The electrocardiogram in congenital heart disease and mitral stenosis

1.1. Mean levels of right ventricular pressure, flow, and work, but particularly mean levels of right ventricular work, are considerably higher in congenital heart disease than in mitral stenosis. 2.2. In congenital heart disease only abnormal electrocardiograms appeared above a mean right ventricular systolic ejection pressure of 30 mm. Hg. In mitral stenosis normal or borderline electrocardiograms appeared frequently up to a mean pressure level of 60 mm. Hg. 3.3. In congenital heart disease almost all electrocardiograms were abnormal above a right ventricular work load of 1 kg. M./min./sq.M. In mitral stenosis, normal electrocardiograms often occurred at work levels above 1 kg. M./min./sq. M. 4.4. In both mitral stenosis and congenital heart disease, the pattern of partial right bundle branch block appeared at almost all levels of right ventricular pressure and work, and thus this pattern appeared to be almost as significant as the classic pattern of right ventricular hypertrophy in the detection of right ventricular hypertension and presumptive right ventricular hypertrophy. 5.5. Gross electrocardiographic differences between congenital heart disease and mitral stenosis were present in all precordial leads; this was most marked in V 3R and V 1 , where the R wave in congenital heart disease was three to four times as tall as the comparable R wave in mitral stenosis. 6.6. In congenital heart disease, the electrocardiogram is remarkably accurate (91 per cent of cases) in the detection of right ventricular hypertrophy. In this disease no definite correlation was present between abnormalities of individual waves such as the height of R or RS ratio over the right precordium and levels of pressure or work. 7.7. The electrocardiogram in mitral stenosis is less diagnostic (51 per cent of cases) in the detection of right ventricular hypertrophy. But when the electrocardiogram is abnormal, a definite correlation is present between the height of R and RS ratios over the right precordium and levels of right ventricular pressure and work. 8.8. These differences in the total electrocardiographic picture suggest fundamental differences in the genesis of right ventricular hypertrophy in the two diseases.