dubin d Flashcards
WPW (wolff-parkinson-white) syndrome
an abnormal accessory Bundle of Kent short-circuits usual delay of AV node and causes ventricular pre-excitation, produces delta wave on EKG just before normal ventricular depolarization begins
(lown-ganong-levine) LGL syndrome
the AV node is bypassed by an extension of the anterior internodal tract. without the AV node conduction delay, this “James bundle” conducts atrial depolarizations directly to the His Bundle without delay,
blocks
retard or prevent the conduction of depolarization, may occur in SA node, AV node, His bundle, Bundle Branches, Left Bundle Branch
sinus block
an unhealthy sa node stops pacing for at least one complete cycle, may induce an escape beat from an automaticity focus
SSS (sick sinus syndrome)
a wastebasket of arrhythmias caused by SA node dysfunction associated with unresponsive supraventricular automaticity foci, which are also dysfunctinoal and can’t employ their normal escape mechanism to assume pacing responsibility, marked bradycardia
Bradycardia-Tachycardia Syndrome
when patients with SSS develope intermittent episodes of SVT mingled with sinus bradycardia
first degree AV block
retards AV node conduction, prolongs PR interval more than one large square, PR interval is consistently prolonged the same amount every cycle and following sequence is normal
second degree AV block
allows some atrial depolarizations to conduct to the ventricles, while some atrial depolarizations are blocked, leaving lone P waves, 2 types
Wenckebach blocks
second degree blocks of AV node, produce a series of cycles with progressive blocking of AV node conduction until the final P wave is totally blocked in the AV Node, eliminating the QRS complex, consistent P:QRS ratio like 3:2, 4:3, etc, innocuous
Mobitz blocks
second degree blocks of Purkinje fiber bundles, produce a series of cycles consisting of one normal P-QRS-T cycle preceded by a series of paced P waves that fail to conduct through the AV node. ratios like 3:1, 4:1, 5:1, pathological, widened QRS
mobitz
if there is a 2:1 av block and parasympathetic stimulation has no effect of eliminates block, it was a _______ block
wenckebach
if there is a 2:1 av block and parasympathetic stimulation increases the number of cycles/series, it was a _______ block
third degree AV block
completely blocks AV conduction, automaticity focus below the block escapes to pace the ventricles at its inherent rate
downward displacement of the pacemaker
the failure of all automaticity centers above the ventricles-bad prognosis
bundle branch block (BBB)
caused by a block in the right or left bundle branch, the blocked branch delays depolarization to the ventricle that it supplies, causes two joined QRS’s on the EKG, QRS is 3 small squares (.12s) or greater, and there are 2 R waves
