjects whose arrhythmias were reproducible may form a group destined to manifest clinical cardiovascular disease in long-term follow-up studies.     

Prevalence of arrhythmias during 24-hour electrocardiographic monitoring and exercise testing in patients with obstructive and nonobstructive hypertrophic cardiomyopathy.

Many patients with hypertrophic cardiomyopathy die suddenly and unexpectedly, a significant number perhaps due to arrhythmia. Of 100 patients initially evaluated for signs or symptoms suggestive of heart disease or a family history of hypertrophic cardiomyopathy, 51 were selected solely because they met the echocardiographic criteria for the disease, and 49 patients were selected primarily because they had: 1) normal sinus rhythm despite left atrial enlargement, 2) a history of syncope, 3) a family history of premature death, or 4) a history of paroxysmal atrial fibrillation. All 100 patients were studied by 24-hour ambulatory electrocardiographic monitoring and 74 of them also underwent treadmill exercise testing. More than 50% of patients in repetitive ventricular premature depolarizations, including 19% who had ventricular tachycardia. Monitoring was superior to exercise testing for exposing these arrhythmias. Two patients experienced cardiac arrest within 2 months of monitoring; in each, monitoring had revealed ventricular tachycardia. Two patients with paroxysms of supraventricular tachycardia during monitoring developed fixed atrial fibrillation within 1 year. These preliminary observations suggest that monitoring may help identify patients at increased risk for significant arrhythmic events.     

Ventricular arrhythmias in children: the validity of exercise stress tests for their diagnosis and management

One hundred ninety-six children ranging in age from 4 years to 15 years with premature ventricular contraction (PVC) on a resting electrocardiogram (ECG) underwent exercise tests and 29 of them were found to have significant ventricular arrhythmias. They included 8 patients with 2 PVC's in row, 8 patients with 3-4 PVC's in row, and 13 patients with more than 5 PVC's in row (ventricular tachycardia: VT). These 29 patients were evaluated with exercise tests by two-step exercise ECG (TSE) and by treadmill (TM), and with 24 hour continuous ECG monitoring (Holter monitoring). 141 ECG's, 77 TSE's, 77 TM's and 46 Holter monitoring were obtained in total, and the incidence of the each study revealing findings compatible with the final diagnosis was 3%, 15%, 51% and 26%, respectively. For detection of 2 PVC's in row, the sensitivity of TSE and TM was not different, but for picking up 3-4 PVC's in row and VT, TM was significantly superior to TSE. Among the VT patients, there were a few cases in whom neither TM nor Holter monitoring alone was sufficient to confirm the diagnosis. Children with symptoms suggestive of ventricular arrhythmias should be carefully evaluated with a combination of exercise tests and Holter monitoring.     

The incidence of arrhythmias during exercise stress tests among children with Kawasaki disease: A single‐center case series

Objective: Based on 2017 guidelines, participation in competitive sports with prior history of Kawasaki Disease (KD) requires those with coronary artery aneurysms (CAA) z score ≥ 5 to undergo evaluation for evidence of inducible ischemia or arrhythmias. The use of exercise stress testing (EST) to evaluate arrhythmias among KD patients has never been reported. This retrospective single-center case series study sought to describe the presence of inducible arrhythmias during EST in KD patients with or without CAA.
Methods: Single-center retrospective review of medical records of patients diagnosed with KD between 1989-2015 at Texas Children’s Hospital, Houston, Texas who underwent EST were included.
Results: Among 1007 patients diagnosed with KD, 95 (9%) underwent 165 ESTs at a median time of 9.6 years (IQR 5.8-11.3 years) from diagnosis. Of these 95 patients, 37 had normal coronaries, 21 dilated (z score 2 to <2.5), 10 small (5 >z ≥2.5), 12 medium (10>z ≥ 5 absolute dimension <8 mm), 10 large (z ≥10 or absolute dimension ≥8 mm), 5 severe (myocardial infarct or bypass graft). Supraventricular tachycardia was not seen. Ventricular arrhythmias during EST were uncommon and seen only among patients with CAA z ≥5. Ventricular tachycardia occurred in a single patient with a large CAA, known VT and ICD. High-grade ventricular ectopy was seen in one patient who had severe CAA and underwent bypass grafting.
Conclusions: Arrhythmias on EST were noted only among patients with CAA z ≥5. The current guidelines are a reasonable approach to increasing healthy activity among KD patients. Clarification regarding which inducible arrhythmias meet criteria for activity restriction may be helpful to guide sport participation.     

Comparison of hemodynamics during hyperthermal immersion and exercise testing in apparently healthy females aged 50-60 years.

BACKGROUND: Owing to excessive worries regarding adverse cardiac events, hyperthermal balneotherapy for patients with coronary artery disease is underprescribed. However, very few cardiac events occur in similar heat stress during Finnish sauna bathing. Exercise testing has proven to be a safe diagnostic procedure even in survivors of myocardial infarction. METHODS: We compared the effects of hyperthermal immersion and exercise testing on cardiac hemodynamics in 21 apparently healthy women aged 50-60 years. The maximal symptom-limited bicycle exercise test was performed according to the modified protocol of Wasserman. Hyperthermal immersion was carried out in 40 degrees C water and was completed by increasing the core temperature by about 2 degrees C. The left ventricular function was evaluated using continuous measurement of thoracic electric bioimpedance during both tests. The blood pressure, index of contractility and heart rate were measured directly, whereas the cardiac index, left cardiac work index and systemic vascular resistance index were calculated. RESULTS: The hemodynamic response, as assessed at continuous non-invasive monitoring, showed substantial differences between hyperthermal immersion and exercise testing. Overall, we found a significantly lower hemodynamic load during hyperthermal immersion in comparison with exercise testing. Entering the bath, there was a significant decrease in the left cardiac work, contractility and blood pressure. We recorded a slight increase in the heart rate towards peak hyperthermal immersion. However, other modulators such as the mean arterial pressure, index of contractility, cardiac index and left cardiac work index decreased even below resting values. CONCLUSIONS: Excessive hyperthermal immersion induced a lower hemodynamic load in apparently healthy women than standard maximal exercise testing.     

Cardiopulmonary stress testing in children who have had congenital heart disease surgery. Physical exercise recommendations during school hours

Introduction and objectives

To analyze and discover if stress testing with exhaled gases in children who have had congenital heart surgery is useful so we could make physical exercise recommendations according to heart disease, type of surgery performed, present hemodynamic state and level of exercise practiced.

Methods

Prospective study of 108 children, who performed stress testing with exhaled gases, electrocardiogram monitoring and blood pressure. A questionnaire was used to obtain variables concerning heart disease, surgery, present functional condition and level of exercise practiced. Exercise recommendations were given after stress testing, and after a year 35 patients answered a questionnaire.

Results

There were significant differences between lesion severity and heart rate at rest and during effort, systolic pressure at rest and during effort, oxygen uptake, oxygen pulse, carbon dioxide production and test duration. A relationship was observed between level of weekly exercise and greater oxygen uptake and test duration, but this was not observed with the underlying heart disease. We observed that best performance occurred with fast repairing for 59 children with cyanotic heart disease. Increased exercise level was recommended for 48 children.

Conclusions

The cardiopulmonary function study allows us to examine the physical performance of children who have had congenital heart surgery and provides us with important data so that we can recommend better physical exercise planning.Full English text available from: www.revespcardiol.org     

Comparison of treadmill exercise testing and psychologic stress testing soon after myocardial infarction.

Are physical or psychologic stressors more useful for evaluating psychologic stress in patients with coronary heart disease? To evaluate this question, patients underwent physical and psychologic testing 7 weeks after myocardial infarction. The psychologic stress test consisted of an open-ended interview, a videotape depicting stressful scenes and a puzzle task. In 20 men whose mean age ± standard deviation was 52 ± 1 years, the interview produced the following peak heart rate and systolic blood pressure responses: 83 ± 18 beats/min and 140 ± 13 mm Hg, which were 8 and 10 percent, respectively, above values at rest (P < 0.05). Symptom-limited treadmill exercise testing in 10 of these patients elicited maximal heart rate and systolic blood pressure values of 152 ± 24 beats/min and 172 ± 32 mm Hg, respectively; ischemic S-T segment depression or angina pectoris occurred in 6 of the 10 patients, whereas none had demonstrated ischemia with psychologic testing. A second consecutive series of 20 patients demonstrated cardiovascular responses to physical and psychologic stress similar to those of the first series. Again, ischemic abnormalities were absent during psychologic stress, whereas exercise-induced ischemic abnormalities were noted in 3 of 20 patients. Ischemic abnormalities are unlikely to appear during psychologic stress testing in patients with a high heart rate and systolic blood pressure threshold for ischemic abnormalities during exercise testing. Standard methods of physical exercise testing are superior to currently available psychologic stress tests for evaluating the cardiovascular response to most commonly encountered psychologic stressors.     

Usefulness of atropine in patients with chronotropic incompetence and poor exercise capacity during treadmill stress testing

BackgroundAtropine, an anticholinergic agent, has been shown to increase heart rate and enhance the sensitivity of dobutamine stress echocardiography in the detection of CAD in patients with chronotropic incompetence; however, the addition of atropine to exercise stress testing EST, in these types of patients has not been well studied previously.ObjectiveInvestigating the usefulness and accuracy of atropine in decreasing the number of inconclusive results of EST in patients with chronotropic incompetence and poor exercise capacity.MethodsThirty patients (16 males and 14 females with the age range of 40:73 years with mean of 55 ± 8) out of 180 patients who preformed EST were chosen as having chronotropic incompetence or poor exercise capacity by Borg scale. Atropine was administered during the exercise phase in doses of 0.5 mg per minute until test conclusion or the maximum dose of 2 mg was reached. All patients were subjected to stress myocardial perfusion imaging SMPI to confirm accuracy.ResultsConclusive test results were achieved in 29 patients (97%). Heart rate and blood pressure were markedly increased with statically highly significant difference (P value <0.001), patients on b-blocker treatment had lower maximum heart rate compared to other patients with significant difference. Twenty-three (79%) patients had negative test results and six (21%) patients had positive test results, and if compared to SMPT results, EST was considered better positive than negative test, with higher specificity than sensitivity and accuracy.ConclusionsAtropine injection during EST significantly reduced the inconclusive test results in patients with chronotropic incompetence and poor exercise capacity.     

Use of atropine in patients with chronotropic incompetence and poor exercise capacity during treadmill stress testing

Background

Treadmill stress testing (TMST) is a valuable diagnostic test for ischemic heart disease. However, the inability to achieve the target heart rate because of either chronotropic incompetence or poor exercise capacity is a major limitation to its utility. We evaluated the usefulness of atropine in decreasing the number of tests with inconclusive results in patients with a poor chronotropic response or exercise capacity during TMST.

Methods

The study comprised 126 patients undergoing TMST. In subjects experiencing fatigue at submaximal exercise, atropine was administered in doses of 0.5 mg per minute until the test conclusion (positive test results or target heart rate achieved) or until a maximum dose of 2 mg was administered.

Results

Thirty-three of the 126 patients (26%) required atropine (mean dose, 1 mg) during the study; 23 of the 33 patients (70%) proceeded to achieve their target heart rate (n = 17) or positive test results (n = 6). The mean increase in heart rate after atropine administration was 25 beats/min (range 3-53 beats/min). Atropine was required in 39% of patients receiving β-blockers, versus 21% of patients not receiving β-blockers (P = .02). Among patients receiving atropine, a conclusive test was achieved significantly more often in patients not receiving β-blockers (94% vs 46%, P = .01). No adverse events were associated with the use of atropine. Atropine administration resulted in conclusive tests more often in subjects with poor chronotropic response than in subjects with poor exercise capacity (78% vs33%, P = <.001).

Conclusion

The use of atropine as an adjunct to standard TMST can help decrease the number of inconclusive tests, even in patients taking β-blockers. Larger studies are warranted to further define the role of atropine in diagnostic TMST.     

Cardiovascular responses of patients with cardiac disease to talking and exercise stress testing.

The blood pressure (BP), heart rate (HR), and premature ventricular contraction responses of patients with cardiac disease during talking were compared with those during exercise stress testing (EST). BPs, HR, and heart rhythm were recorded in 52 patients with cardiac disease before and during talking about an intentionally neutral topic and compared with changes during EST. The systolic and diastolic BP and HR increased significantly during talking. Diastolic BP increased significantly more during talking than during EST stages 1 and 2. The increase in diastolic BP during EST stage 3 did not differ from the increase during talking. HR and systolic BP increased more during EST than during talking. Nine patients had premature ventricular contractions during both EST and talking, two during EST only, and one while talking only. The verbalization protocol provides information about changes in diastolic BP that are not seen with EST. It also may be of value for evaluating heart rhythm, HR, and systolic BP changes for patients whose disabilities preclude EST.     

Usefulness of exercise-induced ST-segment depression in the inferior leads during exercise testing as a marker for coronary artery disease.

Multiple lead systems are shown to have a higher sensitivity than that of single leads for detecting coronary artery disease (CAD) during exercise testing, but the value of ST-segment depression isolated to the inferior leads is questionable. To ascertain the diagnostic accuracy of inferior limb lead II compared with that of precordial lead V5, a retrospective analysis of 173 men was performed (108 in a training population and 65 in a validation cohort). All patients had a standard exercise test and underwent diagnostic coronary angiography within 15 days of the exercise test (range 1 to 65). Sixty-three patients had greater than or equal to 1 coronary stenoses greater than or equal to 70%, or left main lesion greater than or equal to 50%, whereas 45 patients in the training population did not. Exclusion criteria were female sex, left ventricular hypertrophy, left bundle branch block or resting ST-segment depression on the baseline electrocardiogram, previous myocardial infarction or revascularization procedures, and any significant valvular or congenital heart disease. Lead V5 had a better combination of sensitivity (65%) and specificity (84%) (chi-square = 24.11; p less than 0.001) than that of lead II (sensitivity 71%, specificity 44%) (chi-square = 2.25; p = 0.13) at a single cut point, and this improved specificity was substantial (95% confidence interval for observed difference 22 to 58%). Receiver-operating characteristic curve analysis also revealed that lead V5 (area = 0.759) was markedly superior to lead II (area = 0.582) over multiple cut points (z = 3.032; 2p = 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical applications of T-wave alternans assessed during exercise stress testing and ambulatory ECG monitoring

Analytical methods to measure T-wave alternans (TWA), a beat-to-beat fluctuation in the morphology of the ST-segment and T wave in the electrocardiogram (ECG), have been developed to address the unmet challenge of identifying individuals at increased risk for sudden cardiac death. Conventional noninvasive markers including left ventricular ejection fraction have significant limitations as many individuals who die suddenly have relatively preserved ventricular mechanical function. TWA is an attractive marker as it is closely linked to ECG heterogeneity and abnormalities in calcium handling, key factors in arrhythmogenesis. The objectives of this review are to summarize the clinical evidence supporting use of TWA in risk stratification and to discuss its current and potential applications in guiding device and medical therapy.