Table 1. Comparison of clinical and electrocardiographic findings in myotonic dystrophy type 1 patients with normal and abnormal echocardiogram.

Parameter	Total (n=27)	Normal ECHO (n=17)	Abnormal ECHO (n=10)
Age (years)	39.1±14.1	47.4±11.10	34.2±13.6*
Male	16	9	7
Female	11	8	3
Duration of illness (years)	21.0±13.3	17.4±2.8	25.9±13.2
Cardiac symptoms	8	5	3
PR interval >200 ms	8	2	6
Left anterior fascicular block	7	5	2
QTc ms	414.6±30.1	414.0±27.8	415.5±34.7
Proximal weakness	19	11	8
Severe distal weakness (MRC <4)	13	7	6
Congenital myotonic dystrophy	6	5	1

^*P=0.017