Intracoronary electrocardiogram for early detection of myocardial viability during coronary angioplasty in acute myocardial infarction.

PURPOSE: The clinical value of the intracoronary electrocardiogram (ECG) for detecting myocardial viability in acute myocardial infarction was evaluated by thallium-201 scintigraphy and left ventriculogram at the chronic stage. METHODS: Intracoronary ECGs, recorded from the tip of a guidewire during emergency coronary angioplasty, were obtained in 65 patients with reperfused anterior myocardial infarction. Further ST segment elevation of greater than 0.2 mV detected during the balloon inflation was taken as significant. The left ventricular segmental shortening was measured from left ventriculograms recorded at acute and chronic stages. The infarct area was defined as viable when a thallium uptake of more than 50% was detected on thallium-201 myocardial scintigraphy at the chronic stage. RESULTS: During emergency coronary angioplasty, significant ST segment elevation was noted in 45 patients (Group A); however, the ST segment was not significantly elevated in the other 20 patients (Group B). The infarct area of 42 patients in Group A and three patients in Group B was viable on scintigraphy. Improvement left ventricular wall motion of the infarct area was observed in 39 of the 42 patients in Group A and the three patients in Group B. Therefore, intracoronary ECG can predict reversible dysfunction with excellent sensitivity (92.9%) and specificity (73.9%). CONCLUSIONS: The myocardium within an infarct area can be regarded as viable when a further ST segment elevation occurs on intracoronary ECG during emergency coronary angioplasty. It is useful, therefore, to monitor the intracoronary ECG during coronary angioplasty balloon inflation to assess the myocardial viability of the infarct area.     

Value of the intracoronary electrocardiogram to monitor myocardial ischemia during percutaneous transluminal coronary angioplasty

To enhance detection of ischemia during percutaneous transluminal coronary angioplasty (PTCA), unipolar intracoronary electrocardiograms (ECGs) were recorded during PTCA in 25 patients from the tips of guidewires positioned distal to stenoses being dilated. Surface electrocardiographic leads chosen to reflect likely areas of reversible ischemia during PTCA were recorded simultaneously. In 21 of 29 stenoses dilated (72%), ST segment elevation and/or T wave peaking in intracoronary ECG appeared during balloon inflation and disappeared after deflation, accompanied by transient angina on 19 occasions. Two patients had transient ST segment elevation in intracoronary ECGs during PTCA without associated angina. ST changes in the surface ECG during PTCA were seen on only nine occasions (31%), always accompanied by ST segment elevation in the intracoronary ECG that appeared earlier and was of much greater magnitude. Five patients with prior myocardial infarction and aneurysm formation had fixed ST segment elevation in the intracoronary ECG unrelated to balloon inflation. Myocardial ischemia during PTCA can be detected easily with intracoronary ECGs and with greater sensitivity than that of the surface ECG. Furthermore, intracoronary ECGs may help to clarify the nature of chest pain during balloon inflation or during suspected complications.     

The value of the intracoronary electrogram for the early detection of myocardial ischaemia during coronary angioplasty.

The clinical value of intracoronary electrography for the detection of myocardia ischaemia was assessed during coronary angioplasty and compared to a standard technique of surface ECG monitoring. In 73 patients undergoing single lesion angioplasty, an intracoronary electrogram and four representative surface ECG leads were obtained. During angioplasty of the left anterior descending artery leads, I, V3, V5, V6 were recorded. For the circumflex artery leads I, aVL, aVF, V6, and for the right coronary artery leads II, III, aVF, V6 were monitored. Eight patients were excluded due to transient intraventricular conduction disturbances during balloon inflation; 65 patients remained for further analysis. Out of a total of 154 balloon inflations (35 in the circumflex, 71 in the left anterior descending and 48 in the right coronary artery), the percentage that produced a greater than or equal to 1 mm ST segment elevation, the time to the appearance of a greater than or equal to 1 mm ST segment elevation and the maximal ST segment elevation were recorded. During inflations in the circumflex artery, the respective values of these three parameters were 20%, 22.6 +/- 11.5 s and 0.37 +/- 0.80 mm in V6, the most sensitive surface lead, versus 70% (P less than 0.001), 14.4 +/- 9.6 s (P less than 0.01) and 5.82 +/- 6.35 mm (P less than 0.0001) on the intracoronary electrogram.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prediction of reversible myocardial dysfunction by positron emission tomography, low-dose dobutamine echocardiography, resting ECG, and exercise testing.

