Exercise-induced S-T segment elevation in variant angina

A Practical Approach to Invasive Testing in Ischemia with No Obstructive Coronary Arteries (INOCA)

Up to 65% of women and approximately 30% of men have ischemia with no obstructive coronary artery disease (CAD; commonly known as INOCA) on invasive coronary angiography performed for stable angina. INOCA can be due to coronary microvascular dysfunction or coronary vasospasm. Despite the absence of obstructive CAD, those with INOCA have an increased risk of all-cause mortality and adverse outcomes, including recurrent angina and cardiovascular events. These patients often undergo repeat testing, including cardiac catheterization, resulting in lifetime healthcare costs that rival those for obstructive CAD. Patients with INOCA often remain undiagnosed and untreated. This review discusses the symptoms and prognosis of INOCA, offers a systematic approach to the diagnostic evaluation of these patients, and summarizes therapeutic management, including tailored therapy according to underlying pathophysiological mechanisms.

A series of unfortunate events: prinzmetal angina culminating in transmural infarction in the setting of acute gastrointestinal hemorrhage

Prinzmetal angina or vasospastic angina is a clinical phenomenon that is often transient and self-resolving. Clinically it is associated with ST elevations on the electrocardiogram, and initially it may be difficult to differentiate from an acute myocardial infarction. The vasospasm induced in this setting occurs in normal or mildly to moderately diseased vessels and can be triggered by a number of etiologies including smoking, changes in autonomic activity, or drug ingestion. While the ischemia induced is usually transient, myocardial infarction and life-threatening arrhythmias can occur in 25% of cases. We present the case of a 65-year-old female where repetitive intermittent coronary vasospasm culminated in transmural infarction in the setting of gastrointestinal bleeding. This case highlights the mortality associated with prinzmetal angina and the importance of recognizing the underlying etiology.

Clinical characteristics of patients with exercise-induced ST-segment elevation without prior myocardial infarction

BACKGROUND

Exercise-induced ST-segment elevation is a relatively uncommon problem and occurs more frequently in patients who have had a myocardial infarction. Data is limited on the characteristics of Taiwanese patients without prior myocardial infarction who develop exercise-induced ST-segment elevation.

METHODS AND RESULTS

Exercise-induced ST-segment elevation developed in 9 of 6,147 consecutive patients without myocardial infarction who underwent treadmill exercise testing at out institution over a 4-year period. The clinical and angiographic characteristics of these patients were studied. Angiographically normal coronary arteries with coronary vasospasm were found in 5 patients, hemodynamically significant coronary stenosis was found in 3 patients, and coexisting spasm in angiographically normal coronary arteries combined with hemodynamically significant coronary stenosis in the different vessel was found in 1 patient. During a median follow-up of 71 months, 2 patients with coronary vasospasm developed recurrent angina after self-discontinuation of calcium antagonists and 2 patients (1 with coronary vasospasm and 1 with hemodynamically significant coronary stenosis) died of cardiac causes before arrival at the emergency department.

CONCLUSION

Coronary vasospasm was a more common underlying pathology of exercise-induced ST-segment elevation in this Taiwanese cohort. Coronary angiography +/- intracoronary ergonovine provocation testing is necessary in these patients to identify the underlying pathology and appropriate treatment.

Giant R wave, convex ST-segment elevation, and negative T wave during exercise treadmill test

The giant R wave syndrome is characterized by giant R wave accompanied by widening of the QRS complex, marked ST segment elevation, QRS axis deviation, and the formation of monophasic QRS-ST complex with obliteration of S wave in leads facing the ischemic zone. This report describes a 65-year-old-man with variant angina who had a transient giant R wave syndrome during an exercise treadmill test. Initially, at peak exercise, there was a convex ST segment elevation ending in a negative T wave in the same (inferior) leads which showed giant R waves. Later, in the recovery period and coinciding with an amelioration of myocardial ischemia, there was a less marked increase of R wave amplitude associated with concave ST segment elevation and positive T wave in the inferolateral leads. Subsequently, a ST segment depression in the inferolateral leads preceded the ECG normalization. The patient had also a concave ST segment elevation and positive T wave in inferolateral leads during a spontaneous episode of variant angina at rest. An emergency coronary arteriography showed a dominant right coronary artery with an 80% and a 75% diameter stenosis of the middle and distal segment, respectively; the other arteries and left ventriculogram were normal. The underlying mechanisms of the different shapes of ST segment elevation and T waveform in the setting of acute transmural myocardial ischemia are discussed.

