[Prevalence, signification and prognosis of auricular arrhythmia in dilated myocardiopathies. Apropos of 236 cases].

A population of 236 patients with dilated cardiomyopathy (DCM) was studied and followed up for an average of 38.8 +/- 27 months. The most common atrial arrhythmia was atrial fibrillation (AF) which was observed in 27 p. 100 of cases. Patients with AF (n = 43) and without it (n = 193) at the time of diagnosis were compared: the subjects with AF were older (p = 0.036), had a higher left ventricular ejection fraction and lower end diastolic pressures (p = 0.022). AF was associated with mitral valve prolapse (p = 0.007) and with signs of adiastole (p = 0.0015); the most significantly correlated variable was echocardiographic dilatation of the left atrium (p = 0.0012). AF was the presenting symptom of DCM in 13 cases (5.5 p. 100); in 10 cases (4 p. 100) it was the main clinical and therapeutic problem, realizing an arrhythmic form of DCM. Electrical conversion was successful in 7 out of 11 patients with a 2 year follow-up: 3 patients remained in sinus rhythm for over 6 years and have no clinical symptoms, posing the problem of the dominant if not exclusive underlying role of AF in these cases of DCM. An example illustrated by several echocardiographic examinations is presented. Embolic complications were observed in a quarter of the cases with AF and this arrhythmia was present in half the patients with embolic phenomena. However, the prognosis in the groups with and without AF was not significantly different.