New tests to assess lung function. Exercise testing in pulmonary evaluation: clinical applications.
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To determine the relative value of clinical findings, results of low-level treadmill electrocardiographic (ECG) exercise testing and left ventricular (LV) ejection fraction (EF) for predicting cardiac events in the year after an acute myocardial infarction (AMI), 72 patients who had had an uncomplicated AMI were studied with either radionuclide angiography or 2-dimensional echocardiography to assess LVEF and a low-level treadmill exercise test before hospital discharge. All patients were followed for 1 year. Nineteen patients (26%) had at least 1 cardiac event: coronary artery bypass grafting (11 patients), recurrent AMI (6 patients) or cardiac death (6 patients). Multiple logistic regression analysis revealed that total cardiac events were predicted by exercise ECG ST-segment depression or angina, prior AMI, ventricular ectopic activity during exercise and digoxin therapy (cumulative r = 0.58, p less than 0.001). Coronary artery bypass grafting was predicted by exercise ECG ST-segment depression or angina (r = 0.29, p = 0.01). Recurrent AMI was predicted by exercise ECG ST-segment depression or angina, prior AMI and ventricular ectopic activity during exercise (cumulative r = 0.49, p less than 0.001). Cardiac death was predicted by an LVEF of 40% or less (r = 0.38, p = 0.01). The presence of both an LVEF of 40% or less and ECG ST-segment depression on treadmill exercise testing defined a subgroup of patients with a high incidence of early cardiac death (33%).(ABSTRACT TRUNCATED AT 250 WORDS)
To better understand the relationship between the transient myocardial ischemia seen during an exercise test and ischemic activity out of hospital, 39 patients with well-documented coronary artery disease underwent standard treadmill exercise testing (Bruce protocol) and 24 to 48 hr of continuous ambulatory electrocardiographic monitoring during normal daily activities. A total of 245 episodes of transient ischemia were recorded in 21 of 32 patients with positive exercise electrocardiograms (group I), whereas seven patients with negative test results (group II) had no episodes of transient ischemia, during monitoring out of hospital (p less than .01). Certain measures in the exercise test were related to the severity of ischemia out of hospital: there were more episodes and a greater total duration of transient ischemia per 24 hr of ambulatory monitoring in patients who developed ischemic electrocardiographic changes before 6 min of exercise (p less than or equal to .021) or at a heart rate of less than 150 beats/min (p = .005) and in those in whom these ST segment changes persisted for more than 5 min after exercise (p less than or equal to .016). In contrast, there was no relationship between transient ischemia out of hospital and the commonly quoted exercise variables: chest pain, total exercise duration, and the maximum levels of heart rate, systolic blood pressure, and double product. Thus, patients with coronary artery disease and negative exercise electrocardiograms are most unlikely to experience active ischemia during normal daily life.(ABSTRACT TRUNCATED AT 250 WORDS)
Twenty departments of clinical physiology in Sweden, doing annually 30,000 exercise stress tests, mainly of patients, completed a questionnaire regarding how they carried out exercise testing. Bicycle ergometry was predominantely used. The criteria for inclusion of patients for exercise testing and for interruption of the test were generally wide, allowing the patient to work until symptoms limited the test. In a second part of the investigation, the departments continuously reported all complications that occurred during an 18-month period which included 50,000 exercise tests. The complication rate was 18.4, the morbidity rate was 5.2, and the mortality rate was 0.4 per 10,000 tests. The number of complications leading to permanent damage was low and it could not be proved that the exercise test had induced a higher complication rate than otherwise would have occurred during the observation period. Patients with aortic stenosis had a high risk for complications. With adequate safety measures and a well-trained staff, exercise stress testing can be regarded as a safe method to be used in the evaluation of even very ill patients.
