A modified treadmill exercise protocol for computer-assisted analysis of the ST segment/heart rate slope: methods and reproducibility

A new treadmill exercise protocol, modified from the standard Bruce method, was designed to improve ST segment/heart rate slope accuracy and applicability by reducing heart rate increments between exercise stages. In 150 patients exercised according to the new protocol and in 150 patients exercised according to the Bruce protocol, similar exercise tolerance and similar overall heart rate, systolic blood pressure and double product responses to exercise were observed. The mean increment in heart rate between exercise stages of the new protocol was ten beats/minute, which was significantly lower than the 27 beats/minute/stage found with the Bruce protocol. The accuracy of computer-measured ST segment depression was validated by comparison with physician measurement in a separate subgroup of patients with angina pectoris, and serial testing demonstrated stronger interest reproducibility for the ST segment/heart rate slope than for either measured ST segment depression, peak heart rate achieved or duration of exercise.     

曲美他嗪对稳定型劳力性心绞痛患者 心肌缺血的影响

目的探讨曲美他嗪对冠心病(CHD)稳定型劳力性心绞痛患者心肌缺血的影响。方法选择经冠状动脉造影确诊的CHD稳定型劳力性心绞痛患者14例,在原有治疗不变的情况下,加用曲美他嗪治疗12周,治疗前后均行平板运动试验,观察用药前后下述指标的变化①用药前后每周心绞痛发作的次数;②每周硝酸甘油片的用量;③心率及心率和收缩压的乘积;④运动诱发心绞痛发作所需的时间;⑤运动后ST段下降0.1mV所需的时间;⑥运动持续时间。结果患者每周心绞痛发作的次数及硝酸甘油片的用量均明显下降(P＜0.05);心率及心率和收缩压乘积轻度变化(P＞0.05);明显延长运动诱发心绞痛所需的时间及运动后ST段下降≥0.1mV所需的时间(P＜0.05)。结论曲美他嗪能改善运动诱发的心肌缺血,对CHD劳力性心绞痛患者有一定的疗效。     

Usefulness of dobutamine in producing myocardial ischemia. Comparison with ergometry

Fifty six patients were studied while in the Coronary Care Unit: 17 with unstable angina and 39 with acute myocardial infarction. All patients underwent dobutamine stress testing (doses of 5, 10, 15 and 20 micrograms/kg/min every 5 min) and exercise testing (modified protocol to finish at an energy expenditure of approximately 5 METS): 4-5 days after the last crisis of angina or 6-8 days after the onset of noncomplicated acute myocardial infarction. The heart rate increased from 72 +/- 10 to 104 +/- 12 beat/min with dobutamine (p = 0.00001) and from 84 +/- 11 to 118 +/- 15 beat/min with exercise testing (p = 0.00001). The systolic blood pressure increased from 116 +/- 9 to 138 +/- 11 mmHg with dobutamine (p = 0.00001) and from 117 +/- 8 to 156 +/- 7 mmHg with exercise testing (p = 0.00001). Due to different reasons 33 patients did not finish the exercise protocol, while only 8 patients did not finish the dobutamine testing. The ST segment wast elevated in 22 cases with dobutamine and in 9 cases with exercise, eight of them coinciding in both tests. The ST segment was depressed in 36 cases with dobutamine and in 21 cases with exercise, 20 of them coinciding in both tests. Angina was present in 11 cases with dobutamine and in four exercise, three of them coinciding. If the unfinished tests or those with angina or ST segment depression are considered abnormal, there were 40 abnormal tests with dobutamine and 38 with exercise, 32 of them coinciding.(ABSTRACT TRUNCATED AT 250 WORDS)     

Lack of rebound during intermittent transdermal treatment with glyceryl trinitrate in patients with stable angina on background beta blocker.

