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.

Photocurable extracellular matrix sealant for cessation of venous hemorrhage

“…Nonetheless, all three pcECM formulations performed very well under burst testing compared to pressures they would be exposed to in vivo. Central venous pressures of healthy individuals typically range from 0 to 6 mmHg [43][44][45] over one cardiac cycle and can increase 20-30 mmHg in patients undergoing heart failure. 46 All three pcECM formulations withstood pressure at least 10 times greater than pressures typically observed within the VC under any condition.…”

“…46 All three pcECM formulations withstood pressure at least 10 times greater than pressures typically observed within the VC under any condition. Additionally, systolic pressure in the aorta typically ranges from ≤120 mmHg 43 in healthy individuals to ≤180 mmHg under severe hypertension. 47 Burst strength experiments in this study showed that the low and medium crosslinking density pcECM formulations could withstand the highest arterial pressures even under hypertension, suggesting these formulations could be suitable for arterial hemorrhage applications as well.…”

The Role of Patient-Specific Morphological Features of the Left Atrial Appendage on the Thromboembolic Risk Under Atrial Fibrillation

“…For the simulation of sinus rhythm conditions, a uniformly distributed pressure was applied at the open surface of the fluid, based on the physiological atrial pressure described in the Wiggers diagram ( 37 , 38 ). Then, as described above, a virtual change of temperature was applied to the structure to simulate active contraction (see Figure 4 ).…”