We studied different algorithms to identify patients with heart failure who could potentially benefit from revascularization. Thirty-five coronary artery bypass (graft) patients with an ejection fraction of 35 +/- 7% underwent preoperative 18F-fluoro-2-deoxyglucose positron emission tomography (PET), low-dose dobutamine echocardiography (LDDE), and exercise testing. Follow-up by echocardiography and coronary angiography was performed 6 months after coronary artery bypass grafting. The sensitivity for prediction of reversible myocardial dysfunction was highest for PET and for ST depression or angina pectoris during exercise testing (100 and 93%, p = NS), 71% for LDDE (p < 0.05 vs. PET), and 50% for resting ECG (p < 0.02 vs. PET and exercise test). The specificity did not differ between LDDE (81%), PET (67%), and resting ECG (71%), but was lowest for exercise testing (33%; p < 0.02 vs. PET, LDDE, and resting ECG). Accuracies were: PET 80%, LDDE 77%, exercise testing 62%, and resting ECG 58% (p < 0.05 vs. PET). In patients with a negative exercise test, recovery was unlikely, and further viability testing may not be needed. In patients with a positive test, recovery may occur, and additional PET or LDDE should be performed. In these cases, PET with an 18F-fluoro-deoxyglucose uptake of > or =70% as the criterion for viability yields optimum diagnostic characteristics. This strategy awaits further evaluation in larger patient populations with heart failure.     

经皮冠状动脉腔内成形术中冠状动脉内心电图的应用研究

目的　探讨冠状动脉内心电图（ＩＣ－ＥＣＧ）在经皮冠状动脉腔内成形术（ＰＴＣＡ）术中的应用。方法对４４例冠心病病人的５１支冠状动脉行ＰＴＣＡ时记录ＩＣ－ＥＣＧ和体表ＥＣＧ,分析心绞痛组、心肌梗塞溶栓再通组、溶栓未通组ＩＣ－ＥＣＧ的缺血性心电图改变情况,并与体表监护导联ＥＣＧ相比较。结果９６．１％的血管行球囊扩张时ＩＣ－ＥＣＧ有缺血性改变;心绞痛组、心肌梗塞溶栓再通组及溶栓未通组的ＩＣ－ＥＣＧ的ＳＴ段上移程度有明显差别。结论ＩＣ－ＥＣＧ比体表ＥＣＧ在反映心肌缺血方面更敏感,ＰＴ－ＣＡ时ＩＣ－ＥＣＧ的ＳＴ段变化能一定程度地反映残余心肌的成活情况。     

QT interval shortening and ST elevation in intracoronary ECG during PTCA.

Percutaneous transluminal coronary angioplasty (PTCA) can provide a unique model of transient and reversible myocardial ischemia. The aim of this study was to assess the serial changes in QT interval during elective PTCA-induced transient ischemia. The serial changes in QT interval before, during, and after PTCA of the left anterior descending artery (LAD) were measured in patients who showed ST elevation in intracoronary electrocardiogram. Twelve consecutive patients who showed ST-segment elevation during PTCA-induced ischemia anterior precordial leads of the electrocardiogram (ECG) were enrolled in the present study. Target lesions for PTCA were all in the LAD. There were six patients with angina pectoris, two with non-Q-wave infarction, and four with Q-wave myocardial infarction. During balloon inflation, QTc interval shortened in both intracoronary ECG (ic-ECG) (0.472 +/- 0.013 vs 0.436 +/- 0.014) and surface ECG (0.462 +/- 0.012 vs 0.438 +/- 0.011). However, a significant shortening of the QT interval was more rapidly observed in the ic-ECG (20 s) than in the surface ECG (40 s). We conclude that the QT interval in both ic-ECG and surface ECG becomes shortened in PTCA-induced myocardial ischemia, and that the ic-ECG might be a good probe for detecting survived viable myocardium in the infarcted zone.     

