Also, stimulation at a physiological back up frequency is provided in {HEAD ~ the event} of {TAIL ~ a detected ventricular pause} 
of
Also , stimulation at a physiological back up frequency is provided in { HEAD ~ the event } of { TAIL ~ a detected ventricular pause }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL