Effects of ex vivo platelet supplementation on platelet aggregability in blood samples from patients treated with acetylsalicylic acid, clopidogrel, or ticagrelor.

BACKGROUND: Transfusion of platelet concentrate is often used to treat bleeding in patients on platelet inhibitors, but little is known about its efficacy between different inhibitors. We assessed the effect of ex vivo platelet supplementation on platelet aggregability in blood samples from patients treated with acetylsalicylic acid (ASA), clopidogrel, or ticagrelor. METHODS: Platelet aggregability was investigated with multiple electrode aggregometry with adenosine diphosphate (ADP), arachidonic acid (to assess ASA-dependent aggregability), and thrombin receptor activating peptide-6 (TRAP) as activators in whole-blood samples from patients treated with ASA (n=10), ASA+clopidogrel (n=15), or ASA+ticagrelor (n=15), and from healthy controls (n=10). Aggregability was measured before and after supplementation of AB0-compatible fresh apheresis platelets (+46, +92, and +138×10(9) litre(-1)). RESULTS: Both ASA-dependent and ADP-dependent aggregability improved in a dose-dependent fashion after platelet supplementation. ASA-dependent aggregability was completely restored in all patient groups, but there was only a small improvement in ADP-dependent aggregability in patients on dual antiplatelet therapy. There was less effect of platelet supplementation on ADP- and ASA-dependent aggregability in ticagrelor-treated patients than in clopidogrel-treated patients [3.9 (95% confidence interval 1.6-6.3) vs 9.0 (5.2-12.8) AU×min (P=0.021) and 48 (36-59) vs 69 (60-78) AU×min (P=0.004), respectively, at the highest platelet dose]. CONCLUSIONS: Platelet supplementation improved platelet aggregability independently of antiplatelet therapy. The effect on ADP-dependent platelet inhibition was limited however. Reduced effect of platelet transfusion is more likely within 2 h of drug intake in patients treated with ASA+ticagrelor compared with ASA+clopidogrel.

The role of modern cardiovascular imaging in (suspected) coronary artery disease in competitive athletes.

This overview addresses different non-invasive imaging methods in diagnosing CAD before clearing the athlete for participation in sports activity. Keep in mind the risks and benefits of exercising for the competitive athlete and to use the SCORE-information as a first evaluation tool. It is essential to gather relevant information and to complement anatomical evaluations with functional evaluations. Exercise testing also has an added value in athletes as it will inform both the physician and the athlete on the aerobic fitness of the individual, a key factor in risk assessment.

Dynamic on-line vectorcardiography improves and simplifies in-hospital ischemia monitoring of patients with unstable angina.

OBJECTIVES: This study sought to validate computerized vectorcardiography against the established technique of Holter electrocardiographic (ECG) monitoring and to compare the feasibility of the two methods for monitoring patients with unstable angina pectoris. BACKGROUND: Detection of myocardial ischemic episodes is an important objective in patients admitted to the hospital for unstable angina pectoris. Standard ECG monitoring may be sufficient for detection of symptomatic episodes but will often overlook silent ischemia. Holter ECG monitoring has a higher likelihood of discovering such episodes, but analysis is time-consuming, and the results are not available on-line. METHODS: We simultaneously monitored 53 consecutive patients with unstable angina, 46 of whom had technically adequate 24-h Holter ECGs and computerized vectorcardiograms. RESULTS: The Holter tapes had a mean (+/- SD) of 15.3 +/- 10.3 h of recording with both channels technically adequate for analysis compared with 23.7 +/- 1.77 h of vectorcardiographic recording that could be analyzed (p < 0.01). Of the 15 symptomatic episodes detected by Holter ECG monitoring, 13 were also detected with dynamic vectorcardiography. In contrast, eight patients had 18 episodes of chest pain, with simultaneous ST segment changes detected by dynamic vectorcardiography; only 9 of these episodes were also detected by Holter ECG monitoring. CONCLUSIONS: Monitoring of myocardial ischemia with dynamic vectorcardiography seems to be more efficient than Holter monitoring and may have a higher sensitivity. Computerized, continuous vectorcardiography has a complete real-time capacity, allowing monitoring over prolonged periods of time, and the results are immediately available without time-consuming analysis.

Admission risk assessment by cardiac troponin T in unstable coronary artery disease: additional prognostic information from continuous ST segment monitoring. TRIM study group. Thrombin Inhibition in Myocardial Ischemia.

