title: [Studies on P waves of mitral valvular diseases by the high-speed and magnified electrocardiograms].
abstract: Atrial waves of the electrocardiograms (ECG) of 50 cases of normal subjects and 113 cases of mitral valvular diseases (76 cases of mitral stenosis, 20 cases of mitral insufficiency and 17 cases of mitral steno-insufficiency) were studied by means of the high-speed and magnified electrocardiography. Leads II and V1 and three scalar leads of Frank system (X, Y and Z leads) were recorded by this method. Morphologic observations as well as the quantitative measurements of the amplitudes and the durations of P waves were carried out. Correlations among the various parameters of the P waves and hemodynamic data were examined. and the electrocardiographic criteria for the diagnosis of the left atrial overloading were investigated. The results obtained were as follows: 1) More detailed informations regarding to P waves were obtained by means of the high-speed and magnified ECG. 2) On statistical comparisons of the mean values of the P waves among the normal and the three groups of mitral valvular diseases, the amplitude, the duration and the peak time in lead II were larger in the latter, and the amplitude of positive and negative phases, the duration of negative phase of the diphasic P waves in lead V1 were learger in the latter, while the duration of positive phase was larger in the former. In leads X and Z of Frank system the findings were similar to those in leads II and V1 respectively. 3) The mean values of the instantaneous amplitudes of each 10 msec interval of P waves of scalar ECG of Frank system were compared among the normal and the three groups of the mitral valvular diseases..
mesh_terms: D002306:Cardiac Volume; D004562:Electrocardiography; D006439:Hemodynamics; D006801:Humans; D008944:Mitral Valve Insufficiency / Q000175:diagnosis*; D008946:Mitral Valve Stenosis / Q000175:diagnosis*