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PubMed1982

Octant vectorcardiography and automatic diagnosis of coronary artery disease.

Octant vectorcardiography is based on two new principles--octants and peaks (Laufberger 1980, 1981, 1982). The octants divide the cardioelectrical space into eight parts. The peaks are characterized by the maxima of six sets recorded and printed by a computer. Special characteristics may be determined for the diagnosis of coronary artery disease, namely reversed rotation, the appearance of the fifth octant and successively deteriorating findings of the octant vectorcardiography examination. Electronic equipment was constructed providing automatic display of octants and peaks. From the results the state of the coronary artery disease can be stated immediately.

Coronary Disease↗
PubMed1980

[Diagnosis of limited septal infarction associated with a posterior or postero-inferior infarction. Value of vectorcardiography and clinical, coronary angiographic and developed correlations].

In patients with posterior or postero inferior infarction, a limited septal infarction may be detected by vectorcardiography, septal extension being a sign of disease of the left anterior descending artery. In order to confirm this hypothesis, 31 posterior or postero inferior infarction with septal extension were selected by vectorcardiography from more than 500 ECGs recorded after the acute phase of a clinically and biologically documented infarction. The following criteria were chosen: 1. Anterior deviation of the QRS, associated or not with superior deviation of the initial deflection lasting over 25 ms and clockwise rotation of the frontal loop (posterior infarct: 9 cases, postero inferior infarct: 22 cases). 2. Abnormalities of the initial phase of the QRS in the horizontal plane, associated with a reduced amplitude and duration of the initial deflection. The clinical, ECG, vectorcardiographic and angiographic (14 cases) features of these 31 postero septal infarcts were compared with those of 31 posterior septal infarcts were compared with those of 31 posterior or postero inferior infarcts (24 coronary angiographies). 1. From the clinicl point of view, in the acute phase postero septal infarction did not differ from posterior infarction and the early prognosis was favourable. On the other hand, with an average follow-up of 2 years, the outcome of postero septal infarction was statistically more complicated than that of strict posterior infarction (52 p. 100 compared to 19 p. 100, p < 0.01). 2. From the electrocardiographical point of view, septal extension of posterior infarction was only suspected in 25 p. 100 cases. In the acute phase, ST depression in V2 to V5 sometimes associated with reduction of the R wave in the right precordial leads and QS waves in V4R, suggesting a "rudimentary" or "subendocardial" infarct. 3. From the angiographic point of view, although disease of the posterior vessels was equally common in posterior and postero septal infarction (86 p. 100 compared to 92 p. 100 NS), stenosis of the left anterior descending artery was statistically more common in postero septal infarction than in posterior infarction (86 p.100 compared to 29 p. 100, p < 0.001). Thallium myocardial scintigraphy, when performed, showed the double myocardial lesion in the antero septal and postero inferior walls in postero septal infarction. These results validate the vectorcardiographical criteria retained for diagnosis of postero septal infarction and confirmed the superiority of the vectorcardiogramme over the electrocardiogramme in the diagnosis of double infarction. Therefore, the vectorcardiogramme in the diagnosis of double infarction. Therefore, the vectorcardiogramme allows selection of the patients with postero diaphragmatic infarction with a limited septal extension, for whom coronary angiography should be proposed. A "postero septal" infarct diagnosed on vectorcardiogramme has a high probability of stenosis of the left anterior descending artery.

Coronary Angiography↗
PubMed1994

Prognostic information from on-line vectorcardiography in acute myocardial infarction.

