Diagnostic and prognostic significance of exercise-induced premature ventricular complexes in men and women: a four year follow-up

Two hundred eighty patients (197 men and 83 women) with normal rest electrocardiograms and no history of prior myocardial infarction were referred for evaluation of chest pain. It was found that exercise-induced premature ventricular complexes had a lower sensitivity, specificity, positive predictive value and negative predictive value in predicting significant coronary artery disease than exercise-induced ST segment depression greater than or equal to 1 mm. The incidence of exercise-induced premature ventricular complexes was not significantly different in patients with no significant coronary artery disease, single vessel disease or multivessel disease. The site of origin of exercise-induced premature ventricular complexes was not helpful in predicting the presence or severity of coronary artery disease. At a mean follow-up period of 47.1 months, exercise-induced premature ventricular complexes did not predict coronary events (cardiac death or nonfatal myocardial infarction) in men or women.     

Evaluation of cardiac arrhythmias by exercise testing.

Exercise testing is an important noninvasive method for the exposure of arrhythmias. It provides complementary information to that obtained from ambulatory monitoring or electrophysiologic testing. By producing a number of important physiologic changes, especially activation of the sympathetic nervous system and an increase in circulating catecholamines, exercise testing provides a more complete assessment. On continuous monitoring, exercise-induced ventricular premature beats may be found in up to 34% of healthy subjects, in 60 to 70% of those with heart disease and in all patients who have experienced sustained ventricular tachycardia. Couplets or nonsustained ventricular tachycardia can be found during exercise in 0 to 6% of healthy subjects, in 15 to 31% of patients with heart disease and in 75% of those with sustained ventricular tachycardia. Even in patients with heart disease, there is only a small risk of inducing sustained ventricular tachycardia or ventricular fibrillation during exercise. The prognostic relevance of exercise-induced ventricular arrhythmias in patients with coronary artery disease or cardiomyopathy has not been clearly established. There appears to be an increased risk, however, in patients with ventricular premature beats as well as ST-segment depression or in patients with repetitive forms of ventricular arrhythmias during exercise which cannot be medically controlled. In healthy subjects, exercise-induced ventricular premature beats are of no prognostic relevance. In particular, for patients in whom arrhythmias are induced by exercise, exercise testing should be used to assess the effectiveness of antiarrhythmic drug treatment. Importantly, serious cardiac toxicity, often not observed at rest or during routine activities, may become apparent during exercise testing. It should be a standard part of arrhythmia assessment and management.     

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.     

Superior QRS axis of ventricular premature complexes: An additional criterion to enhance the sensitivity of exercise stress testing

The presence or frequency of ventricular premature complexes during exercise is not highly predictive for identifying patients with coronary artery disease. To determine whether the morphologic features or axis of exercise-induced ventricular premature complexes may increase this predictability, a study was made of 63 symptomatic patients with coronary artery disease (electrocardiographic evidence of infarction or occlusive lesions seen on coronary angiography, or both) and 10 control patients with normal coronary arteriograms. In 48 of the 63 patients with coronary artery disease the exercise-induced ventricular premature complexes had a superior frontal plane QRS axis between ?30 ° and ?120 °; in 12 the axis was between ?30 ° and +150 °, and in 2 the axis was indeterminate, between +150 ° and ?120 °. In all 10 control subjects without coronary artery disease the QRS axis of the exercise-induced ventricular premature complexes was in the normal range, between ?30 ° and +150 °. If the standard criterion of 1 mm S-T segment depression were used to predict coronary artery disease during exercise stress testing, 25 of the 63 patients with coronary artery disease would have had a normal or borderline exercise test. However, in 21 of these 25 patients the exercise-induced ventricular premature complexes had a superior axis, a criterion that would enhance the predictive sensitivity of the exercise test from 60 to 94 percent. A left bundle branch block pattern of ventricular premature complexes was not helpful in detecting patients with coronary artery disease, although a right bundle branch block pattern was infrequent in the control subjects. The occurrence of ventricular premature complexes with a superior axis during exercise testing can enhance the exercise test's sensitivity for detecting the presence of coronary artery disease, particularly when this criterion is used in patients with a nondiagnostic S-T segment response to exercise.     

Sensitivity and specificity of nuclear phase analysis versus ejection fraction in coronary artery disease

Phase standard deviation (SD) and skew characteristics of the first Fourier harmonic of equilibrium radionuclide volume curves were examined and compared during rest and during supine bicycle exercise with ejection fraction (EF) changes and the development of ischemia in 17 control subjects and in 2 groups of patients (n = 57) with coronary artery disease (CAD). Group I comprised 37 patients with CAD; IA was a subgroup of 20 patients with previous myocardial infarction (MI) and IB a subgroup of 17 patients with CAD without MI (all with coronary stenosis greater than 75% diameter narrowing). Group II comprised 20 patients with CAD who had undergone coronary bypass surgery. In the Group I subjects, phase SD was the most sensitive indicator of CAD at rest (Group I, 56%; Group IA, 70%, and Group IB, 29%), and the EF was the most sensitive indicator at submaximal (Group I, 78%; Group IA, 86%, and Group IB, 64%) and maximal exercise (Group I, 70%; Group IA, 93%, and Group IB, 53%). When phase SD and skewness were combined with EF changes, little increase in sensitivity occurred in Group I (rest 61%, submaximal exercise 88% and maximal exercise 76%). The results from Group II subgroups were qualitatively similar to those observed with Group I subgroups. These data reveal a marginally improved sensitivity for detection of CAD during supine bicycle radionuclide ventriculography when phase measurements were added to changes in global EF values.     

Incidence and significance of decreases in systolic blood pressure during graded treadmill exercise testing.

The incidence of decreases in peak systolic blood pressure during treadmill exercise was investigated in 460 patients with definite or suspected coronary heart disease. All patients were studied with coronary cineangiography. Exercise was continued to one of the following end points: chest pain, 85 to 90 percent of the patient's age-predicted maximal heart rate, ventricular tachycardia or a sustained decrease of 10 mm Hg or more below the peak level of systolic blood pressure. Twenty-two patients with 75 percent or greater stenosis of one or more major coronary arteries manifested a decrease in systolic pressure 10 mm Hg or more during exercise. These included 15 (17 percent) of 88 patients with three vessel, 7 (7 percent) of 101 with two vessel and 0 of 90 with single vessel disease. The decrease in pressure was reproducible in the seven patients who underwent a second exercise test before alteration of therapy; this decrease was abolished in the six patients who exercised again after coronary bypass graft surgery.A decrease in systolic pressure of 10 mm Hg or more also occurred during exercise testing in 3 of 23 patients with noncoronary organic heart disease; all 3 had an obstructive cardlomyopathy that had not been suspected clinically. Only 1 of 158 subjects with chest pain and no demonstrable heart disease had a decrease in systolic blood pressure with exercise. Declines in blood pressure were not observed during 650 maximal exercise tests performed on 560 clinically normal men.In conclusion, if one excludes subjects with cardiomyopathy or significant heart valve disease, a sustained exercise-induced decrease in peak systolic blood pressure of 10 mm Hg or more is a highly specific sign of multiple vessel coronary artery disease. This phenomenon is best explained by acute left ventricular pump failure secondary to extensive myocardial ischemia.     

Clinical significance of exercise-induced silent myocardial ischemia in patients with coronary artery disease

Exercise-induced silent myocardial ischemia is a frequent feature in patients with coronary artery disease. The purpose of this study was to compare the clinical and angiographic characteristics of 269 patients who complained of chest pain during an exercise test (group I) with those of 204 who developed exercise-induced silent myocardial ischemia (group II). Group I patients more frequently had anginal symptoms of class III and IV of the Canadian Cardiovascular Society than did group II patients, who had milder symptoms (p less than 0.001). The only angiographic difference observed between the two groups was a slightly but significantly higher left ventricular end-diastolic pressure in group II patients (p less than 0.05), who also showed a longer exercise duration (p less than 0.01) with a higher heart rate-systolic pressure product (p less than 0.01) and more pronounced ST segment depression at peak exercise (p less than 0.001). Moreover, ventricular ectopic beats during exercise were more frequently observed in group II patients (p less than 0.05). Coronary bypass surgery was performed in 45% of patients of group I and in 24% of patients of group II (p less than 0.05). Survival curves of medically treated patients did not show any statistically significant difference between the two groups. Thus, although patients with a defective anginal warning system may have more pronounced signs of myocardial ischemia and a greater incidence of ventricular arrhythmias during exercise, their long-term prognosis is not different from that of patients who are stopped by angina from the activity that is inducing myocardial ischemia.     