OBJECTIVES: We investigated whether the addition of 24 h of continuous vectorcardiography ST segment monitoring (cVST) for an early (within 24 h of the latest episode of angina) determination of cardiac troponin T (cTnT) could provide additional prognostic information in patients with unstable coronary artery disease (UCAD), i.e., unstable angina and non-Q wave myocardial infarction. BACKGROUND: Determination of cTnT at admission and cVST are individually reported to be valuable techniques for the risk assessment of patients with UCAD. METHODS: Two hundred and thirty-two patients suspected of UCAD were studied. Patients were followed for 30 days, and the occurrence of cardiac death or acute myocardial infarction (AMI) were registered. RESULTS: One ST segment episode or more (relative risk [RR] 7.43, p = 0.012), a cTnT level > or = 0.20 microg/liter (RR 3.85, p = 0.036) or prestudy medication with calcium antagonists (RR 3.31, p = 0.041) were found to carry independent prognostic information after multivariate analysis of potential risk variables. By combining a cTnT determination and subsequent cVST for 24 h, subgroups of patients at high (25.8%) (n = 31), intermediate (3.1%) (n = 65) and low risk (1.7%) (n = 117) of death or AMI could be identified. CONCLUSIONS: Twenty-four hours of cVST provides additional prognostic information to that of an early cTnT determination in patients suspected of having UCAD. The combination of biochemical and electrocardiographic methods provides powerful and accurate risk stratification in UCAD.

Long-term outcome in congenitally corrected transposition of the great arteries: a multi-institutional study.

OBJECTIVES: The purpose of this study was to determine long-term outcome in adults with congenitally corrected transposition of the great arteries (CCTGA), with particular emphasis on systemic ventricular dysfunction and congestive heart failure (CHF). BACKGROUND: Patients with CCTGA have the anatomical right ventricle as their systemic pumping chamber, with ventricular dysfunction and CHF being relatively common in older adults. METHODS: Retrospective analysis of records of 182 patients from 19 institutions were reviewed to determine current status and possible risk factors for systemic ventricular dysfunction and CHF. Factors considered included age, gender, associated cardiac defects, operative history, heart block, arrhythmias and tricuspid (i.e., systemic atrioventricular) regurgitation (TR). RESULTS: Both CHF and systemic ventricular dysfunction were common in groups with or without associated cardiac lesions. By age 45, 67% of patients with associated lesions had CHF, and 25% of patients without associated lesions had this complication. The rates of systemic ventricular dysfunction and CHF were higher with increasing age, the presence of significant associated cardiac lesions, history of arrhythmia, pacemaker implantation, prior surgery of any type, and particularly with tricuspid valvuloplasty or replacement. Aortic regurgitation (a previously unreported problem) was also relatively common in this patient population. CONCLUSIONS: Patients with CCTGA are increasingly subject to CHF with advancing age; this complication is extremely common by the fourth and fifth decades. Tricuspid (systemic atrioventricular) valvular regurgitation is strongly associated with RV (anatomical right ventricle connected to aorta in CCTGA patients; systemic ventricle in CCTGA) dysfunction and CHF; whether it is causative or a secondary complication remains speculative.

Key factors in the identification of the high-risk patient with unstable coronary artery disease: clinical findings, resting 12-lead electrocardiogram, and continuous electrocardiographic monitoring.

This article reviews a range of methods for identifying high-risk patients with unstable coronary artery disease, including clinical evaluation, the resting 12-lead electrocardiogram, continuous vectorcardiography, and a combined risk evaluation using continuous vectorcardiography and measurement of troponin-T. Clinical evaluation is not very accurate for identifying high-risk patients and modern techniques have not been fully validated in clinical trials. The combination of continuous vectorcardiography and biochemical monitoring is a very powerful method of identifying both very high- and very low-risk patients and may be increasingly used in the future.

Heparin is more effective than inogatran, a low-molecular weight thrombin inhibitor in suppressing ischemia and recurrent angina in unstable coronary disease. Thrombin Inhibition in Myocardial Ischemia (TRIM) Study Group.