The present study assesses the prognostic information from continuous on-line vectorcardiography in patients with acute myocardial infarction (AMI). A series of 203 patients with AMI were studied. Vectorcardiographic (VCG) recordings were obtained continuously for 24 hours. Analysis was performed on-line with the commercial system MIDA CoroNet. QRS vector difference (QRS-VD), ST change vector magnitude (STC-VM), and ST vector magnitude (ST-VM) were monitored. Patients were followed for 538 +/- 220 days. During follow-up, 36 patients died from cardiac causes and 38 patients had reinfarction. A significantly higher occurrence of transient VCG changes (QRS-VD, STC-VM, and ST-VM; p < 0.001) was seen in patients who died from cardiac causes or experienced either cardiac death or reinfarction at follow-up. The end value for QRS-VD was higher in patients who died from cardiac causes and correlated with the maximal value for creatine kinase when all patients were considered (r = 0.66; p < 0.001). Significantly lower mortality was seen in patients with VCG trend curves suggestive of coronary reperfusion (p < 0.01). In multivariate analysis, occurrence of transient changes in STC-VM, high QRS-VD end value, and VCG trend curves not suggestive of reperfusion gave additional prognostic information beyond that of age, gender, maximal creatine kinase value, heart size on chest x-ray, occurrence of ventricular fibrillation during hospitalization, and the inability to perform exercise tests. VCG monitoring during the first 24 hours of hospitalization for an AMI is a promising method for early detection of patients with increased risk for subsequent cardiac death or reinfarction.

Aged↗
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↗
PubMed1983

Continuous vectorcardiography in acute myocardial infarction. Natural course of ST and QRS vectors.

We made continuous recordings of the X, Y and Z Frank leads in 43 patients with their first myocardial infarction admitted within 4 hours of the onset of pain. Sequential hourly analysis of the ST and QRS vector changes during the first 24 hours was performed. In short-term survivors (n = 38) mean serial changes of ST vectors showed an initial rapid decline until the 8th-10th hour, whereas QRS vector changes lasted longer and were completed within 13.5 +/- 3.6 hours (inferior infarction) and 10.2 +/- 2.4 hours (anterior infarction) respectively. The initial ST vector magnitude was significantly correlated to the subsequent cumulative QRS vector change (r = 0.82). The individual ST vector changes showed a rapid decline in 33 of 38 patients (87%), whereas in 5 patients the ST vector magnitude increased to reach its maximum after 4-6 hours. After the initial decline new increases of the ST vector magnitude was noted in 16 patients on 20 occasions. In 13 instances this was associated with recurrent pain. The spatial change of ST vector direction with reference to the initial direction was significantly greater when recurrent ST rises were accompanied by additional QRS vector changes, compared to those without associated QRS changes (P less than 0.025). The individual QRS vector slopes could be characterized as (1) monophasic (n = 21, 55%), (2) polyphasic (n = 11, 29%) and (3) irregular (n = 6, 16%). We conclude that continuous vectorcardiography is a suitable method for following ST and QRS vector changes that accompany acute myocardial infarction and that ST vector changes can be used to predict subsequent QRS vector changes.

Adult↗
PubMed1988

Spatial quantitative vectorcardiography in aortic stenosis: correlation with hemodynamic findings.

Thirty-four patients with hemodynamically documented valvar aortic stenosis without congestive heart failure were studied by the corrected Frank lead system vectorcardiography, with special emphasis on the angular characteristics of spatial R max to define the severity of the lesion. Spatial QRS-T angle demonstrated a highly significant correlation with the peak left ventricular systolic pressure (r = 0.72, P less than 0.001) and a significant correlation with peak transvalvar aortic gradient (r = 0.49, P less than 0.01). Furthermore, all patients with a QRS-T angle of more than 90 degrees had significant aortic stenosis (TVG greater than or equal to 50 mm Hg). The peak left ventricular systolic pressure and transvalvar aortic gradient also demonstrated a significant negative correlation with azimuth angle (r = -0.36 and -0.34, respectively; P less than 0.05) and a positive correlation with spatial R max magnitude (r = 0.38 and 0.41, respectively; P less than 0.05). There was no correlation between elevation angle of spatial R max and left ventricle systolic pressure or transvalvar aortic gradient. Our study indicates that spatial quantitative vectorcardiographic angular characteristics, particularly spatial QRS-T angle, may be a useful adjunct to other noninvasive techniques to assess the severity of valvar aortic stenosis.

Adolescent↗
PubMed1991

Value of exercise vectorcardiography and exercise radionuclide ventriculography in identification of coronary arterial disease in patients with left bundle branch block.

