Heart block

Heart block.  Photo from www.sciencephoto.com

What is it and why is it there?

Often, the electrocardiographic examination (on physical examination, in response to complaints on health, on admission to the hospital) in the conclusion appears the word "blockade". At the same tangible violations of the heart can not be. At the same time, some blockade may result spasmodic contraction of the heart, in particular, to "fall out" of the individual pulses or substantial slowing of heart rate. In order to understand what a heart block, and whether they are dangerous, to say a few words about the conduction system of the heart.

Contraction of the heart to ensure his work is influenced by electrical impulses that are created and carried to all areas of the heart muscle so-called conduction system of the heart. Normally, the pulse occurs in the sinus node, located in the upper part of the right atrium, then extends to the atrium, causing their decline, with the atria — through the atrioventricular (AV) node — to the ventricles, in which the vascular system branches out like the branches of a tree for the pulse all of their sites. Violation of the electrical pulseany portion of the conducting system of the heart called the blockade.

Heart block can occur in almost any myocardial diseases: angina pectoris, myocarditis, kardiosklerosis, myocardial infarction, hypertrophy of the heart, high load on the heart muscle (eg, athletes), as well as an overdose or incorrect use of certain drugs. Sometimes heart block may be caused by genetic predisposition or impaired fetal development of the heart.

Classification of blockades

Heart block is classified either by the way on what part of the heart does not pass the signal (output of the sinus node, AV node, individual branches of the conduction system), or the degree of severity, the strength of the blockade. By the extent of closure release:

  1. blockade of I degree, ie impulses are carried out with a significant delay;
  2. blockade of II degree — incomplete, ie part of the pulse is not carried out at all;
  3. blockade of the III degree — complete, ie pulses are generally not held. With a full blockade of the pulses at the ventricles (the so-called complete transverse blockade), The frequency of contractions can fall to 30 per minute and below (and the normal frequency of an adult at rest is 60-80 beats per minute). If the interval between contractions is several seconds, the possible loss of consciousness ("cardiac syncope"), pale man, can begin cramping — the symptoms of the so-called attack Morgagni-Adams-Stokes), The result of which can be fatal.

All of the blockade may be resistant (There are constant) andtransient (There are only a few moments).


Many heart block its dangerous consequences, even death, so if you noticed at irregular heartbeat — Contact your cardiologist for a complete examination. It is also possible need to consult Arrhythmologists doctor.

Normal electrocardiogram to evaluate cardiac contraction only at the time of the study, while a heart block may occur intermittently. Therefore, for the detection of transient blockades in so-called Holter monitoring andtreadmill test. For the diagnosis of the cardiologist may also appoint echocardiography.


In the event of an attack Morgagni-Adams-Stokes a person should be put and call "ambulance."

Blockade of the individual branches of the conduction system usually does not require treatment, but may indicate the presence of a heart disease, in need of therapy. Some of the blockade eliminated by appropriate use of medications. However, the full blockade significantly deteriorate the condition and prognosis of patients, an indication for pacemaker implantation, the use of temporary or permanent ventricular electrical stimulation.

Since some drugs used to treat heart disease, contribute to the emergence of blockades, should strictly observe the prescription dosage and time of taking the drugs, as well as coordinate with the cardiologist medicine prescribed by other doctors.

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