Premature ventricular contraction
A premature beat is a heartbeat that occurs outside of the normal heart rhythm. It is one of the arrhythmia. The actual rhythm can remain unaffected or moved. Extrasystoles not arise in the normal pacemaker center ( sinus node ), but in ectopic excitation centers ( ectopic focus). The person she feels often as palpitations. Extrasystoles are primarily in adolescents more common, but are usually insignificant and harmless. Occasionally, however, they can also indicate a significant heart disease. Fibrillation typically begins with an extrasystole in the relative refractory period.
Depending on the place of origin in the heart differentiates ventricular contractions (PVCs, development in one of the chambers of the heart ) and supraventricular premature beats ( PAC, emergence usually in one of the atria )
Causes
Extrasystoles often come in healthy before disease without value, triggering factors can be excitement, fatigue, increased activity of the autonomic nervous system or drugs such as alcohol, nicotine or caffeine. However, there are also the heart organic diseases as a trigger in question, especially coronary heart disease, as well as cardiomyopathies or inflammation of the heart muscle ( myocarditis). Further causes can lead to premature beats outside of the heart. These include an excess of thyroid hormones ( hyperthyroidism), various medications, electrolyte disturbances or Roemheld syndrome.
Molding
Supraventricular extrasystole
Supraventricular extrasystoles arise above the division ( bifurcation ) of the His bundle, mostly in the atrium (atrium ). They are divided into atrial PAC ( ectopic atrial myocardium in the center ) and nodal PAC ( ectopic center at the AV node, and AV junctional PAC ). In atrial SVPB the sinus node is mitentladen. So its rhythm shifts exactly to the conduction time from the ectopic focus to the sinus node ( nichtkompensatorische pause). In the nodal extrasystole atrial discharged decline. Both chambers of the heart can bring out its rhythm ( supraventricular arrhythmia). PAC in healthy individuals do not require therapy, the presence of heart disease primarily it is treated.
Ventricular extrasystole
In a ventricular extrasystole, the excitement spreads of a ventricular ectopic ( located outside of the normal pacemaker structures) focus on the heart chambers from. Either the heart rhythm is unaffected, since the next sine excitation after extra-systolic refractory period of the ventricles arrives (especially at low heart rates and earlier extrasystole ), or there is a compensatory pause. A distinction of right ventricular left ventricular extrasystoles. The incident extrasystoles have a widened QRS complex.
Multiple extrasystoles of an exciting center ( Monotop ) appear in the ECG similar ( monomorphic ). Polytopes extrasystoles arise, however, in different arousal centers and therefore also differ on the ECG ( polymorphic ). Pairs occurring extrasystoles are called couplets, three or more consecutive premature beats directly as volleys. Follow on any normal excitation of the heart, a PVC, one speaks of bigeminy.
The classification of PVCs depends on the Lown classification. As with the PAC, the VES is not worthy of treatment in healthy individuals. In the presence of triggering disease, primarily these are treated. For complex arrhythmia in underlying cardiac disease may be necessary, treatment with antiarrhythmic drugs.
A polymorphic couplet
Ventricular bigeminy with early incident extrasystoles
- Disease in cardiology