Heart Blocks

What it is?

The term “heart rhythm disturbances” refers to arrhythmias and heart blocks. Arrhythmias are disturbances in the frequency, regularity and consistency of heartbeats. With prolonged stoppages of breathing, heart blockades (cardiac arrest) can develop, and the duration of cardiac arrest can reach 8-10 seconds. That is, heart block is a deterioration or complete loss of the ability of one or another part of the myocardium (heart muscle) to conduct excitation.

Why does this happen?

The activity of the heart is possible only due to the fact that it has its own “brain” inside, which regulates the heart rate. This is the sinus node. It has the ability to rhythmically generate electrical impulses that, like circles from a stone thrown into water, spread throughout the myocardium of the atria and ventricles, causing them to contract. The sinus node, which sets the rhythm for the work of the entire heart, is called, accordingly, the pacemaker. And although almost any myocardial cell is capable of independently generating electrical impulses, normally the electrical activity of the sinus node dominates the activity of all other heart cells. If the functioning of the sinus node is disrupted, then new sources of electrical impulses may appear in various parts of the heart muscle (myocardium), which compete with the sinus node or even suppress its activity. The very propagation of the activation wave throughout the heart can also be blocked. All these unpleasant and undesirable phenomena are accompanied by disturbances in heart rhythm - arrhythmias, and in the worst case - heart block.

Heart blocks can occur with atherosclerosis, angina pectoris, myocarditis, cardiosclerosis, myocardial infarction, as well as with overdose or misuse of certain medications. In some cases, heart block may be caused by a family history.

What happens?

Heart blocks are classified either by the part of the heart where the signal does not pass, or by the degree of severity, by the strength of the blockade.

Based on how developed the blockade is:

1. First degree blockade, i.e. impulses are carried out with a significant delay;

2. Second degree blockade - incomplete, i.e. some impulses are not carried out at all;

3. Third degree blockade - complete, i.e. impulses are not transmitted at all.

With complete heart block, the ventricular rate can drop to 30 beats per minute or lower (and the normal resting rate in an adult is 60–80 beats per minute). If the interval between contractions reaches several seconds, then loss of consciousness (“cardiac syncope”) is possible, the person turns pale, and convulsions may begin - these are symptoms of the so-called Morgagni-Adams-Stokes attack), which can result in death.

All blockades can be persistent (exist constantly) or transient (occur only at certain moments), and congenital complete transverse blockade is very rare.

Diagnosis

Heart blockades are dangerous due to their consequences, even death, so if you suffer from arrhythmias, do not bring your heart to a state of heart blockade - contact a cardiologist and undergo a full examination. You may also need to consult an arrhythmologist.

A regular electrocardiogram allows you to evaluate heart contractions only at the time of the study, while heart blocks can occur periodically. Therefore, to identify transient blockades, the so-called Holter monitoring and treadmill test are used. To clarify the diagnosis, the cardiologist may also prescribe an echocardiogram.

Treatment

If a Morgagni-Adams-Stokes attack occurs, the person must be laid down and an ambulance called.

Most blockades can be overcome by using regular medications. However, complete blockades are an indication for the implantation of an artificial pacemaker and for the use of temporary or permanent ventricular electrical stimulation.