New protocol to detect coronary spastic angina without fixed stenosis

A new combined test, accelerated exercise following mild hyperventilation (HV), was examined to determine whether it is effective at detecting a positive response in patients with pharmacologically-induced coronary vasospasm and near normal coronary arteries. Fifty-eight consecutive patients who underwent both triple non-invasive spasm provocation tests and diagnostic coronary angiography were enrolled. They all had pharmacologically-induced coronary vasospasms and no significant organic stenosis. In these patients, an HV test was performed first, followed by a treadmill exercise test (TET), and finally the new combined test under no medication within 3 days. Of the 58 patients, positive responses were observed in 9 patients to the HV, in 15 to the TET, and in 35 to the newly combined test. The remaining 21 patients had negative responses although the triple sequential tests were perfomed. Thus, the sensitivities of the HV test, TET, and newly combined test were 16% (9/58), 26% (15/58), and 63% (35/56), respectively. Forty-six subjects with near normal coronary arteries and no ACh-provoked spasm served as controls. None of these subjects had positive responses to any of these three tests, and thus their specificity was all 100%. No serious or irreversible complications were seen in this study. We recommend this newly-combined protocol for the induction of coronary artery spasm in patients with vasospastic angina pectoris and without significant stenosis as a diagnostic tool.

Relationship between T-wave normalization on exercise ECG and myocardial functional recovery in patients with acute myocardial infarction

BACKGROUND

Several studies suggested that T-wave normalization (TWN) in exercise ECG indicates the presence of viable myocardium. But the clinical implication of this phenomenon in patients with acute myocardial infarction who received proper revascularization therapy was not determined. Precisely the aim of this study was to investigate the relationship between TWN in exercise ECG and myocardial functional recovery after acute myocardial infarction.

METHODS

We studied 30 acute myocardial infarction patients with negative T waves in infarct related electrocardiographic leads and who had received successful revascularization therapy. Exercise ECG was performed 10-14 days after infarct onset using Naughton protocol. Patients were divided into 2 groups according to presence (group I; n = 14) or not (group II; n = 16) of TWN in exercise ECG. Exercise parameters and coronary angiographic findings were compared between groups. Baseline and follow-up (mean 11 months) regional and global left ventricular function was analyzed by echocardiography.

RESULTS

Exercise parameters were similar between groups. There was no difference in baseline ejection fraction and wall motion score between group I and II (EF; 56 +/- 12% vs 52 +/- 11%, p = ns. WMS; 21 +/- 3 vs 23 +/- 4, p = ns) and it was improved at the tenth month by similar magnitude (group I/group II, EF% change = 12 +/- 12% vs 7 +/- 6%, p = ns, WMS% change = 6 +/- 6% vs 7 +/- 5%, p = ns). The finding of no relation between TWN and functional recovery was observed also when the patients were analysed according to infarct location and presence or absence of Q-waves.

CONCLUSION

As the exercise-induced TWN in patients with acute myocardial infarction was not related with better functional recovery of dysfunctional regional wall motion and ejection fraction, TWN does not appear to be an indicator of myocardial viability.

Usefulness of accelerated exercise following mild hyperventilation for the induction of coronary artery spasm : comparison with an acetylcholine Test

STUDY OBJECTIVES

This study was performed to compare the results of accelerated exercise following mild hyperventilation and a standard acetylcholine (ACh) test for the induction of coronary artery spasm in patients with drug-induced coronary artery spasm.

METHODS AND RESULTS

The subjects were 74 patients with angiographically confirmed coronary artery spasm who were examined using accelerated exercise (ie, exercise that was accelerated every minute according to the protocol of Bruce and Horsten) following mild hyperventilation and who were not receiving any medication. ACh was injected in incremental doses of 20 microg and 50 microg into the right coronary artery and incremental doses of 20 microg, 50 microg, and 100 microg into the left coronary artery. Positive coronary spasm was defined as > or =99% luminal narrowing. Accelerated exercise following a mild hyperventilation test was as useful for detecting evidence of ischemia as was an ACh test (48 patients [64.9%] vs 49 patients [66.2%], respectively; not significant). No difference was observed between ischemic changes on ECG as a result of the newly combined method and the occurrence of ACh-induced spasm. ACh-induced coronary vasospasm occurred in 61 patients (82.4%). In the remaining 13 patients, intracoronary administration of ergonovine provoked coronary spasms. No serious irreversible complications were detected as a result of this newly combined method.

CONCLUSIONS

The effectiveness of our newly combined procedure is equivalent to that of an ACh test to diagnose patients with coronary artery spasm.

Investigation of the most effective provocation test for patients with coronary spastic angina: usefulness of accelerated exercise following hyperventilation

This study sought to compare the clinical usefulness of the hyperventilation plus cold stress test or the hyperventilation combined with accelerated exercise test with other single tests in patients with coronary spastic angina. The study examined 24 patients (23 men, mean age 66 years) with angiographically confirmed coronary spastic angina and less than 50% stenosis. Moreover, none had spontaneous ST segment elevation before the study. Under no medication for at least 24 h prior, 4 procedures were performed from 09.00 h to 11.00 h: (i) a hyperventilation test for 5 min (HV(5)); (ii) HV(5) combined with a cold stress test for the last 2 min (HV(5)+CS(2)); (iii) a treadmill exercise test based on Bruce's protocol (TM(3)); and (iv) a treadmill exercise test accelerated at 1 min intervals according to Bruce's protocol immediately after HV(5) (HV(5)+TM(1)). The rate of appearance of chest pain and ischemia-induced ECG changes due to HV(5)+TM(1) were significantly higher than the other 3 tests. HV(5)+CS(2) was not superior to HV(5) alone. The incidence of provoked ST segment elevation due to HV(5)+TM(1) was higher than with the other 3 procedures. Thus, in patients with coronary spastic angina, no spontaneous ST segment elevation and near normal coronary arteries, HV(5)+CS(2) was no more useful than HV(5) alone. It is recommended that the newly designed HV(5)+TM(1) combination test be used for documenting evidence of ischemia in patients with coronary spastic angina, low disease activity and near normal coronary arteries.

A case of variant angina pectoris with similar findings on both rest and matched exercise thallium-201 studies

A patient with variant angina showed similar findings on both the rest and matched exercise 201Thallium (201Tl) myocardial perfusion scintigrams. The 65-year old man was admitted to hospital because of rest angina. His electrocardiogram during the attack disclosed ST segment elevation on inferior leads. However, emergency coronary arteriogram showed no fixed stenosis. Intracoronary injection of acetylcholine induced a spasm on the distal right coronary artery, but not in the left coronary artery. In the rest 201Tl study, septal perfusion was low on the early image, although partial redistribution of this site was observed on the delayed image without the appearance of chest pain or electrocardiographic ischemic change. Similary, in the 201Tl exercise study undergone 2 weeks later, septal redistribution was diagnosed because the early image had decreased septal perfusion. Both the exercise 123I-metaiodobenzylguanidine study and the rest 123I-betamethyl-p-iodophenyl-pentadecanoic acid study showed inferior abnormalities on the early and delayed images. Although a coronary spasm was not induced in the left anterior descending artery with the acetylcholine test, septal redistribution was observed on the delayed image of both the rest and exercise 201Tl studies. The mechanism of the redistribution on the rest 201Tl study was unclear.

Repolarization alternans: techniques, mechanisms, and cardiac vulnerability

Sudden cardiac death continues to be the leading cause of mortality in developed countries. Electrical alternans of the ST segment and the T wave on the surface ECG as a noninvasive marker of patients at risk is a phenomenon that was initially observed early in this century and was seen then to be associated with cardiac rhythm disturbances. Substantial evidence indicates that T wave alternans (TWA) is related to myocardial ischemic as a harbinger of malignant ventricular arrhythmias because it reflects dispersion and heterogeneity of repolarization. Recent data have demonstrated a significant correlation between TWA and vulnerability to ventricular arrhythmias in individuals with or without organic heart disease, it also predicts the results of electrophysiological testing and arrhythmia-free survival in patients with a variety of cardiac diseases. This article reviews the historical background of TWA and discusses the early experimental and recent clinical evidence implying an integral link between TWA and ischemia-induced cardiac vulnerability.

