Corrected (Frank), uncorrected (cube), and standard electrocardiographic lead systems in recording augmented right ventricular forces in right ventricular hypertension

Electrocardiographic diagnosis of chamber enlargement

The purpose of this article is to review the changing role of the electrocardiogram in the diagnosis of cardiac chamber enlargement. Electrocardiographic criteria for the diagnosis of ventricular hypertrophy and atrial enlargement are reviewed in relation to autopsy, angiographic, echocardiographic and imaging findings. The electrocardiographic theory underlying the recognition of hypertropphy or dilation incorporates a number of sound physical principles that may lead to meaningful correlations with the tissue mass, chamber diameter and intracardiac blood volume. However, there are limiting factors related to the variable orientation of the heart in the chest, variable extracardiac factors and nonspecificity of each depolarization and repolarization abnormality used in the diagnosis of hypertrophy or dilation. This explains the superiority of the new noninvasive methods, in particular echocardiography, in the diagnosis of hypertrophy. Echocardiography is superior to electrocardiography in the detection of mild hypertrophy, and is more useful in the serial follow-up of changes during progression or regression of chamber enlargement.

New vectorcardiographic criteria for diagnosing right ventricular hypertrophy in mitral stenosis: comparison with electrocardiographic criteria

Frank-lead vectorcardiograms (VCGs) and standard 12-lead electrocardiograms (ECGs) were analyzed to develop simple, linear, quantitative criteria for the diagnosis of right ventricular hypertrophy (RVH). The study subjects included a population with a definite RVH (84 patients with mitral stenosis proved by cardiac catheterization and pulmonary arterial systolic pressure > 40 mm Hg) and a population with minimal likelihood of RVH (173 young, healthy volunteers and 151 normal subjects proved by cardiac catheterization). VCGs were evaluated to identify criteria that provided maximum sensitivity and at least a 95% specificity: the maximum QRS magnitude had to be < 1.8 mV and either (1) the amplitude at -45 degrees (transverse plane) had to be < 0.3 mV or (2) the maximum anterior amplitude plus the maximum rightward amplitude minus the amplitude at -45 degrees must be greater than or equal to 0.5 mV. Application of these criteria achieved 60% (50 of 84) sensitivity in patients with RVH, similar to that for previous VCG criteria but significantly better (p < 0.01) than the best sensitivity with any ECG criteria (27%, 23 of 84). The specificity of the proposed criteria was 96% (310 of 324), significantly better (p < 0.001) than the 78% specificity (252 of 324) of existing VCG criteria. Thus, linear measurements of the QRS complex displayed on the VCG identify 60% of patients with moderate-to-severe RVH and falsely indicate RVH in only 4% of normal subjects.

Quantification of the Frank and McFee-Parungao orthogonal electrocardiogram in valvular pulmonic stenosis. Correlations with hemodynamic measurement

In 66 patients with congenital valvular pulmonic stenosis and intact ventricular septum, correlations were obtined among various multiple hemodynamic and orthogonal vectorcardiographic parameters. The Frank and McFee-parungao lead systems were used. The most important hemodynamic parameter evaluated was right ventricular pressure (RVP). RVP correlated best with X terminal to the right (XTR) in both Frank (R = 0.68) and McFee (R = 0.61) systems. The correlation between RVP and Z anterior was poor. The direction of the initial QRS vector on the X axis was helpful in predicting severity. With X initial to the right, especially in McFee, the RVP is most likely to be systemic or less, while with X initial to the left, the RVP is frequently but not necessarily suprasystemic. T vector spatial orientation is not helpful in the assessment of severity.

Simple quantitative vectorcardiographic criteria for the diagnosis of right ventricular hypertrophy

The vectorcardiogram is a useful supplement to the conventional electrocardiogram in the recognition of right ventricular hypertrophy. Many quantitative criteria have been proposed. However they are often too complicated for routine clinical application. Based on the distribution of the QRS loop area in the various quadrants in the vectorcardiogram in 198 normal subjects, three simple criteria for diagnosis of right ventricular hypertrophy are derived: 1) the anterior and rightward QRS loop area in the transverse plane is greater than 70% of the total; 2) the QRS loop area in the right posterior quadrant of the transverse plane is greater than 20% of the total; 3) the QRS loop area in the right inferior quadrant in the frontal plane is greater than 20% of the total. Vectorcardiogram recordings in 97 patients with atrial septal defect, mitral stenosis, and chronic obstructive lung disease with pulmonary hypertension met one or more of the criteria in 80 (83%). The conventional electrocardiogram of these patients was suggestive of right ventricular hypertrophy in 64 (66%). It is concluded that the proposed vectorcardiographic criteria provide a sensitive means for the diagnosis of right ventricular hypertrophy. Their specificity however was not tested.

Electrocardiogram and vectorcardiogram in Turner phenotype with normal chromosomes and pulmonary stenosis

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A study of the human heart as a multiple dipole electrical source. 3. Diagnosis and quantitation of right ventricular hypertrophy

The multiple dipole electrocardiographic (MDECG) method proposed earlier was evaluated further by testing its ability to diagnose and quantitate right ventricular hypertrophy (RVH). Two series of subjects were used. The first series consisted of patients with conditions giving a pressure overload of the right ventricle (RV), the RV systolic pressure (RVSP) being used to indicate the severity of RVH. The second series consisted of patients for whom a surgeon's visual estimate of RV size was available. A series of normal subjects was also used. For the first series a sensitivity of 85% for RVH diagnosis by MDECG was obtained, the specificity based on the normal series being 94%. The second, more inhomogeneous, series yielded a sensitivty of 75% and a specificity of 75%. This diagnostic performance was better than that obtained with conventional electrocardiographic or vectorcardiographic methods applied to the same patients.

To assess the quantitative ability of the MDECG, the results obtained for the first series were correlated with RVSP. A coefficient of determination for r 2 of 86% (standard error of RVSP estimate being 11 mm Hg) was obtained.