second-degree heart block

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second-degree heart block

A form of atrioventricular block in which only some atrial impulses are conducted to the ventricles. Two variants exist: Mobitz I (Wenckebach) and Mobitz II. In Mobitz I, the P-R intervals become progressively longer until a QRS complex is dropped. Because of the dropped beats, the QRS complexes appear to be clustered (grouped beating) on the electrocardiogram. In Mobitz II, P-R intervals have a constant length, but QRS complexes are dropped periodically, usually every second, third, or fourth beat.
See also: heart block
References in periodicals archive ?
1)" Alternative explanations included vagal effects, second degree AV block with escape complexes, dual AV nodal pathways, and ".
89 Conduction blocks First Degree AV Block 0 3(8%) Second Degree AV Block 1(7%) 1(2.
A twenty-four hour cardiac holter monitor revealed baseline sinus rhythm and confirmed the presence of second degree AV block of the Wenckebach type.
Her rhythm resolved from complete AV block to second degree AV block (Mobitz type 2) on her fourth day of hospitalization (Fig.
Accordingly, the incomplete AV dissociation is due to high-grade second degree AV block, and the overall ventricular rate of only 41/min is the cause of the patient's weakness and presyncope.
Type 1 second degree AV block and then first-degree AV block (PR: 0,28 sec, rate72 beat/min) were observed on the second and third days of the admittance respectively.