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