Exercise stress testing before and after successful multivessel percutaneous transluminal coronary angioplasty.

Controversy exists regarding the diagnostic accuracy, optimal technique, and timing of exercise testing after percutaneous coronary intervention. The objectives of the present study were to analyze variables and the power of exercise testing to predict restenosis or a new lesion, 6 months after the procedure. Eight-four coronary multi-artery diseased patients with preserved ventricular function were studied (66 males, mean age of all patients: 59 +/- 10 years). All underwent coronary angiography and exercise testing with the Bruce protocol, before and 6 months after percutaneous coronary intervention. The following parameters were measured: heart rate, blood pressure, rate-pressure product (heart rate x systolic blood pressure), presence of angina, maximal ST-segment depression, and exercise duration. On average, 2.33 lesions/patient were treated and restenosis or progression of disease occurred in 46 (55%) patients. Significant increases in systolic blood pressure (P = 0.022), rate-pressure product (P = 0.045) and exercise duration (P = 0.003) were detected after the procedure. Twenty-seven (32%) patients presented angina during the exercise test before the procedure and 16 (19%) after the procedure. The exercise test for the detection of restenosis or new lesion presented 61% sensitivity, 63% specificity, 62% accuracy, and 67 and 57% positive and negative predictive values, respectively. In patients without restenosis, the exercise duration after percutaneous coronary intervention was significantly longer (460 +/- 154 vs 381 +/- 145 s, P = 0.008). Only the exercise duration permitted us to identify patients with and without restenosis or a new lesion.

Prognostic significance of ST-T segment alterations in patients with non-Q wave myocardial infarction.

OBJECTIVE: To determine whether, among patients with non-Q wave myocardial infarction, the characteristics of the segment ST-T shifts at presentation in the diagnostic electrocardiogram can identify those with more severe coronary artery disease and predict a poor clinical outcome. DESIGN: Prospective controlled clinical trial. SETTING: Primary referral medical centre. PATIENTS: 93 patients (mean (SD) 62.0 (7.5) years) were studied: 41 with non-Q wave myocardial infarction and T wave inversion and 52 with ST segment depression. Cardiac events and mortality rates were assessed over 42 months. Age, sex, risk factors, creatinine kinase MB isoenzyme peak, and left ventricular function were comparable. RESULTS: 31 patients with T wave inversion myocardial infarction (94.6%) had total occlusion of the infarct related artery, compared with 12 patients with ST segment depression myocardial infarction (26.7%) (P < 0.05). When compared with patients with T wave inversion, patients with ST segment depression had a higher incidence of cardiac events during the first month and in the 41 subsequent months: 9.6% and 30.8% v 0% (P < 0.01) and 9.8% (P < 0.02), respectively. For the same observation periods, the mortality rates in patients with T wave inversion were 4.9% and 7.3%, and in patients with ST segment depression they were 5.8% and 9.6%, respectively. CONCLUSION: These data suggest that during a non-Q wave myocardial infarction the presence of ST segment depression is related to higher rates of short and long term cardiac events when compared with T wave inversion--possibly because of a higher incidence of residual stenosis of the infarct related artery.

Holter monitoring in Chagas' heart disease.

Electrocardiographic rhythm disturbance evaluation by Holter monitoring is increasingly becoming a useful methodologic tool for risk stratification as well as for therapeutic assessment in patients with Chagas' disease. Furthermore, late potential analyses, now being directly obtained from Holter recording has promising perspectives in enhancing identification of patients with high risk profiles for development of malignant ventricular arrhythmias. In addition, recently incorporated to Holter studies, heart rate variability analysis will certainly contribute to a better understanding of the characteristic autonomic nervous system disarray that commonly affects chagasic patients.

Signal-averaged electrocardiogram in chronic Chagas' heart disease.