Twelve patients (8 male and 4 female, age ranged 39-60 years) with suspected coronary arterial disease with left bundle branch block were evaluated for ischemia by simultaneous exercise vectorcardiography and radionuclide-ventriculography. Selective coronary angiography revealed normal coronary arteries in 5 and significant coronary arterial disease in 7 patients. Radionuclide ventriculography revealed no significant difference in resting left ventricular ejection fraction in patients with normal coronary arteries (44.0 +/- 13.9%) and coronary arterial disease (45.7 +/- 11.9%). Exercise radionuclide ventriculography showed positive response suggestive of ischemia in 11 patients (11/12), including all 5 with normal coronary arteries and 6/7 with coronary arterial disease. The magnitude of spatial 'R' maximum cardiac vector in both groups at rest (normal coronary arteries: 1.61 +/- 0.22 mV, coronary arterial disease: 1.63 +/- 0.35 mV) did not show any significant difference. On exercise, the magnitude of spatial 'R' maximum cardiac vector uniformly increased in patients with normal coronary arteries (1.61 +/- 0.22 to 1.75 +/- 0.25 mV, P less than 0.01) and decreased in 6 and remained unchanged in 1 patient with coronary arterial disease (1.63 +/- 0.35 to 1.34 +/- 0.46 mV, P less than 0.01). There was no change in rotational characteristics of QRS and T loops at end exercise in either group. Our preliminary observations indicate that exercise induced alteration of the magnitude of the maximal spatial 'R' cardiac vector appears to be an useful parameter to diagnose underlying coronary arterial disease in patients with left bundle branch block. Having a high false positive response, exercise radionuclide ventriculography appears to be of limited value in these patients.

Adult↗
PubMed1995

Comparison using dynamic vectorcardiography and MIBI SPECT of ST-segment changes and myocardial MIBI uptake during percutaneous transluminal coronary angioplasty of the left anterior descending coronary artery.

The quantitative relation between ST-segment changes and the severity and extent of myocardial ischemia during coronary occlusion remains unclear. This study assesses whether ST-segment changes during percutaneous transluminal coronary angioplasty (PTCA) correlate with the amount of myocardium at risk, measured with technetium-99m hexakis 2-methoxyisobutyl isonitrile (MIBI; also called sestamibi) single-photon emission computed tomography (SPECT). Quantitative continuous dynamic vectorcardiography was performed during PTCA of the left anterior descending coronary artery in 11 patients (mean age 64.3 years) without previous myocardial infarction. Change in the magnitude of the ST vector (STc-VM) was continuously recorded. A standardized protocol of balloon inflations was used and technetium-99m MIBI was injected intravenously at the onset of the third inflation. SPECT imaging was performed 60 minutes later and compared to a rest acquisition. SPECT was quantified by bull's-eye analysis using: (1) the change in the pathologic/normal area count ratio (delta P/N) as an index of the severity of ischemia; and (2) planimetered defect size during PTCA as an indicator of the size of the area at risk. The delta P/N from baseline to balloon occlusion (22 +/- 11%) was correlated, albeit loosely, to the maximum value of STc-VM (245 +/- 186 microV, r = 0.62, p < 0.05), but there was no correlation between the size of the scintigraphic defect and STc-VM. Likewise, the sum of ST-segment elevation was correlated to delta P/N (r = 0.72, p < 0.02), but not to the size of the scintigraphic defect.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Ischemia monitoring with on-line vectorcardiography compared with results from a predischarge exercise test in patients with acute ischemic heart disease.

Information from 24-hour monitoring with on-line vectorcardiography, starting immediately after admission, was compared with results from a predischarge exercise test 3-13 days after admission. A total of 169 patients with acute myocardial infarction and 73 patients with unstable angina pectoris were investigated. Patients were followed for 487 +/- 135 days. During the follow-up period, 19 patients (8%) died from cardiac causes and 34 (14%) were hospitalized for a myocardial infarction. The QRS vector difference (QRS-VD), ST change vector magnitude (STC-VM), ST vector magnitude (ST-VM), and ST vector leads X, Y, Z were monitored. Patients with ST depression on the exercise test showed higher occurrence of transient, supposedly ischemic, episodes of QRS-VD, STC-VM, and ST-VM than patients without ST depression. The sensitivity and specificity of identifying patients with ST depression at the exercise test were respectively, 71 and 47% for QRS-VD episodes, 58 and 56% for ST-VM episodes, and 55 and 65% for STC-VM episodes. The maximum ST depression at the exercise test was related to the maximum ST depression in vector lead X (r = .44, P < .001) and the number of STC-VM (r = .40, P < .001), ST-VM (r = .37, P < .001), and QRS-VD (r = .33, P < .001) episodes on the VCG. In multivariate analysis, maximum ST depression in vector lead X and STC-VM episodes were the best determinants for ST depression at the exercise test. In a Cox regression model, the optimal combination of exercise test data in patients who died from cardiac causes exhibited a global chi-square value of 20.0. The combination of these data and the number of STC-VM episodes increased the global chi-square value to 30.6. This study indicates that in patients with acute ischemic heart disease, early continuous vectorcardiographic monitoring may predict the results from a predischarge exercise test and also contributes independent prognostic information beyond that of exercise test data.

