Cardiac Arrhythmia - First Degree Atrioventricular Block

First Degree Atrioventricular Block

If each wave of depolarisation that originates in the sinoatrial node is conducted to the ventricles and there is a delay in conduction at the junctional area, then the PR interval will be prolonged (>0.20 seconds). This is not really a block, since conduction passes down the normal channels, however it is referred to as first degree atrioventricular block.

                                                                            Conduction

Electrocardiogram