[Wolff-Parkinson-White syndrome and cardiopathies].

Forty-nine cases of Wolff-Parkinson-White syndrome (WPW) were diagnosed out of 10 750 patients with cardiac disease (0.45 p. 100), 24 cases out of 3 761 congenital malformations and 25 cases in the 6 989 patients with acquired heart disease. Right ventricular pre-excitation was recorded in 31 cases; 13 in the lateral zone, 12 in the posterior paraseptal zone and 6 in the anterior paraseptal zone. Left ventricular pre-excitation was recorded in 18 cases: 8 in the lateral zone, 5 in the anterior paraseptal and 5 in the posterior paraseptal zones. WPW and congenital heart disease: Out of 20 cases of Ebstein's anomaly, 5 cases of WPW were observed: 4 right posterior and 1 right lateral pre-excitations. Out of 218 cases of hypertrophic obstructive cardiomyopathy, 7 cases of WPW were observed, 4 of which were congenital. Three cases of WPW were recorded in 699 patients with ventricular septal defects. Out of 1 348 cases of atrial septal defect, 5 cases of pre-excitation were recorded, including 3 right posterior pre-excitations associated with an ostium primum defect. Pre-excitation was also observed in isolated cases of corrected transposition of the great arteries, supravalvular aortic stenosis, aortic incompetence and patent ductus arteriosus. Pre-excitation and acquired heart disease: Five cases of pre-excitation were recorded out of 305 cases of dilated cardiomyopathy (1.62 p. 100). Eleven cases of pre-excitation were recorded in a total of 3 471 cases of valvular heart disease (0.31 p. 100): 9 in rheumatic valve disease and 2 in mitral valve prolapse. Nine cases of pre-excitation were observed in 2 850 cases of coronary artery disease. Intermittent Wolff-Parkinson-White syndrome: Ventricular pre-excitation masks the ECG changes of complete right bundle branch block in Ebstein's anomaly, complete left bundle branch block in aortic incompetence and dilated cardiomyopathy, and the in-complete right bundle branch block often seen in mitral valve prolapse. The characteristic appearances of WPW depend on the zone of pre-excitation. Right ventricular hypertrophy observed in ventricular septal defect with pulmonary stenosis and mitral stenosis may be masked by right lateral pre-excitation. Changes of inferior wall myocardial infarction may be masked by left anterior wall pre-excitation. On the other hand, the effects of WPW on left ventricular hypertrophy are variable, high amplitudes of the resultant forces seeming to depend on late and isolated activation of one of the left ventricular walls.