Basistaya (from lat. bis -, double -, and Greek. systole - reduced) - intermittent, two-phase contraction of the left ventricle. The essence of bisystolic, which was described by B. N. Samples (1908), is that for one beats the left ventricle is reduced twice, and the first, less intensive reduction separated from the second 0,03-0,05 sec. basistaya observed in case of insufficiency of aortic valves in patients with severe hypertrophy and dilatation of the left ventricle of the heart. Clinically B. is expressed by the double apical impulse, which shall be confirmed by a cardiogram, and split the first heart sound. The last is caused by occurrence incremental tone at the time a second, more intense reduction ventricle. During feeling major artery (carotid, subclavian) is defined distinct split of the pulse wave, register and on spirogramma these vessels (called pulsus bisferiens); on the smaller arteries of this split was not revealed. The phenomenon of bisystolic many scientists are not recognized.