Relation between the site of origin of ventricular premature complexes and the presence and severity of coronary artery disease

The clinical implications of ventricular premature complexes in patients with coronary heart disease have received increasing interest. It has been suggested that ventricular premature complexes of right ventricular origin have more benign implications than those that originate from the left ventricle. To define more precisely the relation between the site of origin of ventricular premature complexes and the presence and severity of coronary heart disease in patients with a chest pain syndrome, 39 patients with ventricular premature complexes of right or left ventricular contour who were undergoing cardiac catheterization and coronary arteriography for evaluation of chest discomfort were studied. Ninteen patients had left and 17 had right ventricular premature complexes and 3 had both. Of the 19 with left ventricular premature complexes, 15 had coronary artery disease (12 with two or three vessel obstruction and 3 with single vessel obstruction). Four had normal cardiac catheterization studies. Twelve patients had asynergy on ventriculography. The 17 patients with right ventricular premature complexes had similar angiographic findings. Eleven of the 17 had coronary artery disease (8 with triple vessel disease and 3 with isolated obstruction of the left anterior descending coronary artery). Six had normal arteries. Eight of the 11 with coronary artery disease and right ventricular premature complexes also had asynergy. All three patients with both left and right ventricular premature complexes had coronary obstructive disease. These findings indicate that in patients with a chest pain syndrome there is no relation between the site of origin of ventricular premature complexes and either the prevalence or severity of coronary artery disease.     

Silent myocardial ischemia after percutaneous transluminal coronary angioplasty and its prognostic significance.

A cohort of 175 patients who underwent successful percutaneous transluminal coronary angioplasty (PTCA) were subjected to a treadmill exercise test to determine the prognostic significance of silent and symptomatic myocardial ischemia during the follow-up (average 11.7 months). The cardiac events during the follow-up were defined as cardiac death, nonfatal myocardial infarction, class III angina, and need for repeat angioplasty or coronary artery bypass surgery. During exercise, 39 patients (22%) had abnormal exercise-induced ST depression without chest pain (Group I). A group of 22 patients (13%) had both exercise-induced chest pain and ST-segment depression (Group II), and 114 patients (65%) had normal exercise test and no chest pain (Group III). The groups were similar in sex distribution, history of previous myocardial infarction, distribution of vessel disease, and presence of left ventricular dysfunction. Group III included more patients with complete revascularization. Follow-up data revealed that cardiac event rates in Groups I and II were significantly higher than in Group III (41%, 41%, vs. 16%) (p less than 0.01). The event rates in Groups I and II with multivessel angioplasty also were significantly higher than in Group III (58%, 61%, vs. 21%) (p less than 0.01). Exercise-induced silent myocardial ischemia is frequently seen early after successful PTCA and is more prevalent in patients undergoing multivessel angioplasty and incomplete revascularization. Both silent and symptomatic ischemia early after PTCA are predictors of an unfavorable prognosis.     

Hyperkinetic ventricular arrhythmias in very elderly people with and without cardiac disease. Correlation with left ventricular echocardiographic parameters

BACKGROUND: Morphological and functional changes induced by aging can hamper a clear distinction between pathological or paraphysiological phenomena in very old people. The incidence of hyperkinetic ventricular arrhythmias, for example, progressively increases in the elderly, even in the absence of overt cardiac disease. METHODS: One-hundred fifty-two clinically stable patients older than 80 years, submitted within 15 days to clinical evaluation, 24-hour continuous ambulatory ECG monitoring and echo Doppler examination, in the absence of antiarrhythmic treatment, were retrospectively selected in order to evaluate the incidence of ventricular arrhythmias, in patients with and without significant heart disease. The further aim of the study was to correlate the number of arrhythmias with left ventricular morphological and functional parameters, echocardiographically assessed. From the initial population, 80 patients (41 males, age 83 +/- 3 years) had significant heart disease (ischemic, hypertensive or valvular): Group I. Seventy-two patients (30 males, age 83 +/- 3 years) had no clinical or instrumental signs of heart disease: Group II. RESULTS: Considering echocardiographic data, Group I patients had a significantly higher left ventricular end-diastolic diameter (52 +/- 6 mm vs 47 +/- 4 mm, p < 0.01), lower ejection fraction (57 +/- 10% vs 64 +/- 6%, p < 0.01) and higher mass (275 +/- 84 g vs 208 +/- 46 g, p < 0.01), when compared with Group II. From ECG monitoring data, significant differences between the two groups were recorded in the incidence of premature ventricular beats per hour (79 +/- 163 vs 15 +/- 34, Group I vs Group II, p < 0.01) and presence of complex phenomena (couplets, triplets and runs: 51% vs 22%, p < 0.01). In old patients with documented cardiac disease a significant correlation was present between premature ventricular beats incidence and left ventricular end diastolic diameter (r = 0.39, p < 0.05) and left ventricular ejection fraction (r = 0.40, p < 0.05), while in patients without heart disease, no significant correlation was found between incidence of premature ventricular beats and echocardiographic morpho-functional parameters. CONCLUSIONS: In conclusion, hyperkinetic ventricular arrhythmias are globally frequent in old persons of very advanced age (more than 80 years), but, also in this subset, a significant distinction in terms of incidence and severity of arrhythmias is present between subjects with and without cardiac disease. A significant correlation between incidence of premature beats and non-invasive morpho-functional left ventricular parameters is present only for patients with overt heart disease.     

