Functional Characteristics of the Left Ventricular Inflow and Outflow Tracts.

• The heart chambers contract sequentially and any significant alteration in spread of the electrical activity may bring about a change in sequence. While recording contractile force from multiple sites on a single ventricle, it was noted that different portions of the ventricular myocardium showed consecutive onset of systole. Puff employed high-speed cinematography to study changes in ventricular configuration during systole.He reported that the inflow and outflow tracts contract consecutively, simulating a peristaltic wave along the main blood pathway through each ventricle. His observations suggest that, during ventricular systole, the oblique tracts of fibers twist and the papillary muscles become opposed in such a way as to produce physical separation of the inflow and outflow tracts. While studying synchrony of ventricular contraction, we observed that the intervals between initial pressure elevations in different chambers were influenced by the position of the catheters within the chambers. We also noted that the wave form of force recordings from the ventricular muscle depended strongly upon the placing of the strain gauges relative to the orientation of the muscle layers. We examined therefore the inflow and outflow tracts of the left ventricle to learn whether these are simply convenient anatomical terms or represent functional car-