Pseudo-atrioventricular dissociation caused by interpolated ventricular extrasystoles in the presence of dual atrioventricular nodal pathway.
This report describes a patient manifesting with ventricular extrasystoles. The pause occasioned by extrasystoles often is followed by narrow QRS complexes not preceded by P waves, but at times is followed by a sinus P wave. At first glance, the pattern suggests a diagnosis of atrioventricular (A-V) junctional escape complexes. Analysis reveals that ventricular extrasystoles are, in fact, interpolated; the sinus P wave that follows the extrasystole is conducted to the ventricles with a very prolonged P-R interval (up to 0.80 s). The phenomenon is due to the presence of a dual A-V nodal pathway. The sinus impulse that follows the extrasystole is blocked in the fast pathway but may still be conducted to the ventricles through the slow pathway, resulting i a very prolonged P-R interval.
Luzza
F
F
Cattedra di Malattie Cardiovascolari, Università di Messina, Italy.
Oreto
G
G
D000368:Aged; D001145:Arrhythmias, Cardiac / Q000503:physiopathology*; D001283:Atrioventricular Node / Q000503:physiopathology*; D005117:Cardiac Complexes, Premature / Q000503:physiopathology; D004562:Electrocardiography; D005260:Female; D006801:Humans