Task of the pacemaker
A pacemaker is needed when the heart is no longer able to beat regularly on its own. This can have various causes. For example, the sinus node, the heart‘s own pacemaker, no longer works reliably or there are problems in the conduction system.
In both cases the pacemaker can take over the missing function. There are different types of pacemakers. Those that replace the function of the sinus node are responsible for producing an electrical signal that is then sent through the entire excitation conduction system of the heart.
Other pacemakers restore the connection between the atria and the ventricles. In this case, a signal arriving from the atria is transmitted through the AV node to the ventricles. This allows the ventricles to continue working in the usual way. The latest pacemakers can also directly record disturbances in heart activity, so-called cardiac arrhythmias. In addition, today’s pacemakers are able to adapt the heart rate to the respective physical activity of the person.
Function of the pericardium
The pericardium encloses the heart almost completely. Only the vessels that come directly from the heart (pulmonary artery and aorta) pass through it. The most important task of the pericardium is to protect the heart.
It is also connected to the surrounding tissue and thus gives the heart its hold in the thorax. The pericardium consists of two different layers, between which there is about 10-15 ml of fluid. This allows the two layers to slide against each other and allows the heart to move freely.
This is necessary for the heart to be able to tense and relax. However, there is not unlimited space in the pericardium. If too much fluid or a certain amount of blood gets between the pericardium and the heart, the heart is significantly restricted in its pumping function because it can no longer expand completely.