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Biomedical subjects

C R Brohet

Publications and source records attributed to C R Brohet.

24 records · Page 2Linked to original sources
PubMed1977

A computer system automatic analysis of vectorcardiograms.

This computer system performs the analysis of orthogonal electrocardiograms for vectorcardiographic (VCG) display and classification. The data acquisition can be performed 'on-line' with the complete analysis in 'real-time', or off-line by processing a magnetic tape. The original computational methods for beat averaging and wave recognition are described. Some features, such as the quality of the visual display of the VCG traces, the availability of a measurement matrix allowing the quantitative analysis of the VCG and the use of a data bank for storage, retrieval and statistical studies make this system very efficient for clinical purposes, introducing the concept of 'Computer Assisted Vectorcardiography'.

Diagnosis, Computer-Assisted↗
PubMed1977

Spatial Frank vectorcardiogram in left posterior fascicular block. Criteria and correlation with clinical and electrocardiographic data.

Computer processing of spatial QRS parameters (Frank vectorcardiogram) was used to study left posterior fascicular block. The best set of vectorcardiographic criteria was sought in order to characterise the classic pattern of left posterior fascicular block. Using these criteria, 18 cases were selected from a group of 4600 patients and 340 healthy subjects; isolated left posterior fascicular block was seen in 10 cases, and was associated with right bundle-branch block in 8 cases. It is shown that some external factors can influence the aspect of the spatial QRS loop in left posterior fascicular block: cardiomegaly tends to produce a superior displacement of the main QRS forces: right bundle-branch block enhances the superior displacement of the initial forces and shifts the main QRS forces more anteriorly and to the right. The 'masquerading effect' of the left posterior fascicular block on a concomitant inferior myocardial infarct was also shown. The most important diagnostic feature was the opposite direction of the initial forces (left anterosuperior) and the maximal vector (right postero-inferior): the angle between these two vectors averaged 152 degrees. Other criteria, such as the direction of rotation or the axis of the frontal loop, the vertical direction of the spatial loop, the presence of a Q wave in leads II, III, and aVF of the electrocardiogram, are not mandatory for the diagnosis of left posterior fascicular block.

Adolescent↗
PubMed1977

Reassessment of the diagnostic value of the vectorcardiogram in cystic fibrosis (correlation with clinical score, pulmonary function tests and echocardiogram).

In 21 children with cystic fibrosis, the vectorcardiogram (VCG) was correlated with various indices of the severity of the disease. The best correlation was found between (1) the azimuth angle of the spatial QRS loop area, representing the rightward and posterior shift of the main electrical forces, and pulmonary function tests (PFT): FEV1 % predicted (r = -0.671, P less than 0.005) and VC% predicted (r = -0.607, P less than 0.005), and (2) the right ventricular anterior wall index measured echocardiographically (r = 0.472, P less than 0.05). More VCG parameters correlated significantly with PFT than with the echocardiogram. This shows the major influence of pulmonary changes on the VCG of those patients. In several subgroups with different clinical scores, the VCG were analyzed and compared to normal limits of age- and sex-matched controls. In this small series, the VCG was a specific but not very sensitive method for predicting the degree of severity of the disease. Echocardiography and vectorcardiography can be considered as two complementary techniques in the evaluation of cystic fibrosis.

Adolescent↗
PubMed1975

P wave abnormalities in the orthogonal electrocardiogram: Correlation with ventricular overload in pulmonic and aortic valvular heart disease.

The correlation between several P wave measurements form the orthogonal electrocardiogram (SVEC III lead system) extracted by computer analysis and simple hemodynamic parameters related to ventricular dysfunction was studied in two groups of patients. Group I consisted of 32 patients with pulmonic valvular stenosis and intact interventricular septum. There was a significant correlation between electrocardiographic criteria of right atrial overload and the two hemodynamic parameters studied: peak pulmonic systolic pressure gradient and right ventricular end diastolic pressure (r = 0.502, p smaller than 0.005 and r = 0.661, p smaller than 0.001 respectively). Group II consisted of 49 patients with aortic valve disease. In this group, a significant correlation between the electrocardiographic parameters of left atrial overload and the left ventricular end diastolic pressure could be demonstrated only be a multivariate regression analysis (r = 0.630, p smaller than 0.005). The P wave measurements that are well correlated with the ventricular end diastolic pressure can be considered as valuable criteria for atrial enlargement secondary to a decrease of ventricular compliance, such as seen in ventricular hypertrophy, failure or in ventricular constrictive or restrictive diseases. The pathophysiologic mechanisms of the influence of the ventricular overload (dysfunction) on the atrial function and the resulting P wave changes are discussed.

Adolescent↗
PubMed1975

Quantative analysis of the vectorcardiogram in obesity. The effects of weight reduction.

Vectorcardiograms (VCG) recorded in 37 subjects with marked chronic EXOGENOUS OBESITY (AVERAGE WEIGHT: 285 LBS.) WERE COMPARED before and after a significant weight reduction (average weight loss: 86 lbs). They were also compared with the VCGs of 293 age and sex matched controls with normal body weight. The SVEC III corrected orthogonal lead system was used, and out of several hundred vectorcardiographic measurements obtained by computer processing, 59 measurements representing various scalar, planar and spatial voltage and angular measurements were selected for study and comparisons. No significant differences were found between the measurements of obese subjects and those of the controls. Of 59 VCG measurements, 13 showed significant differences after weight reduction (paired t test) although they remained within the range of normal controls. There was a trend toward decrease of P and QRS amplitudes after weight reduction. There were no significant changes in the angular measurements. Although they are statistically significant these changes in voltage are too small to be detected in clinical vectorcardiography. The possible decrease of a preexisting myocardial hypertrophy superimposed onto the changes in the anatomy of the thorax might explain the effects of weight reduction. In general the reproducibility of VCG measurements obtained by the SVEC III system was greater than that reported in day-to-day operation with the Frank system in normal subjects.

Adipose Tissue↗