Life-threatening cardiovascular consequences of anger in patients with coronary heart disease

Anger is the affective state most commonly associated with myocardial ischemia and life-threatening arrhythmias. The scope of the problem is sizeable-at least 36,000 (2.4% of 1.5 million) heart attacks are precipitated annually in the United States by anger. The lethal cardiovascular consequences in ischemic heart disease are attributable to the unique physiology of this state, which activates high-gain central neurocircuitry and the sympathetic nervous system, leading to acute sinus tachycardia, hypertension, impaired myocardial perfusion, and a high degree of cardiac electrical instability. Exciting new tools have emerged from the fields of epidemiology, behavioral medicine, and cardiovascular physiology that offer considerable promise in accelerating our understanding of the pathophysiology of anger and in developing means to sever the link between anger and its life-threatening consequences.

Therapeutic significance of exercise-induced ST-segment elevation in patients without previous myocardial infarction

Twelve patients with exercise-induced ST-segment elevation without prior myocardial infarction, electrocardiographic evidence of left ventricular hypertrophy or left bundle branch block underwent thallium-201 tomography immediately after exercise and 4 hours later. Coronary angiography and left ventriculography were performed within an average of 8 days of exercise testing. Five patients had repeat exercise thallium-201 tomography after medical therapy or revascularization. All patients had large, reversible perfusion defects (average defect size 33.5 +/- 13%), with 11 of 12 patients having a > or = 25% stress perfusion defect. In 10 patients with atherosclerotic coronary artery disease, the average stenosis of the involved vessel was 93 +/- 9% (range 70 to 100). The electrocardiographic leads with ST-segment elevation predicted the site of reversible hypoperfusion. Two patients had extensive, reversible anterior hypoperfusion due to exercise-induced spasm of minimally stenosed left anterior descending coronary arteries. Follow-up exercise testing in 5 patients showed abolition of reversible hypoperfusion and ST changes after medical therapy or revascularization. In patients without prior myocardial infarction, exercise-induced ST-segment elevation signifies extensive, reversible hypoperfusion that can be abolished by revascularization in patients with critical coronary stenoses and by medical therapy in those with coronary vasospasm.

Ambulatory heart rate and ST-segment depression during painful and silent myocardial ischemia in chronic stable angina pectoris

The relation between heart rate and ischemic ST-segment depression was studied in 70 patients with documented obstructive coronary artery disease (CAD) and reproducible effort angina. Symptom-limited treadmill exercise testing was performed before and after a 2-week placebo period and 24-hour FM ambulatory electrocardiographic monitoring at the end of the placebo period. The means (+/- standard deviation) of the basal and placebo values for exercise time, heart rate and maximal ST-segment depression were: 6.4 +/- 2.6 minutes vs 6.9 +/- 2.8 minutes (difference not significant [NS]), 125 +/- 17 beats/min vs 125 +/- 19 beats/min (NS) and 2.3 +/- 0.8 mm vs 2.1 +/- 0.8 (NS), respectively. Ambulatory monitoring revealed 205 episodes of significant ST-segment depression (J + 80 ms; 49 episodes with more than 1 mm, 83 with more than 2 mm, 39 with more than 3 mm and 34 with more than 4 mm). Of all episodes of ST-segment depression, 130 (64%) were asymptomatic. The episodes lasted for 3 to 110 minutes. The maximal 24-hour ambulatory heart rate and ST-segment depression during ischemic episodes were expressed as a percentage of those seen during exercise-induced ischemia. When all ambulatory ischemic episodes (both symptomatic and asymptomatic) were compared with exercise-induced ischemic changes in the individual patient, there was little difference in heart rate (91 +/- 15% vs 90 +/- 18%, NS) but there was a greater magnitude of ST-segment depression (122 +/- 57% vs 104 +/- 52%, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Delayed myocardial ischemia induced by anger