Thrombin has been suggested as one of the main pharmacologic targets in unstable coronary syndromes. Electrocardiographic signs of ischemia during continuous monitoring convey prognostic information in these patients. This study assessed the anti-ischemic and clinical effects of the novel low-molecular weight thrombin inhibitor inogatran in patients with unstable angina and non-Q-wave infarction without persistent ST-segment elevation on hospital admission. Within 24 hours of the last episode of chest pain, 324 patients were randomized to 72 hours of treatment with inogatran or heparin. Continuous ST-segment analysis with computerized vectorcardiography was used to monitor ischemia for 24 hours. The occurrence of cardiac events during the first 7 days were studied and compared with ischemic episodes during the initial 24 hours. The heparin-treated patients had less episodes of ischemia (ST vector magnitude [ST-VM]: 1 +/- 2.6 vs 2 +/- 4.5, p < 0.001 and ST change vector magnitude [STC-VM]: 3 +/- 4.7 vs 6 +/- 7.6, p < 0.001) than the patients receiving inogatran. This was paralleled by a lower incidence of the combined end point of death, nonfatal infarction, refractory or recurrent angina during the first 7 days for the heparin-treated patients (35%) compared with the inogatran-treated patients (50%) (p < 0.05). Patients who had episodes of ischemia in spite of anti-ischemic therapy were at increased risk of all events studied. Heparin is more effective than inogatran in suppressing myocardial ischemia and clinical events at short-term follow-up. Continuous ST-segment monitoring with vectorcardiography identifies nonresponders who are at an increased level of risk.

Dynamic QRS-complex and ST-segment monitoring in acute myocardial infarction during recombinant tissue-type plasminogen activator therapy. The TEAHAT Study Group.

Changes of the QRS complex are the electrocardiographic expression of irreversible injury of the myocardium. In humans, the process of infarction occurs over several hours. A more rapid development of QRS changes has been reported in patients treated with thrombolytic agents. Patients with strongly suspected acute myocardial infarction (AMI) included in a placebo-controlled trial of 100 mg of recombinant tissue-type plasminogen activator (rt-PA) were monitored for 24 hours with continuous, on-line vectorcardiography. The magnitude of the QRS vector changes correlated with infarct size estimated by the maximal value of lactate dehydrogenase-1 (r = 0.69, p less than 0.001) as well as with left ventricular ejection fraction 30 days after randomization (r = 0.49, p less than 0.001). Treatment with intravenous rt-PA limited total QRS vector change but the QRS vector changes observed occurred more rapidly and reached a plateau 131 minutes earlier in patients treated with rt-PA than in those receiving placebo (p less than 0.01). A certain pattern of highly variable ST vector magnitude was identified and was associated with higher maximal lactate dehydrogenase-1 values (23 +/- 13 vs 14 +/- 10 mu kat/liter, p less than 0.001) and a tendency to higher 1-year mortality (24 vs 9%, p = 0.08) than in patients without this pattern. In patients with this pattern, rt-PA did not affect maximal lactate dehydrogenase-1, time to maximal creatine kinase and final magnitude of QRS vector change.

Esophageal dysfunction in syndrome X.

Syndrome X is defined as anginal chest pain accompanied by objective signs of ischemia on exercise testing or myocardial scintigraphy, but with angiographically "normal" coronary arteries. The etiology of this enticing syndrome is still not known. Besides myocardial ischemia, esophageal dysfunction and visceral hypersensitivity may play a role in the development of pain. The purpose of this study was to study esophageal function and visceral sensitivity in patients with syndrome X. Twenty consecutive patients with the diagnosis of syndrome X were investigated with esophageal manometry and a 24-hour pH recording. Visceral esophageal sensitivity was explored by balloon distention of the distal esophagus, as well as by instillation of acid. Twelve patients (67% of the 18 evaluated) had some abnormality on 24-hour pH monitoring; 2 had abnormal global acid exposure time (pH <4) and 7 had symptoms coincidental with episodes of pH <4. Seven patients (35%) had esophageal dysmotility including 5 with the "nutcracker" esophagus. Esophageal hypersensitivity to acid (n = 9) or distention (n = 13) was seen in 14 of the 20 patients. Eleven patients received acid suppressive therapy that resulted in amelioration of chest pain in 8 (73%). Thus, results suggest that esophageal hypersensitivity rather than gross functional abnormality is an important factor for the development of chest pain in patients with syndrome X, and that acid in the context of a hypersensitive esophagus is the main culprit. Acid suppression may ameliorate pain in a substantial proportion of patients.

Relative contributions of a single-admission 12-lead electrocardiogram and early 24-hour continuous electrocardiographic monitoring for early risk stratification in patients with unstable coronary artery disease.

