VASCULAR collapse is frequently associated with paroxysmal tachycardia. The medical literature consists for the most part of single case reports and reveals that whereas in some cases collapse is associated with rapid ventricular rates, in others it is absent with equally rapid rates.123456789101112131415 I16 have observed vascular collapse in 15 of 125 cases of tachycardia, and have pointed out that it occurred only under specific conditions, thus justifying its designation as one of the cardinal manifestations of paroxysmal tachycardia. In the present study 128 new cases have been added to the 125 previously reported, making a total of 253. All . . .