Vectorcardiographic Analysis Research Articles

Artificial intelligence-supervised vectorcardiography for the diagnosis of a young adult with abnormal origin of the right coronary artery from aorta.

Coronary anomalies occur in 0.2% to 1.2% of the population, with the anomalous aortic origin of the coronary arteries accounting for one third of these cases. Clinical presentations can vary from asymptomatic to experiencing cardiac symptoms and sudden death, making diagnosis challenging. In this report, we present a novel artificial intelligence-supervised vectorcardiographic analysis and the subsequent successful surgical treatment of a young patient.

Prediction of the success of electrical cardioversion in patients with atrial fibrillation using parameters obtained by spectral and vectorcardiographic analysis of the ECG

Abstract Introduction Electrical cardioversion (ECV) still presents a treatment option for atrial fibrillation (AF). Despite the great success rate in the acute setting, its long-term success rate is low. The aim of the study was to find predictors of SR maintenance after ECV using spectral and vectorcardiographic (VCG) analysis of the ECG curve. Methods Consecutive patients with AF referred for elective ECV were prospectively enrolled. The digital ECG recording obtained before the ECV was analyzed using spectral and VCG analysis. All patients had Holter monitoring and clinical follow-up three months after cardioversion to assess SR maintenance. Atrial fibrillation activity was analyzed by spectral analysis, determining the dominant frequency (DF), RI (regularity index) and OI (organization index). QRS complexes were analyzed by vectorcardiography and dXmean, dYmean and dZmean (derivation of VCG signals) parameters were determined. Using logistic regression (LR) with backward parameter reduction, separate and combined predictive models of SR maintenance were calculated based on both the analysis from the VCG data and the spectral analysis data. Additional models with a forward selection of clinical variables were also calculated. The efficiency of the models was evaluated on a separate test subset of the data (N=32). Results A total of 80 patients were enrolled (age 70+10 years, 48 (64%) men, CHADSVASc 3.17+1.5, BMI 29.75kg/m2). At the 3-month follow-up, AF recurrence was present in 36 patients (45%). Using only vectorcardiographic parameters, dXmean (OR 3.07, 95 %CI 1.14- 8.63), p=0.001) and dYmean (OR 0.26, 95% CI 0.09-0.72), p <0.001) best predicted the SR maintenance (AUC of 0.72). Using only spectral analysis parameters, the best predictor was DF (OR 3.07, 95%CI 1.14-8.63), p=0.012) with AUC of 0.66. By combining the results of spectral analysis and vectorcardiography, an AUC of 0.78 was achieved. Among the clinical parameters, the most significant predictors were insufficiently controlled arterial hypertension and previous history of stroke. Conclusion Digital analysis of ECG curves using deeper mathematical models provides a better predictive model than classical clinical and echocardiographic models. The combination of spectral analysis of fibrillation atrial activity and vectorocardiographic analysis of QRS complexes revealed more accurate predictive information compared to both analyses alone.

BRAVEHEART: Open-source software for automated electrocardiographic and vectorcardiographic analysis

Background and ObjectivesElectrocardiographic (ECG) and vectorcardiographic (VCG) analyses are used to diagnose current cardiovascular disease and for risk stratification for future adverse cardiovascular events. With increasing use of digital ECGs, research into novel ECG/VCG parameters has increased, but widespread computer-based ECG/VCG analysis is limited because there are no currently available, open-source, and easily customizable software packages designed for automated and reproducible analysis. Methods and ResultsWe present BRAVEHEART, an open-source, modular, customizable, and easy to use software package implemented in the MATLAB programming language, for scientific analysis of standard 12-lead ECGs acquired in a digital format. BRAVEHEART accepts a wide variety of digital ECG formats and provides complete and automatic ECG/VCG processing with signal denoising to remove high- and low-frequency artifact, non-dominant beat identification and removal, accurate fiducial point annotation, VCG construction, median beat construction, customizable measurements on median beats, and output of measurements and results in numeric and graphical formats. ConclusionsThe BRAVEHEART software package provides easily customizable scientific analysis of ECGs and VCGs. We hope that making BRAVEHART available will allow other researchers to further the field of ECG/VCG analysis without having to spend significant time and resources developing their own ECG/VCG analysis software and will improve the reproducibility of future studies. Source code, compiled executables, and a detailed user guide can be found at http://github.com/BIVectors/BRAVEHEART. The source code is distributed under the GNU General Public License version 3.