Patients with unstable coronary syndromes are a heterogeneous group with varying degrees of ischemia and prognosis. The present study compares the prognostic value of a standard electrocardiogram (ECG) obtained at admission to the hospital with the information from 24-hour continuous electrocardiographic monitoring obtained immediately after admission. The admission ECGs and 24 hours of vectorcardiographic (VCG) monitoring from 308 patients admitted with unstable coronary artery disease were analyzed centrally regarding standard electrocardiographic ST-T changes, ST-vector magnitude (ST-VM), and ST change vector magnitude episodes. End points were death, acute myocardial infarction, and refractory angina pectoris within a 30-day follow-up period. ST-VM episodes (> or = 50 microV for > or = 1 minute) during VCG monitoring was the only independent predictor of death or acute myocardial infarction by multivariate analysis. ST-VM episodes during vectorcardiography was associated with a relative risk of 12.7 for having a cardiac event, hypertension was associated with a relative risk of 1.7, and ST depression on the admission ECG was associated with a relative risk of 5.7. Patients with ST depression at admission had an event rate (death or acute myocardial infarction) of 17% at 30-day follow-up. Patients without ST depression could further be risk stratified by 24 hours of VCG monitoring into a subgroup with ST-VM episodes at similar (8%) risk and a subgroup without ST-VM episodes at low (1%) risk (p = 0.00005). Continuous VCG monitoring provides important information for evaluating patients with unstable coronary artery disease. It is recommended that patients not initially estimated at high risk based on the admission ECG are referred for 24 hours of VCG monitoring for further risk stratification.

Comparison of medical care and one- and 12-month mortality of hospitalized patients with acute myocardial infarction in Minneapolis-St. Paul, Minnesota, United States of America and Göteborg, Sweden.

We compared medical care and mortality through 1-year of hospitalized acute myocardial infarction (AMI) patients in 2 large metropolitan areas in the United States and Sweden. All hospitalized AMI discharges (International Classification of Diseases, 9th revision [ICD9] codes 410) occurring among 30 to 74-year-old residents of the Minneapolis-St. Paul metropolitan area in 1990 and Göteborg, Sweden, in 1990 to 1991 were identified and their medical records examined. There were dramatic differences in medical care during the index hospitalization of AMI patients between Minneapolis-St. Paul and Göteborg. Use of thrombolytic therapy, coronary angioplasty, bypass surgery, calcium antagonists and lidocaine was more common in Minneapolis-St. Paul; beta blockers were more frequently used in Göteborg, and aspirin use was similar. Despite these large differences, neither 28-day nor 1-year mortality of hospitalized AMI patients differed significantly. The marked differences found in the early treatment of AMI between Minneapolis-St. Paul and Göteborg, combined with the negligible differences observed in short- and long-term mortality, raise questions about the most effective and efficient allocation of medical resources.

Successful repair of extensive inferior myocardial infarction with septal and free wall rupture.

A woman had severe cardiogenic shock complicating rupture of both the interventricular septum and the inferior free wall of the left ventricle. She survived with emergency surgery.

Growth hormone responses to clonidine and GRF in spontaneously hypertensive rats: neuroendocrine evidence for an enhanced responsiveness of brain alpha 2-adrenoceptors in genetical hypertension.

Clonidine induces growth hormone (GH) release in rat. According to previous investigations this effect is mediated by postsynaptic alpha 2-adrenoceptors in the hypothalamus exerting a stimulatory influence on the recently discovered GH releasing factor (GRF). In the present study it is demonstrated that spontaneously hypertensive rats (SHR) of the Wistar-Kyoto strain display enhanced GH responses to clonidine as compared to normotensive Wistar-Kyoto control rats. In contrast, the GH responses to GRF are similar in hypertensive and normotensive animals. These findings indicate that brain alpha 2-adrenoceptors are more responsive in SHR than in normotensive controls. Since the enhanced GH responses to clonidine were observed also in young, prehypertensive SHR they are probably not secondary to the elevated blood pressure. The possible importance of an altered alpha 2-adrenergic neurotransmission for the development of elevated blood pressure in SHR is discussed.

Continuation of CPR on admission to emergency department after out-of-hospital cardiac arrest. Occurrence, characteristics and outcome.