To assess the effects of coronary vasodilators and exercise on the blood flow dynamics of aortocoronary bypass grafts (ACBG), two-dimensional Doppler echocardiography was performed in 43 consecutive patients with ACBG of the left coronary artery. Doppler velocity signals of 14 internal mammary artery grafts (IMAG) and three saphenous vein grafts (SVG) were imaged in 15 patients using 5MHZ and 7.5MHZ convex-linear Doppler flow probes. Cross-sectional blood flow velocities and graft internal dimensions were continuously measured before and after the sublingual administration of nitroglycerin (0.3 mg) and nifedipine (20 mg), during isometric handgrip and bicycle ergometer exercise tests. 1. Regurgitant flow in isometric contraction time to early systole was observed in 14 of the 15 patients. Pulsatile diastolic blood flow with mean velocity of 14 +/- 6 cm/sec and volume of 49 +/- 25 ml/min was significantly higher than those in systole (7 +/- 7 cm/sec and 8 +/- 7 ml/min) as observed in IMAG and SVG. IMAG showed smaller vessel dimensions, higher flow velocities and lower flow volumes compared with those of SVG. 2. Nitroglycerin and nifedipine increased blood flow volumes (75 +/- 12%, 79 +/- 11%) and velocities (29 +/- 8%, 28 +/- 8%) due to dilatation of graft vessels (18 +/- 3%, 19 +/- 3%). Nifedipine, in contrast to nitroglycerin, induced sustained increases in graft flows. 3. Isometric handgrip and ergometer bicycle exercise tests increased blood flow volumes (34 +/- 9%, 61 +/- 14%) and velocities (31 +/- 11%, 42 +/- 12%) with elevation of double products (22 +/- 14%, 37 +/- 26%). Ergometer bicycle exercise induced similar responses in systole and diastole, whereas isometric handgrip test induced higher ratios of graft flow volume in systole (67 +/- 25%) compared to those in diastole (28 +/- 9%). In conclusion, two-dimensional color Doppler echocardiography is a promising means for the quantitative analysis of blood flow dynamics, assessments of the variable effects of coronary vasodilators and the physiological responses to exercise tests for the aortocoronary bypass graft flow in the early postoperative state.
Resting ST segment depression has been identified as a marker for adverse cardiac events in patients with and without known coronary artery disease. To correlate this with exercise testing, coronary angiography, and how it impacts on long-term prognosis, a retrospective study was performed on 476 patients, of whom 223 had no clinical or electrocardiographic evidence of prior myocardial infarction while 253 were survivors of an infarction. All patients performed a standard exercise test and underwent diagnostic coronary angiography within an average of 32 days of their exercise test (range 0 to 90 days). Exclusions were women, those with left bundle branch block, left ventricular hypertrophy, use of digoxin, previous revascularization procedures, or significant valvular or congenital heart disease. Long-term follow-up was carried out for an average of 45 months (+/- 17). Of the patients without prior infarction, 23 (10%) had persistent resting ST segment depression, and of those with a prior history of infarction, 37 (15%) also had resting ST segment depression. Patients with resting ST segment depression and no prior myocardial infarction had a higher prevalence of severe coronary disease (three-vessel and/or left main) (30%) than those without resting ST segment depression (16%) (95% confidence interval [CI] for observed difference -5.0% to 33.9%, p = 0.12). The criterion of greater than or equal to 2 mm of additional exercise-induced ST segment depression was a particularly useful marker in these patients for the diagnosis of any coronary disease (likelihood ratio 3.35, 95% CI 0.56 to 19.93, p = 0.06). Patients with resting ST segment depression and a prior myocardial infarction had a 2.5 times higher prevalence of severe coronary artery disease compared with patients without resting ST segment depression (43% versus 17% prevalence, respectively, 95% CI for observed difference 9.38% to 42.8%, p less than 0.001) and also had larger left ventricles postinfarction (left ventricular end-diastolic volume index 102 ml/m2 compared with 96 ml/m2, p less than 0.001).(ABSTRACT TRUNCATED AT 400 WORDS)
