|Air Date||March 6, 2004|
|Previous episode:||Next episode:|
|Kaito's Nightmare||Darkness of The Heart|
Heartbeat is the fourty-ninth episode of Mermaid Melody Pichi Pichi Pitch.
Sheshe and Mimi steal the two captured mermaids' pearls. Once they are used to power their evil microphones, the sisters dare the four Mermaid Princess to fight them. Aqua Regina gives the Mermaid Princesses a new song. Hippo retrieves the "key" that allows him to transform into his true self – the Hippocampus.