AIM: To describe the occurrence, characteristics and outcome among patients with out-of-hospital cardiac arrest who required continuation of cardiopulmonary resuscitation (CPR) on admission to the emergency department. PATIENTS: all patients in the municipality of Göteborg who suffered out-of-hospital cardiac arrest, were reached by the emergency medical service (EMS) system and in whom CPR was initiated. Period for inclusion in study: 1 Oct. 1980-31 Dec. 1992. RESULTS: of 334 out-of-hospital cardiac arrests, 2,319 (68%) were receiving on-going CPR at the time of admission to hospital. Of these, 137 patients (6%) were hospitalized alive and 28 (1.2%) could be discharged from hospital. Of these patients, 39% had a cerebral performance categories (CPC) score of 1 (no cerebral deficiency), 18% had a CPC score of 2 (moderate cerebral deficiency), 36% had a CPC score of 3 (severe cerebral deficiency) and 7% had a CPC score of 4 (coma) at discharge. Among patients discharged. 76% were alive after 1 year. CONCLUSION: among consecutive patients with out-of-hospital cardiac arrest, CPR was ongoing in 68% of them on admission to hospital. Among these patients, 6% were hospitalized alive and 1.2% were discharged from hospital. Thus, among patients with ongoing CPR on admission to hospital, survivors can be found but they are few in numbers and extensive cerebral damage is frequently present.

Optimal treatment after acute myocardial infarction in the elderly.

Elderly patients with acute myocardial infarction (AMI) more often have a previous history of cardiovascular disease than do younger patients. Furthermore, they less frequently present with typical symptoms and a typical electrocardiogram pattern. Whereas age is the most important predictor for mortality after AMI, the relationship between age and morbidity is more complex. Treatment of elderly patients with AMI is very similar to treatment of younger patients. However, the risk of intolerability to various drugs increases with age, and in many instances doses have to be adjusted. In many trials, the number of lives saved with various interventions seem, if anything, to be more numerous among the elderly. However, it should be remembered that experience with various treatments in the elderly (patients aged > 80 years) is limited. Whether experiences with people aged up to 80 years can be extrapolated to higher age groups is debatable. With increasing age, there is an increased frequency of other disabling diseases, as well as generalised atherosclerosis. It might very well be that even in the elderly it is possible to relieve symptoms and improve morbidity, even though the effects on the prognosis are likely to be less marked.

Ischaemia detected by continuous on-line vectorcardiographic monitoring predicts unfavourable outcome in patients admitted with probable unstable coronary disease.

BACKGROUND: Several methods have been suggested for risk stratification of patients with unstable coronary syndromes. However, most of these are applied several days after hospital admission. METHODS: In this study we investigated the prognostic value of continuous ST-segment and QRS vector monitoring with computerized vectorcardiography (VCG), serial measurements of creatine kinase isoenzyme MB (CK-MB), predischarge stress testing and baseline data in patients with unstable angina pectoris or non-Q-wave infarction. RESULTS: During the 24 h VCG monitoring, 56 (29%) of the 195 patients had ST-vector magnitude (ST-VM) episodes of ischaemia. Seventy-four (38%) patients had a peak CK-MB value of 6 micrograms/l or higher during the 48 h sampling period. Several discrete variables were associated with death or non-fatal infarction at 1 year of follow-up in an univariate analysis. Among these were age > or = 65 years, female sex, St depression on the admission ECG or VCG monitoring, and elevated CK-MB levels, but neither the occurrence, duration nor intensity of chest pain. With Cox's proportional hazards regression analysis, ST-VM episodes on VCG monitoring were identified as independent markers of the risk of death (P = 0.013), death or non-fatal infarction (P = 0.035) and death, non-fatal infarction, unstable angina during the first year, or revascularization before hospital discharge (P = 0.005). CONCLUSIONS: VCG monitoring of ischaemia provides independent prognostic information in unstable angina. High-risk patients can easily be identified within 24 h of hospital admission. Whether early intervention based on these criteria will result in improved prognosis remains to be shown in future studies.

Dynamic vectorcardiography for early diagnosis of acute myocardial infarction compared with 12-lead electrocardiogram. BIOMACS Study Group.

BACKGROUND: The aim of the study was to assess the diagnostic accuracy of multilead continuous vectorcardiography (VCG) for early diagnosis of acute myocardial infarction (AMI) in patients admitted to hospital because of suspicion of AMI. VCG was compared with resting 12-lead electrocardiogram (ECG) on admission. METHODS: In a multicentre study, 107 patients with chest pain (< or = 12 h) were included. The diagnosis of AMI was on the basis of World Health Organization criteria. Continuous VCG was recorded for 12-24 h and the data were evaluated blindly at 2 and 6 h of recording and after the completion of recording (12-24 h). RESULTS: AMI was diagnosed in 74 patients. The VCG recording had a diagnostic accuracy of 71% after 2 h and 86% after both the 6 h and the completed VCG recording. Compared with ECG on admission, the VCG recording after 6 h showed a significantly greater sensitivity: 86% compared with 62% (P < 0.01). In patients with non-diagnostic ECG on arrival (n = 55), VCG after 6 h had a diagnostic accuracy of 85%, a sensitivity of 82% and a specificity of 89%. CONCLUSIONS: VCG might be useful for early diagnosis of AMI, especially in patients with non-diagnostic ECG.