直接经皮冠状动脉腔内成形术中冠状动脉内心电图判定存活心肌的价值

目的 应用99mTc-MIBI心肌断层显像(SPECT)评价冠状动脉内心电图(IC-ECG)判定急性心肌梗死(AMI)存活心肌的价值。方法 56例急性前壁心肌梗死患者，接受了直接经皮冠状动脉腔内成形术(PTCA)，梗死相关动脉前降支(LAD)达到TIMI3级血流后IC-ECG自PTCA导引导丝尾端引出作为参照基线，在进一步球囊扩张时IC-ECG ST段再次抬高大于0．2mV时认为具有判定梗死相关部位有存活心肌的意义。测定并比较急性期及恢复期左心室梗死相关区域节段性缩短率(LVSS)与射血分数(LVEF)，梗死区域存活心肌通过恢复早期静息与硝酸甘油介入两次99mTc-MIBI SPECT量化判定。结果 4l例病人(A组)行直接PTCA时IC-ECG ST段明显抬高，15例(B组)未出现相应变化，A组INSS、INEF。在恢复期均显著大于B组，两次99mTc-MIBISPECT显示，硝酸甘油介入后显像A组梗死缺损区面积明显减少，核素放射性计数百分比亦明显增加，B组则无明显改变，说明A组梗死区域有较多存活心肌，与IC-ECT ST段抬高意义一致。结论 直接PTCA过程中可通过球囊扩张时IC-ECG ST段抬高变化初步判定梗死相关区域的心肌活性。     

吸烟量对急性心肌梗死墓碑形ST段患者临床预后的影响

目的 :探讨吸烟量对急性心肌梗死 （AMI）早期墓碑形ST段抬高患者发病年龄、临床险恶特点和心电图特征的影响。方法 :分析心电图检测AMI早期墓碑形ST段抬高患者 5 9例中不吸烟 11例 ,少量吸烟 18例 ,大量吸烟 30例的临床特点和心电图某些指标。结果 :吸烟患者占 81% ,其中大量吸烟患者占 6 3%。吸烟者AMI发病年龄提前 ,前壁或复合前壁多见 ,并发泵衰竭 ,恶性心律失常、MI扩展发生比例大 （P <0 .0 5 ）。 1周内病死率高 （P <0 .0 1） ,心电图指标PTFv1负值增大 ,QTc间期延长、ST段抬高 /振幅加大和血清肌酸激酶显著升高 （P <0 .0 5 ）均以大量吸烟居多。吸烟量越大时间越长 ,AMI病死率相对危险度越高。结论 :吸烟能影响墓碑形ST段抬高AMI患者的近期预后。     

Intracoronary electrocardiogram during coronary angioplasty.

This prospective study examines the data derived from the intracoronary electrocardiogram (ECG) (derived from the coronary guide wire) compared with that from four standard surface leads (I, II, III, and V2) in documenting myocardial ischemia during coronary angioplasty. Intracoronary and surface ECGs were simultaneously recorded in 300 consecutive patients (mean age 59 +/- 10; range 33 to 80 years; 246 males [82%] during coronary angioplasty in 368 lesions (167 left anterior descending [46%], 85 left circumflex [23%], 107 right coronary arteries [29%], and nine bypass grafts [2%]), before balloon inflation, at 1 minute of inflation, and at the end of the procedure. ST segment changes (greater than 0.1 mV) were observed in the intracoronary ECG in 306 lesions (83%) (151 left anterior descending [88%], 75 left circumflex [89%], and 80 right coronary arteries [73%]) versus in 245 lesions (67%) in the surface ECG (126 left anterior descending [73%], 43 left circumflex [47%], and 76 right coronary arteries [70%]; [p less than 0.0001]). The mean ST segment shift was 0.5 +/- 0.4 mV in intracoronary and 0.1 +/- 0.2 mV in standard leads (p less than 0.0001). ST elevation was seen in 97% of cases with intracoronary ECG changes versus in 83% with surface ECG changes. The remainder had ST depression. A total of 48 lesions (13%) did not produce ECG changes and 62 (16%) had silent ischemia. In 75 lesions (21%), ECG changes were seen only in the intracoronary ECG, compared with 14 lesions (4%) with changes only in the surface ECG (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