Exercise testing in the assessment of ventricular arrhythmias (author's transl)

During exercise, ventricular arrhythmias may be observed in 50% of healthy subjects and up to 85% of patients with heart disease. For the quantitative as well as qualitative assessment of ventricular arrhythmias, continuous ECG (Holter) monitoring is superior to the Exercise ECG. Both methods together render a 10% increase in sensitivity over that achieved through the use of one method only. In patients with repeated ventricular tachycardias, assessment through electrical stimulation is more preferable than the use of the exercise ECG or continuous ECG monitoring. In patients with coronary artery disease, ventricular arrhythmias during exercise, depending on their incidence and complexity, may indicate a two to eight-fold increase in the likelihood of cardiac death. The reproducibility of ventricular arrhythmias during repeated exercise testing is reported between 30 and 77%. Thus, in the individual patient, the complete absence of an exercise-induced arrhythmia during treatment does not permit differentiation between therapeutic effect and spontaneous variability. Accordingly, the exercise ECG is generally not an adequate method for assessment of antiarrhythmic treatment.     

Idiopathic ventricular arrhythmia in children. Apropos of 24 cases

The severity and prognosis of idiopathic ventricular arrhythmias in childhood were studied in 24 patients (12 boys, 12 girls) with an average age of 8 years at the time of diagnosis of the arrhythmia. Investigations included clinical assessment and analysis of basal ECG (morphology of the arrhythmias) and dynamic recordings (Holter and exercise stress testing). The clinical course was followed for an average of 3.8 years. The patients were classified in two groups: monomorphic arrhythmias (Group I) and polymorphic arrhythmias (Group II). Group I was divided into 4 subgroups: isolated ventricular extrasystoles (IA), 11 patients; ventricular extrasystoles with bursts of ventricular tachycardia (IB), 6 patients; sustained ventricular tachycardia without intercritical extrasystoles (IC), 1 patient; accelerated idioventricular rhythm (ID), 2 patients. Subgroups IA, IB and ID were characterised by the absence of symptoms, the disappearance of the arrhythmia on exercise, the decreased efficacy of antiarrhythmic drugs and an excellent prognosis. Therapeutic abstention was the rule in these patients. Patients in Group IC were characterised by the variability of their symptoms, the absence of exercise induced arrhythmias, the need for treatment in most cases and a good long-term prognosis. Group II was divided into 2 subgroups: adrenergic polymorphic ventricular tachycardia (IIA), 2 patients, and non-adrenergic polymorphic ventricular tachycardia (IIB), 2 patients. Patients in Subgroup IIA were characterised by syncope on exercise or emotion, the need for betablocker therapy which considerably improved the patients symptoms but which did not usually prevent sudden death.(ABSTRACT TRUNCATED AT 250 WORDS)     

The predictive value of anginal chest pain as an indicator of coronary disease during exercise testing

To determine the significance of anginal chest pain during exercise testing, a series of 302 patients undergoing coronary arteriography with exercise testing was reviewed. Of the 302 patients, 85 had ischemic ECG changes and chest pain (Group I); 87 patients had ischemic ECG changes but no chest pain (Group II); 25 patients had chest pain but no ischemic ECG changes (Group III); 105 patients had neither chest pain nor ischemic ECG changes (Group IV). Coronary artery disease was present in 95 per cent of Group I, 75 per cent of Group II, 72 per cent of Group III, and 28 per cent of Group IV. Of those patients with coronary disease, multiple vessels were involved in 94 per cent of Group I, 51 per cent of Group II, 67 per cent of Group III, and 21 per cent of Group IV. The predictive value for presence and extent of coronary disease showed Group I > Groups II and III > Group IV (p < 0.025). We conclude that (1) anginal chest pain during exercise testing predicts the presence and extent of coronary disease more accurately than its absence; (2) the presence of chest pain even without an ischemic ECG response during exercise testing appears to be as predictive of coronary disease as an ischemic ECG response alone; and (3) the combination of anginal chest pain during exercise testing and an ischemic ECG response is highly predictive of multivessel coronary artery disease.     

