The atrioventricular (AV) block is a partial or complete interruption of the momentum transfer of the atria to the chambers. The most common cause is an idiopathic fibrosis and sclerosis of the conduction system. The diagnosis results from the ECG. Symptoms and treatment depend on the degree of blockage. If treatment is necessary, include pacing (stimulation) usually do so.
The most common causes of AB block are:
The atrioventricular (AV) block is a partial or complete interruption of the momentum transfer of the atria to the chambers. The most common cause is an idiopathic fibrosis and sclerosis of the conduction system. The diagnosis results from the ECG. Symptoms and treatment depend on the degree of blockage. If treatment is necessary, include pacing (stimulation) usually do so. The most common causes of AB block are: idiopathic fibrosis and sclerosis of the line system (about 50% of patients) Ischemic heart disease (40%) The remaining cases of atrioventricular block caused by drugs (such as beta-blockers, calcium channel blockers, digoxin, amiodarone) Increased vagal tone valvulopathy Congenital cardiac, genetic or other disorders The AV block may be partially or completely. Blocks of the first and second degree are partially. Blocks third degree are complete. AV block first degree Allen veritable P waves following QRS complexes. However, the PR interval is longer than normal (> 0.20 s, atrioventricular block). When atrioventricular block atrioventricular block first degree, the transition is slowed without the heart for a few beats exposes. All real P-wave followed by QRS complexes. However, the PR interval is longer than normal (> 0.20 sec). When heart block. Degree, there is no relationship between P-waves and QRS complexes; the frequency of the P-waves is greater than that of QRS complexes. The AV block, first degree may be physiologically younger patients with high vagal tone and in trained athletes. The AV block, first degree is rarely symptomatic and requires no treatment. Further evaluation may be indicated when it is accompanied by another heart disease or it seems that it is caused by drugs. AV block II. Some degree veritable P waves do not follow QRS complexes other again. There are three types of the AV block II. Degree. When AV block Mobitz type II. Grade I) is the PR interval with each stroke longer and longer until the atrial pulse is no longer forwarded and the QRS complex precipitates (Wenckebach phenomenon). The AV conduction takes place again at the next stroke, and the sequence is repeated (AV-block II. Grade type 1). AV block II. Grade type 1, the PR interval is longer and longer with every stroke until the atrial pulse is no longer forwarded and the QRS complex precipitates (Wenckebach phenomenon). The AV conduction takes place on the next swing again and the sequence is repeated. The AV block II. Degree type 1 may be physiologically younger and experienced cyclist people. The blockade is about 75% of patients with narrow QRS complexes in the AV node. In the remaining about 25% is below the blockade of the AV node (His bundle, thigh or fascicles). For a complete blockage typically a reliable junctional escape rhythm develops. Treatment is therefore not necessary, as long as the blockade caused no symptomatic bradycardia and transient or reversible causes are excluded. The therapy consists of a pacemaker implantation. II also for asymptomatic patients with AV block. Grade type 1 below the AV node, which was discovered in a study carried out for other reasons electrophysiological examination, pacing therapy can potentially be helpful. When AV block II. Type 2 degree (Mobitz type) is the PR interval constant. The pulses are intermittently not passed and the QRS complexes fall it from. This cycle is repeated typically every third (3: 1 block) or fourth (4: 1 block) (. II degree AV block type 2) P-wave. AV block II. The degree of type 2 PR interval remains constant. The pulses are intermittently not passed and the QRS complexes fall it from. This cycle is repeated typically every third (3: 1 block) or fourth (4: 1 block) P-wave. The AV block second degree type 2. Is always pathological. The blockage is 20% of patients in the bundle of His in the remaining patients in the two legs. The blockage may be depending on the ratio of said transferred to the blocked pulses asymptomatic or associated with drowsiness, presyncope, or syncope. When AV block II. Grade type 2 there is a risk of the development of a higher-grade or symptomatic of a total AV block, wherein the escape rhythm probably originates from the ventricles and thus is too slow and unreliable, in order to maintain a sufficient systemic supply. 2 Therefore, the diagnosis of an AV block II. Grade type pacemaker indication. In a high-grade AV block II. Degree, every other P-wave (or several P-waves) block (AV-block II. Degree (highly).). AV block II. Degree (highly). The distinction between AV block II. Grade type 1 and type 2 is difficult because two P-waves are never forwarded one after the other. It is difficult to predict the risk of a total AV block. Therefore, there is in this case the indication for pacemaker implantation. In patients with any form of an AV block II. And degree of structural heart disease therapy should be considered with a permanent pacemaker, when the AV block is not due to a transient or reversible cause. AV-block III. This degree is a total heart block (AV-block III. Grade). AV-block III. Degree, there is no electrical connection between the atria and ventricles, and no relationship between P-waves and QRS complexes (AV dissociation). Cardiac function is maintained by a junctional or ventricular escape pace. Escape rhythms, originating above the bifurcation of the His-bundle, produce narrow QRS complexes and a relatively high and reliable heart rate> 40 beats / min. Patients present with mild symptoms (eg. As fatigue, postural dizziness, exercise intolerance). Escape rhythms, which have their origin below the bifurcation which produce wider QRS complexes, slower and unreliable heart rates and cause severe symptoms (eg. B. syncope, syncope and cardiac insufficiency). The ECG signs of AV dissociation such as cannons-A-waves, blood pressure fluctuations and changes in the volume of the first heart sound show (S1). At a lower escape rhythm is due to prolonged asystole at higher risk for syncope and sudden cardiac death. Most patients need a pacemaker (see table: Pacemaker codes). If there is a blockage due to therapy with antiarrhythmic drugs, discontinuation of medication can be helpful, but a temporary stimulation can thereby be necessary. AV blockade, which was caused by an acute inferior myocardial infarction, testifies usually from an AV node dysfunction and possibly responds to atropine or disappear spontaneously within a few days. An AV blockade, which is caused by an anterior myocardial infarction, evidence of an extensive myocardial necrosis involving the His-Purkinje system and requires immediate use of a transvenous pacemaker with temporary external pacing. A spontaneous solution of the blockade may be possible, but requires an evaluation of the AV node and infranodalen via line (z. B. by an electrophysiological examination, stress tests, and 24-h ECG). Most patients with congenital heart block. Grades have a junctional escape rhythm, which ensures an adequate heart rate. However, these patients need before they reach middle age a permanent pacemaker. Less commonly, patients with congenital heart block and a slow escape rhythm, at a young age, may need already in early childhood, a permanent pacemaker that.