Angina, Unstable↗
PubMed1984

Relation between the location of the infarcted area in body surface isopotential mapping and the location of myocardial infarction in vectorcardiography.

In order to examine whether our method of determining the location of the infarcted area in body surface isopotential mapping (MAP) is adequate for clinical use, a comparison was made between the location of the infarcted area using MAP and the location of myocardial infarction using vectorcardiography (VCG). The percentage of agreement between MAP and VCG in the retrospective study was 91.7% in the anterior wall, 76.7% in the lateral wall, 93.3% in the inferior wall and 73.3% in the posterior wall. The reason for the disagreement between these two methods was investigated, and criteria for determining the infarcted area using MAP and vectorcardiographic criteria for myocardial infarction were partly corrected in anterior, lateral and (high) posterior infarction to increase the clinical accuracy of both methods. Consequently, the percentage of agreement in the four walls ranged from 83.7% to 87.9%, and the diagnostic value of MAP for the infarcted area was not inferior but was more sensitive than that of VCG except in anterior infarction. In the prospective study, the same result was obtained. Secondly, in order to establish the superiority of MAP or VCG, the sensitivity and specificity of MAP and VCG to SCG (thallium-201) were calculated. Except in the anterior wall, the sensitivity of MAP to SCG was higher than that of VCG to SCG, especially in the lateral and posterior walls. Accordingly, it is suggested that MAP is the method of choice in determining the infarcted area in clinical cases.

Electrocardiography↗
PubMed1985

Comparative accuracy of computerized spatial vectorcardiography and standard electrocardiography for detection of myocardial infarction.

New computerized spatial vectorcardiographic variables were analyzed by discriminant analyses for group classification of 94 patients with acute myocardial infarction and 79 normal subjects. Using the integral of the sequential magnitudes of the spatial vectors during the period of initial abnormal depolarization (IAD) of the QRS at a discriminating value of 3 mv X msec., 87% of the subjects were correctly classified with a sensitivity of 85%; specificity of 88%; and an overall predictive accuracy of 87%, p less than .00001. The period of initial abnormal depolarization in which the vectors were integrated was determined by the first derivative of the sequential magnitudes of the spatial vectors of the QRS waveform (dm/dt). The mean value of dm/dt during the period of abnormal depolarization was a poor discriminating variable. The predictive accuracy of this new electrocardiographic criterion for diagnosis of myocardial infarction compared favorably with other computerized methods such as vectorcardiography, polarcardiography, Aitoff spatial trajectory, the 12-lead ECG derived by the Frank XYZ leads as well as the standard 12-lead ECG.

Computers↗
PubMed1987

Myocardial infarction size and location: a comparative study of epicardial isopotential mapping, thallium-201 scintigraphy, electrocardiography and vectorcardiography.

Based on epicardial isopotential mapping (the Ep Map), which was calculated from body surface isopotential mapping (the Body Map) with Yamashita's method, using the finite element technique, we predicted the location and size of the abnormal depolarized area (the infarcted area) in 19 clinical cases of anterior and 18 cases of inferoposterior infarction. The prediction was done using Toyama's diagnostic method, previously reported. The accuracy of the prediction by the Ep Map was assessed by comparing it with findings from thallium-201 scintigraphy (SCG), electrocardiography (ECG) and vectorcardiography (VCG). In all cases of anterior infarction, the location of the abnormal depolarized areas determined on the Ep Map, which was localized at the anterior wall along the anterior intraventricular septum, agreed with the location of the abnormal findings obtained by SCG, ECG and VCG. For all inferoposterior infarction cases, the abnormal depolarized areas were localized at the posterior wall and the location also coincided with that of the abnormal findings obtained by SCG, ECG and VCG. Furthermore, we ranked and ordered the size of the abnormal depolarized areas, which were predicted by the Ep Map for both anterior and inferoposterior infarction cases. In the cases of anterior infarction, the order of the size of the abnormal depolarized area by the Ep Map was correlated to the size of the abnormal findings by SCG, as well as to the results from Selvester's QRS scoring system in ECG and to the angle of the maximum QRS vector in the horizontal plane in VCG.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrocardiography↗
PubMed1999