Continuous vectorcardiographic monitoring of ischemia during coronary angioplasty in patients with bundle-branch block.

BACKGROUND: Patients with the combination of bundle-branch block and ischemic heart disease have a poor outcome. There is no established criterion for detection of transient ischemia when bundle-branch block is present. OBJECTIVE: To elucidate vectorcardiographic changes during coronary angioplasty of patients with bundle-branch block. DESIGN AND METHODS: The QRS complex and ST-segment changes of 29 patients with bundle-branch block were studied during elective coronary angioplasty using continuous vectorcardiography. Data for the patients with bundle-branch block were compared with data for narrow-QRS-complex controls, matched for the vessel dilated, sex, and age. RESULTS: Patients with bundle-branch block were found to have more pronounced changes in the QRS-vector difference as a response to coronary occlusion than did controls. ST-vector magnitude responded in a similar way during coronary occlusion of patients with and without bundle-branch block but from different baselines. ST change-vector magnitude was found to be the most sensitive parameter for detection of ischemia in patients with bundle-branch block as well as for controls. CONCLUSION: Monitoring of transient ischemia during coronary angioplasty for patients with bundle-branch block is feasible using continuous vectorcardiography. A change in ST vector magnitude > 100 microV is suggested to indicate significant ischemia in the presence of bundle-branch block.

Clinical implications of early ST-segment variability. A report from the ASSENT 2 ST-monitoring sub-study.

OBJECTIVES: Evolution of the ST-segment during acute myocardial infarction has been shown to yield more information on prognosis than invasive measurements. By continuous ST-monitoring even very occasional dynamic changes can be analysed. We have recently suggested these variations to be of prognostic importance and possibly reflect individual abilities to deal with a vascular event. We wanted to confirm these findings. METHODS: Four hundred and forty-eight patients were included in the vectorcardiographic sub-study of the second Assessment of Safety and Efficacy of a New Thrombolytic (ASSENT 2) trial. Patients underwent 24 h of ST-monitoring. ST-trend curves were blindly analysed by two independent observers. RESULTS: ST-variability, defined as an increase of the ST-segment shift of > or = 25 microV for 2 min or more, was found to predict death, reinfarction at 30 days or urgent revascularization. By combining variability with resolution of the ST-segment elevation we could identify a high-risk group with 9.9%, and a low-risk group with only 0.8% 30-day mortality. Hypertensive patients, suggested to have an impaired secretion of endogenous t-PA, expressed significantly more ST-variability, possibly a non-invasive marker of impaired capability of dissolving and preventing thrombi. CONCLUSION: Small variations in ST-segment shift during the first 4 h of acute myocardial infarction predict worse outcome.

Transcutaneous electrical nerve stimulation in unstable angina pectoris.

BACKGROUND: Silent ischemia is a strong predictor of unfavorable outcome in unstable angina pectoris. Dynamic continuous vector cardiography provides online detection of ischemic episodes. Transcutaneous electrical nerve stimulation (TENS) has been reported to have antianginal effects in patients with severe coronary artery disease and this is associated with a reduction in myocardial ischemia. The aim of the present study was to investigate the applicability of TENS in patients with unstable angina in the coronary care unit and the effects on vector cardiographic and biochemical markers of ischemia. METHODS: Thirty patients (14 in the TENS group and 16 in a placebo group) were included in a single-blind, placebo-controlled study after being admitted to the coronary care unit. Continuous vector cardiography, leakage of cardiac enzymes and consumption of analgesics were recorded for 24 h. RESULTS: TENS was well tolerated and did not interfere with standard treatment, although vectorcardiographic recording during actual stimulation was disturbed. There was a reduction in the number of silent ischemic ST change vector magnitude episodes (P = 0.02) and their duration (P = 0.01) in the TENS-treated group, and a nonsignificant reduction in the total number of ST change vector magnitude (painful plus silent) episodes (P = 0.09) and their duration (P = 0.05) and in leakage of cardiac enzymes (P = 0.12). There were no detectable differences in terms of episodes of pain leading to stimulation or consumption of analgesics. CONCLUSIONS: TENS seems to be a safe additional treatment in unstable angina pectoris and may reduce the number of ischemic events, by mechanisms apparently unrelated to the reduction of pain.