OBJECTIVE--To assess whether intermittent transdermal treatment with glyceryl trinitrate causes clinically significant rebound in patients maintained on beta blockers for stable angina pectoris. DESIGN--Serial treadmill exercise testing in a double blind, randomised, placebo controlled cross over trial. Baseline exercise testing was performed at 0900 and 1100 at visit 1. Transdermal glyceryl trinitrate patches releasing 15 mg/24 h were applied at 2200 the evening before visits 2 and 3, and exercise testing was performed at 0900 the next morning. The patch was removed and replaced with either an identical patch or matching placebo and exercise tests were repeated two hours later. The alternative treatment was given at visit 3. SETTING--Tertiary referral centre. PATIENTS--14 patients with stable angina pectoris maintained on beta blocker treatment alone. MAIN OUTCOME MEASURES--Time to angina, 1 mm ST segment depression, and total time, together with heart rate, systolic blood pressure, and rate-pressure product. RESULTS--Active treatment improved treadmill performance at 0900 and 1100. Time to angina, time to 1 mm ST segment depression, and total time fell significantly on placebo compared with the 0900 exercise test on active treatment, but were not significantly different to the baseline exercise test either. CONCLUSIONS--Intermittent transdermal treatment with glyceryl trinitrate is not associated with the rebound phenomenon in patients maintained on beta blockers for stable angina pectoris.     

Double-blind randomised crossover trial comparing isosorbide dinitrate cream and oral sustained-release tablets in patients with angina pectoris

Percutaneous isosorbide dinitrate cream and sustained-release tablets were compared in a double-blind randomised crossover trial in 28 patients with coronary artery disease and chronic stable angina pectoris. Twenty-two patients completed the trial. Both preparations significantly increased the mean exercise time to the onset of angina (P less than 0.001) and to termination of exercise (P less than 0.001) compared to the pre-treatment period. There were no significant differences between the cream and tablets with respect to frequency of anginal attacks, glyceryl trinitrate consumption, heart rate and ST segment depression at the onset of angina, ST segment depression at maximal exercise and the double product of heart rate and systolic blood pressure at maximal exercise. Equal numbers of patients expressed preference for cream and tablets. We conclude that in this group of patients isosorbide dinitrate sustained-release tablets have no clinical advantage over isosorbide dinitrate cream which, may, therefore, be of particular value for those patients with angina pectoris who dislike taking tablets or who prefer this form of nitrate preparation.     

Prognostic significance of transient myocardial ischaemia after first acute myocardial infarction: five year follow up study.

OBJECTIVE--To assess the five year prognostic significance of transient myocardial ischaemia on ambulatory monitoring after a first acute myocardial infarction, and to compare the diagnostic and long term prognostic value of ambulatory ST segment monitoring, maximal exercise testing, and echocardiography in patients with documented ischaemic heart disease. DESIGN--Prospective study. SETTING--Cardiology department of a teaching hospital. PATIENTS--123 consecutive men aged under 70 who were able to perform predischarge maximal exercise testing. INTERVENTIONS--Echocardiography two days before discharge (left ventricular ejection fraction), maximal bicycle ergometric testing one day before discharge (ST segment depression, angina, blood pressure, heart rate), and ambulatory ST segment monitoring (transient myocardial ischaemia) started at hospital discharge a mean of 11 (SD 5) days after infarction. MAIN OUTCOME MEASURES--Relation of ambulatory ST segment depression, exercise test variables, and left ventricular ejection fraction to subsequent objective (cardiac death or myocardial infarction) or subjective (need for coronary revascularisation) events. RESULTS--23 of the 123 patients had episodes of transient ST segment depression, of which 98% were silent. Over a mean of 5 (range 4 to 6) years of follow up, patients with ambulatory ischaemia were no more likely to have objective end points than patients without ischaemic episodes. If, however, subjective events were included an association between transient ST segment depression and an adverse long term outcome was found (Kaplan-Meier analysis; P = 0.004). The presence of exercise induced angina identified a similar proportion of patients with a poor prognosis (Kaplan-Meier analysis; P < 0.004). Both exertional angina and ambulatory ST segment depression had high specificity but poor sensitivity. The presence of exercise induced ST segment depression was of no value in predicting combined cardiac events. Indeed, patients without exertional ST segment depression were at increased risk of future objective end points (Kaplan-Meier analysis; P < 0.0045). These findings may be explained in part by a higher prevalence of left ventricular dysfunction in patients without ischaemic changes in the exercise electrocardiogram (P < 0.05). CONCLUSION--There seem to be limited reasons to perform ambulatory ST segment monitoring in survivors of a first myocardial infarction who can perform exercise tests before discharge. Patients at high risk of future myocardial infarction or death from cardiac causes are not identified. Ambulatory monitoring and exertional angina distinguish a small subset of patients who will develop severe angina pectoris demanding coronary revascularisation during follow up. Patients without exercise induced ST segment depression comprise a high risk subgroup in terms of subsequent objective end points. The role of ambulatory ST segment monitoring performed in unselected patients immediately after infarction when risk is maximal remains to be clarified.     