Vectorcardiographic analysis of ventricular depolarization and repolarization inhomogeneities in adult patients with newly diagnosed obstructive sleep apnea syndrome

Vectorcardiographic analysis of ventricular depolarization and repolarization inhomogeneities in adult patients with newly diagnosed obstructive sleep apnea syndrome

Beat-to-Beat Vectorcardiographic Analysis of Ventricular Depolarization and Repolarization in Myocardial Infarction

ObjectivesIncreased beat-to-beat variability in the QT interval has been associated with heart disease and mortality. The purpose of this study was to investigate the beat-to-beat spatial and temporal variations of ventricular depolarization and repolarization in vectorcardiogram (VCG) for characterising myocardial infarction (MI) patients.MethodsStandard 12-lead ECGs of 84 MI patients (22 f, 63±12 yrs; 62 m, 56±10 yrs) and 69 healthy subjects (17 f, 42±18 yrs; 52 m, 40±13 yrs) were investigated. To extract the beat-to-beat QT intervals, a template-matching algorithm and the singular value decomposition method have been applied to synthesise the ECG data to VCG. Spatial and temporal variations in the QRS complex and T-wave loops were studied by investigating several descriptors (point-to-point distance variability, mean loop length, T-wave morphology dispersion, percentage of loop area, total cosine R-to-T).ResultsPoint-to-point distance variability of QRS and T-loops (0.13±0.04 vs. 0.10±0.04, p< 0.0001 and 0.16±0.07 vs. 0.13±0.06, p< 0.05) were significantly larger in the MI group than in the control group. The average T-wave morphology dispersion was significantly higher in the MI group than in the control group (62°±8° vs. 38°±16°, p< 0.0001). Further, its beat-to-beat variability appeared significantly lower in the MI group than in the control group (12°±5° vs. 15°±6°, p< 0.005). Moreover, the average percentage of the T-loop area was found significantly lower in the MI group than the controls (46±17 vs. 55±15, p< 0.001). Finally, the average and beat-to-beat variability of total cosine R-to-T were not found statistically significant between both groups.ConclusionsBeat-to-beat assessment of VCG parameters may have diagnostic attributes that might help in identifying MI patients.

Detection of myocardial ischemia before, during, and after coronary angioplasty using a vectorcardiographic analysis

Detection of myocardial ischemia before, during, and after coronary angioplasty using a vectorcardiographic analysis

Quantitative electrocardiographic and vectorcardiographic study on newly-diagnosed non-insulin-dependent diabetic and non-diabetic control subjects.

Quantitative electrocardiographic (ECG) and vectorcardiographic (VCG) analysis was carried out in 113 newly diagnosed, middle-aged, non-insulin-dependent diabetics (61 men, 52 women) and 125 non-diabetic control subjects (56 men, 69 women) in order to explore changes attributable to non-coronary heart disease (diabetic cardiomyopathy) in diabetics. Diabetic men had a prolonged PQ interval and women a more negative P-terminal force and a more leftward frontal QRS axis than their non-diabetic counterparts, but no other significant differences we found between diabetic and non-diabetic subjects in various quantitative ECG and VCG variables when the effect of confounding factors (age, obesity, coronary heart disease, hypertension, drugs) was taken into account. The more negative P-terminal force and left axis deviation in diabetic women could be explained by a concomitant left ventricular hypertrophy among them. Non-insulin-dependent (type 2) diabetes, which is commonly preceded by a long duration of asymptomatic hyperglycaemia, is not associated, early in its clinical course, with major ECG and VCG abnormalities suggestive of diabetic cardiomyopathy.

The vectorcardiographic study of the P loop in adults with ostium secundum atrial septal defect.

Frank vectorcardiographic P loops with satisfactory signal-to-noise ratio were obtained from 44 patients with ostium secundum atrial septal defect (OSASD), confirmed at operation, by using computer-averaging technique of 8 successive beats. Morphological and quantitative analyses of the P loop were made in order to reveal those characteristics of the P loop in OSASD which seemed most typically to show volumetric or diastolic overloading of the right atrium. Twenty-three automatically measured parameters of the P loop were compared with hemodynamic variables such as the systolic right ventricular pressure (s-RVP) and the left-to-right shunt ratio.A majority of the maximal P-vector directions in 3 projection planes and the P duration were within normal 95 percentile ranges. The magnitude of the maximal horizontal, the magnitude of mean polar and the magnitude of the maximal spatial P-vector increased above the 97.5 percentile values considered as the upper limit of normality in 66%, 55%, and 50% of the cases, respectively. These findings seem to suggest that the vectorcardiographic analysis of the P loop with computer-averaging technology is a valuable screening tool of right atrial diastolic overloading.Although the horizontal P loop of normal subjects showed many different patterns, the horizontal P loop of OSASD could be divided morphologically into 3 groups (Type A, Type B, and Type C). Thirteen cases (30%) out of 44 were of Type A, 22 cases (50%) Type B, and 9 cases (20%) Type C. There was a significant age difference between the individual mean values in the 3 groups (p<0.01), and there was a significant difference between the mean values in the shunt ratio of groups 'Type A and Type B' and group 'Type C' (p<0.01). The horizontal P loop pattern seems to be very important in the vectorcardiographic diagnosis of the presence and degree of the right atrial diastolic overloading.There was a significant correlation between 5 P-loop parameters and s-RVP, and between 3 of the parameters and the shunt ratio. The correlation between magnitude of the maximal horizontal P vector (XmV) and the shunt ratio (Y%) was the highest of all (r=0.426, p<0.01), the regression equation being Y=130.7X+49.8 (SEE=11.5%). These findings seem to suggest that the horizontal P loop can provide valuable information for the vectorcardiographic diagnosis of the presence of right atrial diastolic overloading and for estimating the degree of its severity.

Simulation study of QRS-T waves based on an eccentric spherical model of the heart.

The relationship between the difference in the action potential duration in the myocardium and the T wave investigated by a mathematical model of the electrical activity of the heart. In this study we constructed an eccentric spherical model which duplicates the ventricles except for the interventricular septum. Our model is assumed to be composed of the working myocardium and the excitation conduction system which is uniformly distributed on the endocardial surface. The ventricular gradient was defined as a linear decrease (beta msec/cm) of the duration of the action potential from the endocardium to the epicardium according to the concept proposed by Wilson. Theoretical analysis based on this model strongly suggest that the ventricular gradient of 10-40 msec/cm accounts for the normal QRS-T angle since vectorcardiographic analysis have revealed that the QRS-T angle closely correlates with the angle (theta) between the directions of the propagation waves of depolarization and repolarization. The QRST waves in the standard limb and chest leads were calculated from the sum of the time-varying dipoles derived from the action potential, assuming that the heart was in a homogenous conducting medium. Simulated QRS-T waves were compatible with the clinically observed electrocardiograms not only under normal conditions but also with changes in the spacial position of the heart and the wall thickness. Positive T waves were obtained in the left precordial leads when the ventricular gradient was more than 20 msec/cm and when the amplitude of T wave increased with the transmural gradient. Our model also indicates that differences in the velocities of the excitation wave in the conduction system and the working myocardium may affect the polarity of the T wave.

