Atrioventricular block
![Sinus rhythm with acute inferior infarction complicated by Type I A-V block manifest in the form of 5:4 Wenckebach periods; R-P/P-R reciprocity.](/Images/godic/202412/22/Type_I_A-V_block_5-to-4_Wenckebach_periods2045.png")
![Sinus rhythm (rate = 100/min) with 3:2 and 2:1 Type II A-V block; RBBB](/Images/godic/202412/22/Sinus_rhythm_with_3-to-2_and_2-to-1_Type_II_A-V_block2045.png")
![Sinus tachycardia with complete A-V block and resulting junctional escape](/Images/godic/202412/22/Complete_A-V_block_with_resulting_junctional_escape2045.png")
An atrioventricular block (AV block) is a type of heart block in which the conduction between the atria and ventricles of the heart is impaired. Under normal conditions, the sinoatrial node (SA node) in the atria sets the pace for the heart, and these impulses travel down to the ventricles. In an AV block, this message does not reach the ventricles or is impaired along the way. The ventricles of the heart have their own pacing mechanisms, which can maintain a lowered heart rate in the absence of SA stimulation.