OBJECTIVE: To assess the use of cardiopulmonary exercise testing (CPET) in major hospitals and medical centers throughout the Kingdom of Saudi Arabia (KSA) and to seek information on the way CPET is conducted. METHODS: Self-reported questionnaires on the use of CPET were mailed during the fall of 2002 to 54 major public and private hospitals and medical centers throughout the KSA. The response rate was 64.2%. The returned questionnaires were coded and data were analyzed. RESULTS: The findings indicated that more than 85% of the sample was not employing CPET in their medical centers. However, all of the surveyed centers were regularly performing stress electrocardiogram tests. Approximately 21% of those medical centers who did not have CPET are planning to have it in the near future. The most frequent reasons for not conducting CPET were lack of equipment, lack of trained technicians and lack of training in interpreting test results. Moreover, the most important reasons for conducting the CPET were pulmonary problems, followed by cardiac disorders. Treadmill and leg ergometer were used most as an exercise mode. Bruce protocol as well as institution specific protocols were equally used during CPET. Finally, there appears a lack of local cardiorespiratory data, especially for healthy Saudi females at all ages as well as older male group. CONCLUSION: Cardiopulmonary exercise testing as a diagnostic tool for cardiopulmonary diseases was extremely underutilized in Saudi hospitals and medical centers. Much greater efforts are needed to raise the awareness among physicians on the usefulness of CPET.
OBJECTIVE: To explore the mechanism of the left cardiac sympathetic denervation (LCSD) surgery to reduce the incidence of cardiac events for long QT syndrome (LQTS) patients. METHODS: 12 LQTS patients were selected to do exercise test (ET) to mimic sympathetic activation. The dynamic alterations on ECG during exercise and recovery phases (Rec) were observed and the exercise test characteristics for LQTS patients before and after surgery were summarized and compared. RESULTS: The QTc at resting was shortened from 0.54 s +/- 0.04 s to 0.50 s +/- 0.04 s, P = 0.026, while the maximum heart rate during exercise decreased from 141 beat/min +/- 18 beat/min to 124 beat/min +/- 14 beat/min, P = 0.003. QTc was shortened during exercise, however, it was prolonged during the early recovery phase (before ET 0.54 s +/- 0.02 s, ET 10 min 0.46 s +/- 0.02 s, Rec 4 min 0.55 s +/- 0.03 s); LCSD could reduce such abrupt alteration of QTc during early recovery phase (after surgery: before ET 0.53 s +/- 0.03 s, ET 10 min 0.48 s +/- 0.03 s, Rec 4 min 0.53 s +/- 0.05 s). QT/RR interval slope, representing the adaptation response of QT interval to heart rate, became steeper after exercise (from 0.61 +/- 0.06 to 0.71 +/- 0.07 after exercise, P < 0.01). LCSD made the slopes become less steep both before exercise (from 0.61 +/- 0.06 before surgery to 0.55 +/- 0.07 after surgery, P = 0.013) and after exercise (from 0.71 +/- 0.07 before surgery to 0.66 +/- 0.06 after surgery, P = 0.018). Notched T wave alterations occurred in 7 patients at the end of exercise and/or during early recovery phase before surgery, and LCSD diminished such alteration in 4 patients. CONCLUSION: The slope between QT and RR both the pre-exercise and post-exercise slopes, interval becomes less steep after LCSD, which suggests that exaggerated delay in repolarization with decreasing heart rate for LQTS patients is improved by LCSD. This may be one of the mechanisms of LCSD efficacy for treating LQTS patients. Exercise test is one of tools to evaluate the effect of LCSD on LQTS patients.
