MYOCARDIAL DYSFUNCTION THERAPEUTIC AGENT

The present invention establishes a method for treating cardiac dysfunction. An oligonucleotide of 15-30 bp comprising a nucleotide sequence complementary to a part of the intron 55 region of a dystrophin gene, which comprises the sequence of 5′-TGTCTTCCT-3′ or 5′-CAGCTTGAACCGGGC-3′ (SEQ ID NO: 64) (wherein "T" may be "U" in either sequence), a pharmacologically acceptable salt thereof, or a solvate thereof. A prophylactic and/or a therapeutic for cardiac dysfunction, comprising the above-described oligonucleotide, a pharmacologically acceptable salt thereof, or a solvate thereof. A suppressor of Dp116 expression, comprising the above-described oligonucleotide, a pharmacologically acceptable salt thereof, or a solvate thereof.