The coordinate parallel method was adopted in this study on the double pole lead vector by inference. The standard lead was used as an example, and the theoretical adjustment lead axis was compared with the Burger experiment adjustment lead axis, and with the Einthoven ideal symmetrical lead axis, too. The theoretical adjustment lead axis was noted to be very close to the Burger experiment adjustment lead axis.
Electrocardiography ; methods ; Humans ; Mathematical Computing ; Vectorcardiography ; instrumentation ; methods

The vectorcardiography was performed on 34 cases with PRWP of precordial leads. We have studied the vectorcardiographic finding for the differential diagnosis of disease entities were obtrained; 1) Poor R-Wave progression of precordial leads has simply considered as suggestion of anterior myocardial infarction, ischemic heart disease, chronic lung disease and normal variant. 2) The sensitivity and specificity of myocardial infarction criteria were 85.8% and 63.0% respectively in left sagittal plane and 85.8% and 66.7% respectively in horizontal plane. 3) The seneitively and specificity of more than 90 QRS-T vector angle in left sagittal plane were 100.0% and 62.5% respectively in ischemic heart disease and myocardial infarction. 4) The sensitively and specificity of chronic lung disease criteria were 85.7% and 51.9% respectively. 5) Vectorcardiographic study was considered as effective differentiating method for patients with PRWP in EKG.
Diagnosis, Differential* ; Electrocardiography* ; Humans ; Lung Diseases ; Myocardial Infarction ; Myocardial Ischemia ; Sensitivity and Specificity ; Vectorcardiography*

OBJECTIVETo evaluate the possibility of resultant cardiac vector of ex vivo guinea pig heart.

METHODSECGs were recorded in 4 directions on every plane, and in each direction 4 points at different distances from the anterior, posterior, right and left of isolated guinea pig ventricles immersed in normal saline and distilled water.

RESULTSMain upward waves of ECGs were recorded at all points in 4 directions at 3 levels in the two media. The voltage distribution of normal electrocardial field of the QRS wave was of all-round outward shape, which did not match the resultant cardiac vectors between the left and right and between the anterior and posterior ventricular walls.

CONCLUSIONThere are some confusion and contradiction in the resultant cardiac vector based on the voltage distribution of electrocardial field around ex vivo guinea pig heart.

Animals ; Electromagnetic Fields ; Female ; Guinea Pigs ; Heart ; physiology ; In Vitro Techniques ; Male ; Vectorcardiography ; methods

We studied the wall motion characteristics of the ascending aorta by velocity vector imaging (VVI) in primary hypertension patients. The ascending aortas both in 30 patients with primary hypertension and 30 normal controls were examined by Acuson sequoia 512 equiped with VVI. The maximum velocity (Vs, Ve) of every point on the anterior wall of ascending aorta both in systole and diastole was measured. The aortic diameter was wider in the hypertension patients than that in the healthy subjects (P<0.05). The movement amplitude of the anterior wall of the ascending aorta in long axis view in the hypertension patients was lower than that in the healthy subjects (P<0.05). The motion and time to peak in systole of each point of the ascending aorta in the healthy subjects had no significant difference (P>0.05). The velocity curves of the anterior wall of ascending aorta both in the hypertension and healthy subjects were regular, and the curve in systole was named S wave and that in diastole named E wave. The velocity of S wave and E wave was slower in the hypertension patients than that in the healthy subjects (P<0.05). The time to peak of S wave on the anterior wall of ascending aorta in systole was shorter in the hypertension patients than in the healthy subjects (P<0.05). VVI could be used to accurately and directly observe the movement character of the ascending aorta walls, which would help us understand the elasticity of great arteries in patients with hypertension.
Aorta/pathology ; Aorta/*physiopathology ; Aorta/ultrasonography ; Blood Flow Velocity ; Case-Control Studies ; Echocardiography/*methods ; Elasticity ; Hypertension/pathology ; Hypertension/*physiopathology ; Vectorcardiography/*methods ; Ventricular Dysfunction, Left/physiopathology ; Young Adult

A new computer-assisted vector-cardiogram analyzing system Model TJ-IV developed based on Model TJ-III, has been using in the routine clinical work in order to evaluate its features and performances. The system employs a 586 computer with a CPU of 120 MHz, a special low-noise amplifier, a 12 bit A/D tranducer and the C language for programming. The examinations of 206 cases were performed and all the vector-cardiograms were analyzed by the computer system and by manipulative methods respectively. In comparison with the manipulative methods the system has a very high accuracy of picture-recognition. The accuracy for distinguishing the onsets and terminals of orthogonal ECG waves is 98% while that for distinguishing the peaks and troughs of the waves is 100%. These waves include P, Q, R, S, R' and S' waves. The new system is capable to provide the parameters of more than 591 items, including 46 newly-developed diagnostic parameters. The testing and analyzing of 12 parameters of orthogonal ECG and plane VCG have proved that the results of the aboved two methods have no difference. The new system has a very high accuracy of picture-recognition and index calculation with many technical problems existing in the old versions, solved--a great improvement of safety and anti-interference and an increase of the detecting & diagnostic speed.
Adolescent ; Adult ; Aged ; Automatic Data Processing ; Computer Systems ; Diagnosis, Computer-Assisted ; instrumentation ; Female ; Humans ; Male ; Middle Aged ; Myocardial Infarction ; diagnosis ; Reference Values ; Reproducibility of Results ; Signal Processing, Computer-Assisted ; Software ; Vectorcardiography ; instrumentation

