Ventricular arrhythmias occur when the heart's impulse originates in the ventricles rather than the normal top-down depolarization, greatly reducing efficiency. There are five types of ventricular dysrhythmias, including premature ventricular contractions (PVCs), ventricular tachycardia, ventricular fibrillation, idioventricular rhythm, and asystole. PVCs originate from an irritable ventricular focus, producing an ectopic beat with a wide QRS complex but no preceding P wave and usually opposite the T wave, followed by a compensatory pause as the sinus node skips its next beat.
2. Ventricular Arrhythmias
The heart normally depolarizes from
the top down
When the impulse originates in the
ventricles, the process is reversed
and the hearts’ efficiency is greatly
reduced
3. Ventricular Arrhythmias
Most serious heart arrhythmia
The ventricles are the lowest site in
the conduction system
The heart has lost its effectiveness
The heart is functioning on its last level
of backup support
4. Ventricular Arrhythmias
There are five Ventricular Dysrhythmias
Premature Ventricular Contractions
Ventricular Tachycardia
Ventricular Fibrillation
Idioventricular Rhythm
Asystole
5. Premature Ventricular Contractions
Not a rhythm, but rather an ectopic
beat originating from an irritable
ventricular focus
A PVC will come earlier than
expected in the cardiac cycle and
will interrupt the regularity of the
underlying rhythm
6. Premature Ventricular Contractions
Because PVC’s originate in the
ventricles, the QRS complex will be
wider than normal
There is no P wave preceding the
QRS complex
8. Premature Ventricular Contractions
Compensatory pause
The extra action potential causes
the SA node to become refractory
to generating its next scheduled
beat. Thus it must "skip a beat" and
it will resume exactly 2 P to P
intervals after the last normal sinus
beat.
9.
10. Premature Ventricular Contractions
Unifocal PVC’s
If a single focus in the ventricles
has become irritable and is the
source for the PVC’s, all the PVC’s
will look the same
