動悸が激しくなることがよくあります。

palpitation (e.g. heart); pulsation; throbbing

indicates sentence subject (occasionally object); indicates possessive (esp. in literary expressions); but; however; still; and

violent; furious; tempestuous; extreme; intense; fierce; fervent; vehement; incessant; relentless; precipitous; steep

to become; to get; to grow; to be; to reach; to attain; to result in; to prove to be; to consist of; to be composed of; to succeed; to be complete; to change into; to be exchanged for; to play a role; to be promoted; to do ...

thing; matter; incident; occurrence; event; something serious; trouble; crisis; circumstances; situation; state of affairs; work; business; affair; after an inflectable word, creates a noun phrase indicating something the speaker does not feel close to; nominalizing suffix; pretending to ...; playing make-believe ...; alias; aka; nickname; alternative name; also known as

nicely; properly; well; skillfully; skilfully; frequently; often

to be (usu. of inanimate objects); to exist; to live; to have; to be located; to be equipped with; to happen; to come about