An<unk><unk><unk>  is defined as an ectopic ventricular<unk>  at a rate between 40 bpm and 100 to 120 bpm. This rate is faster than the intrinsic<unk>  (40 bpm) but slower than that of ventricular tachycardia (which would be > 100 to 120 bpm). The ventricular origin of this<unk>  can be demonstrated by the usual EKG criteria which include AV dissociation, fusion beats, and capture complexes.
The rate of cardiac contraction is determined by the intrinsic rate of depolarisation of the cardiac cells. In normal hearts the sinoatrial node in the atria depolarises at a rate of 70 beats per minute. This suppresses the intrinsic depolarisation of the other parts of the heart.
The<unk><unk><unk>  occurs when depolarisation rate of a normally suppressed focus increases to above that of the "higher order" focuses (the sinoatrial node and the atrioventricular node). This most commonly occurs in the setting of a sinus bradycardia.
Accelerated idioventricular rhythm definition
Paroxysmal supraventricular tachycardia classification
First degree AV block classification
Atrial flutter classification
Wide complex tachycardia epidemiology and demographics
Pulseless ventricular tachycardia classification
Third degree AV block classification
Chronic stable angina definition