Temporal and positional variability of the ST segment during continuous vectorcardiography monitoring in healthy subjects.

Continuous vectorcardiography ST-segment monitoring (cVST) is a well-established method in the diagnosis and risk evaluation of patients with acute myocardial ischemia. Previous investigations have demonstrated that electrocardiographic ST-segment changes are to be expected, during both repeated measurements and changes in body position. We prospectively analyzed the influence of spontaneous temporal variation (technical and biological noise) and changes in body position on the ST segment (ST-vector magnitude [ST-VM]) during cVST of 21 healthy human subjects. The 95% expectancy range of the spontaneous intraindividual ST-VM variation was found to be +/-8 microV for the error of measurement, and +/-14 and +/-24 microV during 24-hour and day-to-day cVST measurements, respectively. Positional ST-segment changes in the orthogonal leads were frequent, especially in leads X and Z, and in the left lateral position. Positional orthogonal ST-segment changes resulted in significant ST-VM changes in two of seven subjects. It is concluded that the low spontaneous temporal ST-VM variation must be considered as good reproducibility. Moreover, the present findings support currently used ST-VM ischemia criteria. However, the impact of positional changes on ST-VM seems to be of importance (with the possibility of false-positive results) and should be taken into account during cVST.

Adult↗
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↗
PubMed1997

Reproducibility of on-line vectorcardiography measurements in patients with and without acute ischaemic heart disease.

OBJECTIVES: The aim of the present study was to determine inter and intraobserver variations of measurements with on-line vectorcardiography (VCG). DESIGN: The VCG registrations were evaluated by two independent observers. One observer also evaluated the VCG registrations on two separate occasions. Monitored VCG variables were: ST vector magnitude (ST-VM), ST vector lead X (ST-X), ST change vector magnitude (STC-VM) and QRS vector difference (QRS-VD). SUBJECTS: On-line VCG was performed for 24 hours in 60 patients (10 with low probability of ischaemic heart disease, 25 with unstable angina pectoris and 25 with acute myocardial infarction). RESULTS: A close correlation between the two observers and small coefficients of variation were found regarding the ST-VM initial value (r = 0.99, 4.7), the ST-X maximum depression (r = 0.99, 3.2) and the QRS-VD end value (r = 0.98, 5.6). A less close correlation and higher coefficients of variation were found regarding the number of QRS-VD episodes (r = 0.94, 41.5), ST-VM episodes (r = 0.89, 37.8) and STC-VM episodes (r = 0.87, 35.1). Correlation coefficients and coefficients of variations for VCG measurements performed on two separate occasions by one observer ranged from 0.97 to 0.99 and from 18.1 to 1.8 respectively. Three (12%) of 25 patients with acute myocardial infarction did not meet the VCG infarction criterion (QRS-VD > or = 15 microVs) by both observers. In addition, five (20%) of the 25 patients with unstable angina pectoris met the VCG infarction criterion by both observers. CONCLUSION: The inter and intraobserver variation for VCG interpretations was low, but the number of QRS-VD, ST-VM and STC-VM episodes varied between the two observers. This finding suggests that additional training may improve the results. Caution is also recommended in using VCG to rule out or establish the diagnosis of acute myocardial infarction.

Acute Disease↗
PubMed1998

Ischaemia monitoring with on-line vectorcardiography during dobutamine stress echocardiography in patients after an episode of unstable coronary artery disease.

