[Duchenne muscular dystrophy: electrocardiographic analysis of 131 patients].
BACKGROUND
Cardiac involvement is known to occur in patients with Duchenne muscular dystrophy (DMD). The electrocardiogram (ECG) shows some typical changes in DMD, which makes it a useful test for the diagnosis of cardiac lesion in this disease.


OBJECTIVE
To evaluate the electrocardiographic changes in patients with DMD and to correlate these changes with the age of the population studied.


METHODS
ECG of 131 patients diagnosed with DMD were examined. Several electrocardiographic variables were analyzed, and the patients were divided into two groups - one with and one without changes, for each variable studied. The correlation between the two groups and the age of the patients was analyzed. Garson's criteria were used to establish the electrocardiographic parameters of normality.


RESULTS
ECG was abnormal in 78.6% of the patients. All showed normal sinus rhythm. The following percentages were found for the main variables studied: short PR interval = 18.3%; abnormal R waves in V1 = 29.7%; abnormal Q waves in V6 = 21.3%; abnormal ventricular repolarization = 54.9%; abnormal QS waves in inferior and/or upper lateral wall = 37.4%; conduction disturbances in right bundle branch = 55.7%; prolonged QT C interval = 35.8%, and wide QRS = 23.6%. Unpaired t test was used to establish the correlation between age and the electrocardiographic variables studied in the two groups. Statistically significant differences were found only for the abnormal repolarization variable.


CONCLUSIONS
Electrocardiographic abnormalities are common in DMD, revealing early cardiac involvement. Only the abnormal ventricular repolarization variable was more frequent, however at a lower age range (p < 0.05).
Santos
Maria Auxiliadora Bonfim
MA
Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brasil.
Costa
Francisco de Assis
Fde A
Travessa
Aline Ferreira
AF
Bombig
Maria Teresa Nogueira
MT
Fonseca
Francisco Helfenstein
FH
Luna Filho
Bráulio
B
Mussi
Aurélia
A
Souza
Dilma de
Dd
Oliveira
Acary de
Ad
Povoa
Rui
R
D000367:Age Factors; D002648:Child; D004562:Electrocardiography; D006331:Heart Diseases / Q000175:diagnosis*; D006801:Humans; D008297:Male; D020388:Muscular Dystrophy, Duchenne / Q000150:complications* / Q000175:diagnosis; D012016:Reference Values