The objectives of this study were to develop a reproducible behavioral model that simulates the anger state and to characterize its influence on myocardial blood flow in both the normal and compromised coronary circulations. Fourteen mongrel dogs of both sexes were studied. The animals were instrumented for the recording of electrocardiogram, arterial blood pressure, and left circumflex coronary arterial blood flow. A critical level of coronary stenosis was achieved with an adjustable occluder placed just distal to the flow probe. Anger was induced in the instrumented animals by having another dog challenge their access to food. In the absence of coronary artery stenosis, provocation of anger increased heart rate from 107 +/- 6 to 215 +/- 15 beats/min, arterial blood pressure from 95 +/- 4 to 142 +/- 5 mm Hg, and coronary blood flow from 31 +/- 5 to 72 +/- 9 ml/min. These variables returned to the preanger levels within 2 to 4 min. Induction of anger was repeated after a critical stenosis was applied to the left circumflex coronary artery. Anger increased heart rate from 112 +/- 6 to 210 +/- 16 beats/min, arterial blood pressure from 99 +/- 3 to 142 +/- 6 mm Hg, and coronary arterial flow from 23 +/- 5 to 35 +/- 7 ml/min. Within 2 to 4 min after the bout of anger, all dogs exhibited significant reductions in coronary arterial flow (35% of baseline; p less than .001), increases in coronary vascular resistance (557% of baseline; p less than .002), and ischemic ST segment changes in leads II, III, and aVF.(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise-induced ST-segment depression and elevation in the same patient. A case for mixed angina

A patient with significant left anterior descending coronary disease is presented who developed significant ST segment elevation and depression at different times under similar testing conditions. Currently proposed explanations for exercise-induced ST segment elevation are discussed. This patient likely represents a case of spasm superimposed on significant obstructive disease, so-called mixed angina.

Chest pain and electrocardiographic ST-segment elevation occurring in the recovery phase after exercise in a patient with normal coronary arteries

Exercise-induced ST-segment elevation usually occurs in patients with coronary artery disease. We report a case in which ST-segment elevation occurred during the recovery phase of exercise in a patient with normal coronary arteries.

Assessment of left ventricular function in coronary artery disease with the nuclear probe during intervention studies

The nuclear probe was used for measuring left ventricular function in 11 normal subjects and the results compared with those using a digital gammacamera. The probe was then used to measure left ventricular function in patients with coronary artery disease during dynamic exercise and stress atrial pacing. The ability of the probe to detect changes induced by glyceryl trinitrate was also evaluated in separate parallel studies. In the 11 normal subjects there was a good correlation between the left ventricular ejection fraction measured by the gammacamera and the nuclear probe both at rest and during exercise. Exercise increased this value by at least 5% in all normal subjects during measurements with both the gammacamera and the nuclear probe. The mean (SD) difference was -0.3% (2.60) at rest and 2.3% (5.02) at peak exercise. Both exercise and pacing produced angina in the patient group and the mean (SEM) value fell from 52% (3.5) to 28% (2.6) and from 46% (5.1) to 34% (3.2) respectively. Glyceryl trinitrate prolonged the exercise and pacing times, and the corresponding falls in ejection fraction were significantly reduced. The non-imaging nuclear probe is a cheap and portable instrument capable of assessing left ventricular function in patients with cardiac disease. It is designed for high count rate acquisition over a short period of time and can thus provide both beat to beat and summated left ventricular time activity curves suitable for quantitative analysis. It therefore has important advantages in the clinical setting and during controlled interventions compared with the gammacameras.

Influence of left ventricular function and severity of coronary artery disease on exercise-induced pulmonary thallium-201 uptake

Pulmonary uptake of thallium-201 during exercise was measured in 58 patients with coronary artery disease and compared with the results from 21 patients with normal coronary arteries and 5 normal volunteers. A quantitative method was used to assess the pulmonary thallium uptake relative to cardiac activity (heart/lung ratio). This ratio was calculated for exercise and for redistribution imaging. The mean exercise heart/lung ratio for the group with coronary artery disease was 1.43 +/- 0.36 SD (n = 58); and for the "normal" group was 2.76 +/- 0.41 (n = 26) (P less than 0.001). Increased pulmonary uptake after exercise in the coronary disease group was reversible (mean redistribution heart/lung = 1.96 +/- 0.37 SD; P less than 0.001). The exercise heart/lung ratio differed significantly between groups with single-, two- and three-vessel disease; patients with and without prior infarction; and patients with exercise-induced ST segment depression and elevation. Linear regression analysis between ejection fraction calculated from equilibrium radionuclide angiography at rest and the exercise heart/lung ratio in the coronary artery disease group gave the equation: exercise heart/lung = 0.857 +/- 0.014 ejection fraction for n = 58; r = 0.695; P less than 0.001. It would appear that the exercise heart/lung ratio is a simple and valuable non-invasive index which should be used as part of routine thallium scan interpretation to provide additional information on left ventricular function after exercise and as an indicator of the severity of obstructive coronary artery disease.