Statin Use and Ventricular Arrhythmias During Clinical Treadmill Testing

Background: Premature ventricular complexes (PVCs) during exercise are associated with adverse prognosis, particularly in patients with intermediate treadmill test findings. Statin use reduces the incidence of resting ventricular arrhythmias in patients with coronary artery disease; however, the relationship between statin use and exercise-induced ventricular arrhythmias has not been investigated.
Methods and Results: We evaluated the association between statin use and PVCs in 1,847 heart-failure-free patients (mean age 58, 95% male) undergoing clinical exercise treadmill testing between 1997 and 2004 in the VA Palo Alto Health Care System. PVCs were quantified in beats per minute and frequent PVCs were defined as PVC rates greater than the median value (0.43 and 0.60 PVCs per minute for exercise and recovery, respectively). Propensity-adjusted logistic regression was used to evaluate the odds of developing PVCs during exercise and recovery periods associated with statin use. There were 431 subjects who developed frequent PVCs during exercise and 284 subjects had frequent recovery PVCs. After propensity score adjustment, subjects treated with statins (n = 145) had 42% lower odds of developing frequent PVCs during exercise (odds ratio [OR] 0.58, 95% confidence interval [CI] 0.37–0.93) and 44% lower odds of developing frequent PVCs during recovery (OR 0.56, 95% CI 0.30–0.94). These effects were not modified by age, prior coronary disease, hypercholesterolemia, exercise-induced angina, or exercise capacity.
Conclusions: Statin use was associated with reduced odds of frequent PVCs during and after clinical exercise testing in a manner independent of associations with coronary disease or ischemia in our study population.     

活动平板运动试验诱发冠心病心律失常

目的 探讨活动平板运动试验诱导冠心病（ＣＨＤ）心律失常的临床特点。方法 使用ＭａｒｑｕｔｔｅＣＡＳＥ１６系统按Ｂｒｕｃｅ方案对３４例ＣＨＤ患者进行活动平板运动试验,并分析心电图记录到的心律失常发生率,发生时间,类型及缺血范围,ＣＨＤ类例,射血分数与心律失常发生的关系。结果 活动平板运动试验诱发ＣＨＤ心律失常的发生率为８０％（２７／３４）,以室性过速性心律失常多见,心律失常的发生随运动负荷增加而增加     

Exercise-induced polymorphic ventricular tachycardia in adults without structural heart disease

Patients with catecholaminergic polymorphic ventricular tachycardia present at a young age with exercise-induced ventricular arrhythmias (VAs) and may have a positive family history. We describe 8 patients who presented with exercise-induced symptoms as adults, have a negative family history, and responded to beta-blocker therapy. The study evaluated exercise treadmill electrocardiographic data from patients referred for exercise-induced VA. Inclusion criteria consisted of development of bidirectional, pleomorphic, or polymorphic ventricular tachycardia with exercise, adult age at first onset, negative family history, and no evidence of structural heart disease. We correlated VA configurations with respect to heart rate before and after beta-blocker therapy. Patients displayed a pattern of increasing ventricular complexity with increasing heart rate. The appropriate beta blocker (n = 7) or calcium channel blocker (n = 1) was defined as the dose that resulted in control of symptoms. Three patients showed suppression of VA with sinus tachycardia at peak heart rate. Six patients had decreased VA defined as absence of higher complexity arrhythmias. With drug therapy, average heart rate associated with premature ventricular complex couplets/triplets increased, whereas duration and complexity of premature ventricular complexes decreased. One patient had an automatic implantable cardiac defibrillator placed but has had no discharges from the device since starting the appropriate beta blocker. In conclusion, these patients appear to respond well to beta-blocker or calcium channel blocker therapy with decreased ectopic complexity and an increased heart rate threshold for inducing VA.     