Comparison of clinical variables and variables derived from a limited predischarge exercise test as predictors of early and late mortality after myocardial infarction

An exercise test limited to 5 METS or 70% of age-predicted maximal heart rate was performed 1 day before hospital discharge by 225 survivors of acute myocardial infarction, all of whom were subsequently followed up for at least 5 years. The mortality rate was 11.1% during the first year, but averaged only 2.9% per year from the second to fifth year. Over the entire follow-up period, the five variables that predicted mortality by multivariate analysis were QRS score, an exercise-induced ST segment shift, previous infarction, failure to achieve target heart rate or work load and ventricular arrhythmia during the exercise test. Because mortality differed markedly before and after 1 year, Cox regression analyses were performed separately for both of these periods. The factors that were predictive of mortality during the first year were an exercise-induced ST shift (p less than 0.0001, relative risk 7.8), failure to increase systolic blood pressure by 10 mm Hg or more during exercise (p = 0.0039, relative risk 4.3) and angina in hospital 48 hours or longer after admission (p = 0.0046, relative risk 3.4). None of these three variables was predictive of mortality after 1 year. Previous infarction (p = 0.0007), QRS score (p = 0.0042) and ventricular arrhythmia during the exercise test (p = 0.016) were predictive of mortality after the first year. Thus, clinical and exercise test variables are complementary predictors of mortality after myocardial infarction. An abnormal ST segment response during an early limited exercise test and angina in the hospital are common strong predictors of mortality to 1 year, but not thereafter. Late mortality correlates with markers of poor left ventricular function.     

Myocardial ischemia during daily activities: the importance of increased myocardial oxygen demand

The role of increased myocardial oxygen demand in the pathophysiology of myocardial ischemia occurring during daily activities was evaluated in 50 patients with coronary artery disease and exercise-induced ST segment depression. Each patient underwent ambulatory electrocardiographic (ECG) monitoring for ST segment shifts during normal daily activities and symptom-limited bicycle exercise testing with continuous ECG monitoring. All 50 patients had ST depression greater than or equal to 0.1 mV during exercise. A total of 241 episodes of ST depression were noted in the ambulatory setting in 31 patients; only 6% of these were accompanied by angina pectoris. Significant (0.1 mV) ST depression during ambulatory monitoring was preceded by a mean increase in heart rate of 27 +/- 12 beats/min. Patients with ischemia during daily activities developed ST depression earlier during exercise (7.9 +/- 4.4 vs. 14.2 +/- 6.4 min, p less than 0.001) and tended to have significant ECG changes at a lower exercise heart rate and rate-pressure product than did those without ST depression during ambulatory monitoring. In the 31 patients with ischemia during daily activities, the mean heart rate associated with ST depression in the ambulatory setting was closely correlated with the heart rate precipitating ECG changes during exercise testing (r = 0.74, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

The threshold for myocardial ischemia varies in patients with coronary artery disease depending on the exercise protocol