UNLABELLED: The aim of the study was to register the prevalence of late potentials (LP) in patients with chronic Chagas' heart disease (CCD) and the relationship with sustained ventricular tachycardia (SVT). 192 patients (96 males), mean age 42.9 years, with CCD were studied through a Signal Averaged ECG using time domain analysis. According to presence or absence of bundle branch block (BBB) and SVT, four groups of patients were created: Group I (n = 72): without SVT (VT-) and without BBB (BBB-): Group II (n = 27): with SVT (VT+) and BBB-; Group III (n = 63): VT- and with BBB (BBB+); and Group IV (N = 30): VT+ and BBB+. The LP was admitted, with 40 Hz filter, in the groups without BBB using standard criteria of the method. In the group with BBB, the root-mean-square amplitude of the last 40 ms (RMS) < = 14 microV was considered as an indicator of LP. RESULTS: In groups I and II, LP was present in 21 (78%) of the patients with SVT and in 22 (31%) of the patients with SVT (p < 0.001), with Sensitivity (S) 78%; Specificity (SP) 70% and Accuracy (Ac) 72%. LP was present in 30 (48%) of the patients without and 20 (67%) of the patients with SVT, in groups III and IV. p = 0.066, with S = 66%; SP = 52%; and Ac = 57%. In the follow-up, there were 4 deaths unrelated to arrhythmic events, all of them did not have LP. Eight (29.6%) of the patients from group II and 4 (13%) from group IV presented recurrence of SVT and 91.6% of these patients had LP. CONCLUSIONS: LP occurred in 77.7% of patients with SVT and without BBB. In the groups with BBB, there was association of LP with SVT in 66.6% of the cases. The recurrence of SVT was patient in 21% of the cases from which 91.6% had LP.

[Prognosis of asymptomatic aortic valve stenosis evaluated with exercise test]. / Prognóstico da estenose valvar aórtica assintomática pelo teste de esforço.

PURPOSE: to evaluate the exercise test as a prognostic factor for asymptomatic patients with aortic valve stenosis. METHODS: During 60 months 70 patients with aortic valve area < or = 1 cm2 without any other heart lesion were studied. The patients underwent Dopplerechocardiograms exercise tests (considered positive in the presence of electrocardiographic changes or symptoms) and clinical follow-up in order to determine the onset of symptoms or sudden death. RESULTS: The event-free probability was 50% after 16 months of follow-up. There was no relationship between the occurrence of events and the sex or to the transvalvar gradient. However, there was a statistically significant association between the incidence of events (p = 0.0124), valvar area (p = 0.0003) and exercise test results (p = 0.0001). CONCLUSION: Patients with significant aortic stenosis even without symptoms, have a low survival rate and the exercise test is a good prognostic factor during follow-up.

[The contribution of event monitor recorder to the diagnosis of symptoms]. / Contribuição do monitor de eventos no diagnóstico de sintomas.

PURPOSE: To evaluate the contribution of the loop memory recorder in improving the diagnosis of symptoms related to cardiac arrhythmias. METHODS: The study population was 64 patients whose Holter monitorization was inconclusive as to the diagnosis of symptoms related to cardiac arrhythmias. Each wore a patient-activated ambulatory electrocardiogram device for 15 days. The ECG recording during the occurrence of symptoms were sent to the ECG receiving center by phone. RESULTS: Two patients did not conclude the study. The majority of the patients (85.5%) experienced symptoms in the fifteen days of monitorization, and in 62.2% of these patients electrocardiographic events were observed. The main symptoms experienced by these patients were: palpitation (67.7%), dizziness (32.3%), and syncope (29%). Other symptoms like breast pain, fatigue, indisposition and dyspnea were also noted in 30.6% of the patients. The main electrocardiographic disturbances observed were: sinus tachycardia (45.5%), isolated premature beats (30.3%), supraventricular tachycardia (21.2%), ventricular tachycardia (3%) and third degree AV block (3%). We also observed that the first symptomatic recording occurred mainly in the initial days of monitorization (69.4%) in the first 5 days). The percentage of diagnoses was 35.5% in patients whose Holter monitoring had been inconclusive. CONCLUSION: The cardiac loop ECG recorder therefore achieved an important incremental diagnostic yield.

[Intermittent ventricular pre-excitation in the presence of total atrioventricular block]. / Pré-excitação ventricular intermitente na presença de bloqueio atrioventricular total.

