The Wright table of the cardiac cycle: a stand-alone supplement to the Wiggers diagram

Abstract

The Wright table is introduced as a novel tool for teaching and learning the cardiac cycle. It supplements the nearly 100-yr-old Wiggers diagram, which is information rich but difficult for many students to learn. The Wright table offers a compact presentation of information, viewable both in terms of how 1) each compartment’s pressures and flows change over time; and 2) the heart works as a pump, first filling and then emptying the ventricles, thereby moving blood from low-pressure venous to high-pressure arterial compartments. This new four-by-four display of interrelated aspects of cardiac cycle events offers a more integrated view of the phases of ventricular filling and emptying than can be easily observed in the Wiggers diagram. It also shows how ECG-related waves of depolarization and repolarization drive the events of each subsequent phase. The Wright table is a stand-alone teaching aid; however, it is designed such that weaknesses of the Wiggers diagram are complemented by strengths of the Wright table, and vice versa. Results of an anonymous student survey support the utility of the Wright table in medical education. Three modifications of the Wright table, each modeling specific cardiac conditions (i.e., paradoxical split S2 in left bundle branch block, mild aortic stenosis, and moderate aortic stenosis), are included to illustrate how the Wright table might be used in clinical training and research. In summary, the Wright table of the cardiac cycle provides new perspectives for visualization of the cardiac cycle in health and disease.