It is generally accepted that angina pectoris and, presumably, myocardial ischemia occur at a fixed heart rate-systolic blood pressure product in a given patient. This concept of a fixed threshold has recently been challenged. To evaluate the effects of varying exercise intensity on the ischemic threshold, 33 patients with coronary artery disease and provokable myocardial ischemia, documented by thallium-201 myocardial perfusion imaging, underwent two exercise tests 2 to 7 days apart. A symptom-limited incremental treadmill exercise test was followed by a 20 min submaximal treadmill test at an intensity approximating 70% of the peak heart rate attained during the incremental test. During the incremental exercise test, angina pectoris developed in 16 patients and 17 patients were asymptomatic. At least 0.1 mV of ST segment depression developed in all subjects during the incremental exercise test at a mean exercise duration of 5.3 +/- 2.6 min, a rate-pressure product of 19,130 +/- 5,735 and oxygen uptake of 19.6 +/- 7.0 ml/kg per min. During the submaximal exercise test, 28 (85%) of the 33 patients had significant ST segment depression. Of these patients, 24 (86%) were asymptomatic, including 10 patients who had previously reported anginal symptoms during the incremental test. The average time to onset of 0.1 mV ST segment depression during the submaximal test was 8.1 +/- 4.5 min. These changes occurred at a rate-pressure product of 15,250 +/- 3,705 and an oxygen uptake of 14.3 +/- 5.9 ml/kg per min, and were significantly (p less than 0.001) lower than values observed during the graded exercise.(ABSTRACT TRUNCATED AT 250 WORDS)     

Exercise-induced silent ischemia: age, diabetes mellitus, previous myocardial infarction and prognosis

The purposes of this study were 1) to determine the prognosis of silent ischemia in an unselected group of patients referred for exercise testing, and 2) to assess whether age or the presence of myocardial infarction or diabetes mellitus influences the prevalence of silent myocardial ischemia during exercise testing. The design was retrospective, with a 2 year mean follow-up period. The study group consisted of 1,747 predominantly male in-patients and outpatients referred for exercise testing at a 1,200 bed Veterans Administration hospital. The main result was that the mortality rate was significantly greater (p = 0.02) among patients with abnormal ST segment depression than in patients without ST depression. The presence or absence of angina pectoris during exercise testing was not significantly related to death. The prevalence of silent ischemia was not significantly different among patients categorized according to myocardial infarction or diabetes mellitus status, but was directly related to age. It is concluded that, in patients with an ischemic ST response to exercise testing, the presence or absence of angina pectoris during the test does not alter the risk of death. The prevalence of silent ischemia during exercise testing is not statistically different among patients with recent, past or no myocardial infarction or with insulin-dependent or noninsulin-dependent diabetes mellitus.     

Prognostic value of late exercise test after myocardial infarction

The parameters of a maximal exercise stress test, without therapy, 30 to 186 days after myocardial infarction were related to cardiac death, recurrent nonfatal infarction, coronary artery by-pass surgery, development of angina pectoris and ST segment depression during subsequent stress test in 209 patients. During a follow-up period of 9.5 to 119 months (medium 52) 12 patients died, 14 developed recurrent nonfatal myocardial infarction, 4 were submitted to coronary surgery, respectively 53 and 69 patients presented angina and ST segment depression at the first test, 23 and 33 developed them subsequently. Among the exercise parameters only the systolic blood pressure less than 140 mmHg was predictive of future mortality. Angina and ST segment depression when present at the first stress test were significantly related between them and with low heart rate, low maximal systolic blood pressure and low work load, but not with cardiac mortality, reinfarction and by-pass surgery. Our results show a low predictive value of the late maximal exercise test after a myocardial infarction. Probably that depends on evolution of coronary disease, which does not provide long-term prognostic informations.     

X syndrome--report of six cases]

Six patients (2 males and 4 females, mean age of 46 years) with X syndrome were reported in this paper. All patients presented with typical exertional angina pectoris. In 4 patients the angina had a variable threshold of onset, it often occurred at rest and occasionally nocturnally. The electrocardiogram during chest pain showed ST segment depression of more than 0.05-0.1 mV in all 6 patients. The treadmill or bicycle ergometer exercise test was positive in 4 cases (ST segment depression > 0.1 mV), equivocal in 1 (ST segment < 0.1 mV) in whom the 201Tl exercise myocardial perfusion scan showed sign of ischemia, and negative in 1 in whom atrial pacing at heart rate of 135 beats/min induced angina and ST segment depression of 0.1-0.15 mV. Echocardiograms and X ray chest films revealed no sign of ventricular hypertrophy or enlargement. The 201Tl exercise myocardial perfusion scan was performed in 5 patients, which showed signs of ischemia in 4 patients and suspected to have ischemia in 1. Left ventriculograms and coronary angiograms were normal in all 6 patients. Ergonovine provoking test (total dose of 0.4 mg) was negative in 5 patients, it was not performed in 1 in whom there was no evidence of coronary artery spasm by angiogram during appearance of electrocardiographic ischemic changes and chest pain. Left ventricular endomyocardial biopsy was performed in 1 patient, which showed significant smooth muscle cell proliferation in the medial layer of a small artery with diameter of 62.5 mu which produced narrowing of the lumen.(ABSTRACT TRUNCATED AT 250 WORDS)     