An 8 year old child suffering from asthenia and complete atrioventricular block, probably congenital. During the tread-mill test there was a sudden electrocardiogram change to a ventricular preexcitation pattern. Besides this rare association, we emphasize the importance of the autonomic balance over the accessory pathway's electrophysiological properties. The appearance of a latent accessory pathway might be a substitutive mechanism to counterbalance the serious impairment of physiologic atrioventricular conduction.

[Hypertension and complex ventricular arrhythmias. Evolution following a long-term blood pressure treatment]. / Hipertensão arterial e arritmias ventriculares complexas. Evolução após tratamento de longo prazo da pressão arterial.

PURPOSE: To evaluate the effects of long-term antihypertensive treatment in the frequency as well as in the complexity of ventricular arrhythmias in arterial hypertension. METHODS: Twenty three patients, 14 males and 11 whites, with mean age of 46 years, were submitted to 24 hours ambulatory electrocardiographic monitoring and echocardiographic studies before and 9 months after antihypertensive treatment. RESULTS: There was no significant serum potassium level alteration, but significant reductions of both systolic (from 192 +/- 29mmHg to 161 +/- 25mmHg) and diastolic (from 122 +/- 17mmHg to 99 +/- 16mmHg) blood pressure. Left ventricular percent of fiber shortening significantly increased, even though only from 26 +/- 9% to 30 +/- 9%, and end-systolic wall stress did not change at all (before 258 +/- 94 10(3) dyn/cm2, after 255 +/- 101 10(3) dyn/cm2). Left ventricular mass index showed significant but also a discrete reduction from 211 +/- 75g/m2 to 196 +/- 70g/m2. Ambulatory electrocardiographic monitoring did not show any significant decrease in neither ventricular ectopic beats nor in couplets. Non-sustained ventricular tachycardia episodes remained unchanged too. Four out of 8 patients with more than 30 ventricular ectopic beats per hour reduced it by more than 70%. On the other hand, the number of patients with couplets was reduced from 10 to 8 whilst those with non-sustained ventricular tachycardia increased from 5 to 7. Furthermore, in 7 patients reevaluated 24 months thereafter results were not expressively dissimilar. CONCLUSION: In hypertensive patients with either severe degree of left ventricular hypertrophy or myocardial dysfunction, long-term blood pressure treatment that produce no impressive changes in these abnormalities also do not modify complex ventricular arrhythmias, in spite of a great reduction in the increase blood pressure.

[Intermittent antero-medial divisional block in patients with coronary disease]. / Bloqueio divisional ântero-medial intermitente em paciente com insuficiência coronária.

We report the case of a 69 year-old male who developed congestive heart failure functional class IV (NYHA). The admission electrocardiogram (EKG) revealed sinus rhythm, PR interval of 240 ms, QRS interval of 110 ms, the QRS vector of 0 degree, Q waves from V1 to V6, tall R waves from V1 to V4 that decreased to V5 and V6. The vectocardiogram had anteriorization of the electrical forces of QRS, with vector half area in the horizontal plane at +60 degrees. After two years the patient had a myocardial infarction, the EKG at the admission had the same pattern and after two days developed important changes: enlargement of QRS interval with length of 160 ms, QRS vector of +100 degrees, R waves at D2, D3 e AVF that increase from D2 to D3, QS at D1, AVL, AVR and V1, rS at V2 and V3, R wave is notched and thickened+ at V5 and V6, that return to the initial pattern after one day. The patient progressed to death in the eighth day after infarction. This case reported a intermitent pattern of EKG that is an uncontestable proof to the existence of the left middle fascicular block.

[The electrocardiogram in endomyocardial fibrosis]. / O eletrocardiograma na endomiocardiofibrose.

PURPOSE: To detail the most common electrocardiographic findings on the endomyocardial fibrosis and to correlate with the ventricular form. METHODS: One hundred patients with endomyocardial fibrosis (68 female) with ages between 5 and 64 years old (mean 34 years). According to ventriculographic aspect the patients were divided in three groups: group I--11 patients with predominant right ventricular compromise; group II--58 patients with biventricular involvement, but not necessarily similar in intensity; group III--31 patients with predominant left ventricular compromise. RESULTS: On patients with predominant right ventricular compromise, the electrocardiographic pattern was of QRS complex of low voltage in the frontal plane, presence of incomplete right bundle block and QRS complex with low voltage and with qr or qs aspect in V1 contrasting with QRS complex of great amplitude on V2 and V3. Left anterior hemiblock, aspect of inactive area, and R waves of high voltage on left precordial leads were observed on patients with predominant left ventricular involvement. CONCLUSION: The electrocardiogram of endomyocardial fibrosis, in spite of inespecific, may help in the identification of ventricular involvement.

