One of those d'oh moments ...
testdisk is the answers for this. LVM doesn't matter - at this point; so long as the PV was in fact a partition, and not the entire disk.
You could also simply fix it from fdisk if the partition covered the entire disk.
Have a look at /proc/partitions.
One also assumes this didn't contain your stage1 boot code - else you'd better rectify that too before re-booting.