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At least 19 recordsLinked to original sources
PubMed1975

[Vectorcardiography].

The principle of vectorcardiography is first discussed. The setting out in space is very instructive. An over-valuation of slight vectorcardiographic changes can lead to wrong conclusions. The changes in right hypertrophy may in many cases be important for diagnosis. This is true for cases of intraventricular conduction disturbance and incomplete right bundle branch block. In certain cases of myocardial infarction, the vectorcardiogram can be valuable as additional diagnostic method. Finally the diagnostic possibilities of vectorcardiography in pacemaker patients, contour irregularities of the vector loops, congenital valvular heart disease and ventricular extrasystole, and the question of standardisation are discussed.

Bundle-Branch Block↗
PubMed1978

A minicomputer system for display and rate analysis in vectorcardiography.

A system has been constructed for recording vectorcardiographic signal with a FM taperecorder. Off-line AD-conversion and analysis of rates and magnitudes of partial vectors are made with a minicomputer. The reason for studying particularly initial vectorrates is that according to our hypothesis these contain valuable information for classification of certain cardiac arrythmias according to supraventricular or ventricular impulse focus. Preliminary results confirm the hypothesis. In vectorcardiography one difficulty is to give an easily comprehensible presentation of the vectorloop. In this study a method for '3-dimensional' display has been developed, using a graphic display processor and varying intensities of the beam. The system is to a high degree man-machine interactive.

Arrhythmias, Cardiac↗
PubMed1976

Exercise vectorcardiography in diagnosis of ischaemic heart-disease.

The changes in the cardiac electric field during exercise have been studied by conventional vectorcardiographic techniques. Criteria have been developed to distinguish the changes seen in patients with coronary-artery disease proven angiographically from the changes in patients with normal coronary arteriograms. These criteria were derived from a learning set of 105 patients. Vectorcardiograms were taken immediately before and immediately after a maximal treadmill exercise test. In this group of 105 patients--72 with abnormal coronary arteries and 33 with normal coronary arteries--vectorcardiography before and after exercise diagnosed correctly 86% of the abnormals and 82% of the normals. This gives a sensitivity of 86% and a specificity 82%. ST-segment analysis in the same group gave a sensitivity of 60% and a specificity of 85%. The same criteria applied blind to a second testing set of 92 patients gave a sensitivity of 84% and a specificity of 65%. In the same group ST-T analysis gave a sensitivity of 56% and a specificity of 78%. The sensitivity with these criteria compares favourably with the best results so far achieved with ST-segment analysis aided by computer. This technique can be easily used by the clinician and improves the diagnostic accuracy of exercise testing.

Angina Pectoris↗
PubMed1992

Continuous vectorcardiography in patients with chest pain indicative of acute ischemic heart disease.

To assess the clinical usefulness of continuous on-line vectorcardiography (VCG), we studied 61 patients admitted to the coronary care unit (CCU) with chest pain, supposedly ischemic. Continuous VCG was performed for 24 h, monitoring QRS vector difference (QRS-VD), ST-change vector magnitude (STC-VM) and ST vector magnitude (ST-VM) measured 20 and 60 ms after the termination of the QRS complex. The patients were divided into four groups based on the final diagnosis; group A, 15 patients with normal exercise tests and extracardiac causes of chest pain; group B, 15 patients with unstable angina; group C, 15 patients with non-Q-wave myocardial infarction (MI); group D, 16 patients with Q-wave MI. Treatment was given according to a normal routine. Of 31 patients with MI, 16 received treatment with streptokinase. Groups A and B showed no significant permanent changes in QRS-VD, STC-VM or ST-VM. However, group B showed a higher occurrence of transient episodes (duration: 2 min-6 h) of a significant change of QRS-VD by > 15 microVs and of STC-VM, ST-VM 20 and ST-VM 60 by > 0.1 mV. Groups C and D showed both permanent changes and transient episodes for the studied vector parameters. Transient episodes were significantly fewer in group D than in group B. In patients with MI, the permanent change of vector parameters evolved more rapidly and reached a plateau earlier in those treated with streptokinase (QRS-VD: 178 +/- 82 vs. 293 +/- 100 min, p < 0.001; ST-VM 20: 142 +/- 75 vs. 293 +/- 89 min, p < 0.005). The magnitude of the end value for QRS-VD correlated with infarct size estimated by the maximal value of creatine kinase (r = 0.89; p < 0.001). We conclude that in patients admitted to the CCU with chest pain, continuous VCG monitoring early differentiates patients suffering from ischemic heart disease (IHD) from patients without IHD. It also differentiates patients with unstable angina from patients with MI.

Adolescent↗
PubMed1992

[Dynamic continuous vectorcardiography].

Continuous dynamic vectorcardiography is an ideal method for monitoring patients with myocardial ischemia. The monitoring is a non-invasive and real time registration and simultaneously safe and reproducible. The method has proved valuable for describing the evolution in different ischemic heart diseases. The method measures the electric myocardial activity in three orthogonal leads and a computer calculates the different vectorcardiographic parameters for the ST- and QRS-complexes. Vectorcardiographic registration is feasible for computer analysis, because it can summarize all information in a few parameters. Using continuous registration, the different parameters can show dynamic evolution and, in this way, describe the variability during acute myocardial infarction and unstable angina pectoris. The method also made it possible to evaluate anti-ischemic treatment in patients, as for example thrombolytic therapy.

