The cells are striated. Each cell only has one nucleus. But the giveaway here is probably the cells' branching structure; where their offshoots meet with other nearby cells where they form those intercalated discs. It's cardiac muscle.

这些细胞是条纹状的，每个细胞只有一个细胞核。但这里的信息可能是细胞的分支结构，它们的分支与附近的其他细胞相遇，形成了那些夹层盘。这是心肌。