[Incomplete left branch block associated with myocardial infarct. Experimental electro-vectorcardiography].
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Animals↗
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[The contribution of vectorcardiography to the diagnosis of delta waves of various etiologies].
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Arrhythmias, Cardiac↗
[Topographic diagnosis of true posterior infarction. Comparison of the vectorcardiogram and myocardial scintigraphy].
The aims of this comparative study by vectorcardiography and myocardial scintigraphy in the topographical analysis of primary inferior and/or posterior wall infarction, were: to obtain data confirming the value of identifying true posterior wall infarction; to confirm the diagnostic value of vectorcardiography in this condition. The patients in this retrospective study were admitted to hospital for primary inferior and/or posterior wall infarction and underwent vectorcardiography and myocardial scintigraphy either with Thallium 201 (137 patients) or 99m Technetium (88 patients) in the acute phase. The scintigraphies of all patients included showed hypofixation compatible with inferior and/or posterior infarction as this was used as the topographical reference. The results of vectorcardiography and myocardial scintigraphy were concordant in 164 of the 225 patients (72.8%), 18 with true posterior infarction [%), 110 with inferior wall infarction (48.8%) and 36 with postero-inferior wall infarction (16%). The results were discordant in 61 patients (27.1%); infarcts of the inferior or posterior walls according to one technique, were observed on the posterior or inferior walls with the other. The majority of these cases had postero-inferior wall changes on vectorcardiography and inferior wall infarction alone on scintigraphy (35 patients: 15.5%). The specificity of the vectorcardiographic signs of true posterior wall infarction remained satisfactory.(ABSTRACT TRUNCATED AT 250 WORDS)
Diphosphates↗
[New data in cardiology: the electric charge of the heart].
This study emerging from profound consideration of the basis of vectorcardiography reveals a new electric model of the heart, the starting point for a computer programme of which only the principle is described. Noting inadequacies of vectorcardiography linked to necessary but possibly excessive simplifications, the author suggests a solution based only on Einthoven's postulate of a single dipole: at each instant during the cardiac revolution, the positions of point N, the centre of negative charges and origin of the dipole, of point P, the centre of positive charges and extremity of the dipole, and the value of the load borne by this dipole are calculated. The classical orientations of septal, parietal and basal vectors are thus found. It is shown that electric charge follows a bell-shaped curve and that the velocity of the dipole is compatible with that of the depolarisation wave, in contrast to velocities given by vectorcardiography. The trajectory of the dipole, a veritable "dipologram" visualises breaks in continuity which are interpreted. This new method has the advantage of being entirely confirmable: the dipole provided by the programme enables the calculation of potentials. Comparison between measured potentials and calculated potentials ensures the reliability of results provided by this programme. This method is totally in contrast with conventional vectorcardiography: the dipole is entirely mobile regarding both its origin and extremity, its site in the thorax is precisely identified, and its length is calculated, together with its velocity and the charge which it carries.(ABSTRACT TRUNCATED AT 250 WORDS)
Electricity↗
Vectorcardiographic, electrocardiographic, and angiographic correlations in apparently isolated inferior wall myocardial infarction.
Twenty-six patients with ECG evidence of localized inferior myocardial infarction and poor ejection fraction (less than 50 per cent) were compared with 26 patients with similar ECG's, but with normal ejection fraction (over 50 per cent). The poor ejection fraction group had significantly more frequent and more severe disease in left anterior descending artery and a higher incidence of triple coronary obstruction than the normal ejection fraction group. The poor ejection fraction group had a significantly greater incidence of ventricular asynergy in the anterior and apical segments of left ventricle. Vectorcardiography was available in 35 of the 52 patients studied and frequently supplied diagnostic information not available in the scalar ECG's. Of 18 patients with scalar ECG patterns of isols, vectorcardiography identified five cases with anterior infarction, three with left ventricular hypertrophy, and one with left anterior hemiblock. Vectorcardiography is a valuable supplementary tool in the clinical assessment of patients with apparently isolated inferior infarction. When extensive coronary and poor ventricular function exist, VCG clues may be expected in about half the patients.
Angiocardiography↗
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.
Biomarkers↗
Electrocardiographic and vectorcardiographic findings of patients undergoing reductive ventriculectomy (Batista operation).