Detection of the viable myocardium. A perfusion scintigraphic study, before and after coronary bypass surgery in myocardial infarction patients.

OBJECTIVE: To compare single-photon-emission computed tomography (SPECT) imaging scans using 201Tl and 99mTc-MIBI in detection of viable myocardium, in regions compromised by infarction. METHODS: Thirty-two (59.3 +/- 9.8 years old and 87% male) myocardial infarction patients were studied. All had Q waves on the ECG and left ventricle ejection fraction of < 50%. They underwent coronary and left ventricle angiographies and SPECT before (including 201Tl reinjection) and after coronary artery bypass surgery (CABG). Improvement in perfusion observed after surgery was considered the gold standard for myocardial viability. RESULTS: Among 102 studied regions of the heart, there were 40 (39.2%) areas of transient perfusion defects in the conventional protocol with 201Tl and 52 (51.0%) after reinjection. Therefore, 12/62 (19.4%) more viable regions were identified by reinjection. Using 99mTc-MIBI, only 14 (13.7%) regions with transient defects were identified, all of which were seen also in 201Tl protocols. After surgery, 49 of a total of 93 regions analyzed (52.7%) were viable. Sensitivity, specificity, accuracy, positive and negative prediction values were, respectively, 201Tl SPECT scans--65.3%, 90.9%, 77.4%, 88.9% and 70.2%, reinjection protocol with 201Tl scans--81.5%, 81.8%, 81.7%, 83.3% and 80.0%, 99mTc-MIBI SPECT scans--20.4%, 90.9%, 53.8%, 71.4% and 50.6%. Logistic regression demonstrated that the reinjection protocol with 201Tl was the best predictor of viability (P < 0.001). CONCLUSION: Our data suggest the election of 201Tl for viability studies, especially when using the reinjection protocol.

[Scintigraphy of myocardial perfusion combined with pharmacologic stress with dipyridamole]. / Cintilografia de perfusão miocárdica associada ao estresse farmacológico com dipiridamol.

PURPOSE: To analyze adverse reactions (AR), hemodynamic and electrocardiographic changes and thallium scintigraphy (TS) results, during pharmacological stress with dipyridamole (SD), correlating these data to the presence and extension of coronary artery disease (CAD). METHODS: We studied 126 patients, 66 had no evidence of cardiovascular disease (G1) and 60 had critical occlusive CAD > or = 70% stenosis (G2). Most of them were male, mean age 56.5 +/- 10.9 years old. All patients were submitted to TS after receiving 0.56 mg/kg of dipyridamole intravenously (0.14 mg/min during 4 min) followed by 111MBq of thallium-chloride-201. Conventional ECG was recorded before and after SD; heart rate (HR) and arterial pressure (AP) were monitored during dipyridamole infusion. All signals and/or symptoms were observed. RESULTS: Cine-coronarography showed 22 patients (37%) with one vessel disease (VD) (G2a), 26 (46%) with two VD (G2b) and 12 (20%) with three VD (G2c). Of the 126 patients 63% did not present symptoms. Flushing (25%) and sick-headache (12%) were most frequent AR. Typical angina was reported by one G1 patient (1.5%) and six G2 patients (10%) (p < 0.05). HR increased 18.09 +/- 12.27% and 12.40 +/- 4.90%, systolic blood pressure varied -5.2 +/- 7.5% and -4.3 +/- 6.5% in G1 and G2, respectively. These parameters are not correlated to CAD presence and extension. ST depression and ectopic beats occurred in 5% and 11% of G1 patients, in 15% and 30% of G2 patients, respectively (p < 0.05). Typical angina was more common in G2a and G2b; ST changes in G2b and G2c; and arrhythmia in G2c (not significant). Sensitivity of TS associated to SD was 84%, comparable to stress exercise thallium test. CONCLUSION: TS associated to SD, a noninvasive, safe with low morbidity and few collateral effects method is an option to patients with limitations to physical exercise tests.