The effect of respiration on normal and abnormal Q waves: An electrocardiographic and vectorcardiographic analysis

The diagnostic significance of Q waves in Leads II, III, and aVF when analyzed retrospectively remains controversial. Persistence of the Q wave on inspiration is said to reflect inferior infarction. Studies in the past, which have evaluated respiratory variation as a means to separate normal from abnormal Q waves, were performed utilizing the ECG only, were often retrospective, and frequently there was inadequate documentation of myocardial infarction. The present study was performed prospectively and utilized both electrocardiographic and vectorcardiographic analysis of the first 30 msec. vector before and after inspiration in 33 patients with documented acute myocardial infarction and in 22 normal volunteers. Inferior myocardial infarction was documented prospectively by ECG, VCG, by conventional enzymes, and by MB CPK. The VCG demonstrated increased sensitivity over that of the ECG, but the effect of inspiration noted on ECG and VCG was variable and extremely unreliable as a means of separating normal from abnormal Q waves.

Congenitally cleft atrioventricular valves associated with secundum atrial septal defects

Three patients with the rare association of secundum ASD and congenital clefts of A-V valves are reported. These three patients illustrate the predictive valve of vectoracardiographic analysis in precisely determining the anatomic location of the valvular pathology. The embryologic origins of the lesion are briefly discussed. A review of the literature supports the use of vector analysis in the evaluation of the patients with this type of heart disease.

The importance of reproducibility testing of computer programs for electrocardiographic interpretation: Application to the automatic vectorcardiographic analysis program (AVA 3.4)

The automatic vectorcardiogram analysis (AVA 3.4) program developed by Pipberger and associates has a unique manner of using multivariate statistics to make morphological diagnoses of the QRS and P waveforms. This scheme produces statements of probabilities for up to seven different QRS diagnoses and three different P wave diagnoses. It would require a complicated protocol with a very large population to establish the validity of this approach. However we have described a simple method for evaluating that part of an ECG program which is independent of its criteria or clinical accuracy. Poor performance on this test obviates the need for more time-consuming clinical evaluation. Results of applying this test to the AVA 3.4 program are reported.

A study on vectorcardiographic criteria for evaluating right ventricular hypertrophy in chronic obstructive pulmonary disease.

Vectorcardiographic analysis was mainly made on the basis of hemodynamic findings through right heart catheterization in COPD. From the results obtained in the present study, the authors proposed the following quantitative VCG criteria as a mean for clinical recognition of right ventricular overload in patients with COPD. (I) Individual parameters of the criteria are: i) The QRS loop; (a) P/A (posterior force/anterior force) greater than or equal to 2.8 (b) R/L (rightward force/leftward force) greater than or equal to 0.6 (c) P/6 (posterior force/leftward force) greater than or equal to 1.8 ii) The P loop; Ap/Pp (anterior force/posterior force) greater than or equal to 1.8 (II) Criteria i) "RVH (right ventricular hypertrophy)" should satisfy more than 3 of the above individual parameters. ii) "RVH suspected" should satisfy 1 or 2 of them. iii) "RVH negative" should not satisfy any of them. The recognition rate for RVH by the present VCG criteria was higher than the conventional ECG criteria and there was good correspondence with autopsy findings.

Vectorcardiographic analysis of combined ventricular hypertrophy in adult patients.

Vectorcardiographic analysis of combined ventricular hypertrophy in adult patients.

The vectorcardiogram in Friedreich's ataxia

A Frank system vectorcardiographic analysis has been performed in 10 patients with Friedreich's ataxia. None had clinical signs of heart failure nor kyphoscoliosis. The electrocardiographic patterns were abnormal in five patients showing signs of left ventricular hypertrophy with inversion of T waves and abnormal rotation of the heart axis, and appeared practically normal in the other five. On the contrary, the vectorcardiographic features were abnormal in all ten patients studied. A prominence of lateral forces was present in the VCG of the first group in accordance with the scalar ECG, while patterns suggestive of diffuse myocardial damage were observed in the patients with a normal electrocardiogram. The vectorcardiographic alterations appeared strictly parallel to the degree of nervous involvement; this was particularly evident in three sisters and in two brothers whose vectorcardiographic abnormalities were similar in type and were proportional to the degree of neurological impairment.

