Sequential changes in high frequency notches on QRS complexes in progressive muscular dystrophy of the Duchenne...

In a 3-year follow-up study, sequential changes in the number of high frequency notches (HFN) on QRS complexes were investigated on 72 cases with progressive muscular dystrophy of the Duchenne type (PMD). The patients were classified into eight stages from the mildest, S(1), to the most severe, S(8), according to Swinyard-Deaver's criteria. The number of HFN progressively increased with advancing Swinyard-Deaver's stage. In the terminal stage, however, the number of HFN tended to decrease. The present observations show that the patient tends to have a small number of HFN in the early stages of the disease; with increasing severity of the disease he develops a larger number; in the terminal stage he again exhibits relatively few notches. It is concluded therefore that significant increases or decreases in the count of HFN on QRS complexes can be useful indicators for estimating the extent and severity of cardiac involvement in PMD.