The role of intracoronary thrombus in unstable angina: angiographic assessment and thrombolytic therapy during ongoing anginal attacks

Intracoronary thrombus is regarded as a potentially important factor in the etiology of unstable angina, but the incidence of intracoronary thrombus in unstable angina has not been clearly defined. To determine the occurrence of intracoronary thrombus during ongoing angina pectoris, coronary angiography was performed during spontaneous ischemic attacks in 37 patients with prolonged rest angina. All patients exhibited significant (greater than 50%) stenoses of at least one major coronary artery. Of the 37 patients, 21 (57%) had intracoronary thrombus in major coronary arteries, whereas 14 (38%) had fixed narrowings without evidence of intracoronary thrombus and two exhibited coronary spasm. ST segment elevation was observed in 16 of 21 patients with thrombus and in all of the patients with coronary spasm, but all the patients with organic stable obstruction showed ST segment depression. Twenty of the 21 patients with thrombus improved after thrombolytic therapy with intracoronary injection of urokinase; obstructed arteries were reopened, or narrowings were attenuated, with relief of ischemic symptoms. In patients with fixed obstructions, the rate-pressure product during active symptoms was significantly higher than during an asymptomatic period, indicating that a transient increase in myocardial oxygen demand may contribute to the ischemic attack in these patients. A high incidence (71%) of recurrent symptoms was observed in patients with intracoronary thrombus even after successful thrombolysis, in contrast to a much lower incidence (36%) in those without intracoronary thrombus. Myocardial infarction within 4 weeks after catheterization was observed more frequently in patients with intracoronary thrombus (24%) than in those without thrombus (7%).(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical significance of exercise-induced ST-segment elevation in lead aVR and V1 in patients with chronic stable angina pectoris and strongly positive exercise test results

Electrocardiographic abnormalities in lead aVR and V1 are rarely analyzed on exercise electrocardiograms. Clinical significance of exercise-induced ST-segment changes in lead aVR and V1 during strongly positive electrocardiographic exercise test (EET) in patients with chronic stable angina pectoris remains unclear. The aim of the study was to assess the value of lead aVR and V1 on the exercise electrocardiogram for the detection of left main coronary artery stenosis (LMCAS) and its equivalent (LMCASE) in patients with chronic stable angina pectoris and the strongly positive EET result. The study group consisted of 118 consecutive patients (mean age 58.8 +/- 9.5 years, range 38-77 years), including 30 (25.4%) women. Patients were divided into three groups. In group I, 31 patients with ST elevation in lead aVR and V1, in group II 66 patients with isolated ST elevation in lead aVR, and in group III 21 patients without ST elevation in lead aVR, induced with exercise, were included. Coronary arteriography results were compared among these groups. In patients with isolated exercise-induced ST elevation in lead aVR, the prevalence of LMCAS was five times more frequent than in patients without lead aVR ST elevation (25.8% vs 4.8% p<0.05). There were no differences in the prevalence of LMCASE and multi-vessel coronary disease in the studied groups. In patients with LMCAS significant ST elevation in lead aVR during strongly positive EET were observed (0.25 +/- 0,4 mm vs 1.43 +/- 0.6 mm p = 0.003), whereas there were no significant exercise-induced electrocardiographic changes in lead V1 (0.61 +/- 0.6 mm vs 0.77 +/- 0.6 mm p = 0.08). Sensitivity of isolated exercise-induced ST elevation in lead aVR in detection of LMCAS was 85.0%, specificity - 50.0%, positive predictive value - 25.8%, negative predictive value - 94.2%, and total accuracy - 55.9%. Exercise-induced ST elevation in lead aVR on the strongly positive exercise ECG may detect LMCAS in patients with chronic stable angina pectoris.     

