A Wiggers diagram is a medical chart that summarizes several aspects of cardiovascular health on one chart. Blood pressure, ventricular volume, arterial blood flow, and an electrocardiogram are simultaneously plotted against time on this chart. By combining the measurements in one place, the Wiggers diagram enables doctors to review the health of the entire cardiac cycle.
The Wiggers diagram is named for Carl J. Wiggers, a cardiologist who spent his career in research and teaching. In addition to being the director of Physiology at Western Reserve University in Cleveland, Ohio from 1917 to 1953, Dr. Wiggers held several leadership positions in the American Physiological Society, including president of the society in 1949 and 1950. He also authored several textbooks on circulatory physiology and the cardiovascular system.
The primary benefit of the Wiggers diagram is that it shows several aspects of the cardiac cycle together over time so that doctors can ensure the heart is beating properly. In a healthy heart, electrical impulses from the nervous system control the four chambers. The cycle begins when blood flows into both atria of the heart. When the atrioventricular valves open, blood flows from the atria into the ventricles, assisted by a slight contraction of the atria. Once both ventricles are full of blood, the atrioventricular valves close and the ventricles contract, forcing blood out through the semilunar valves to the pulmonary artery and aorta before the cycle repeats.
The phases of the cardiac cycle are easy to follow on a Wiggers diagram. The electrocardiogram shows the electrical impulses governing the cycle. The systolic and diastolic blood pressures, ventricular volume, and arterial flow measurements all show the movement of blood flow through the heart. Seeing all of these in one place, charted against time, allows doctors to see the relations between the stages of the cardiovascular cycle and diagnose conditions that may exist when components of the cardiac cycle are not working smoothly.
For example, one possible heart condition is atrial fibrillation, a rapid ongoing spasm in the muscles that contract the atria. Blood flow from the atria to the ventricles is primarily a passive result of pressures with atrial contractions providing a slight augment that increases during exertion. A patient suffering from atrial fibrillation could experience shortness of breath and impaired muscle performance as well as suffering from the increased possibilities of strokes. Hints of the atrial fibrillation would show up on the Wiggers diagram, however, in the form of changes in the electrocardiogram activity, a decrease in ventricular volume, and changes in diastolic blood pressure when the blood is moving through the atrioventricular valves. Medicine could then be prescribed to help minimize the risks associated with the condition.