Noninvasive assessment of ventricular arrhythmias in clinical practice: prognostic implications

Frequency and complexity of ventricular arrhythmias increases with age and increasing severity of heart disease. However, fatal ventricular fibrillation occurs frequently in the absence of symptomatic warning arrhythmias. Several classifications of ventricular arrhythmias are discussed. The morphology of ventricular premature complexes (VPC), their frequency and complexity at rest, during ordinary activity, or after exercise do not influence life expectancy of subjects without heart disease, nor in those with coronary artery disease with no history of myocardial infarction. In the survivors of myocardial infarction, the frequency and "complexity" of ventricular arrhythmias appears to be an independent risk factor for sudden and nonsudden cardiac death. However, the low specificity and predictive value of ventricular arrhythmias makes their assessment difficult for practical purposes. The prognosis of most patients with ventricular arrhythmias is determined predominantly by the condition of the heart. "Complex" arrhythmias at rest and during exercise do not appear to worsen prognosis and life expectancy in individuals without heart disease. Ambulatory electrocardiographic monitoring has serious limitations as a guide for clinical decision making. Ventricular tachycardias in patients with coronary artery disease are not strictly related to the frequency and "complexity" of ventricular premature complex, but correlate with the presence of ventricular aneurysms, poor ventricular function and late potentials in the signal-averaged high frequency electrocardiogram. Recording of such late potentials is a new and promising noninvasive technique for identification of patients with serious arrhythmias but the sensitivity and specificity of this method remains to be established.     

The effect of acebutolol on cardiac arrhythmias in patients with chronic coronary artery disease

The effect of the beta-blocking drug acebutolol on the severity of cardiac arrhythmias and the incidence of exercise-induced arrhythmias was studied in 15 patients with chronic coronary artery disease using ambulatory Holter monitoring and bicycle ergometry. We found a significantly lower grading of arrhythmias both on long-term ECGs and during and after exercise. Furthermore, there was a significant decrease in the incidence of VPBs during and after exercise (18.15 +/- 7.7 on placebo vs. 3.46 +/- 1.7 on acebutolol). It is concluded that acebutolol favorably influences the incidence and severity of ventricular arrhythmias in patients with chronic coronary artery disease.     

Ventricular arrhythmias during exercise testing: mechanism, response to coronary bypass surgery and prognostic significance

To investigate the determinants and prognostic significance of ventricular arrhythmias during exercise testing, 86 patients with such arrhythmias were identified from a consecutive series of 446 patients who underwent treadmill exercise testing and cardiac catheterization. The prevalence of these arrhythmias was 19% in the total group but increased to 30% in the 120 patients with 3-vessel or left main coronary artery disease. Patients with exercise-induced arrhythmias were more likely to have 3-vessel or left main coronary artery disease, a lower resting ejection fraction, greater than or equal to 2 mm of ischemic ST depression and more severe segmental wall motion abnormalities than patients without this finding (p less than 0.05). Repeat exercise testing in 22 patients with exercise-induced arrhythmias after coronary bypass surgery revealed that persistence of these arrhythmias was associated with either severe wall motion abnormalities preoperatively or residual ischemic ST depression during the post-operative exercise testing. At a mean follow-up period of 5.3 years, the presence of exercise-induced ventricular arrhythmias was not associated with increased cardiac mortality in the medically treated patients.     

Exercise-induced arrhythmias in diuretic-treated patients with uncomplicated systemic hypertension

Although hypertensive patients have been shown to have a higher prevalence of arrhythmias during ambulatory monitoring when treated with diuretic drugs than when untreated, the effects of maximal aerobic stress on arrhythmia frequency in such patients is unknown. The incidence of arrhythmias during graded maximal treadmill exercise in a group of 68 subjects with mild, clinically uncomplicated systemic hypertension treated chronically with diuretics alone for a median of 4.5 years was compared with that in an age-matched normotensive control group. The prevalence of exercise-induced arrhythmias was higher in the group treated with diuretics than in the control group, 57% vs 38% (p less than 0.05). This difference was entirely due to the higher incidence of isolated atrial or ventricular premature complexes in the diuretic-treated patients, 44% vs 26% (p less than 0.05). There was no difference in the incidence of frequent (more than 10% of beats) or complex supraventricular or ventricular premature complexes between the diuretic-treated and control groups. Within the diuretic group, no difference in the incidence of simple or complex arrhythmia was found between men and women, between those with and those without rest or exercise-induced electrocardiographic abnormalities or between those with a serum potassium level of less than 3.7 mEq/liter vs those with a level of 3.7 mEq/liter or greater. Thus, patients with uncomplicated hypertension treated with chronic diuretic monotherapy do not appear to be at increased risk for major arrhythmias during aerobic exercise.