tachy- / brady-
tachy- and brady- mean fast or slow (Greek).
"TACK-ee / BRAY-dee." Coach: "Tachy races; brady takes a break."
Examples: tachycardia, bradycardia, tachypnea, bradypnea, tachyarrhythmia.
Also: bradyarrhythmia, tachysystole, bradykinesia, tachyphylaxis, bradysystole.