Different types of mechanical assistance have been considered in the management of central circulatory insufficiency. Four major maneuvers have been considered: (1) total or partial cardiopulmonary bypass; (2) postsystolic myocardial augmentation; (3) venoarterial shunt, and (4) selective right or left ventricular bypass.
In postsystolic myocardial augmentation the augmenting ventricle (Fig. 1) is a blindended diverticulum which aspirates blood during the true ventricular systole and returns the blood to the arterial tree during ventricular diastole, when the aortic valve is closed. Thus, the ventricle contracts against reduced resistance. Such counter-cycling can reduce and perhaps can eliminate the intraventricular pressure curve. The real problem lies in phasing and synchronization of the augmenting ventricle. We have developed such equipment and an electronic circuit which enables the phasing of the augmenting systole to be accurately placed, utilizing the QRS complex of the electrocardiogram.
Partial bypass of the heart and lungs by means of a
WATKINS DH, DUCHESNE ER. Postsystolic Myocardial AugmentationI. Developmental Considerations and Technique. Arch Surg. 1961;82(6):839-855. doi:10.1001/archsurg.1961.01300120053007