Intrathoracic pressure deviations attenuate left ventricular filling and stroke volume without pronounced myocardial mechanical alterations in healthy adults.

Intrathoracic pressure modulates cardiac loading conditions, which then influence left ventricular (LV) chamber function, and may occur with underlying myocardial mechanical alterations. We investigated the independent effects of inspiratory negative and expiratory positive intrathoracic pressure on septal geometry, LV chamber function, and rotation, twist, and strain indices. After baseline, 20 healthy adults (11M/9F, 23 ± 4 yr) performed resistive breathing to manipulate inspiratory (-30, -20, -10 cmHO) or expiratory (+10, +20 cmHO) intrathoracic pressure.