Biomed.- 4.2.3 Conclusion Questions
Anna's autopsy revealed that she had an internal pacemaker. What does the pacemaker replace in the heart? Explain.
A pacemaker replaces the SA node of the heart. Though not placed in the right atrium like the node, the wires of a pacemaker are fed through a vein leading to the superior vena cava with then leads down into the right atrium. From there, depending on if the patient requires a single or dual chamber pacemaker, the wires are fed into the chambers of the heart. If the heart rate becomes too slow, the pulse generator portion of the pacemaker sends electrical impulses through the wires to help control the timing of the contractions of the chambers.
In the space below, explain what an EKG can tell a physician about the heart of a specific patient.
An EKG is telling of immediate problems, such as a heart attack, but also the rhythmic behavior of the different chambers of the heart. By measuring the time intervals, a doctor can tell how long it takes for energy to pass through the heart which can indicate the heart's health and efficiency.
Given Anna's medical history, describe the most likely reason she needed a pacemaker.
Genetically, Anna has an increased risk of early heart disease and therefore needs a pacemaker to keep her heartbeats strong and healthy.
What do you think would happen in the heart if the AV node could no longer do its job? Explain how this would affect the contraction of the heart and the movement of blood.
If the AV node could no longer do it's job, the heart's ventricles would not be able to contract. Because the AV node directs energy to the interventricular septum, if it were unable to complete it's job, the energy would not make it and would only travel to the atria. This would cause only the atria to contract, but not the ventricles. A pacemaker would be needed to then stimulate the ventricles so they can move blood throughout the heart and body.