OBJECTIVETo observe whether there was difference between the head-chest leads electrocardiogram (HCECGs) and routine lead electrocardiogram (RLECGs) in the manifest accessory pathways in patients with Wolff-Parkinson-White syndrome.

METHODSHCECGs and RLECGs were recorded simultaneously in patients with Wolff-Parkinson-White syndrome, whose manifest accessory pathways had been confirmed by radiofrequency catheter ablation and intra-cardiac electrophysiology according to the same standard set beforehand. The diagnosis of pathways location was made by analysis of each HCECG and RLECG by two senior physicians in clinical electrophysiology. The diagnostic accuracy of the HCECGs and RLECGs was evaluated by the comparison with that of the intra-cardiac electrophysiology. The delta wave size was also compared between HCECGs and RLECGs.

RESULTSThe diagnostic accuracy in the manifest accessory pathways was 86.2% (50/58) in RLECGs, and 84.4% (49/58) in HCECGs in the 58 patients with Wolff-Parkinson-White syndrome, showing no significant difference between them (P > 0.05), but each delta wave in HCECG was more evident than that in RLECG.

CONCLUSIONHCECG and RLECG both have high diagnostic accuracy in the manifest accessory pathways in patients with Wolff-Parkinson-White syndrome.

Body Surface Potential Mapping ; Electrocardiography ; Humans ; Wolff-Parkinson-White Syndrome ; diagnosis ; physiopathology

In this paper, a method based on the convex hull algorithm is presented for extracting modelling data from the locations of catheter electrodes within a cardiac chamber, so as to create a 3-D model of the heart chamber during diastole and to obtain a good result in the 3-D reconstruction of the chamber based on VTK.
Algorithms ; Body Surface Potential Mapping ; methods ; Catheter Ablation ; Humans ; Image Processing, Computer-Assisted ; methods

Surface Laplacian of the body surface potential (Laplacian ECG--LECG) is a new approach to resolve spatially distributed bioelectrical source. In this paper, we discussed an LECG sensor which integrated triple concentric ring electrodes and signal adjustor on a printed board. The LECG is measured directly by this sensor. The frequency, amplitude and phase of the power line interference were detected by a nonlinear adaptive filter so that interference was eliminated. The wavelet shrinking technique was used to eliminate the rest of random noise. And we got the high quality LECG signal. It laid the foundation for heart disease diagnosis.
Algorithms ; Body Surface Potential Mapping ; methods ; Electrocardiography ; methods ; Electrodes ; Humans ; Signal Processing, Computer-Assisted

In this article, some details about the parameter optimization of body surface Laplacian electrodes are presented theoretically and practically. The influence of these parameters on the performance of the electrodes is studied to derive some rules which have to be obeyed during the design. An evaluation routine based on relative error analysis and the noise level of amplifier is prompted. Furthermore, the paper particularly indicates that, it would be helpful to reduce the relative error when assuming that the effective radius b is equal to the inner radius r(i) of the ring electrode. Finally, we suggest that in the presence of weak bioelectrical signals, the effective radius of the electrodes should be reasonably increased in order to improve signal-to-noise ratio (SNR).
Body Surface Potential Mapping ; methods ; Electric Impedance ; Electrodes ; Humans ; Signal Processing, Computer-Assisted

The endeavors to solve the inverse problem of electrocardiography embody the approach to calculate the epicardial potentials using the measured body-surface-potential distribution; it is important for pathology and very useful for clinical application. In this paper, we construct the 2D human torso model using the FEM method and solve the forward problem. In the constructed state-space equations, and the relationship between the body surface potentials and epicardial potentials in the FEM torso model is the measurement equation, and the relationship of the adjacent states is the state process equation. To solve the problem of uncertainty of the parameters, we design the likelihood function and introduce the Expectation Maximization (EM) algorithm. Step E (Expectation) estimates the parameters using the Kalman filter; step M (Maximization) re-estimates the parameters using the likelihood functions, step E and step M iterate. Simulations of the whole process show that EM algorithm leads to better convergence of the solutions than does the traditional Kalman filtering, and the relative errors are much smaller than before.
Algorithms ; Body Surface Potential Mapping ; methods ; Finite Element Analysis ; Humans ; Models, Cardiovascular ; Signal Processing, Computer-Assisted