[Value of computerized exercise stress test in the differential diagnosis of ischemic phenomena of obstructive versus nonobstructive origin]. / Valor do teste de esforço computadorizado no diagnóstico diferencial entre fenômenos isquêmicos de origem obstrutiva e não-obstrutiva.

PURPOSE: To describe groups of patients who have obstructive and non-obstructive coronary artery disease, through computadorized exercise stress test. METHODS: The test was done in 121 patients, all male, divided into 3 groups: GN group, 50 patients with normal electrocardiographic response to exercise; GLO group, 40 patients with obstructive coronary artery disease and GNO group, 31 patients with normal coronary arteries, showing one or more of the following entities: intramural coronary traject, coronary tortuosity, slow flow, mitral valve prolapse or left ventricular hypertrophy. GLO and GNO groups presented with abnormal response of the ST segment during exercise. The quantitative variables registered by computer were particularly analyzed as follows: STL (point Y depression), slope, index and ST segment integral. The magnitude of ST vector was visually measured and quantified. The statistic study was made through ANOVA and multiples comparison by the Scheffe's method, Fisher's test, quisquare and sensibility, specificity and accuracy calculation. RESULTS: There was a significant statistic difference among the 3 groups relative to slope and index (p < 0.05). The integral variable of ST segment did not allow us to differentiate the GLO and GNO groups. In the association study between the ST vector magnitude and abnormal T loop, there was an increase in sensibility of 15% in the exercise stress test. CONCLUSION: The ST segment slope below zero values, define patients having obstructive disease, and the opposite, non-obstructive disease. Values of ST segment index lower than -2 are linked to obstructive disease and higher than -2 linked to non-obstructive. Values of ST segment lower than -7 microV. s separate individuals with normal exercise stress test from those with ischemic type response. The magnitude of ST vector equal to or lower than 0.20mV define normal vectorcardiographic response to the exercise.

[Do mitral valve components have the same predictive value in percutaneous balloon mitral valvuloplasty? Doppler echocardiography study]. / São os componentes do aparelho valvar mitral de mesmo valor preditivo na valvoplastia mitral por cateter balão? Estudo ecodopplercardiográfico.

PURPOSE: To evaluate the predictive value of mitral valve components in percutaneous balloon mitral valvuloplasty (PBMV). METHODS: 53 patients undergoing PBMV were submitted to an echocardiographic analysis of mitral valve in order to note mobility, thickness, calcification of leaflets and subvalvar apparatus (SV). Mitral valve area (VA) before and after PBMV was obtained using continuous wave Doppler. Patients were divided in group 1 (VA enhance inferior to 50%) and 2 (VA enhance equal or superior to 50%) and subgroups A (VA post PBMV inferior to 1.5 sqcm) and B (VA post PBMV equal or superior to 1.5 sqcm). Correlations between the score of each component of mitral valve and the results were established. RESULTS: Concerning to the total score, there was no significant difference between the groups and subgroups. Differences were significant when SV was analysed separately (p less than or equal to 0.001). VA average in patients with SV compromising grade 3 (1.28 +/- 0.26 sqcm) was inferior to those with grade 1 or 2 (p less than or equal to 0.001). CONCLUSION: SV has a higher predictive value in the success of PBMV.

[Study of myocardial viability by thallium-201 SPECT. Conventional redistribution versus reinjection]. / Estudo da viabilidade miocárdica através do SPECT-Tálio-201. Redistribuição convencional versus reinjeção.

