The assessment of the effects were done by clinical observation and with hemodynamic parameters measured from M-mode echocardiogram of the left ventricle.

Ninety minutes after the first dose of 6mg, endsystolic dimensions were decreased significantly while stroke volume, ejection fraction, fractional shortening, mean rate of circumferential fiber shortening and stroke work were increased significantly.

Left ventricular ejection time and cardiac output were not changed measurably with prazosin therapy. Seventeen out of 20 showed clinical improvement from NYHA functional class IV or III to III or II at the end of a week, majority of them reported improving their symptoms following the first dose of parazosin. We conclude that the oral parazison is safe and effective in the treatment of severe CHF of various causes.