Acute and chronic effects of sustained action buccal nitroglycerin in severe congestive heart failure

Vasodilators, such as nitroglycerin, have been widely used in the treatment of acute and chronic heart failure for therapeutic manipulation of the venous and arterial circulations to improve left ventricular function. We have tested the efficacy of a new formulation for sustained release buccal delivery of nitroglycerin (biological life 5-6 hr) in 21 patients with severe congestive heart failure due to ischaemic cardiomyopathy using maximal treadmill exercise testing and radionuclide angiography. A single-blind placebo-controlled acute and an open chronic phase (4 weeks) of treatment were employed. The mean dose was 23.4 mg daily, and clinical assessment suggested significant improvement in 15 patients. The mean ejection fraction (placebo) of 14.1% +/- 1.6 SEM increased to 19.1% +/- 1.7 (acute) and to 21.6% +/- 1.7 (chronic treatment) (P less than 0.001; n = 16). The mean exercise time increased from 3.02 +/- 0.4 min (basal) to 5.95 +/- 0.6 min (chronic) (P less than 0.001). Segmental wall motion abnormality was shown to improve after treatment for 4 weeks. There were no major side effects. Nine patients were reassessed after 24 weeks on the same regimen; exercise time and left ventricular ejection fraction were similar to the 4-week period, thus demonstrating a sustained improvement in cardiac function and functional capacity. A worthwhile functional and objective haemodynamic improvement was demonstrated in these patients with severe chronic congestive heart failure. This mode of treatment may have useful therapeutic value in the management of patients with a wide range of ischaemic heart failure.

The relation of tooth extraction to anginal attack

This clinical study retrospectively compared the relationship of anginal attack during dental extractions with factors such as blood pressure, heart rate, rate-pressure product, and electrocardiographic findings. The anesthetic procedure produced the greatest change in the various parameters. No direct relationship could be observed between anginal attack and doses of lidocaine, epinephrine, and premedicative drug or time required for treatment.

Disappearance of exercise-induced ST-segment depression associated with transient left anterior hemiblock

To our knowledge, this is the first case reported of total disappearance of exercise-induced ST-segment depression in the presence of transient left anterior hemiblock at peak exercise. An unusual paradoxic increase in T-wave amplitude was also noticed. The significant ST-segment displacement reappeared when the transient left anterior hemiblock disappeared during the recovery phase. Based on current review, the presence of transient left anterior hemiblock during exercise seems to correlate well with the proximal left anterior descending coronary artery disease. Therefore, the presence of transient left anterior hemiblock during exercise with either normalization of exercise-induced ST-segment depression or paradoxic increase in T-wavse amplitude at peak level may be a useful end-point to stop the test for patients who do not reach 2 mm ST-segment depression or who remain asymptomatic.

Antihypertensive effects of nifedipine combined with cardioselective beta-adrenergic receptor antagonism by atenolol

The calcium-channel blocker, nifedipine, was used as additional oral therapy to beta-adrenergic receptor blockade by the cardioselective agent, atenolol, in the therapy of 31 patients with hypertension. Initial studies were directed towards control of associated angina pectoris in 15 of the patients, but no effects were found on angina except in two patients. However, arterial blood pressure was consistently reduced in all patients. Further studies on 16 patients were therefore directed towards the use of nifedipine as an antihypertensive agent in addition to atenolol and a thiazide diuretic. Nifedipine (10 mg sublingually) acutely dropped blood pressure by about 30/20 mm Hg (systolic/diastolic) within 20 minutes. Follow-up studies made after 4 to 8 weeks showed that the initial acute response to nifedipine predicted the long-term response to oral nifedipine, 10 mg twice daily. Of 31 hypertensive patients tested, only one failed to respond to nifedipine.

Reversible ischaemia of right ventricle detected by exercise thallium-201 scintigraphy

Exercise and redistribution thallium-201 imaging is commonly used for the detection and evaluation of left ventricular ischaemia and infarction. The right ventricle is frequently visualised after stress and sometimes on redistribution images. The visualisation of the right ventricle at rest is thought to be abnormal and is suggestive of pressure or volume overload of the right ventricle, either a result of pulmonary hypertension or secondary to left ventricular dysfunction. Using stress and delayed 201Tl imaging we have shown reversible left and right ventricular ischaemia and fixed left ventricular perfusion defects in two patients with multivessel coronary artery disease and left ventricular dyskinesia caused by prior myocardial infarction. Judging by the rarity of this finding as well as taking into consideration 201Tl kinetics, it is suggested that reversible right ventricular ischaemia after exercise may only be detected in patients with coronary artery disease who have severely compromised ventricular function. This finding may have therapeutic and prognostic significance.

