The ventricular patterns in the right precordial leads in mitral stenosis

Abstract

1. 1. Routine 12-lead electrocardiograms were recorded in 173 patients with mitral stenosis, 136 of whom had right ventricular hypertrophy assessed clinically and radiologically. In fifty-five of these patients Leads V 1 and V 6 were recorded synchronously. 2. 2. A great variety of QRS patterns were obtained from precordial Lead V 1 and these fell into five groups: 2.1. A. Clinical and radiologic evidence of right ventricular hypertrophy was present in sixty-seven of the 104 patients who showed normal rS or S complexes in Lead V 1. 2.2. B. Rs complexes or single R waves occurred in Lead V 1 in twenty-one patients, all of whom had clinical evidence of right ventricular hypertrophy which was confirmed radiologically in fifteen cases. There was no relationship between the height of the R wave and the time of onset of the intrinsicoid deflection in these twenty-one cases, and the criteria for the electrocardiographic diagnosis of right ventricular hypertrophy were not completely fulfilled in any. 2.3. C. RSR′ patterns were obtained in thirty-six patients, all of whom had clinical and radiologic evidence of right ventricular hypertrophy, but in twenty the form of the complexes was similar to that sometimes obtained in normal subjects. In all patients there was delay in the intrinsicoid deflection and in two right bundle branch block was present. 2.4. D. A qR complex was recorded from V 1 in nine patients, all of whom showed clinical and radiologic evidence of right ventricular hypertrophy. Delay in the onset of the intrinsicoid deflection occurred in all. 2.5. E. Polyphasic complexes occurred in three patients who showed right ventricular hypertrophy on clinical and radiologic examination. 3. 3. It is probable that in many patients in this series, the degree of right ventricular hypertrophy was insufficient to produce forces capable of outweighing those incident to simultaneous left ventricular excitation. The absence of classical electrocardiographic signs of right ventricular hypertrophy in any patient in Groups 1 and 2 of the present series suggests that there is a need for the clear definition of the electrocardiographic signs of right ventricular hypertrophy in mitral stenosis. 4. 4. The lack of correlation between the height of the R wave and the time of onset of the intrinsicoid deflection in the V 1 Rs and R complexes suggests that delay in onset of the intrinsicoid deflection is not a reliable sign of right ventricular hypertrophy in mitral stenosis. 5. 5. Synchronous leads showed an essential similarity between RSR′ and qR complexes in Lead V 1. Evidence is presented to show that a qR pattern in right precordial leads in patients with mitral stenosis is not due to potentials derived from the left ventricle. 6. 6. The tall secondary R′ waves of RSR′ complexes and the R waves of qR complexes were considered to be due to the slow passage of the stimulus through the wall of the right ventricle when stimulation of the left ventricle was almost complete. It is suggested that in mitral stenosis the slow passage of the stimulus is related to the type of thickening of the right ventricular wall, which in this disease consists largely of hypertrophied trabeculae.