左主干病变心电图分析

目的分析左主干病变冠心病心绞痛患者的心电图改变。方法30例冠脉造影诊断为左主干病变的患者,对其心绞痛发作时各导联ST段的变化及临床资料进行分析。结果30例中除7例急性心肌梗死患者呈现典型心电图演变外,有20例患者ST段广泛压低(5个导联以上)。17例患者胸痛发作的心电图中可见STaVR抬高,其中13例STV1也可见抬高,但是程度均低于aVR导联。结论左主干病变引起心肌缺血的心电图改变表现为广泛导联ST段压低及aVR导联ST段抬高。     

Exercise Testing in the Detection of Severe Coronary Artery Disease

Summary: The clinical value of exercise testing in the detection of severe coronary artery disease remains undefined. This question was examined in 289 men and 45 women. The diagnosis of coronary artery disease could be reliably made without exercise testing in patients with angina pectoris which markedly restricted walking or which was accompanied by pathological Q waves on the ECG. Such patients usually had coronary artery disease involving two or three major vessels.
Exercise testing was an aid to diagnosis in patients with a normal standard ECG and chest pain suspicious of myocardial ischaemia, either mild angina or atypical. When exercise testing resulted in both angina and ST segment depression in men, coronary artery disease was present in 38 of 41 (93%) of cases. On the other hand, three vessel disease was found in only six of 100 (6%) of men whose exercise test did not evoke angina and ST segment change. A normal exercise test in a woman with suspicious chest pain and a normal ECG was associated with normal coronary arteries in 14 of 15 (93%) of cases. It may be concluded that exercise testing is of most diagnostic value in the assessment of patients with a normal standard ECG and a differential diagnosis of mild angina pectoris and atypical chest pain.     

Intracoronary ST segment evolution during primary coronary stenting predicts infarct zone recovery

In patients with acute myocardial infarction (AMI), early ST segment elevation resolution on ECG predicts myocardial reperfusion and LV recovery. Intracoronary ECG is more sensitive than surface ECG to detect regional ischemia. In patients undergoing primary percutaneous coronary intervention (PCI), we investigated if failed myocardial reperfusion, despite successful infarct vessel recanalization, could be rapidly and easily identified by intracoronary ST segment monitoring from guidewire recording. We recorded intracoronary and standard ECG during primary coronary stenting (PCI) in 50 patients with AMI (59 ± 11 years; anterior AMI in 66%). All patients had a successful PCI and underwent 2D echocardiography soon after PCI and 6 months later. Following PCI, intracoronary ST resolution ≥ 50% from baseline was documented in 39 patients (78%; group A; from 11 ± 8 to 1 ± 2 mm) but not in 11 (22%; group B; from 11 ± 8 to 8 ± 5 mm). Group A had slightly shorter ischemic time (202 ± 94 vs. 238 ± 112 min in B; P = 0.2) and smaller peak CK values (2,752 ± 2,038 vs. 4,802 ± 3,671 U/L in B; P = 0.02). After PCI, ST resolution was found on standard ECG in 34 (87%) group A and in 3 (27%) group B patients. At 6‐month follow‐up, left ventricular ejection fraction was greater in group A (47% ± 8% vs. 39% ± 8% in B; P < 0.001) with improved wall motion score index (from 2.2 ± 0.3 to 1.7 ± 0.3 in A; from 2.3 ± 0.4 to 2.1 ± 0.4 in B; P < 0.001). There were no significant differences between intracoronary and standard ECG for sensitivity (92% vs. 86%) and specificity (62% vs. 57%) to predict improved infarct zone recovery after 6 months. ST elevation resolution on intracoronary recording during PCI predicts infarct zone recovery. Monitoring ST segment evolution by intracoronary ECG allows prompt and inexpensive identification in the catheterization laboratory of those patients without myocardial reperfusion, who may require adjunctive therapeutic interventions after successful infarct vessel recanalization. Catheter Cardiovasc Interv 2005;64:53–60. © 2004 Wiley‐Liss, Inc.     