Humans↗
PubMed1979

Estimation of size of infarcted focus by spatial quantitative vectorcardiography in patients with acute anterior myocardial infarction.

The study included 113 patients with acute myocardial infarction of the left ventricular anterior wall. The patients were repeatedly followed up from the first hours of the affection onward in the course of the individual stages of treatment (stage of intensive monitoring and therapy; intermediate stage; initial rehabilitation with application of active therapy; early mobilization, activation and rehabilitation). A new approach to the estimation of the size of the infarcted focus is described, namely, the method using spatial quantitative vectorcardiography. It was found that the spatial localization of the 40-ms vector, especially its azimuth, is a specific indicator, with the aid of which the localization, extent and depth of the lesion in the left ventricular anterior wall can be assessed with a high probability in most instances. The compensatory adaptive and reparative capacity of the affected myocardium, estimated on the basis of spatial quantitative VCG, is closely correlated with the size of the infarcted focus.

Humans↗
PubMed1978

Use of vectorcardiography for the detection of +Gz-related cardiac pathology in miniature swine.

Vectorcardiograms were recorded from anesthetized, adult miniature swine 1-2 weeks before high sustained +Gz exposure and 2-6 h after exposure. Each +Gz run consisted of one 60-s exposure, respectively, to 3, 5, 7, and 9 +Gz, with 3 min rest between each +Gz plateau. The full range, from severe to minor, of +Gz-induced cardiac pathology was observed in this group of miniature swine. In spite of the large variation in the amount and degree of cardiac pathology, there were no post-exposure vectorcardiographic changes which might be diagnostic of +Gz-induced cardiac pathology. The results of this study indicate that vectorcardiography, performed after +Gz exposure, is not a reliable technique for detecting the presence of +Gz-induced cardiac pathology in miniature swine.

Aerospace Medicine↗
PubMed1975

Advances in clinical vectorcardiography.

With use of the Frank lead system, still loop and timed vectorcardiograms were recorded in more than 5,000 patients sujected to complete right and left hear catheterization and selective coronary cine angiography. Data so obtianed demonstrated clincila superiority of the vectorcardiogram over the standard 12 lead scalar electrocardiogram. Specific advantages of the vectorcardiogram include (1) recognititin of undetected atrial and ventrcular hypertropy, (2) greater sensitivity in identification of myocardial infaraction, and (3) superior capability for diagnosis of multiple infaractions in the presnece of fascicular and burnany number of simultaneously recoreded electrocardiographic leadsfor the analysis of complex arrhythmias and beat to beat changes in intraventricula conduction. SINCE THE VALIDITY AND USEFULNESS OF THIS TECHNIQUE HAVE BEEN ESTABLISHED, IT SHOULD BECOME PART OF THE ROUTINE NONINVASIVE EVALUATION OF PATIENTS WITH CARDIOVASCULAR DISORDERS.

Adult↗
PubMed1991

Analysis of bites on three-dimensional vectorcardiography after coronary artery ligation in dogs.

The serial changes in the QRS loops of vectorcardiograms were investigated following ligation of a branch of the left anterior descending artery (LAD) by the three-dimensional rotation method in 18 dogs. Concave inflections of the QRS loop, defined as "bites," were best delineated when the loop was viewed from a left cranial or right caudal direction. Bites appeared 48 +/- 8 minutes after LAD ligation in all of the dogs, and their development was closely related to the temporal changes in the % sigma R and QRS point score on a standard 12-lead electrocardiogram. Q waves were not observed on the electrocardiograms in 9 dogs. In the remaining 9, they appeared 117 +/- 18 minutes after LAD ligation. The bite duration, area, and amplitude were compared with the anatomical extent of the infarcts. A significant positive correlation was found between bite duration and infarct size. The detection of bites on the three-dimensionally rotated vectorcardiogram appears to have a high sensitivity for anterior myocardial infarction and could potentially become a useful diagnostic tool.

Animals↗
PubMed1992

12-lead vectorcardiography in ischemic heart disease.

The conventional approach to recording the vectorcardiogram is to use a specially designed set of electrodes that derive 3-orthogonal leads, ideally corrected with respect to lead strength and direction. This has disadvantages in that it entails a separate recording as opposed to the use of the 12-lead ECG that is universally used. On the other hand, recently developed equations allow the vectorcardiogram to be derived from the 12-lead ECG, and although there is not a one-to-one correspondence with the vectorcardiogram derived using a corrected orthogonal lead system, it has been shown that there is a high degree of similarity between the two derivations. This article discusses the advantages of utilizing the "derived 12-lead vectorcardiogram," which is claimed to have information that is complementary to that of the scalar 12-lead ECG display. It is suggested that using the combination of the 12-lead ECG and the vectorcardiogram derived therefrom, provides the optimum approach to ECG interpretation as compared to using either method alone.

Coronary Disease↗