Diltiazem: effects on exercise performance in patients with coronary artery disease

We evaluated a new slow-channel calcium-blocking agent, diltiazem hydrochloride, in 10 patients with documented fixed coronary artery disease who had reproducible angina and greater than or equal to 0.1 mV ST segment depression on ECG treadmill exercise testing after 1 week of single-blind placebo administration. Subsequently, over the next 6 weeks, either diltiazem (30 mg/tablet) or placebo were administered for 1 week each in a randomized double-blind triple crossover design, as one tablet four times a day, two tablets three times a day or two tablets four times a day, for a total diltiazem dose of 120, 180 and 240 mg/day, respectively. Treadmill (electrocardiogram) exercise testing was performed at the end of each week. Only diltiazem at 240 mg/day increased significantly the time to angina pectoris (P less than 0.05), time to ST segment depression (P = 0.01), time to maximal exercise (P less than 0.02), and heart rate at maximal exercise (P less than 0.05) without effecting significantly the maximal rate-pressure product compared to the corresponding placebo values. In addition, using only the diltiazem data, a significant high dose response was observed for time to angina (P less than 0.05), ST segment depression (P less than 0.005), and maximal exercise (P less than 0.025). No adverse reactions were reported during the study. Therefore, we conclude that 240 mg/day of diltiazem improves significantly exercise performance in patients with angina pectoris due to fixed coronary artery disease and adverse effects, rarely, if ever, occur at this dosage.     

Comparison of exercise thallium-201 perfusion scintigraphy and coronarography in the prognostic stratification of patients with post-infarction residual ischemia]

The goals of this study were: 1) to determine and compare the prognostic utility of exercise 201Thallium scintigraphy with coronary angiography in patients with residual ischemia at the symptom limited bicycle exercise testing performed at hospital discharge after a first uncomplicated acute myocardial infarction 2) to verify the ability of perfusion scintigraphy to identify better than coronary angiography a subset of these patients at low risk for future events, despite the ischemic response at the exercise stress testing. Accordingly, follow-up data were obtained prospectively for 72 consecutive patients with adequate left ventricular rest systolic function, and with exercise induced greater than or equal to 1 mm ST-segment depression and/or typical angina pectoris. A planar 201Thallium scintigraphy and coronary angiography were performed within 2 months after acute myocardial infarction. By 31 +/- 29 months 38 patients had no events, while 34 experienced a cardiac event: 3 died of cardiac causes, 2 had nonfatal recurrent myocardial infarction, 29 were rehospitalized for severe class III or IV angina pectoris (4 were treated medically, 25 were revascularized: 20 had coronary bypass surgery, 5 coronary angioplasty). Each of the 3 angiographic classification of coronary artery disease (number of vessels with greater than or equal to 70% reduction of luminal diameter, jeopardy score and Gensini score) accurately identified patients with subsequent cardiac event by Mantel and Cox analysis (respectively p = 0.01, p = 0.0000, p = 0.002). Among 201Thallium variables, the number of segments demonstrating redistribution on delayed images (p = 0.0000), the number of segments with persistent defect (p = 0.0003) and increased 201Thallium uptake by the lungs (p = 0.0100) effectively stratified the probability of survival by the same analysis. Furthermore, the number of perfusion defects, either transient or persistent, with exercise 201Thallium scintigraphy provide additive prognostic information to any of the 3 angiographic coronary artery disease classifications considered. On the contrary, when 201Thallium stress findings are known, coronary angiography data in general are not additive in risk stratification. 17 patients with no reversible perfusion defect remained stable at follow up (52 +/- 28 months) despite development of typical angina pectoris (11/17) and/or ischemic ST segment depression (12/17) during exercise testing.(ABSTRACT TRUNCATED AT 400 WORDS)     

Effects of combined alpha and beta adrenoceptor blockade in patients with angina pectoris. A double blind study comparing labetalol with placebo.

The effects of a combined alpha and beta receptor antagonist, labetalol, were investigated in 10 patients with chronic stable angina pectoris. The optimal dose was determined during an initial dose titration study when the patients were treated with 200 mg, 400 mg, and 600 mg (six patients) of labetalol a day. The effective dose was then compared with placebo in a double blind randomised study. The effects of the drug were monitored with angina diaries, treadmill exercise testing, and 48 hour ambulatory electrocardiographic ST segment monitoring. Plasma labetalol concentrations were measured during each treatment period. The mean effective antianginal dose of labetalol was 480 (SD 140) mg/day given by mouth twice a day. There was a dose related reduction in daytime and nocturnal heart rate, the frequency of pain was significantly reduced by 41%, and exercise duration was significantly increased by 44% with labetalol when compared with placebo. The frequency and duration of the episodes of ST segment depression were significantly reduced by 56% and 73% respectively with labetalol. Adverse effects resulted in a reduction of the dose of labetalol in two patients. Thus labetalol is an effective agent in the treatment of angina pectoris.     

Effects of combined alpha and beta adrenoceptor blockade in patients with angina pectoris. A double blind study comparing labetalol with placebo

The effects of a combined alpha and beta receptor antagonist, labetalol, were investigated in 10 patients with chronic stable angina pectoris. The optimal dose was determined during an initial dose titration study when the patients were treated with 200 mg, 400 mg, and 600 mg (six patients) of labetalol a day. The effective dose was then compared with placebo in a double blind randomised study. The effects of the drug were monitored with angina diaries, treadmill exercise testing, and 48 hour ambulatory electrocardiographic ST segment monitoring. Plasma labetalol concentrations were measured during each treatment period. The mean effective antianginal dose of labetalol was 480 (SD 140) mg/day given by mouth twice a day. There was a dose related reduction in daytime and nocturnal heart rate, the frequency of pain was significantly reduced by 41%, and exercise duration was significantly increased by 44% with labetalol when compared with placebo. The frequency and duration of the episodes of ST segment depression were significantly reduced by 56% and 73% respectively with labetalol. Adverse effects resulted in a reduction of the dose of labetalol in two patients. Thus labetalol is an effective agent in the treatment of angina pectoris.     

Thallium-201 scintigraphy after dipyridamole infusion with low-level exercise. III. Clinical significance and additional diagnostic value of ST segment depression and angina pectoris during the test

Intravenous dipyridamole thallium testing is a useful alternativeprocedure for assessing coronary artery disease (CAD) in patientswho are unable to perform maximal exercise tests. IschaemicST segment depression and angina pectoris are frequently observedduring the test, in particular when exercise is added to dipyridamoleinfusion. To establish the clinical significance and additionaldiagnostic value of these markers of ischaemia during dipyridamolelow-level exercise testing (DXT) 57 patients with CAD (groupA), 21 patients with normal or near-normal coronary arteriesat coronary arteriography (group B), and 20 healthy subjectswith low likelihood of CAD (group C) were studied. During DXT ischaemic ST segment depression was observed in 28patients (47%) of group A and in two patients (10%) of groupB. Angina pectoris was experienced by 35 patients (61%) of groupA and by five patients (24%) of group B. The positive predictivevalue of both ST depression and angina pectoris was high (88and 93%, respectively), but the negative predictive values werelow (42 and 40%, respectively). Combining ST segment analysiswith the findings of thallium imaging significantly increasedthe diagnostic accuracy of the test. ST segment depression, angina pectoris, and thallium abnormalitieswere highly specific findings if the study population consistedof asymptomatic subjects with a low likelihood of CAD (groupC). Sensitivity for the detection of the presence of CAD increasedwith the extent of CAD for all parameters studied. Thus, STdepression and angina pectoris, alone or in combination, duringDXT have little diagnostic significance, although sensitivityis increased in patients with triple-vessel CAD. Analysis ofthe ST segment provides additional information and should thereforebe included in the overall interpretation of the test results.A marked difference in the false positive rates for all parameterswas observed between asymptomatic subjects and angiographicallynormal patients with chest pain syndromes, which can be explainedby selection bias.     

Which exercise test variables are of prognostic importance post-myocardial infarction?

The prognostic value of parameters noted on pre-discharge exercise testing was assessed in 300 survivors of acute myocardial infarction. Exercise testing was performed at a mean of 9 days post-infarction. Each patient's data were studied for the presence of ST-segment depression or elevation 0.1 mV in any of the 12 leads recorded, angina pectoris, exertional hypotension and duration of exercise. The patients were followed for a mean of 12 months and the incidence of death, reinfarction, angina pectoris, heart failure and coronary revascularization procedures was noted.

All variables studied, other than the presence of exercise-induced ST-segment elevation, were significantly associated with the occurrence of subsequent cardiac events (P < 0.001). Exercise-induced ST-segment depression identified 80% of patients who developed complications and was significantly more sensitive than any of the other variables as a prognostic marker (P < 0.05). The finding of angina pectoris, an abnormal blood pressure response or a limited exercise tolerance in association with exercise-induced ST-segment depression heightened the prognostic implications of this variable.     

Influence of exercise training soon after myocardial infarction on regional myocardial perfusion and resting left ventricular function.

There is scant information regarding the effect of exercise training begun soon after hospital discharge for myocardial infarction (MI) with respect to subsequent improvement in exercise tolerance, enhancement of regional myocardial perfusion, or left ventricular function. Accordingly, 19 post-MI patients (mean age 53 +/- 7 years) underwent treadmill exercise quantitative thallium-201 (Tl-201) scintigraphy and rest radionuclide angiography (RNA) prior to and after 12 weeks of thrice-weekly exercise training which was targeted to 70-85% of maximum exercise heart rate achieved. Training was begun at 25 +/- 3 days after hospital discharge. Eight Tl-201 scan segments were each scored from 1-6 points based upon uptake and washout criteria with 6 being the most severe defect (greater than 50% reduction in Tl-201 events with no delayed redistribution). When matched to the pretraining peak workload on exercise testing, 12 weeks of training significantly lessened heart rate (120 +/- 4 to 97 +/- 4, p less than 0.001), peak systolic blood pressure (142 +/- 6 to 129 +/- 5 mmHg, p less than 0.01), and significantly reduced double product [17.2 +/- 10.8 to 12.7 +/- 9 (x10(3), p less than 0.001]. Training was associated with a reduction of exercise-induced ST depression or angina (42 to 16%) which was not statistically significant. The mean resting by RNA ejection fraction was 50 +/- 3% prior to training and 51 +/- 3% after training. There was no significant change in overall Tl-201 defect score or the number of defect regions per patient scan comparing pre- and post-training scintigrams.(ABSTRACT TRUNCATED AT 250 WORDS)     

The Sensitivity of the Symptom Angina Pectoris as a Marker of Transient Myocardial Ischaemia in Chronic Stable Angina Pectoris

ABSTRACT Therapeutic decisions in patients with angina pectoris are traditionally based on the history reported by the patient, since objective evidence of myocardial ischaemia during daily life is often not available. In this study, ambulatory ST segment monitoring was performed in 60 patients with a history of chronic stable angina pectoris, positive exercise test and/or positive coronary angiography, and a correlation was made between the episodes of chest pain and ST segment change. The patients were grouped according to the results of exercise testing and coronary arteriography, and one group was studied with and without antianginal medication. Overall, 195 episodes of angina were noted, only 94 of which (48%) were accompanied by ST segment depression. Pain and ST segment changes were best correlated in patients with a positive exercise test, positive angiography and who were not receiving antianginal medication. In 101 episodes of chest pain, ST segment change could not be identified; in 18 (18%) there was sinus tachycardia, in 12 (12%) ventricular premature beats, and in 71 (70%) sinus rhythm solely. Thus, anginal pain appears not to be the reliable indicator of transient myocardial ischaemia as was previously thought, a finding which supports the use of objective methods in identifying episodes of transient myocardial ischaemia in daily life.