QRS And T Waves: A Case Study

The heart is the organ that provides both blood and oxygen throughout the whole body. First, deoxygenated blood enters the right atrium via the vena cava and when the pressure inside the atrium becomes higher than that of the right ventricle, the tricuspid valve opens and allows the blood to flow from high to low pressure. The valve then closes to ensure blood only flows in one direction (Tandy 2017). After oxygenation, the blood enters the left atrium via the pulmonary veins and fills it until the pressure inside the atrium is greater than that of the left ventricle. This then causes the mitral valve to open and then close again after the pressure in the ventricle becomes greater. The blood returns to the vena cava and the cycle repeats. The cardiac cycle is a series of contractions of the ventricles and atria that are generated by myocardial …show more content…
An electrocardiogram, also known as an ECG or EKG, can be used to measure these electrical changes occurring in the heart that creates the P, QRS, and T waves at the skin level (NIH 2016). The P wave represents atrial depolarization where the SA node fires a signal that travels to the atrium and converges at the AV node. The QRS wave shows ventricular depolarization, and the T, ventricular repolarization. The QRS is the largest wave seen on the ECG because the ventricles make up the most mass of the heart. The pulse wave can be recorded using a pulse plehtysmograph placed on a subject’s finger along with the leads attached on the right ankle, right wrist, and left wrist. One way that a person’s heart rate can be affected is through placing a cold ice pack along their forearm and recording the heart rate once the pack has