Indirect blood pressures recorded with a random zero sphygmomanometer were compared with simultaneous intra-arterial blood pressures recorded with the Oxford system. Twenty five patients undertook a graded bicycle exercise test, cycling at workloads increasing from 41, 65, 114, and 163 W (250 to 400, 700, and 1000 kpm per min) with each grade being maintained for three minutes unless the exercise test was terminated earlier at the point of fatigue. Intra-arterial pressures were recorded continuously and indirect measurements made at steady state levels in the 30 seconds before each change in grade and immediately after the termination of the exercise protocol. The mean difference in systolic blood pressure at 5.5 minutes of exercise showed that the indirect measurement underestimated the direct measurement. Immediately after the termination of exercise the blood pressure fell precipitiously to a highly significant degree. For both systolic and diastolic pressures there was considerably individual variability. These data confirm that indirect methods of blood pressure measurement during dynamic exercise testing are inaccurate and may provide misleading information.
From 217 old men submitted to a symptom-limited maximal exercise test, 145 had also an exercise thallium scintigraphy; 44 of those patients were submitted to an angiography. The decision to perform angiography in these aged patients was based mostly on their history and their complaints. This decision was likely influenced by the results of the exercise test; even in symptomatic patients, angiography was rarely performed when the exercise data were normal (normal ECG, no angina during the test). The thallium scintigraphy was not a major element in the overall clinical decision making: when the scintigraphy was available, it contributed, however, to refine the decision whether or not to perform an angiography.
BACKGROUND: National Cholesterol Education Program Adult Treatment Panel III (ATP III) guidelines recommend the use of Framingham risk scores (FRS) for cardiovascular assessment of asymptomatic individuals. We hypothesized that risk prediction could be improved with 2 non-ECG exercise test measures, exercise capacity (metabolic equivalents, or METs) and heart rate recovery (HRR). METHODS AND RESULTS: An asymptomatic cohort with baseline treadmill tests (n=6126; 46% women, FRS <20%) was followed up prospectively for 20 years. Individuals with low (median or less) HRR or METs experienced 91% of all cardiovascular disease (CVD) deaths (225/246). After FRS adjustment, low HRR and METs individually were highly significant predictors of CVD death, but low HRR and METs together were associated with substantially higher risk (adjusted hazard ratio compared with high HRR/high METs for women 8.51, 95% CI 3.65 to 19.84; for men, 3.53, 95% CI 2.03 to 6.15; P<0.001 for both). At 10-year follow-up, FRS-adjusted CVD death risk associated with low HRR/low METs was less than at 20 years but remained significant (women 3.83, 95% CI 1.09 to 13.47, and men 2.70, 95% CI 1.11 to 6.55). The application of HRR/METs information to FRS assessment identified those at high risk (>0.5% annual CVD mortality) in half of women with FRS 6% to 9% and 10% to 19% and just under half of men with FRS 10% to 19%. Low HRR/low METs was also associated with an increased relative risk of CVD death in individuals with low-risk FRS (FRS <6% in women and <10% in men), but absolute CVD mortality rates were low in this subgroup. CONCLUSIONS: Exercise testing may be a useful adjunct for clinical risk assessment in asymptomatic women with FRS 6% to 19% and men with FRS 10% to 19%.
We report a 14-year-old male with hypokalemic periodic paralysis. He noticed periodic paralysis at the age of 11. Any complication did not accompany the symptom. At the age of 12, hypokalemia was found during an episode of paralysis, and he was diagnosed as hypokalemic periodic paralysis. The frequency of paralytic attack increased around April 2000. Although long-acting oral potassium (32 mEq/day) was administered, it did not give favorable effect. Therapeutic spironolactone trial also failed. After the reconfirmation of the diagnosis of periodic paralysis by an exercise test, oral acetazolamide (750 mg/day) was started. In subsequent exercise test, the increment of the CMAP amplitude of abductor digiti minimi during exercise became smaller and the decrement of CMAP amplitude after exercise disappeared thereafter, which was assumed to be related with clinical improvement. The noninvasive exercise test is useful not only to diagnose periodic paralysis but also to evaluate therapeutic efficacy.
The purpose of this study was to examine the rating of perceived exertion (RPE) at maximal exercise in children performing three different graded exercise tests on a treadmill. Eighteen children with a mean +/- SD age of 10.3 +/- 1.4 years volunteered for this study. Each subject performed three different graded exercise test protocols on a treadmill. The protocols consisted of walking only, running only, and combination walk/run. Mean VO2max (ml.kg-1.min-1) during the walking trial (47.3 +/- 5.0) was significantly (p < 0.05) less than during the running (52.1 +/- 4.9) and combination trials (51.9 +/- 5.1). Mean HRmax (bpm) was significantly (p < 0.05) lower during the walking test (195.2 +/- 7.9) compared to the running (202.2 +/- 7.4) and combination tests (202.3 +/- 6.6). Mean RPE at maximal exercise was 18.1 +/- 2.1 in the walking trial, 16.8 +/- 3.0 in the running trial, and 16.8 +/- 2.6 in the combination trial, and was significantly (p < 0.05) greater in the walking trial compared to the other two testing protocols. These data indicate that although VO2max during a walking test is lower, effort sensation is higher compared to protocols that use running as the mode of exercise. The factors involved with RPE selection in this age-group remain to be established.
The result of treadmill exercise tests were studied in 158 patients (pts) who were exercised submaximally 1 to 3 month after an acute transmural myocardial infarction. A 4 minute test had initially been performed prior to their discharge, 14 to 20 days after the acute event. Eight pts had and inferior and 65 an anterior infarction; 13 could not be reliable classified and were not further included. In the inferior infarction group, 10/80 had a positive test characterized by ST changes (9 pts), and aniginal pain (4 pts.). In the anterior infarction group, 11/65 had a positive test: ST-changes could be reliable assessed in only 2, while 9 had anginal pain; one had ventridular tachycardia. Fourteen pts underwent coronary arteriography; all showed severe triple vessel disease, and in 8 myocardial revascularization was performed. In pts with a previous anterior myocardial infarction, anginal pain can be a very helpful finding, since ST changes are usually hard to interpret.
Early post-myocardial infarction exercise testing has proved surprisingly safe. S-T elevations portended a bad prognosis as did also marked S-T segment depressions, especially if combined with premature ventricular contractions or short duration of exercise. A poor prognosis was also seen if, at low workloads, blood pressure could not reach 130 mm Hg, the heart rate did not rise above 130 beats per minute, or if there was angina. Complex arrhythmias were only of prognostic value as an independent variable with ambulatory monitoring. Negative findings were of more predictive value than positive results and have important therapeutic implications.
The response to a standardized exercise test was investigated in 12 volunteers and 13 patients with aches, cramps, and pains. In men, creatine kinase (CK) levels peaked (up to 1600 mU per milliliter) between 10 and 20 hours after exercise. High levels of blood lactate during exercise were related to the intensity of work and to high levels of CK after exercise. The patients could be divided into several groups: (1) those with no change in blood metabolites (psychogenic); (2) those with a disproportionate rise in CK (metabolic myopathies); (3) those with a disproportionate rise of lactate (mitochondrial abnormalities); and (4) in one patient with exercise-related pains, subnormal elevation of fatty acid levels. The correlation of changes in blood lactate, CK, and fatty acids may be useful, whereas an isolated measurement, even if outside the normal range, is often meaningless.
It is essential that patients with pacemakers capable of rate modulation undergo some form of exercise testing to assure appropriate rate modulation. Informal exercise testing is a reasonable and less expensive alternative to formal treadmill testing. Empiric adjustment of the rate response parameters by assessing the patient's rate response while walking at a self-determined casual and brisk pace has been used. However, no normals exist to determine the appropriate rate response for a "casual" and "brisk" walk. Volunteers were tested with metronome-guided casual and brisk walks in an effort to standardize the informal exercise and determine expected heart rate response for these levels of activity. Results of the metronome-guided rate response in normal volunteers may be useful in determining the appropriate rate response for pacemaker patients when tested in such an informal manner.