{TAIL ~ The tachycardia rate zone} is defined by a lower threshold limit, and may also be defined by {HEAD ~ an upper threshold limit} if more than one rate zone is used 
{ TAIL ~ The tachycardia rate zone } is defined by a lower threshold limit , and may also be defined by { HEAD ~ an upper threshold limit } if more than one rate zone is used
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH