。
My pulse is fast.
Literal
Pulse [subject-が] is-fast.
脈 ('pulse') with が-marked subject and the i-adjective 速い describes a state. Note that 速い and 早い share the kana spelling はやい — 速い means 'fast (speed)' while 早い means 'early (time),' so the kana-only spelling is ambiguous between the two. In medical contexts the pulse-pattern phrasing is direct and standard — polite form combined with plain everyday vocabulary.