Download Ventricular Arrhythmias

EKG Analysis
Ventricular Arrhythmias
Ventricular arrhythmias
conduct more slowly so the
QRS is wide (greater than .12
seconds)
They are usually caused by an ectopic
focus in the ventricles that has
become “irritable” due to ischemia.
They may also originate from
complete pacemaker failure
Premature Ventricular
Contractions (PVCs)
 Irritable focus causes ventricles to depolarize before the
SA node fires
 Premature beat that has a wide QRS
– QRS and T wave of a PVC usually point in opposite direction
from one another
 “Bad PVCs” – more than 6/minute, coupled, multifocal,
and on or near the T wave of the previous sinus beat
 Suppressed by lidocaine.
Coupled PVCs
Multifocal PVCs
R-on-T Phenomenon: May cause
a run of PVCs or Vfib
Vtach: 3 or more PVCs in a row
 Wide QRS with a regular pattern and a rate of 150-200
 Patient will usually lose consciousness
 Treated with lidocaine; may help to have patient cough if
they are still conscious
 May require DC shock
Vtach
Vtach
Remember, 3 or more PVCs in a row is a run of Vtach
Vfib
 Many ectopic foci firing at the same time
 There is no regular pattern as in Vtach
 No effective cardiac output!
 Requires CPR and DC shock, ie, Defibrillation
Vfib
This is “coarse” vfib
Vfib
This is “fine” vfib
Idioventricular Rhythm
 Ventricles depolarizing on their own because of no
conduction from above
– Rate will be between 20-40
 A rate of 60-120 (all PVCs) is sometimes called “Slow
Vtach”
Agonal Rhythm Leading to
Ventricular Standstill (Asystole)
External Cardiac Pacing :
Pacemakers
 Electrodes most commonly placed in ventricles
 Most pacemakers are “demand” type
 Used for symptomatic bradycardia or heart blocks
 EKG shows a “spike” when pacer fires
Demand Pacemaker
Artifact: 60 cycle interference
Laboratory Exercises # 6
Numbers 9-12
Laboratory Exercises #7
Numbers 1-8