The vectorcardiogram in Duchenne's progressive muscular dystrophy

This study represents a Frank system vectorcardiographic analysis of 34 patients with classic rapidly progressive X-linked recessive Duchenne's muscular dystrophy. The data add to the scanty body of descriptive vectorcardiographic information in this myopathic disorder. In addition the VCG was shown to be a useful supplement to the scalar ECG, and in the context of this analysis sheds light on the mechanisms responsible for the distinctive, uniform electrocardiographic-vectorcardiographic patterns in Duchenne's dystrophy. The characteristic electrocardiographic changes reside in the QRS; conduction abnormalities and rhythm disturbances—except sinus tachycardia—are of incidental importance. Previous studies have shown that the distinctive QRS patterns are not due to thoracic deformity, thoracic muscle atrophy, right ventricular hypertension, or coexisting coronary arteriopathy. The present study confirms that the patterns are not those of right ventricular hypertrophy or abnormal right ventricular conduction, and casts serious doubt on the idea that the essential explanation lies in persistence of the electrocardiographic-vectorcardiographic pattern of infancy and early childhood. The electrophysiologic abnormality may instead represent a genetically determined pattern that stems from disordered electrical activity of a particular zone of left ventricular myocardium.

Bigeminal rhythm, vectorcardiographic patterns in coronary artery disease

Vectorcardiographic analysis of spontaneous bigeminal VCPs in 46 patients with or without coronary disease revealed:o1.The vectorcardiograms of ventricular ectopic beat in normal hearts have smooth depolarization and repolarization patterns.2.The vectorcardiographic analysis of ventricular ectopic beats in most patients with diseased coronaries (M.I. or angina) revealed severe abnormalities of depolarization (bizarre contours, bites, notches, multiple conduction delays) and of repolarization (distorted T loops.)3.Distortion of the vectorcardiogram of ectopic ventricular beats strongly suggests the presence of underlying coronary artery disease, but a normal, smooth pattern of the extrasystolic beat does not always rule out this condition. The vectorcardiograms of ventricular ectopic beat in normal hearts have smooth depolarization and repolarization patterns. The vectorcardiographic analysis of ventricular ectopic beats in most patients with diseased coronaries (M.I. or angina) revealed severe abnormalities of depolarization (bizarre contours, bites, notches, multiple conduction delays) and of repolarization (distorted T loops.) Distortion of the vectorcardiogram of ectopic ventricular beats strongly suggests the presence of underlying coronary artery disease, but a normal, smooth pattern of the extrasystolic beat does not always rule out this condition.

Vectorcardiographic analysis of the pseudoinfarction pattern in idiopathic hypertrophic subaortic stenosis.

Vectorcardiographic analysis of the pseudoinfarction pattern in idiopathic hypertrophic subaortic stenosis.

Inferior atrial rhythms: Vectorcardiographic study and electrophysiologic considerations

The vectorcardiographic analysis of 19 subjects with inferior atrial rhythm as diagnosed by the ECG, has resulted in the following conclusions. 1. 1. There is a predominance of clockwise rotation of the P loop in the frontal plane and counterclockwise rotation in the horizontal and right sagittal planes. 2. 2. The initial limb of the loop and the greatest vector are directed upward and usually leftward. 3. 3. The spatial voltage of the greatest vector and the loop's dimention are within normal limits. 4. 4. No correlation has been observed between the VCG and the ECG classification of nodal and coronary sinus rhythms. 5. 5. The analysis of the horizontal plane permits the identification of several types of IAR, probably based on a different site of the pacemaker. The suggestion is proposed to change the classification of nodal and coronary sinus rhythms to inferior atrial rhythms.

Pacemaker vectorcardiography in patients with myocardial infarction and intraventricular conduction defects

Summary The VCG findings in 15 patients with transvenous pacemakers and myocardial infarction are presented and compared with those obtained in patients with left bundle branch block and myocardial infarction. In some of the cases with antero-septal infarction or antero-lateral wall myocardial infarction, the vectorcardiographic patterns resembled those described in experimentally produced myocardial infarction in dogs with left bundle branch block or in left bundle branch block and myocardial infarction in humans. When intraventricular conduction defects are associated with myocardial infarction, specific changes in the vectorcardiographic analysis could not be described.