Intraventricular Conduction: Difference between revisions
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===Phase 3 Aberration=== | ===Phase 3 Aberration=== | ||
Phase 3 aberration occurs when conduction fibers receive a new impulse, before they have fully repolarized. This can sometimes be observed at the start of paroxysmal supraventricular tachycardias or in a long-short sequence where the refractory | Phase 3 aberration occurs when conduction fibers receive a new impulse, before they have fully repolarized. This can sometimes be observed at the start of paroxysmal supraventricular tachycardias or in a long-short sequence where the refractory period of the long sequence is prolonged. | ||
===Retrograde Concealed Conduction=== | ===Retrograde Concealed Conduction=== | ||
Phase 3 aberration is often the cause of the first wide QRS complex. However at a regular rate retrograde concealed conduction is often the sustaining mechanism. The sequence of QRS widening that is often observed is phase 3 aberration in the first premature beat. This can leave the left bundle (as an example) refractory for the next beat. This next beat is conducted by the right bundle and once it reaches the apex, it is conducted retrograde by the left bundle. This can continue until a new premature ventricular beat causes a compensatory pause and 'resets' the system. | Phase 3 aberration is often the cause of the first wide QRS complex. However at a regular rate retrograde concealed conduction is often the sustaining mechanism. The sequence of QRS widening that is often observed is phase 3 aberration in the first premature beat. This can leave the left bundle (as an example) refractory for the next beat. This next beat is conducted by the right bundle and once it reaches the apex, it is conducted retrograde by the left bundle. This can continue until a new premature ventricular beat causes a compensatory pause and 'resets' the system. | ||