Background:
@EN Mechanism of blood flow during cardiopulmonary resuscitation(CPR) in humans remains controversial and poorly understood, although cardiac or thoracic pump theory was proposed. We investigated cardiac movement, ventricular function and
atrioventricular valve motion with aid of transesophageal echocardiography during precordial compression during CPR in humans.
@ES Methods and results:
@EN During CPR transesophageal echocardiography was performed in 14 patients with non-traumatic cardiac arrest. Manual precordial compression during CPR was performed according to American Heart Association guidelines. Mitral valve closed in 9
and
did
not close in 5 patients during "compression systole". Tricuspid valve closed during compression systole. Compression vector directed to right ventricle, basal portion of interventricular septum and left atrium. The heart rotated clockwise and the
apex
was more displaced than the base("swing motion"). Fractional shortening(FS) and ejection fraction(EF) of right ventricle exceeded those of left ventricle(FS:55±9% VS 18±8%, p<0.05), EF: 79±9% vs 37±16%, p<0.05). FS and EF of left ventricle
was
higher in patients with systolic mitral valve closure than patients with persistent systolic opening of mitral valve(FS: 21±7 VS 13±7, EF: 45±12 vs 22±12%, p<0.05), but FS and EF of right ventricle was not different.
@ES Conclusion:
@EN During precordial compression, the heart rotated clockwise and displaced. Systolic function of right ventricle exceeded left ventricle. Marked compression of right ventricle and systolic closure of tricuspid valve suggested that right
ventricle
functioned as a pump generating blood flow during precordial compression. Closure of mitral valve was dependant on systolic function of the left ventricle.
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