OBJECTIVES: This study investigated the ability of on-line vectorcardiography (VCG) to detect myocardial ischaemia as assessed by dobutamine stress echocardiography after an episode of unstable coronary artery disease. DESIGN: Dobutamine stress test (incrementally infused doses of 5, 10, 20, 30 and 40 microg kg(-1) per minute) was performed during simultaneous VCG monitoring. QRS vector difference (QRS-VD), ST vector magnitude (ST-VM), ST change vector magnitude (STC-VM) and T change vector magnitude (TC-VM) were monitored. A new wall motion abnormality or worsening of abnormal wall motion was regarded as indicating a positive dobutamine stress test. SUBJECTS: Fifty-five patients with unstable angina pectoris and 16 patients with an acute non-Q-wave myocardial infarction were studied 5-8 days after admission. RESULTS: A positive dobutamine stress test was observed in 37 patients (52%). The sensitivity, specificity and total accuracy of identifying patients with a positive dobutamine stress test by VCG were: 38%, 91% and 63% for QRS-VD; 59%, 88% and 73% for ST-VM; 84%, 79% and 82% for STC-VM; and 86%, 23% and 56% for TC-VM. Patients with a positive dobutamine stress test showed higher maximum VCG values than patients with a negative dobutamine stress test (QRS-VD, P < 0.01; ST-VM, P < 0.001; STC-VM, P < 0.001). The maximum VCG values were related to the number of segments showing new or worsening wall motion abnormality (QRS-VD: r=0.41, P < 0.001; ST-VM: r=0.44, P < 0.001; STC-VM: r=0.57, P < 0.001). CONCLUSION: STC-VM and ST-VM seem to be the best VCG variables for detection of myocardial ischaemia as assessed by dobutamine stress echocardiography.

Aged↗
PubMed2001

Vectorcardiography is superior to conventional ECG for detection of myocardial injury after coronary surgery.

OBJECTIVE: The reliability of conventional scalar ECG for diagnosis of perioperative myocardial infarction (PMI) in cardiac surgery has been questioned. For the diagnosis of myocardial infarction in general vectorcardiography (VCG) is superior to ECG. Therefore, the usefulness of conventional VCG and computerized analysis of spatial VCG changes for diagnosis of PMI were studied. DESIGN: VCG registrations were obtained from 218 patients undergoing coronary surgery. The spatial QRS vector loop area of each VCG registration was calculated and the loop area before surgery compared with the loop area after surgery. Conventional VCG criteria for myocardial infarction and set values for loop area reduction were related to sustained elevation of plasma troponin-T and clinical course. RESULTS: Both conventional VCG criteria and spatial changes translated better than Q-waves on scalar ECG into elevation of biochemical markers of myocardial injury and impaired clinical course. CONCLUSION: VCG appears superior to conventional ECG as regards detection of myocardial injury in coronary surgery. Computerized programs have facilitated the registration and the interpretation of VCG and this methodology deserves further evaluation in cardiac surgery.

Cardiac Surgical Procedures↗
PubMed2002

Assessment of myocardium at risk with computerized vectorcardiography and technetium-99m-sestamibi-single photon emission computed tomography during coronary angioplasty.

OBJECTIVE: To compare the myocardium at risk (MAR) as estimated by computerized vectorcardiography (cVCG) with MAR determined by Tc-99m-sestamibi-SPECT using coronary angioplasty as the model for transient transmural ischemia in humans. METHODS AND RESULTS: In 37 patients with stable angina pectoris, cVCG was recorded continuously during coronary angioplasty. The scintigraphic defect was quantified using an automated software program (CEqual). The ST vector magnitude (ST-VM) and the ST change vector magnitude (STC-VM) correlated well with MAR estimated by scintigraphy, ST-VM (r = 0.71, p < 0.001) and STC-VM (r = 0.84, p < 0.001). All patients with STC-VM <50 microV during occlusion had defects of less than 10% of the left ventricle. CONCLUSION: 1) ST-VM and STC-VM give a reasonable useful estimate of MAR size during transient coronary occlusion. 2) STC-VM <50 microV is a reliable limit to identify patients with MAR size less than 10%. 3) ST-VM does not add information to STC-VM with respect to detection of ischemia. 4) The existence of collateral vessels has great impact on both ST-vector changes and scintigraphic imaging of myocardial ischemia.

Adult↗