PURPOSE: To verify if a third series of images acquired by reinjection thallium-201, 24h after conventional myocardial perfusion with the radioisotope, improves the identification of myocardial viability segments. METHODS: We studied 30 patients, mean age 57.7 +/- 9.4 years, with old myocardial infarction using thallium (Tl)-201 SPECT (single-photon-emission computed tomography), and we obtained 3 series of images (stress, redistribution after 4h and reinjection after 24h. Cardiac images were divided in 5 segments (apical, lateral, anterior, septal and inferior) and each one received a value by a score system according to the Tl-201 myocardial uptake (0 = normal uptake; 1 = mild hypoperfusion; 2 = moderate hypoperfusion; 3 = severe hypoperfusion or no myocardial uptake). We considered viable myocardium when the uptake of Tl-201 in the segment related to the myocardial infarction increased at least 1 point in two different axis of Tl-201 SPECT. RESULTS: Seven (23.3%) patients demonstrated increase of Tl-201 uptake only at reinjection images, showing a higher efficacy of the method. Nine (30%) patients showed persistent hypoperfusion at all series of images suggesting only fibrosis in the area related to the infarction. Fourteen (46.7%) patients showed increase of Tl-201 concentration at redistribution images; among these patients, six showed improvement of myocardial uptake at reinjection. This condition were interpreted as regional chronic ischemic process: hibernating myocardium. CONCLUSION: Tl-201 hypoperfusion at redistribution images without significant changes in relation to the stress images do not represent fibrosis at all. The reinjection technic was better than conventional redistribution in the detection of viable myocardium. This data allows a better therapeutic orientation.

[The relationship between conventional ECG and the culprit coronary artery in acute myocardial infarct]. / Relação entre o ECG convencional e a artéria coronária responsável no infarto agudo do miocárdio.

PURPOSE: To evaluate electrocardiogram (ECG) in detecting acute myocardial infarction (AMI) during the first 12 hours of symptoms and its relationship to the culprit coronary artery. METHODS: We studied 68 patients aged 55.6 (30 to 76) years, 61 males, with AMI confirmed by elevated CKMB isoenzyme and cinecoronariography (CINE). In all of them we obtained two ECG: first (i), with < 12 hours of symptoms and a second, > or = 5 days during evolution. ECG were analyzed in order to disclose up and downward ST-T segments > or = 1 mm, new Q waves > or = 0.04 s and R/S > or = 1 plus downward ST-T segment in leads V1 and V2. Then we have done correlation between these and the culprit coronary lesions at CINE. RESULTS: The culprit coronary lesions were: right coronary artery (RCA) in 16, left circumflex (LC) in 26 and left anterior descending (LAD) in 31 cases. According to the ECG, the RCA determined inferior AMI in all patients and the LC only in 62% of cases. Posterior AMI due to LC was seen in 81% of cases at ECG and, associated with lateral AMI, in 52%. Lone lateral AMI was seen in 5% and true posterior in 14% of cases, all of them due to LC. CONCLUSION: False negative ECG (i) in AMI is in fact due to LC occlusion which, frequently, causes posterior wall more then inferior wall myocardial infarction at ECG.

[Left bundle branch block analysis by body surface mapping. Comparison with electrocardiographic and vectocardiographic findings]. / Análise do bloqueio do ramo esquerdo pelo mapeamento eletrocardiográfico de superfície. Comparação com os achados eletro-vetorcardiográficos.

PURPOSE: To compare the correlation between the departure areas (DA), negative or positive, in patients whose electrocardiogram showed left bundle branch block (LBBB) and association with left ventricular hipertrophy (LVH) and myocardial infarction (MI), to the electrocardiographic (ECG) and vectocardiographic (VCG) classic criteria. METHODS: The study was carried out with 46 patients (27 males) with LBBB. These patients had hypertension (19.5%), coronary heart disease (34.7%) and 21 patients with no heart disease (45.8%). RESULTS: The statistic analysis using the Cluster method divided the patients in two groups. Group I (22 patients) showed an average rate for the DA (-2 SD) of 1091 for QRS and of 640 for ST-T. For the DA (+2 SD), the average rate was 618 for QRS and 881 for ST-T; group II (24 patients) showed an averaged for the DA (-2 SD) of 1063 for QRS and of 225 for ST-T. For the DA (+2 SD), the averaged rate was 428 for QRS and 600 for ST-T. CONCLUSION: In general the current ECG/VCG findings, can not differentiate the presence of the association of LBBB to LVH and MI. The DA of ST-T, mainly negative was the most efficient to separate the two groups and help in the differential diagnosis.