Heart block is a conduction deformity of the heart conduction system from the SA node to Purkinje fibres. But the most common site of blockage is the Septum between the upper and lower chambers. That means atrioventricular Septum. It is a fibrous septum which attaches to all four heart valves. They are the atrial semilunar valve, pulmonary semilunar valve, mitral valve and tricuspid valve. The heart has its conduction system, which starts from the right Atrium. Then it goes through the fibrous Septum and then reaches the ventricles. The fibrous Septum of a healthy individual is impermeable to electrical current. But only one place in the middle is permeable. That is the most common place for the conduction blocks. According to the blockage, there are three degrees of blockages. Usually, heart blocks can be identified in ECG.
First-degree heart blocks
Here all the p waves are continued with the QRS complexes. But a prolonged PR interval is present.
Second-degree heart blocks
Some p waves are continued with the QRS complexes, but some are not.
There are three types of heart blocks in second-degree heart blocks.
Morbid’s type 1
The missed QRS complex is present with gradually increasing prolongation of the PR interval in adjacent previous waves.
Morbid’s type 2
Missed QRS Complexes with the same PR interval.
Morbid’s type 3
These are called ratio blocks. Because it usually has a constant wave pattern between the p wave and QRS. For example, After 3 p waves, the QRS complex is present.