Usefulness of intracoronary isosorbide dinitrate in alleviating myocardial ischaemia during coronary balloon angioplasty.

The effect of intracoronary isosorbide dinitrate on provoked myocardial ischaemia during percutaneous transluminal coronary angioplasty (PTCA) was studied in 60 patients who had at least 1 mm electrocardiographic (ECG) ST segment deviation during a 70 s control balloon inflation period. Isosorbide dinitrate (dose 1 mg, 2 mg or 3 mg) or placebo (saline) was administered by slow intracoronary injection, and the ST segment changes recorded again during an identical dilatation period 2-4 min later. Following injection of isosorbide dinitrate, the severity of ST segment deviation decreased (1 mg -31 +/- 30%, P = 0.03; 2 mg -51 +/- 35%, P = 0.0001; 3 mg -36 +/- 32%, P = 0.002) during coronary balloon inflation, and the time until onset of 1 mm ST deviation was prolonged (1 mg +79 +/- 137%, P = 0.06; 2 mg +85 +/- 87%, P = 0.02; 3 mg +78 +/- 109%, P = 0.02). With the 3 mg dose, the time to maximum ECG change increased (+37 +/- 87%, P = 0.02). In the placebo group, there was a small decrease in the severity of ST segment deviation in patients receiving placebo (-23 +/- 32%, P = 0.03), but no change in the time to its onset or in the time to maximum ST deviation. Isosorbide dinitrate did not alter heart rate, systolic arterial pressure or the rate-pressure product at maximum ST segment change, implying that when isosorbide was administered by direct intracoronary injection, a direct cardiac effect was responsible for the major anti-ischaemic effect of the drug.(ABSTRACT TRUNCATED AT 250 WORDS)     

Optimal ECG monitoring during percutaneous transluminal coronary angioplasty of the left anterior descending artery

During percutaneous transluminal coronary angioplasty (PTCA) frontal ECG leads are routinely monitored. The detection of ST segment deviation during the procedure is important for decisions regarding guiding catheter seating and the timing of balloon inflation and deflation. ST segment deviation appears on intracoronary electrograms in the absence of changes on the surface ECG in many patients, while the reverse is true in some individuals. When a precordial lead is employed, V5 or V6 is most commonly selected. The surface ECG leads most sensitive for monitoring ischemia during left anterior descending angioplasty are not known. In nine lead surface ECGs recorded during balloon inflation, a small degree of ST segment elevation occurred in leads I, aVL, and V5. Lead V2 demonstrated an increase in ST displacement from 0.0 ± 0.03 mV to 0.29 ± 0.25 mV during coronary occlusion (p<0.01). We conclude that if V5 or V6 is used as a single precordial lead, surface ECG alterations are easily overlooked. During left anterior descending occlusion the most sensitive surface lead is V2. Optimal ECG monitoring during PTCA in some cases should involve surface lead V2 or the intracoronary lead.     

Adverse Prognosis of ST Depression on the Resting Electrocardiogram in Stable Patients Following Acute Myocardial Infarction

Background: The aim of this study was to analyze the characteristics of stable patients with resting ST segment depression on the resting electrocardiogram (ECG) following an acute ischemic event (i.e., infarction or unstable angina) to better understand its association with subsequent cardiac death and nonfatal infarction. The recent Multicenter Study of Myocardial Ischemia (MSMI) demonstrated that the resting ST segment depression had an independent prognostic value. Methods: We studied clinical features, noninvasive test results and coronary arteriography findings in 99 patients with ST depression on the resting ECG and 837 patients without ST segment depression with respect to endpoints of cardiac death and hospitalization for acute myocardial infarction or unstable angina. Results: Our results showed that patients with resting ECG ST depression were significantly older with a higher incidence of hypertension, angina, claudication, and tobacco use. ST depression on the resting ECG correlated closely with ST segment depression on the 24-hour ambulatory ECG and the exercise ECG but not with redistribution on the thallium perfusion scan. Left ventricular diastolic pressure was higher and exercise duration less in patients with ST depression. Although not achieving statistical significance, patients with ST depression did show more extensive coronary disease and a lower ejection fraction. Conclusions: ECG ST depression was associated with cardiac death and nonfatal reinfarction over the follow-up period only in patients originally admitted with an acute infarction but not in patients hospitalized for unstable angina. The reason for this appears to be an association of ST depression with increased age, the presence of hypertension, the presence of more severe coronary disease, and more extensive myocardial damage.     