BACKGROUND: The Batista operation, or partial ventriculectomy, has been designed by the Brazilian surgeon Dr. Randas Batista as an alternative method for treating patients with idiopathic dilated cardiomyopathy. HYPOTHESIS: This study aimed to analyze electro- and vectorcardiographic data obtained from patients who underwent such surgery, and to evaluate its electrical repercussions on the heart. METHODS: Pre- and postoperative electrocardiography (ECG) and vectorcardiography (VCG) were performed 45 days apart in 15 patients undergoing reductive ventriculectomy. RESULTS: All ECGs showed sinus rhythm, with unchanged QRS duration. Left atrial enlargement (86.6%) and left ventricular hypertrophy (100%) were the most common findings. Bundle-branch blocks (BBBs) were often demonstrated on preoperative studies, predominantly (46.7%) left BBBs. Left anterior fascicular blocks were seen in four patients (26.6%), one associated with right BBB. Electrocardiographic changes suggestive of myocardial infarction (MI) were seen in four patients preoperatively; postoperatively, all had extended to or within the lateral wall. Five additional patients developed lateral MIs postoperatively, for a total of 9 patients (60%) with postoperative signs of infarction (p < 0.05). Electro- and vectorcardiography also showed significant postoperative lowering of QRS voltages (mean 40.74%) in all patients and a consequent difficulty to diagnose left ventricular hypertrophy, although the morphologic features did not change. CONCLUSIONS: These important ECG and VCG alterations are reflections of both the surgical technique and its clinical consequences.
Adult↗
Dynamic QRS complex and ST segment vectorcardiographic monitoring can identify vessel patency in patients with acute myocardial infarction treated with reperfusion therapy.
Reperfusion therapy has lowered the mortality in patients suffering acute myocardial infarction. Failure to reperfuse is associated with significantly higher risk of short- and long-term mortality. Detection of reperfusion is thus important. In a prospective pilot study, we used continuous on-line computerized vectorcardiography to monitor 21 patients with acute myocardial infarction treated with reperfusion therapy to noninvasively detect coronary patency. By using trend analysis of QRS vector difference, we were able to correctly blindly identify 15 of 16 patients with a perfused infarct-related artery and four of six patients with a persistently occluded artery at an early angiogram. The present results are based on a limited number of patients, but suggest that QRS complex and ST segment monitoring with continuous on-line vectorcardiography has substantial potential for monitoring patients with acute myocardial infarction treated with reperfusion therapy.
Coronary Vessels↗
Dynamic changes of the QRS complex in unstable angina pectoris.
Despite intensive medical treatment to control chest pain, about one-third of patients with unstable angina have an unfavourable outcome within a period of 1 to 2 months. Holter monitoring can identify patients with silent myocardial ischaemia that are at a high risk of sustaining a major cardiovascular event. The present paper describes the use of dynamic, continuous, computerized on-line vectorcardiography for real-time monitoring of QRS-complex and ST-segment changes in patients with unstable coronary disease. In many patients a pattern of frequent repetitive episodes of QRS change was observed, with or without concomitant ST change. Whereas no patient had episodes of ST-vector change without also having episodes of significant QRS change, 15 patients had several episodes of QRS changes without any episode of significant ST change. The number of episodes of significant increase of the QRS vector difference correlated weakly but significantly with the number of episodes of significant ST-vector magnitude change (r = 0.34, p less than 0.05). The present study suggests that myocardial ischaemia will influence the QRS complex as well as the ST segment. The mechanism behind the QRS changes observed is not clear but episodes of QRS change without ST change or chest pain, may reflect sudden depressions of left ventricular function, as has been reported by others to occur in patients with coronary artery disease. Dynamic vectorcardiography offers the opportunity to monitor all parts of the QRST complex in real time.
Adult↗
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.
Adult↗
Vectorcardiographic changes during cardioangiography with iodixanol and ioxaglate.
AIM: To compare the electrophysiological effects of two contrast media (CM), the non-ionic dimer iodixanol and the ionic dimer ioxaglate using computerised dynamic vectorcardiography (VCG) during coronary angiography. METHODS: The study was designed as a double-blind, three-period crossover, randomised comparison between iodixanol (320 mg I/ml) and ioxaglate (320 mg I/ml). Group 1 (HVV) received ioxaglate (H) in the first injection in the left coronary artery (LCA) and iodixanol (V) in the following injections. Group 2 (VHH) received iodixanol in the first injection in LCA and ioxaglate in the following injections. The first three injections in the LCA were subjected to electrocardiographic analysis. RESULTS: For five out of six VCG variables, there was a significant difference in response between iodixanol and ioxaglate. For these five variables, the deviations from baseline were greater in the ioxaglate than in the iodixanol group (P<0.05). The most pronounced effects from ioxaglate were seen on the ST-segment and T-wave. CONCLUSIONS: Iodixanol caused less pronounced electrophysiological changes than ioxaglate, especially during the repolarisation phase. Vectorcardiography is a sensitive and reproducible technique for detecting electrophysiological effects induced by CM.
Adult↗
Continuous ST-segment monitoring of patients with left bundle branch block and suspicion of acute myocardial infarction.
OBJECTIVES: Patients with left bundle branch block comprise 5-9% of all patients with acute myocardial infarction. Limited data exist on the usefulness of continuous electrocardiographic monitoring of these patients. We have investigated prospectively the usefulness of real-time continuous vectorcardiography for monitoring patients with left bundle branch block and suspicion of acute myocardial infarction. DESIGN: A prospective multi-centre study. SETTING: Fourteen Swedish coronary care units. SUBJECTS: Patients with left bundle branch block and suspicion of acute myocardial infarction with <6-h symptom duration were included. MAIN OUTCOME MEASURES: All patients were monitored with continuous vectorcardiography for 12-24 h. RESULTS: One hundred thirty-three patients were included, 47% had acute myocardial infarction. Patients with acute myocardial infarction showed a marked relative decrease in ST-vector than those without (P = 0.0002). These changes were most marked in the first 90 min. When comparing patients with acute myocardial infarction receiving thrombolytic therapy or not, those treated with thrombolytics showed more marked decline in ST-vector magnitude (P < 0.0001) and in shorter time (P = 0.0017). All patients showed STC-vector magnitude changes that were more marked in patients with acute myocardial infarction (P = 0.0002). An STC-vector magnitude cut-off value of 65 microV after 90 min of monitoring gave 54% sensitivity and 72% specificity for diagnosis of acute myocardial infarction. CONCLUSION: Real-time continuous vectorcardiographic monitoring of patients with left bundle branch and suspicion of acute myocardial infarction shows significant differences between those with and without acute myocardial infarction and could be of use for early diagnosis and subsequent monitoring.
Aged↗
Continuous ST monitoring: a bedside instrument? A report from the Assessment of the Safety of a New Thrombolytic (ASSENT 2) ST monitoring substudy.
BACKGROUND: Continuous ST monitoring has during the past decade become widespread in coronary care units (CCU) and is now even recommended by international task forces to survey patients with acute coronary syndromes. ST monitoring has also been shown to be a well-validated technology to predict prognosis and coronary artery patency in patients with acute ST-elevation infarction. However, all evaluations in previously presented trials have been made inside a core laboratory by specially trained personnel. METHODS: In the Assessment of the Safety and Efficacy of a New Thrombolytic (ASSENT 2) ST-monitoring substudy, 448 patients with ST-elevation infarction from 22 hospitals were monitored by vectorcardiography. The local nurse responsible for the patient made an evaluation of the ST trend curve. This was compared with a blinded core laboratory evaluation and examined versus 30-day mortality. RESULTS: No significant differences were found between the local and central evaluations of ST-segment recovery. The accuracy of the local evaluation, compared with the central one, in deciding whether patients had > or = 50% ST-segment recovery at 60 or 90 minutes was > 90%. A large low-risk group (30% of the patients) with 0.8% 30-day mortality could be identified by the local evaluation. CONCLUSIONS: ST monitoring with vectorcardiography can accurately be done in the clinical setting. The local evaluation was as least as accurate as the core laboratory evaluation in predicting prognosis.
Chi-Square Distribution↗
Early vectorcardiographic monitoring provides prognostic information in patients with ST-elevation myocardial infarction.
OBJECTIVE: To evaluate the prognostic value of specified vectorcardiographic data obtained during the first hours of ST-elevation myocardial infarction for cardiac outcomes up to 5 years. DESIGN: Three hundred and five patients with ST-elevation myocardial infarction and chest pain for less than 12 h were monitored with continuous vectorcardiography. RESULTS: All patients had follow-up for at least 1 year. The mortality was 5.9% at 30 days and 10.8% at 1 year. The estimated 5-year mortality was 24%. A total of 7.9% had recurrent infarction at 30 days and 11.2% at 1 year. Recurrent infarction or death occurred in 12.1% at 30 days and in 19.7% at 1 year. The presence of ST-VM (plateau) >or= 125 microV was highly predictive of the combined endpoint death or recurrent infarction at 1 year, OR 2.69 (95% CI 1.39-5.23). Multivariate analysis showed that age >or=75 years, anterior myocardial infarction, and the presence of ST-VM (plateau) >or= 125 microV, were independently associated with increased risk of recurrent infarction or death at 1 year and with death at 5-year follow-up. A start value of ST-VM <or=100 microV identified a group of patients with low risk of death or re-infarction within 1 year. CONCLUSION: Continuous vectorcardiography during the first hours after thrombolytic treatment of patients with ST-elevation myocardial infarction provides important prognostic information. A new vectorcardiographic variable, ST-VM (plateau), identifies a group of patients with increased risk of recurrent infarction or death. As well, patients with low risk of recurrent infarction or death were identified by low start values of ST-VM.
Aged↗
Vectorcardiographic monitoring to assess early vessel patency after reperfusion therapy for acute myocardial infarction.
Reperfusion therapy has lowered mortality in patients suffering from acute myocardial infarction. Failure to reperfuse is associated with an increased short- and long-term mortality. In a prospective study we used dynamic vectorcardiography to monitor 96 patients with acute myocardial infarction treated with reperfusion therapy to non-invasively assess coronary patency. The results from continuous monitoring were compared to those obtained from angiography. By using trend-analysis of QRS vector difference and ST vector magnitude, we were able to correctly identify 58 of the 70 patients (83%) with a reperfused infarct-related artery, and 19 of the 26 patients (73%) with a persistently occluded artery demonstrated at an early angiogram (diagnostic accuracy 80%). In patients with high-grade collateral flow to the infarct-related area, the results of the vectorcardiographic monitoring and of angiography showed the largest disagreement, whereas the accuracy of vectorcardiographic monitoring was high: 88% among patients without collaterals. The present results suggest that QRS complex and ST segment vectorcardiographic monitoring is a useful tool for assessing early coronary artery patency, and that dynamic vectorcardiography may help in identifying candidates for emergency coronary angiography.
Acute Disease↗
Non-invasive risk stratification within 48 h of hospital admission in patients with unstable coronary disease.
AIMS: In this study we evaluated the prognostic value of three methods of early risk estimation in patients with unstable coronary disease. METHODS AND RESULTS: The methods evaluated were: clinical risk estimation at hospital admission, continuous ST analysis with computerized vectorcardiography for 24 h and serial measurements of creatinine kinase-MB for 48 h. Twenty-seven (14%) of the 195 patients died or had a non-fatal infarction within one year. Clinical risk evaluation correctly identified a subgroup of patients with low risk but did not otherwise predict outcome. Fifty-six (29%) patients had ST vector magnitude episodes on vectorcardiography, 70 (38%) had three or more episodes of ST change vector magnitude and 74 (38%) had a peak creatinine kinase-MB value of 6 microgram.l-1 or more. The even rate for patients with ST vector magnitude episodes (23%) was significantly higher than for those without (10%; P < 0.05). For patients with and without three or more episodes of ST change vector magnitude the event rate was 23% and 9% respectively (P < 0.05) and for patients with and without creatinine kinase-MB > or = 6 microgram.l-1 the event rate was 23% and 8% respectively (P < 0.01). The positive predictive value of having none, either one or both of the ST or creatinine kinase-MB markers positive was incremental. CONCLUSION: Continuous vectorcardiographic monitoring of ischaemia in combination with serial creatinine kinase-MB measurement considerably improves risk stratification in unstable coronary disease.
Adult↗
Vectorcardiographic monitoring of patients with acute myocardial infarction and chronic bundle branch block.
AIMS: This study was set up to describe vectorcardiographic patterns in patients with bundle-branch block and acute myocardial infarction. METHODS AND RESULTS: Sixty-five patients admitted to the coronary care unit with bundle-branch block and suspected acute myocardial infarction were monitored by dynamic vectorcardiography with trend analysis. In 28 patients, a clinical diagnosis of acute myocardial infarction was made. In patients with left bundle-branch block and acute myocardial infarction, the pattern of QRS vector-difference evolution was similar to that in patients with the narrow QRS complex, while ST vector-magnitude changes increased over time. Using a cut-off value for QRS vector-difference at 12 h of more than 20 microVs and a specific trend curve pattern, acute myocardial infarction in the presence of left bundle-branch block could be diagnosed with an accuracy of 71%. For patients with right bundle branch block, using a maximum ST vector-magnitude of > 200 microV during the first 4 h, acute myocardial infarction could be diagnosed with a 78% accuracy. CONCLUSION: Our results indicate that dynamic vectorcardiography is a valuable tool in diagnosing and monitoring acute myocardial infarction in patients with bundle branch block.
Aged↗
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.
Aged↗