Rythm Class 8

Becomes pacemaker of heart when SA Node, atrial pacemaker sites, and AV junction fail to initiate pulse

Ventricles

What pacemaker cell can the impulse come from in the ventricles?

Any

Are ventricles efficient pacemakers? How many ipms are generated

Least efficient, 20-40 ipms

Occurs earlier than next expected complex

Atria may or may not depolarize

Originates below the Bundle of HIS

Two types?

Premature Ventricular Complex (PVC); unifocal, multifocal

Pattern that occurs every 4th QRS

Quadrigeminy

Pattern that occurs every 3rd QRS

Trigeminy

Pattern that occurs every other QRS - higher degree of irritability in ventricles

bigeminy

A pattern of two consecutive PVC’s indicating a high degree of irritability in the ventricles, which could potentially lead to lethal dysrhythmias.

couplet

Defined as a series of three or more consecutive premature ventricular contractions (PVCs), typically lasting less than 30 seconds, and may indicate increased ventricular irritability.

Run of VT

-R wave of PVC falls on T wave of previous complex

-May lead to lethal dysrhythmia such as V Tach

-PVC occurs during vulnerable period of ventricular repolarization (relative refractory period)

R on T Phenomenon

PVC’s not always dangerous, when is immediate attention required?

If more than 6 in 1 minute

Originates from a single site in ventricles, at a rate of 101-250 ipm

Ventricular Tachycardia

-A type of VT originating from a single site with a heart rate of 41-100 ipm

-VT = 3 or more PVC’s in a row that lasts 3 seconds or less?

-VT= 3 or more PVC’s in a row that lasts greater than 30 seconds?

Accelerated idioventricular dysrhythmia (AIVR)

Un sustained AIVR

Sustained VT AIVR

Resembles a twisting and turning motion along baseline

Looks similar to V Tach

Starts suddenly and frequently proceeded by long QRS

VR often _______ipm, common range ____ipm

Torsades de Pointes “Twisting of the Points”

120-240ipm, common range 170-190

-Lethal dysrhythmia that originates from many different sites within ventricles

-Ventricles make ineffective quivering movements rath than contractions

Patient does not have a pulse, death without treatment, start CPR get AED

2 types

Ventricular Fibrillation (VF or VFib)

Course VFib - waves have higher amplitude - more irregular, more cardiac cells to respond to electrical stimulation

Fine VFib - less amplitude, less cardiac cells to respond to electrical stimulation.

A lethal type of VT originating from a single site with a heart rate of <40ipm

-Atria, AV junction, Bundle of HIS, bundle branches no longer function as pacemakers

-Cardiac muscle too damaged to function

Idioventricular Dysrhythmia

Dying heart dysrhythmia

VR < 20 ipm

Agonal dysrhythmia

-Occurs only when atrial depolarization exists and no ventricular depolarization

-P wave present, P-P interval, no QRS, no P-R interval or R-R interval

AR interval = 60-100 ipm

VR interval =0 ipm (no ventricular contraction)

Ventricular Standstill

Complete lack of electrical connectivity of A’s & V’s

Lethal dysrhythmia

Asystole