Exercise Testing in the Detection of Severe Coronary Artery Disease

Summary: The clinical value of exercise testing in the detection of severe coronary artery disease remains undefined. This question was examined in 289 men and 45 women. The diagnosis of coronary artery disease could be reliably made without exercise testing in patients with angina pectoris which markedly restricted walking or which was accompanied by pathological Q waves on the ECG. Such patients usually had coronary artery disease involving two or three major vessels. Exercise testing was an aid to diagnosis in patients with a normal standard ECG and chest pain suspicious of myocardial ischaemia, either mild angina or atypical. When exercise testing resulted in both angina and ST segment depression in men, coronary artery disease was present in 38 of 41 (93%) of cases. On the other hand, three vessel disease was found in only six of 100 (6%) of men whose exercise test did not evoke angina and ST segment change. A normal exercise test in a woman with suspicious chest pain and a normal ECG was associated with normal coronary arteries in 14 of 15 (93%) of cases. It may be concluded that exercise testing is of most diagnostic value in the assessment of patients with a normal standard ECG and a differential diagnosis of mild angina pectoris and atypical chest pain.     

24-hour ECG monitoring of patients with unstable stenocardia

Twenty-four hours' Holter ECG monitoring was carried out in 100 patients with unstable angina pectoris. The monitoring done promptly upon admission demonstrated transitory ST changes that were usually accompanied by pain in 52% of patients. Painless ECG changes were detected in 11% of patients. ST depression was a common feature, whereas ST elevation was a much rarer one. Transitory ST changes occurred at similar rates in patients with different degrees of coronary arterial involvement, as evidenced coronary-angiographically. Variation in the ST segment and heart rhythm disorders were more typical in patients with poor outcomes (myocardial infarction, sudden death in hospital).     

Clinical presentation and prognosis of left main coronary artery disease in the 1980s

Clinical presentation and course were studied in 127 consecutive patients with angiographically proven left main coronary artery disease. Mean age was 62 (37-79) years. Thirteen patients (10%) had no history of chest pain, seven (5%) had atypical chest pain, and the remaining 107 (85%) typical angina pectoris. Eighty-two patients (65%) had unstable angina, 73 had suffered a myocardial infarction (MI) in the past, and 50 (68%) had post MI angina pectoris. The electrocardiogram was analysed in 102/125 patients during an episode of chest pain and also when they were without chest pain. Outside an episode of chest pain the ST segment was normal in 42 patients (32%), the T wave was normal in 50 patients (38%) and both the ST and T were normal in 33 patients (25%). During chest pain all patients had an abnormal ECG, the most frequent pattern being ST segment depression in leads V3, V4 and V5 (with maximal depression in V4), and ST segment elevation in leads V1 and aVR. The average number of leads with ST-T abnormalities was 6.4. A symptom-limited exercise test on a treadmill with 12-lead ECG monitoring was performed in 89 patients. The exercise test was abnormal in 88 patients (99%), most of whom (74 patients) were already in the first or second stage of the Bruce protocol. The most frequently observed abnormality was ST segment depression of 2 mm or more in leads V4, V5, and V6, and ST segment elevation in leads V1 and aVR. The systolic blood pressure during exercise fell or remained at the same level in 38 patients (43%).(ABSTRACT TRUNCATED AT 250 WORDS)