Some patients are unable to exercise on a treadmill test, but they can still undergo cardiac stress testing by using intravenous medication that causes the heart to work harder.

Please remove spaces between words.
Somepatientsareunabletoexerciseonatreadmilltest,buttheycanstillundergocardiacstresstestingbyusingintravenousmedicationthatcausesthehearttoworkharder.