Exercise testing in patients with variant angina: results, correlation with clinical and angiographic features and prognostic significance

Eighty-two patients with variant angina underwent a treadmill exercise test using 14 ECG leads, and 67 also underwent exercise thallium-201 scans. The test induced ST elevation in 25 patients (30%), ST depression in 21 (26%) and no ST-segment abnormality in 36 (44%). ST elevation during exercise occurred in the same ECG leads as during spontaneous attacks at rest, and was always associated with a large perfusion defect on the exercise thallium scan. In contrast, exercise-induced ST depression often did not occur in the leads that exhibited ST elevation during episodes at rest. The ST-segment response to exercise did not accurately predict coronary anatomy: Coronary stenoses greater than or equal to 70% were present in 14 of 25 patients (56%) with ST elevation, in 13 of 21 (62%) with ST depression and in 14 of 36 (39%) with no ST-segment abnormality (NS). However, the degree of disease activity did correlate with the result of the exercise test: ST elevation occurred during exercise in 11 of 14 patients who had an average of more than two spontaneous attacks per day, in 12 of 24 who had between two attacks per day and two per week, and in only two of 31 who had fewer than two attacks per week (p less than 0.005). St elevation during exercise was reproducible in five of five patients retested during an active phase of their disease, but not in three of three patients who had been angina-free for at least 1 month before the repeat test. Twelve patients wih exercise-induced ST elevation were retested during treatment with calcium antagonist drugs; in 10 of 12, ST elevation did not occur with the second test. During a mean follow-up of 20.3 +/- 14.5 months, death or myocardial infarction occurred in three of the 25 patients with ST elevation during exercise, none of 21 with ST depression and two of 36 with no ST abnormality. We conclude that in variant angina patients, the results of an exercise test correlate well with the degree of disease activity but not with coronary anatomy, and do not define a high-risk subgroup.

Exercise-induced angina provoked by aspirin administration in patients with variant angina

The effects of aspirin (4.0 g/day) given orally to eight patients with variant angina were observed. An exercise stress test performed in the morning was positive in two of seven patients during placebo administration, whereas a test performed in the afternoon at the same exercise work load resulted in negative findings. During aspirin administration, the afternoon exercise test repeatedly provoked anginal attacks associated with electrocardiographic changes (S-T segment elevation in five and S-T depression in two). Rate-pressure product at the end of the exercise test during aspirin administration was significantly lower than that during placebo administration (p less than 0.01). During aspirin administration, the frequency of angina increased markedly, and the attacks occurred not only during the night or early morning but also in the daytime in six of the eight patients. Our observations suggest that aspirin, in this large dose, reduces the capacity for exercise and provokes exercise-induced coronary arterial spasm in patients with variant angina.

S-T segment elevation and coronary spasm in response to exercise

The prevalence rate of exercise- S-T segment elevation of 0.1 mV or greater in symptomatic patients is 3.0 to 6.5 percent in most studies. S-T segment elevation is associated with a more severe degree of myocardial ischemia than depression and frequently implies a high grade coronary stenosis in the vessel that supplies the site of ischemia. Leads V4 to V6 and bipolar lead CM5 have been found to be relatively insensitive in detecting exercise-induced S-T segment elevation. The pathogenesis of S-T segment elevation is different in three clinical patient subsets reviewed. In patients afer infarction, the largest of the three subgroups, exercise-induced S-T segment elevation usually appears in leads with Q waves, is more common after anterior myocardial infarction and implies underlying akinetic of dyskinetic wall motion. Of patients with variant angina, 10 to 30 percent have during exercise S-T segment elevation that is most likely provoked by coronary arterial spasm. The natural history of variant angina is cyclic, and clinical observations and laboratory findings are dependent on particular phases in the disease process and treatment. Finally, 0.2 to 1.7 percent of symptomatic patients without infarction or variant angina have exercise-induced S-T segment elevation. Although most of the latter have fixed high grade coronary arterial stenoses at angiography, the exact pathogenetic mechanism of S-T segment shift in this patient group is not yet fully understood.