tailieunhanh - Ebook Atlas of electrocardiography: Part 2

(BQ) Part 2 book "Atlas of electrocardiography" presents the following contents: Atrial premature beats, atrial tachycardia, effects of adenosine in various supraventricular tachyarrhythmias, supraventricular tachycardia, atrial fibrillation, atrial flutter, multifocal atrial tachycardia, multifocal atrial tachycardia | Atrial Premature Beats a b c Every QRS is followed by a refractory period and the shaded area in the above drawing depicts that refractory period. As depicted part of the intraventricular conduction system . one bundle branch has a longer refractory period and the other part . the other bundle branch has a shorter refractory period. If an atrial premature impulse occurs at point c when the whole intraventricular conduction system has recovered from the refractory period it will be conducted normally tracing c . If a premature atrial impulse occurs at point a when the AV node or intraventricular conduction system is refractory the impulse will not be conducted to the ventricles resulting in a non-conducted APB tracing a . If a premature atrial impulse occurs at point b when one bundle branch is still refractory and the other bundle branch has recovered from the refractory period the impulse will conduct thru the recovered bundle branch bypassing the refractory bundle branch resulting in a di erently aberrantly conducted QRS tracing b . us aberrant conduction results simply because two bundle branches have di erent length of refractory period. 112 Atlas of Electrocardiography Various Manifestations of PACs Atlas of Electrocardiography 113 e tracings contain frequent APBs. One of them is normally conducted A two are aberrantly conducted B and some are not conducted to the ventricle at all ị resulting in pauses. 114 Atlas of Electrocardiography Various Manifestations of PACs Frequent PACs are present in the upper tracing. Non-conducted atrial bigeminy ị causes pauses which simulate sinus node dysfunction middle tracing and sinus bradycardia lower tracing